John Mar shall Williamson
Hemorial
QUAIN'S
ELEMENTS OF ANATOMY
EDITED BY
EDWARD ALBERT SCHAFER, F.R.S.
PROFESSOR OF PHYSIOLOGY AND HISTOLOGY IN UNIVKRSITY COLLEGE, LONDON",
AND
GEORGE DANCER THANE,
PROFESSOR OF ANATOMY IN UNIVERSITY COLLEGE, LONDON.
IN THREE VOLUMES.
VOL. III.— PART II.
THE NERVES.
BY PROFESSOR THANE.
ILLUSTRATED BY 102 ENGRAVINGS.
LONDON :
LONGMANS, GREEN, AND CO.
AND NEW YORK.
1895.
"ft
| All rights \escrved. ]
LONDON :
IADBVRY. AGNEW. & CO. MX. PRINTER?, WHITEFRIARS.
1895"
CONTENTS OF PAKT II.
THE NERVES.
THE CEKEBRO-SPINAL NKUVES
CRANIAL NERVES
Connection with Cerebro-Spinal Axis
.Mode of Exit from the Cranium .
General Distribution
I. Olfactory Nerves . . .
II. Optic Xerve .....
III. Oculomotor Xerve . . . .
Position of Nerves at the Caver-
nous Sinus and as they enter the
Orbit . . .' .
IV. Trochlear Xerve . . . .
V. Trifacial Xerve ....
Ophthalmic Nerve . . . .
Ciliary Ganglion ....
Superior Maxillary Xerve . .
Spheno- Palatine Ganglion .
Inferior Maxillary Xerve
Submaxillary Ganglion
Otic Ganglion . . . .
VI. Abducent Xerve ....
VII. Facial Xerve
VIII. Auditory Xerve ....
IX. Glosso-Pliaryiigeal Xerve . . .
X. Pnemno- Gastric Xerve .
XL Spinal Accessory Xerve
XII. Hypoglossal Xerve
SPINAL NERVES
The Roots of the Spinal Xerves .
Posterior Primary Divisions of the
Spinal Nerves . ....
Suboccipital Nerve ....
Cervical Nerves .....
Dorsal Nerves .....
Lumbar Nerves
Sacral Nerves .....
Coccygeal Nerve
Anterior Primary Divisions of the Spinal
Xerves ......
Cervical Xerves
Suboccipital Xerve
Second Cervical Nerve . . .
Cervical Plexus ....
Superficial Ascending Branches
Superficial Descending Branches .
Deep Branches : Internal Series .
Deep Branches : External Series .
Brachial Plexus .....
Branches above the Clavicle .
Branches below the Clavicle . .
Anterior Thoracic Nerves .
Subscapular Nerves . . .
Circumflex Nerve
Internal Cutaneous Nerve . .
PAGE
221
221
222
223
225
227
227
228
23I
231
233
235
237
238
241
243
248
248
250
269
271
274
275
278
278
280
280
281
281
283
283
283
283
284
285
286
287
287
288
289
291
294
294
294
294
295
Unpt
N«
SPINAL NE it VES — continued.
Brachial Plexus —
Small Internal Cutaneous Nerve
Musculo-Cutaneous Nerve .
Ulnar Nerve .....
Median Nerve ....
Musculo-Spiral Nerve .
Radial Nerve ....
Posterior Interosseous Nerve . .
Dorsal Nerves . . . . .
First Dorsal Nerve .. . . .
>er or Pectoral Intercostal
erves .....
Lower or Abdominal Intercostal
Nerves . . ....
Last Dorsal Nerve
Lumbar Nerves ....
Lumbar Plexus ....
Ilio-Hypogastric and llio-Inguinal
Nerves .
Genito-Crural Nerve
External Cutaneous Nerve . .
Obturator Nerve ....
Anterior Crural Nerve
Fifth Lumbar Nerve
Sacral and Coccygeal Nerves
Fourth Sacral Nerve
Fifth Sacral Nerve ....
Coccygeal Nerve ....
Sacral Plexus
Collateral Branches
Small Muscular Branches
Superior Gluteal Nerve
Inferior Gluteal Nerve .
Small Sciatic Nerve .
Perforating Cutaneous Nerve
Terminal Branches . . . .
Pudic Nerve
Great Sciatic Nerve . . .
Internal Popliteal Nerve .
Posterior Tibial Nerve .
Internal Plantar Nerve
External Plantar Nerve
External Popliteal Neive .
Musculo-Cutaneous Nerve
Anterior Tibial Xerve
SYNOPSIS OF THE SENSORY DISTRIBUTION
OF THE CERERRO-SPINAL NERVES.
Cutaneous Distribution of the Spinal
Nerves to the Trunk and Limbs .
Sensory Distribution of the Spinal
Nerves to the Viscera .
Literature of the Distribution of Sensorv
Nerves
PAGE
296
297
299
3OI
303
304
306
307
307
308
310
312
315
317
317
319
322
322
323
323
323
323
325
325
325
326
326
328
328
328
330
331
332
333
334
335
336
337
338
344
350
351
VI
CONTENTS OF PART II.
SYNOPSIS OF THE MUSCULAR DISTRIBU-
TION OF THE CEREBRO-SriNAL
NERVES . . . . . •. 351
Muscular Distribution of the Spinal
Nerves 354
Literature of the Muscular Distribution
of Spinal Nerves .... 356
SYMPATHETIC NERVES . . . . 357
Gangliated Cords . . . 358
Kami Communicautes . ... 358
Kami Efferentes 360
Pre vertebral Plexuses . . . . 361
Cervical Part of the Gangliated Cord . 361
Upper Cervical Ganglion . . . 361
Ascending Branch and Cranial
Plexuses ..... 362
Pharyngeal Nerves and Plexus . . 363
Upper Cardiac Nerve . . . 363
Branches to Blood- Vessels . . 364
Middle Cervical Ganglion . . . 365
Lower Cervical Ganglion . . . 365
Thoracic Part of the Gangliated Curd . 367
Lumbar Part of the Grangliated Cord . 370
Sacral Part of the Gangliated Cord . 370
The Great Plexuses of the Sympathetic . 372
Cardiac Plexus .
Solar or Epigastric Plexus .
Hypogastric Plexus ....
Pelvic Plexus . . .
Recent Literature of the Sympathetic .
MORPHOLOGY OF THE PERIPHERAL
NERVES
SPINAL NERVES
Segmentation .
Mode of Division .....
Posterior Primary Divisions
Anterior Primary Divisions . . .
Nerves of the Limbs.
Meningeal Divisions . . .
Visceral Divisions ....
Ganglia . . . . . .
Constitution of a Segmental Nerve .
CRANIAL NERVES .....
Constitution of the Cranial Nerves .
Ganglia
Segmentation .....
Course and Distribution . . .
Literature of the Morphology of the
Peripheral Nerves
INDEX
PAGE
372
373
377
377
379
38i
382
384
384
384
384
385
385
387
388
390
390
393
THE NEKVES,
EV G. D. THANE.
IN this section is comprised the descriptive anatomy of the cerebro-spinal and
sympathetic nerves, and their ganglia. Together with these the peripheral division
of the nervous system also includes the organs of the external senses, which will be
described in the following section. The minute structure of the nerves and their
mode of ending in the several tissues and organs of the body are discussed in the
sections General Anatomy and Splanchnology.
The separation of the sympathetic from the cerebro-spinal nerves is convenient
for purposes of description, but do^s nob indicate a difference of origin or an
anatomical independence of the two systems, since the fibres composing the
sympathetic are connected centrally, either -directly or indirectly, with the cerebro-
spinal axis, which they leave as constituents of the roots of certain of the cerebro-
spinal nerves. Moreover, the division cannot in all cases be strictly maintained,
for some of the ganglia (ciliary, spheno-palatine, otic, and submaxillary), which are
described in connection with the cranial nerves to which they are attached, have a
close affinity with those of the sympathetic system, while on the other hand many
of the terminal plexuses distributed to the viscera, and generally regarded as parts
of the sympathetic system, are composed in large part of fibres which pass into them
directly from cerebro-spinal nerves without traversing the cord of the sympathetic.
THE CEREBRO-SPINAL NERVES.
The nerves springing directly from the great cerebro-spinal centre constitute a
series of symmetrical pairs, of which twelve issue from the cranium through different
apertures in its base, and are thence named cranial. The next following nerve passes
out between the occipital bone and the atlas, and the remaining thirty nerves all
issue below the successive segments of the vertebral column. The first is sometimes
distinguished by the name of suboccipital, but to the whole series of thirty-one nerves
the name of spinal will be here given.
CRANIAL NERVES.
The cranial nerves (nervi cerebrates), besides being distinguished by numbers in
the order of their passage through the dura mater lining the cranium, have likewise
received other names, according to the place or mode of their distribution, or their
functions.
The number of the cranial nerves is now universally stated as twelve, following: the
enumeration which was proposed by Saemmering in 1778, but has only recently been adopted
in this country. Previously they were reckoned as nine pairs, in accordance with the
classification of Willis (1664), in which the facial and auditory tog-ether compose the seventh
pair, while the glosso-pharyngeal, pneumo-gastric, and spinal accessory are included in the
eighth. Willis also looked upon the suboccipital as a cranial nerve, and thus counted ten
VOL. m. PT. 2. P
222
THE CRANIAL NERVES.
WILLIS.
SCEMMERRING.
First pair
Second
of nerves . . i
First pair of nerves
Second ,.
Third
Fourth
; ;
Third „
Fourth .,
Fifth
Sixth
• |
Fifth !,
Sixth „
Seventh
Eighth
C portio dura . |
r' \ portio mollis
( n. vagus
" )
( n.accessorms
Seventh
Eighth
( Ninth
\ Tenth .,
Eleventh „
Ninth
Twelfth
Tenth
5> • 1
First ctrvical .
pairs. The two arrangements, as well as the special designations of the several nerves, are
shown in the following table : —
OTHER NAMES.
Olfactory nerves.
Optic.
Common oculomotor.
Pathetic or trochlear.
Trifacial or trigeminal.
Abducent ocular.
Facial motor.
Auditory.
Grlosso-pharyngeal.
Pneumo-gastric or vagus.
Spinal accessory,
Hypoglcssal or lingual motor.
Suboccipital.
Connection with the cerebro-spinal axis. — The place at which a cranial
nerve is attached to the surface of the cerebro-spinal axis is usually termed the
Fig. 140. — VENTRAL ASPECT OF THE
BRAIN-STEM, SHOWING THE ATTACH-
MENTS OF THE PRINCIPAL CRANIAL
NERVES. (Allen Thomson.)
The full description of this figure will
be found at p. 41. The following refer-
ences apply to the roots of the nerves:
I', right olfactory tract, divided near its;
middle ; II, left optic nerve, springing
from the commissure, which is concealed
by the pituitary body ; II', right optic
tract ; the left tract is seen passing back
into i arid e, the internal and external
corpora geniculata; III, left oculomotor
nerve ; IV, trochlear : V, V, large roots
of the trifacial nerves ; + + , small
roots, the + of the right side is placed
on the Gasserian ganglion ; 1, ophthal-
mic, 2, superior maxillary, and 3, in-
ferior maxillary nerves ; VI, left abducent
nerve ; VII, facial ; VIII, auditory ; IX,
glosso-pharyngeal ; X, pneumo-gastric ;•
XI, spinal accessory ; XII, right hypo-
glossal nerve ; at o, on the left side, the
rootlets are seen cut short ; C I, sub-
occipital or first cervical nerve.
superficial origin of the nerve.
From this apparent origin the
nerve-roots can be traced for a
variable depth within the sub-^
stance of the axis to certain col-
lections of nerve-cells or nuclei,
the connection with which is said
to constitute the deep origin of
the nerve. It is evident, how-
ever, that these terms are pro-
perly applicable only to the central connections of the motor or efferent nerves,
the fibres of which are outgrowths of nerve-cells contained in the respective nuclei,
whereas the sensory or afferent fibres originate generally in the cells of the ganglia
found upon the nerve-trunks in the immediate neighbourhood of the axis, and grow
MODE OF EXIT FROM THE CRANIUM.
223
inwards to their so-called nuclei, in which they end without forming, so far as is
known, any direct connection with the nerve-cells.
The superficial attachments of the cranial nerves are quite obvious : the
filaments of the first pair spring from the olfactory lobes of the cerebral hemi-
spheres ; the second pair arise from the optic thalami and the dorsal part of
the mesencephalon ; the third are attached to the crura cerebri or ventral part
of the mesencephalon ; the fourth to the valve of Vieussens ; the fifth to the
pons ; and the remainder to the medulla oblongata, with the exception of the
greater part of the eleventh pair, which arise from the cervical portion of the spinal
cord. The course of the fibres within the cerebro-spinal axis, and their connection
Fig. 141. — LATERAL VIEW OF THE
BRAIN- STEM, SHOWING THE AT-
TACHMENTS OK THE CKANIAL
NKRVE«. (Allen Thomson.)
The full description of this figure
will be found at p. 42. The follow-
ing references apply to the roots of
the nerves ; I, right olfactory tract.
cut near its middle ; II, the optic
nerves immediately in front of the
commissure ; the right optic tract is
seen passing back to the thalamus ( Tit ),
corpora geniculata (i, c), and corpora
quadrigemina (q) ; III, oculomotor
nerve ; IV. trochlear nerve arising at
v, from the valve of Vieussens ; V,
trifacial nerve ; VI, abducent ocular ;
VII, VIII, facial and auditory nerves ;
between them the pars intermedia ;
IX, glosso-pharyngeal ; X, pneumo-
^astric ; XI, spinal accessory ; XII,
hypoglossal ; C I, the separate an-
terior and posterior roots of the sub-
occipital or first cervical nerve.
rh.
with the nerve-nuclei are
more difficult to follow, and
in many respects are as yet
but imperfectly understood.
They have been fully discussed
in the accounts of the parts
of the spinal cord and brain
in which they occur, and to these reference may be made for farther details than are
given in the following descriptions.
Mode of exit from the cranium. — Each of the cranial nerves, after traversing
the subarachnoid space and piercing the arachnoid, from which it receives a sheath
generally of very short extent (see p. 188), enters an aperture in the dura mater (in
the case of the third, fourth, fifth and sixth nerves at some distance from the osseous
foramina by which they emerge), and carries with it in its passage from the cranial
cavity a tubular prolongation of that membrane. Some of these nerves, or their
main divisions, are contained in distinct foramina of the cranium, others are grouped
together in one foramen. The numerous small olfactory nerves descend into the
nose through the cribriform plate of the ethmoid bone ; the optic nerve pierces the
base of the small wing of the sphenoid bone ; the third, fourth, and sixth nerves,
with the ophthalmic division of the fifth, pass through the sphenoidal fissure ; the
superior maxillary and inferior maxillary divisions of the fifth pass respectively
through the foramen rotundum and foramen ovale of the great wing of the
p 2
224
THE CRANIAL NERVES.
sphenoid ; the facial and auditory nerves enter the internal auditory meatus of the
petrous bone ; the glosso-pharyngeal, pneumo-gastric, and spinal accessory nerves
descend through the middle compartment of the jugular foramen between tho
petrous and occipital bones ; and the hypoglossal nerve passes through the anterior
condylar foramen of the occipital bone.
Fig. 142. — A. — SEMIDIAGRAMMATIC VIEW OP A DEEP DISSECTION OF THE CRANIAL NERVES ON THK
LEFT SIDE OF THE HEAD. B. — EXPLANATORY OUTLINE OF THE SAME. (Allen Thomson.) £
The Roman numerals from I to XII indicate the roots of the several cranial nerves as they lie in or
near their foramina of exit ; V, is upon the large root of the fifth with the Gasserian ganglion in front ;
C I, the suboccipital or first cervical nerve ; C VIII, the eighth. The branches of the nerves are
marked as follows, viz. : — 1, supraorbital branch of the fifth ; 2, lachrymal passing into the gland ;
3, nasal passing towards the anterior internal orbital canal, and giving the long root to the ciliary
ganglion, 4' ; 3', termination of the nasal nerve ; 4, lower branch of the third nerve ; 5, superior
maxillary division of the fifth passing into the infraorbital canal ; 5', the same issuing at the infra-
orbital foramen and being distributed as inferior palpebral, lateral nasal, and superior labial nerves,
5"; 6, ganglion of Meckel and Vidian nerve passing back from it; 6', palatine and other nerves
descending from it ; 6", large superficial petrosal nerve ; 7, posterior dental nerves ; 7', placed in the
antrum, which has been opened, points to the anterior dental nerve ; 8, inferior maxillary division of
the fifth immediately below the foramen ovale ; 8', some of the muscular branches coming from it ;
8 x , the auriculo-temporal branch cut short, and above it the small superficial petrosal nerve connected
with the facial; 9, buccal and external pterygoid; 10, lingual nerve ; 10', its distribution to the side
and front of the tongue and to the sublingual gland : 10", submaxillary ganglion ; below 10, the chorda
tympani passing forwards from the facial above 12, to join the lingual nerve ; 11, inferior dental
nerve; 11', the same nerve and part of its dental distribution exposed by removal of the jaw ; 11", its
termination as the mental nerve ; 11"', its mylo-hyoid branch ; 12, twigs of the facial nerve imme-
diately after its exit from the stylo-mastoid foramen to the posterior belly of the digastric and to the
stvlo-hyoid muscle ; 12', temporo-facial division of the facial ; 12", cervico- facial division ; 13, trunk
GENERAL DISTRIBUTION,
225
General distribution. — The greater number of the cranial nerves are entirely
confined in their distribution within the limits of the head, as in the case of the
first six pairs, the auditory, glosso-pharyngeal, and hypoglossal nerves. Of these,
the olfactory, optic, and auditory are restricted to their respective organs of sense ;
while the third, fourth, and sixth are exclusively motor nerves in connection with
of the glosso-pharyngeal passing round the stylo-pharyngeus muscle after giving pharyngeal and
muscular branches ; 13', its distribution on the side and back part of the tongue ; 14, spinal accessory
nerve ; 14', the same after having passed through the sterno-mastoid muscle uniting with branches from
the cervical nerves ; 15, hypoglossal nerve ; 15', its twig to the thyro-hyoid muscle ; 15", its distribu-
tion to the muscles of the tongue ; 16, the descending cervical nerve giving a direct offset to the
anterior belly of the omo-hyoid muscle, and receiving the communicating branches 16 x , from the
cervical nerves ; 17, pneumo-gastric nerve ; 17', its superior laryngeal branch ; 17", external laryngeal
twig; 18, superior cervical ganglion of the sympathetic, uniting with the upper cervical nerves, and
giving at 18' the superficial cardiac nerve ; 19, the trunk of the sympathetic ; 19', the middle cervical
ganglion, uniting with some of the cervical nerves, and giving 19", the large or middle cardiac nerve ;
20, continuation of the sympathetic down the neck ; 21, great occipital nerve ; 22, third occipital.
the muscles of the eyeball and the elevator of the upper eyelid. In the fifth or
trifacial nerve all the fibres derived from the large root, and connected with the
Gasserian ganglion, are entirely sensory in their function, and constitute the whole
of the first and second and the greater part of the third division of the nerve ; but
the last of these divisions has associated with it the fibres of the small or motor
root, so as to become in some degree a compound nerve. As a nerve of sensation
226
THE CRANIAL NERVES.
the trifacial occupies in its distribution the greater part of the head superficially
and deeply, excepting that part of the scalp which is situated behind a perpendicular
line passing through the external auditory meatus. The muscular distribution of
the inferior division of the fifth nerve is chiefly to the muscles of mastication.
The glosso-pharyngeal is also a mixed nerve, and is distributed to the tongue,
pharynx, and part of the ear-passages ; while the hypoglossal is purely a motor
nerve, destined for the muscles of the tongue, its so-called " descending" and other
branches, which supply in part the muscles connected with the hyoid bone, being
composed of fibres derived from the upper spinal nerves.
Fig. 143. —SKETCH OF THE MIDDLE POR-
TION OF THE BASE OF THE SKULL,
SHOWING THE ENTRANCE OP THK
CRANIAL NERVES INTO THE DURA
MATER. (Drawn by T. W. P.
Lawrence.)
The tentorium has bsen divided close
to its attachment to the upper border of
the petrous. On the right side the nerves
are in place ; on the left side they have
been removed, and the apertures in the
dura mater are seen.
Of the remaining nerves, one,
the facial, mainly if not exclu-
sively motor in function,1 is almost
entirely cephalic in its distribu-
tion, giving fibres to all the
superficial and a few of the deeper
muscles of the head ; but one
branch passes downwards in the
neck to the platysma myoides.
Lastly, the tenth or pneumo-
gastric and the eleventh or spinal
accessory nerves differ from the
foregoing in having only a very
limited distribution in the head,
and in furnishing nerves in
much greater proportion to
organs situated in the neck and
trunk. The first of these, after
giving a small branch to the ex-
ternal ear, and supplying nerves to the pharynx and larynx, the trachea, gullet,
lungs and heart, extends into the abdominal cavity as the principal nerve of the
stomach. The other, the spinal accessory, which is classed with the cranial nerves
in consequence of its passing out through one of the foramina of the skull, is
entirely a motor nerve ; it is partially united with the pneumo-gastric near its
origin, and thus furnishes some of the motor fibres of that nerve, but it is mainly
distributed in the sterno-mastoid and trapezius muscles.
P On pages 224 and 225, fig. 142 is introduced in illustration of the general view of
the distribution above given. In this figure the cranium and orbit have been opened up
to the depth of the several foramina through which the nerves pass. The greater part of the
lower jaw has also been removed on the left side, and the tongue, pharynx, and larynx are
1 It is possible that the chorda tympani branch of the facial may convey sensory (taste) fibres from
the tongue.
LI&.DENTIC.
OLFACTORY NERVES. 227
partially in view. The occipital bone has been divided by an incision passing down from the
occipital protuberance and through the condyle to the left of the foramen magnum. The
cervical vertebras have been divided to the left of the middle, and the sheath of the spinal
cord opened so as to expose the roots of the cervical nerves.
I.— OLFACTORY NERVES.
The olfactory nerves are 8lender filaments, about twenty in number, which spring
from the under surface of the olfactory bulb, and descend to the nose through the
foramina in the cribriform plate of the ethmoid bone, each being invested by tubular
prolongations of the membranes of the brain. They form an inner group, which are
lodged for a short distance in grooves on the surface of the vertical plate of the
ethmoid, and then break up into tufts of branches before being distributed to the
mucous membrane over the upper part (1 to 1*5 cm.) of that bone, and an outer
Fig. 144. — DISTRIBUTION OF THE OLFACTORY NERVFS ON THE SEPTUM OF THE NOSE.
(From Sappey, after Hirschfeld and LeveiHe". ) f
The septum is exposed and the anterior palatine canal opened on the right side. I, points to the
olfactory bulb, and the remaining Roman numbers to the several cranial nerves ; 1, the olfactory nerves
as they pass through the cribriform plate ; 2, internal twig of the nasal branch of the ophthalmic
nerve ; 3, naso-palatine nerve. The area of distribution of the olfactory nerves is represented too large.
group which ramify over the mesial surface of the lateral mass of the ethmoid, for
a similar extent. The olfactory fibres do not reach the lower edge of the superior,
or any part of the middle and lower turbinate bones.1 The olfactory nerves are
composed exclusively of non-medullated fibres, and their branches communicate
freely with each other as they descend, thus giving rise to a narrow meshed plexus
beneath the mucous membrane, especially on the outer wall of the fossa. (See also
the anatomy of the nose.)
II.-OPTIC NERVE.
The second pair or optic nerves of the two sides meet each other at the optic
commissure where they partially decussate. From this point they may be traced
backwards round the crura cerebri, under the name of the optic tracts.
The optic tract arises from the pulvinar of the optic thalamus, the geniculate
bodies, and the superior quadrigeminal body. As it leaves the under part of the
thalamus it makes a sudden bend forwards, and then runs, in the form of a
flattened band, obliquely inwards across the upper part of the anterior surface of
1 A. v. Brunn. "Beitriigezur mikroskopischen Anatomic der menschlichen Nasenhohle." Arch.
f. mikroskop. Anat. xxxix, 1892.
228
THE CRANIAL NERVES.
the cerebral peduncle, to which it is closely attached ; after this, becoming more
nearly cylindrical, it is continued between the tuber cinereum and the anterior
perforated space, adhering- to the basal grey matter of the cerebrum, and thus
reaches the optic commissure.
th-i
fithqerv. fe. sup. braclv.
\nf, \irach.
ttcl.l.
.b.
tania. sentif-.
ank.perf sp
Fig. 145. — ORIGIN AND RELATIONS
OF THE OPTIC TRACT. (Gr. D. T. )
The mid-brain has been divided
immediately above the pons, and the
part is viewed from below.
o»fc. mrtte
The optic commissure
or chiasma is of an oblong
form, the longer diameter
(10 — 12 mm.) being directed
transversely. It rests upon
the olivary eminence of the
sphenoid bone, and the in-
ternal carotid artery, ascend-
ing to the brain, is close to it
on each side. A large number
of the fibres of the two nerves decussate in the commissure, but some are continued
from the tract to the nerve of the same side, while those fibres of the tract which
come from the internal geniculate body do not pass into either optic nerve, but
cross in the hinder part of the chiasma to the opposite tract, constituting the
inferior commissure of Gudden (see p. 118).
The optic nerve proper runs from the commissure forwards and outwards through
the optic foramen, having the ophthalmic artery to its lower and outer side. As it
enters the foramen it receives a strong sheath from the dura mater, and a slender
one from the arachnoid, both of which are prolonged as far as the eyeball. Appear-
ing in the orbit between the origins of the recti muscles, it continues its oblique
course, inclining at the same time somewhat downwards, to the eyeball, which it
enters on its posterior aspect about 3 mm. internal to its centre. Here the nerve
perforates the sclerotic and choroid coats, and terminates by expanding in the
retina (see the anatomy of the eye). The nerve has a diameter of 3 — 4 mm., and
is from 30 to 40 mm. long. Its intraorbital part measures from 20 to 30 mm., and
has a slightly flexuous course, its length exceeding the distance in a straight line
from the optic foramen to the eyeball by about 5 mm., so as to allow of the move-
ments of the latter. It is surrounded by the ciliary vessels and nerves, and is
pierced about 10 mm. behind its termination by the central artery of the retina,
which, with a companion vein, runs in the axis of the nerve to the eyeball.
The number of fibres in the optic nerve is estimated at somewhat less than half a million
(Salzer) ; they are mostly of small size.
Varieties. — In a few rare instances absence of the optic commissure has been met with,
each optic tract being continued directly into the optic nerve, and passing- to the eyeball, of
the same side. In some cases it would appear that the decussation of the fibres in the
commissure is complete (see p. 118).
III.— OCULOMOTOK NERVE.
The third nerve, the common motor nerve of the eyeball (motor oculi), gives
branches to all the muscles of the orbit, with the exception of the superior oblique
and external rectus. It also supplies, through its connection with the ciliary
ganglion, the sphincter muscle of the iris and the ciliary muscle of the eyeball.
THE THIRD NERVE.
229
The fibres of the nerve spring mainly from the oculomotor nucleus in the grey
matter of the floor of the aqueduct of Sylvius opposite the superior quadrigeminal
N.HI
Fig. 146. — PLAN OF THE ORIGINS OP THE THIRD, FOURTH AND
SIXTH NERVES. (Modified from Gowers. )
The nerves and their nuclei are projected into the outline of
a median section of the mid brain, and pons : III, third nerve ;
N.III, its nucleus; IV, fourth nerve; N.IV, its nucleus;
P.L. B., posterior longitudinal bundle; VI, sixth nerve; N.VI,
its nucleus.
body (figs. 146 and 151) ; to these are added others
which ascend in the posterior longitudinal bundle
from the nucleus of the sixth nerve of the opposite
side. They pass ventrally through the tegmentum,
and emerge in ten to fifteen bundles from the inner
side of the crus cerebri, commencing close to the
upper border of the pons, and extending upwards
and outwards along the line of the oculomotor
groove. One of these bundles is frequently separated
from the rest, and issues more externally from the anterior surface of the
crus.
internal
carotid artcry'ty
posterior
communicating-
artery
posterior
cerebral
artery
inferior
longitudina^
sinus
— optic nerve
fc— third nerve
tjjs' --fourth nerve
superior cerebellar
artery
/_' — tentorium
inferior
quadrigeminal
body
V *2&7
-£ — -\- falx cerebri
Fig. 147. — THE THIRD AND FOURTH NERVES IN THEIR INTRACRANIAL COURSE.
(Drawn by T. W. P. Lawrence.)
The mid-brain is divided in the aperture of the tentorium, and the cerebrum removed. On the
right side the posterior cerebral and posterior communicating arteries are cut short in order to expose
the origin of the third nerve. On the left side the tentorium and crus cerebri are slightly separated so
as to show the fourth nerve more fully.
230
THE CRANIAL NERVES.
Speedily becoming firm and round, the nerve is directed from the interpeduncular
space forwards, as well as somewhat outwards, between the posterior cerebral and
superior cerebellar arteries to the outer side of the posterior clinoid process, a little
anterior to which it penetrates the layer of dura mater forming the outer boundary
of the cavernous sinus. Contained within this membrane, it continues its course
Fig. 148. — PLAN OF THE THIRD NERVE,
WITH THE CILIARY GANGLION.
(G. D. T.)
The ganglion is seen to be attached
by its short root to the nerve of the
inferior oblique muscle ; LR, its long,
and SR, its sympathetic root.
forwards to the inner end of the sphenoidal fissure, and there divides into two parts,
upper and lower, which enter the orbit between the heads of the external rectus
muscle, and are separated from each other by the nasal branch of the ophthalmic
nerve. As the third nerve lies in the outer wall of the cavernous sinus, it is con-
nected by slender filaments with the cavernous plexus of the sympathetic, and it
receives also a small branch from the ophthalmic division of the fifth nerve.
The upper, the smaller part, is directed inwards over the optic nerve to the
Fig. 149. — VIEW FROM ABOVE OF THE MOTOR NKRVKS OF THE EYEBALL
AND ITS MUSCLES (after Hirschfeld and Leveille, altered). (Allen
Thomson. )
The ophthalmic division of the fifth pair has been cut short ; the
attachment of the muscles round the optic nerve has been opened up,
and the three upper muscles turned towards the inner side, their
anterior parts being removed ; a part of the optic nerve is cut away to
show the inferior rectus ; and a part of the sclerotic coat and cornea is
dissected off showing the ins, ciliary muscle, and choroid coat, with
the ciliary nerves.
«, upper part of the internal carotid artery emerging from the
cavernous sinus ; b, superior oblique muscle ; b't its anterior part
passing through the pulley ; c, levator palpebrse superioris ; d, superior
rectus ; e, internal rectus ; f, external rectus ; f, its upper tendon
turned down ; g, inferior rectus ; h, insertion of inferior oblique
muscle.
II, optic commissure ; II', part of the optic nerve entering the
eyeball ; III, common oculomotor ; IV, trochlear nerve ; V, large root
of fifth ; V, small or motor root ; VI, abducent nerve ; ] , upper
division of third nerve, giving twigs to the levator palpebrse and
superior rectus ; 2, branches of lower division supplying the internal
and inferior recti muscles ; 3, the long branch of the same nerve pro-
ceeding forwards to the inferior oblique muscle, and close to the
number 3, the short root of the ciliary ganglion : this ganglion is also
shown, receiving from behind its long root, which has been cut short,
and giving forward some of its ciliary nerves, which pierce the sclerotic
coat ; 3', marks the termination of some of these nerves in the ciliary
muscle and iris after having passed between the sclerotic and choroid
coats ; 4, the trochlear nerve entering the upper surface of the superior
oblique muscle ; 6, the abducent nerve passing into the external rectus.
superior rectus muscle of the eye and the elevator of the eyelid, to both of which
muscles it furnishes branches.
The lower and larger portion of the nerve divides into three branches ; of these
one reaches the inner rectus ; another the lower rectus ; and the third, the longest
of the three, runs onwards between the lower and the outer rectus, and terminates
below the ball of the eye in the inferior oblique muscle. The last-mentioned branch
is connected with the lower part of the ciliary ganglion by a short thick offset
(short root of the ganglion), and gives one or two filaments to the lower rectus
muscle.
THE THIRD AND FOURTH NERVES.
The several branches of the third nerve enter the muscles to which they are dis-
distributed on the surface which in each is turned towards the eyeball, with the
exception of that to the inferior oblique, which penetrates the hinder border of its
muscle.
The fibres of the third nerve, about 15,000 in number, are generally large ; but there are
some small ones, most of which pass into the ciliary ganglion. In the rootlets of the nerve
Thomsen and G-askell have described a peculiar structure which is regarded by them as the
remains of a degenerated ganglion (Virchow's Archiv, cix, 1887 ; Journ. Phys., x, 1889,
p. 167).
Varieties.— A communication between the third and sixth nerves as they pass the
cavernous sinus has been described, but its existence is denied by most recent observers.
The upper division of the third nerve may have a communication with the nasal (Svitzer,
Sommering, Testut). The third nerve has been seen in a few cases giving a branch to the
external rectus (Cruveilhier, Fasebeck, C. Krause). and in one instance a branch of the third
supplied the place of the sixth nerve which was wanting (Generali). A filament to the
superior oblique muscle is noticed by Volkmann. The branch to the inferior oblique muscle
was seen by Arnold to pass through the lower part of the lenticular ganglion, and by Henle
to pierce the inferior rectus.
POSITION OF CERTAIN NERVES AT THE CAVERNOUS SINUS, AND AS THEY ENTER
THE ORBIT. — There are several nerves, besides the third, placed close together at the
Fig. 150. — THE NERVES IN THE OUTER WALL OF THE
CAVERNOUS SINUS, SEEN IN TRANSVERSE SECTION.
(Langer.)
^ OPHTn. NERVE
n INT. CAR. Af!
cavernous sinus, and entering the orbit
through the sphenoidal fissure. To avoid
repetition hereafter, the relative positions of
these nerves may now be described. The
nerves thus associated are the third, the
fourth, the ophthalmic division of the fifth, and the sixth.
At the cavernous sinus. — In the dura mater which bounds the cavernous sinus
on the outer side, the third and fourth nerves and the ophthalmic division of the
fifth are placed, as regards one another, in their numerical order both from above
downwards and from within outwards. The sixth nerve is placed separately from
the others close to the carotid artery in the cavity of the sinus, and internally to the
ophthalmic nerve. Near the sphenoidal fissure, through which they enter the orbit,
the relative position of the nerves is changed, the sixth nerve being here close to the
rest, and their number is augmented by the division of the third and the ophthalmic
nerves — the former into two, the latter into three parts.
In the sphenoidal /insure. — The fourth and the frontal and lachrymal branches of
the fifth, which are here higher than the rest, lie on the same level, the fourth being
the nearest to the inner side, and enter the orbit above the muscles. The remaining
nerves pass between the heads of the external rectus muscle, in the following order
from above downwards ; the upper division of the third, the nasal branch of the fifth,
the lower division of the third, and, lowest of all, the sixth.
IV.— TROCHLEAR NERVE.
The fourth, trochlear, or pathetic nerve is the smallest of the cranial nerves, and
has the longest course within the cranial cavity. It is distributed solely to the
superior oblique muscle of the eye.
The nucleus of the fourth nerve continues downwards the column of cells giving
origin to the third nerve, being placed in the ventral grey matter of the aqueduct of
232
THE CRANIAL NERVES.
Sylvius opposite the upper part of the inferior quadrigeminal body (fig. 146).
From the nucleus the fibres are directed at first downwards for a short distance, and
then backwards and inwards, arching round the lower part of the aqueduct, to enter
Fig. 151. — PLAN OP THE ORIGINS OF THE THIRD AND
FOURTH NERVES. (G. D. T.)
The midbrain is supposed to be divided at different
levels on the two sides, the section on the right side of
the figure passing through the superior, and on the
left side through the inferior quadrigeminal body : III,
third nerve ; N.I II, its nucleus ; IV, fourth nerve ;
N.IV, its nucleus ; V.D, descending or mesenceohalic
root of the fifth nerve; N. V, its nucleus; C.Q.S,
superior, and C.Q.I, inferior quadrigeminal body;
P.L.B., posterior longitudinal bundle.
the superior medullary velum, where they
cross to the opposite side, the two nerves
thus forming a complete decussation.
Emerging from the upper end of the
superior medullary velum close to the frenulum, and immediately below the
inferior quadrigeminal body, the fourth nerve is directed at first outwards
across the superior peduncle of the cerebellum, and then turns forwards
round the outer side of the crus cerebri (figs. 141, 147), lying parallel to
and between the posterior cerebral and superior cerebellar arteries. It enters an
Fig. 152. — VIEW FROM ABOVE OP THE UPPER-
MOST NERVKS OF THE ORBIT, THE GASSERIAN
GANGLION, &c. (From Sappey, after Hirsch-
feldandLeveille".) §
I, olfactory tract, passing forwards into the
bulb; II, optic commissure; III, oculomotor; IV,
trochlear nerve ; V, large root of the fifth nerve,
a small portion of the lesser root is seen below
it; VI, sixth nerve ; VII, facial ; VIII, audi-
tory ; IX, glosso-pharyngeal ; X, pneumo-gastric ;
XI, spinal accessory ; XII, hypoglossal : 1, Gras-
serian ganglio^ ; 2, ophthalmic nerve ; 3, lachry-
mal nerve ; 4, frontal ; 5, external, 6, internal
branch of the supraorbital nerve ; 7, supratro
chlear nerve ; 8, nasal nerve ; 9, its infratro-
chlear branch ; 10, nasal nerve, passing through
the anterior internal orbital canal ; 11, anterior
deep temporal proceeding from the buccal nerve;
12, middle deep temporal ; 13, posterior deep
temporal arising from the masseteric ; 14, origin
of the auriculo-temporal ; 15, great superficial
petrosal nerve.
aperture in the dura mater immediately
beneath the free margin of the ten-
torium, a little behind the posterior
clinoid process, and runs forwards in
the outer wall of the cavernous sinus,
resting against the upper margin of the ophthalmic nerve, and crossing the third
obliquely on its outer side from below upwards, to the inner end of the sphenoidal
fissure. Passing into the orbit above the external rectus muscle, it inclines inwards
over the levator palpebrae and superior rectus, and finally enters the superior oblique
muscle on its upper surface, and close to its outer border.
THE FIFTH NERVE.
233
While lodged in the outer wall of the sinus, the fourth nerve is connected with
the sympathetic on the carotid artery, and is also joined by a filament from the
ophthalmic nerve.
The fourth nerve consists of about 1,200 fibres, mostly of large size. It also shows close
to its origin the vestiges of a degenerated ganglion (Gaskell).
Varieties. — In one case the fourth nerve pierced the levator palpebras superioris on its
way to the superior oblique (G-. D. T.). The nerve has been observed in several cases sending
a branch forwards to the orbicularis palpebrarum muscle, or to join the supratrochlear, the
infratrochlear, or the nasal nerve. A communication with the frontal nerve is recorded by
Berte.
V. — TRIFACIAL NERVE.
The fifth, trifacial, or trigeminal nerve is the largest of the cranial nerves, and
resembles a spinal nerve in the circumstance that it arises by separate sensory and
Fig. 153. — PLAN OP THE ORIGIN OF THE FIFTH NERVE.
The outline represents the contour of the medulla ohlongata,
pons, and a part of the raidbrain, which are supposed to be
transparent : V.M., motor portion of the fifth nerve ; N.V.M., the
motor nucleus; V.D., descending or mesencephalic root; \r.S.,
sensory portion of the fifth nerve; N.V.S., the upper sensory
nucleus ; V.A., asoending or bulbar root ; S.GLR., gelatinous
substance of llolando, or lower sensory nucleus.
motor roots, and also that the sensory fibres pass
through a ganglion while the motor do not. Its
sensory division, which is much the larger, imparts
common sensibility to the face and the fore part of
the head, as well as to the eye, the nose, the external
ear, and the mouth, including the greater portion of
the tongue ; it may possibly also confer the power of
taste upon the fore part of the latter organ. The
motor root supplies chiefly the muscles of mastication.
The two roots of the nerve appear at the side of
the pons Yarolii, where the transverse fibres of the
latter are prolonged into the middle peduncle of the
cerebellum, and much nearer its upper than its lower
border. The small root issues above the large one,
and the two are separated from one another by a small
band of the cross fibres of the pons. The fibres of the small root arise in part from
the motor nucleus of the fifth nerve beneath the floor of the upper portion of the
fourth ventricle ; they are joined by the bundle known as the descending root of the
fifth nerve, which springs from a collection of large nerve-cells in the grey matter
at the side of the aqueduct of Sylvius. The fibres of the large root pass backwards
into the pons, and some reach the upper sensory nucleus of the fifth nerve, placed
to the outer side of and somewhat deeper than the motor nucleus ; but the greater
number turn downwards and are continued through the substance of the pons into
the medulla oblongata, forming the so-called ascending or bulbar root of the fifth
nerve : their mode of termination is uncertain, but they may break up among the
cells of the gelatinous substanca of Rolando (lower sensory nucleus of the fifth
nerve).
The small root consists mainly of large fibres, and contains a vestigial ganglion (Gaskell).
The large root is mostly composed of fine fibres.
234
THE CKAN1AL NEBVE8.
From the pons, the two roots are directed forwards beneath the anterior extremity
of the tentorium to the middle fossa of the base of the skull, and enter a recess in
the dura mater (cavum MecTceUi) over the summit of the petrous part of the temporal
bone. Here the large root becomes expanded, and its funiculi divide and unite so as
to form a plexiform network which is continued into the Gasserian ganglion. The
small root inclines downwards on the inner side of the large root, and then passes
outwards beneath the ganglion, without its fibres ? being incorporated in any way
with the latter, to join below the foramen ovale the lowest of the three trunks
issuing from the ganglion.
The ganglion of the fifth nerve or Gasserian ganglion (ganglion semilunare)
occupies a depression on the upper surface of the petrous portion of the temporal
bone, near the apex, and is somewhat crescentic in form, the convexity being
turned forwards. It is flattened, and striated on the surface. Its internal part
Fig. 154.— GENERAL PLAN OF THE
BRANCHES OF THE FIFTH PAIR.
(After a sketch by Charles Bell.) ^
1, small root of the fifth nerve ; 2,
large root, passing forwards into the
(rasserian ganglion ; 3. placed on the
bone above the ophthalmic nerve, which
is dividing into the frontal, lachrymal,
and nasal branches, the latter connected
with the ciliary ganglion ; 4, placed on
the bone close to the foramen rotundum,
marks the superior maxillary division,
which is connected below with the
spheno-palatine ganglion, and passes
forwards to the infraorbital foramen ; 5,
placed on the bone over the foramen
ovale, marks the inferior maxillary nerve,
giving off the auriculo-temporal and
muscular branches, and continued by the
inferior dental to the lower jaw, and by
the lingual to the tongue ; a, submaxil-
lary gland, the submaxillary ganglion
placed above it in connection with the
lingual nerve ; 6, chorda tympani ; 7,
facial nerve, issuing from the stylo-
mastoid foramen.
comes into close relation with the posterior extremity of the cavernous sinus and the
internal carotid artery. On its inner side the ganglion is joined by filaments from
the carotid plexus of the sympathetic nerve ; and, according to some anatomists,
it furnishes from its back part filaments to the dura mater. The cells of this
ganglion are similar to those found on the posterior roots of the spinal nerves.
From the convex border of the Gasserian ganglion proceed the three large
divisions of the nerve. The highest (first or ophthalmic trunk) enters the orbit ;
the second, the superior maxillary nerve, is continued forwards to the face between
the orbit and mouth ; and the third, the inferior maxillary nerve, is distributed
chiefly to the external ear, the tongue, the lower teeth, the face below the mouth,
and the muscles of mastication. The first two trunks proceed exclusively from the
ganglion and are entirely sensory, while the third or inferior maxillary trunk,
derived principally from the ganglion, has associated with it also the whole of the
fibres of the motor root, and thus distributes both motor and sensory branches.
THE LACHRYMAL NERVE.
235
I.— OPHTHALMIC NERVE.
The ophthalmic nerve, or first division of the fifth, the smallest of the three
offsets from the Gasserian ganglion, is flattened from side to side, and measures
about an inch in length. It is directed forwards and upwards in the outer wall of
the cavernous sinus, in company with the third and fourth nerves, towards the
sphenoidal fissure, where it ends in branches which pass through the orbit to the
surface of the head and to the nasal fossa. In its course forwards, the ophthalmic
nerve is joined by filaments from the cavernous plexus of the sympathetic.
BRANCHES. — A small recurrent branch (nerrus tentorii) arises from the ophthalmic
trunk near the Gasserian ganglion, and, running backwards across the fourth nerve,
to which it generally adheres closely for some distance, ramifies between the layers of
the ten tori am.
Farther forwards the ophthalmic nerve gives off three slender offsets which join
respectively the third, fourth, and sixth nerves as they enter the orbit.
The terminal branches resulting from the division of the ophthalmic nerve close
to the orbit are the nasal, which is usually the first to arise and springs from the
inner and lower part of the trunk, the frontal and the lachrymal. These branches
Fig. 155.— PLAN OF THE OPHTHALMIC NERVE. (GK D. T.)
The dotted line repi-esents the limit of the orbit, c G,
ciliary ganglion, joined behind by the long root, and giving
off in front the short ciliary nerves.
aie transmitted separately through the sphenoidal
fissure, and are continued through the orbit (after
supplying some filaments to the eyeball and the
lachrymal gland) to their final, distribution in
the nose, the eyelids and the integument of the
forehead.
Lachrymal nerve. — The lachrymal ne"rve
(fig. 152, 3) is external to the frontal at its
origin, and is contained in a separate sheath of
dura mater. In the orbit it passes along the
outer part, above the external rectus muscle, to
the outer and upper angle of the cavity. Near
the lachrymal gland, the nerve has a connecting
filament with the temporal branch of the superior
maxillary nerve ; and when in close apposition
with the gland, it gives many filaments to that
body and to the conjunctiva. Finally, the
lachrymal nerve penetrates the palpebral fascia
externally, and ends in the upper eyelid, and the skin in the neighbourhood of the
external angular process of the frontal bone, the terminal ramifications being joined
by twigs from the facial nerve.
Varieties.— The lachrymal nerve is occasionally smaller than usual, being reinforced by a
twi"- from the temporal branch of the superior maxillary, and it has been seen replaced
entirely by an offset of the latter nerve (Turner, Hyrtl). On the other hand, the lachrymal
nerve has been found sending an offset through the malar bone in the place of the temporal
branch of the superior maxillary nerve, which was absent (G. D. T.).
The lachrymal branch sometimes appears to be derived in part from the fourth nerve, but
in such cases" the additional root is probably composed of fibres that have passed over from
the ophthalmic to the fourth, while these nerves are contained in the outer wall of the
cavernous sinus.
236 THE CRANIAL NERVES.
Frontal nerve. — The frontal nerve (fig. 152, 4), the largest division of the
ophthalmic, also enters the orbit above the muscles, and runs forwards between the
elevator of the upper eyelid and the periosteum. About the middle of the orbit it
divides into two branches, supratrochlear and supraorbital.
(a) The supratrochlear nerve, much the smaller of the two branches, inclines
inwards towards the pulley of the superior oblique muscle, close to which it sends a
filament downwards to communicate in a loop with the infratrochlear branch of the
nasal nerve, and then leaves the orbit between the orbicularis palpebrarum muscle
and the bone. In this position the nerve gives twigs to the skin and conjunctiva
of the upper eyelid, and finally it turns upwards, dividing into branches which per-
forate the orbicularis and frontalis muscles, and are distributed to the integument
of the lower and mesial part of the forehead.
(b) The supraorbital nerve is the continuation of the frontal nerve, and leaves
the orbit by the supraorbital notch or foramen. It divides into two branches, inner
and outer, wrhich ascend on the forehead beneath the frontalis muscle, and are dis-
tributed by numerous slender ramifications to the skin of the fore and upper parts
of the scalp. The outer branch is the larger, and extends backwards nearly to the
lambdoid suture ; the inner branch reaches but a little way over the parietal bone.
In the supraorbital notch a slender filament of the nerve enters an aperture in the
frontal bone, where it is said to be distributed to the diploe and the mucous lining
of the frontal sinus ; as the nerve emerges from the orbit, twigs are sent downwards
to the upper eyelid ; and from its terminal divisions small branches pass to the
pericranium.
The primary division of the supraorbital nerve often takes place before it issues
from the orbit, and in that case only the larger branch passes through the supra-
orbital notch, the smaller one being placed more internally, and not unfrequently
traversing a second slighter notch (frontal notch, Henle) in the orbital margin
(fig. 152, 5, 6).
The branches of the supraorbital nerve, and the same is the case with all the
cutaneous offsets of the fifth, form communications with the adjacent ramifications
of the facial nerve ; in this way sensory fibres derived from the fifth nerve may be
conveyed to the surrounding muscles.
Nasal nerve. — The nasal nerve (oculo-nasal or naso-ciliary} enters the orbit
between the heads of the external rectus muscle, and between the two divisions of
the third nerve. It then inclines inwards over the optic nerve, passing beneath the
superior rectus and superior oblique muscles, to the inner side of the orbit, and
leaves that cavity by the anterior internal orbital canal. In this part of its course
it furnishes a slender branch to the ciliary ganglion, one or two filaments (long
ciliary) directly to the eyeball, and a considerable infratrochlear branch, which arises
just before the nerve enters its canal on the inner side of the orbit.
Arrived in the cranial cavity, the nerve is directed forwards in a groove at the
outer edge of the cribriform plate of the ethmoid bone to a small canal between the
fore part of the plate and the frontal bone, through which it descends to the nasal
fossa. Here it gives off internal or septal and external branches to the mucous
membrane of the fore part of the nasal fossa, and is then continued downwards in
the groove on the back of the nasal bone, to terminate as the anterior or. superficial
branch in the integument of the lower part of the nose.
(a) The branch to the ciliary ganglion, very slender, and from a quarter to
half an inch in length, arises generally between the heads of the external rectus. It
lies on the outer side of the optic nerve, and enters the upper and back part of the
ganglion, constituting its long root.
(b) The long ciliary nerves are situated on the inner side of the optic nerve ;
THE NASAL NERVE. 237
they join one or more of the short ciliary branches from the ciliary ganglion,
and, after perforating the sclerotic coat of the eje, are distributed in the same
manner as those nerves.
(c) The wfmtrochlear nerve runs forwards along the inner side of the orbit,
below the superior oblique muscle, and parallel to the supratrochlear nerve, from
which it receives, near the pulley of the oblique muscle, a filament of connection.
The nerve is then continued below the pulley to the inner angle of the eye, and
ends, in filaments which supply the conjunctiva, the caruncle, and the lachrymal sac,
as well as the integument of the upper eyelid and root of the nose (fig. 171, 22).
(d) The internal or septal branch (fig. 144, 2) supplies the pituitary membrane
over the fore part of the septum, extending downwards nearly as far as the opening
of the nostril.
(e) The external branch (fig. 160, 2), often represented by two or three filaments,
is distributed to the mucous membrane of the fore part of the outer wall of the nasal
fossa, including the anterior ends of the middle and lower turbinate bones.
(/) The anterior or superficial branch (fig. 171, 24) issues between the nasal
bone and the upper lateral cartilage of the nose, and runs downwards under cover of
the compressor naris muscle to the tip of the nose, supplying the skin of the lower
part of the organ.
Varieties. — The nasal nerve occasionally (frequently, Krause) gives filaments to the
superior and internal recti muscles. A branch to the levator palpebrse superioris has also
been met with (Fasebeck). In one case filaments of communication passed from a small
gang-lion connected with the nasal nerve to the third and sixth nerves (Svitzer). In tvro
instances Testut observed absence of the inf ratrochlear branch, its place being supplied by
the supratrochlear nerve. Offsets from the nasal nerve, as it traverses the anterior internal
orbital canal, to the frontal sinus and ethmoidal cells are described by Meckel and Langen-
beck ; and a tpheno-ethmoidal (Luschka) or posterior ethmoidal (Krause) branch is said to pass
through the posterior internal orbital canal to the mucous membrane of the sphenoidal sinus
and posterior ethmoidal cells.
SUMMARY. — The first division of the fifth nerve is altogether sensory in function.
It furnishes branches to the dura mater ; to the eyeball and the lachrymal gland ;
to the mucous membrane of the nose and eyelids ; to the integument of the nose,
the upper eyelid, the forehead, and the upper part of the hairy scalp. It has com-
munications with the third, fourth, and sixth nerves, with numerous branches of the
facial, and with the sympathetic.
Ciliary Ganglion.
There are four small ganglia connected with the divisions of the fifth nerve :
the ciliary ganglion with the first, the spheno-palatine ganglion with the second,
and the otic and submaxillary ganglia with the third. These ganglia, besides
receiving branches from the sensory part of the fifth, are each connected with a
motor nerve from the third, the fifth, or the facial, and with twigs from the sympa-
thetic ; and the nerves thus joining the ganglia are named their roots.
The ciliary, ophthalmic, or lenticular ganglion serves as a centre for the
supply of nerves — motor, sensory, and sympathetic — to the eyeball. It is a small
reddish body, compressed laterally and somewhat four-sided, and measures about
2 mm. from before back. It is situated at the back of the orbit, between the outer
•rectus muscle and the optic nerve, and generally in contact with the ophthalmic
artery ; it is joined behind by branches from the fifth, the third, and the sympa-
thetic nerves ; while from its fore part proceed the short ciliary nerves to the
eyeball. The cells of the ganglion are of the multipolar variety.
VOL. III. PT. 2. Q
238
THE CEANIAL NERVES.
UNION OF THE GANGLION WITH NERVES : ITS BOOTS. — The posterior border of
the ganglion receives three nerves. One of these, the long or sensory root, a slender
filament from the nasal branch of the ophthalmic trunk, joins the upper part of this
border. Another branch, the short or motor root, much thicker and shorter than the
preceding, and sometimes divided into two parts, is derived from the branch of the
third nerve to the inferior oblique muscle, and is connected with the lower part of
the ganglion. The middle or sympathetic root is a very small nerve which emanates
from the cavernous plexus of the sympathetic, and reaches the ganglion close to the
long upper root : these two nerves are frequently conjoined before reaching the
ganglion. The ganglion is sometimes very small, probably from the nerve-cells
being distributed along the nerves which are connected with it.
BRANCHES OF THE GANGLION. — From the fore part of the ganglion arise six or
eight short ciliary nerves, which undergo division as they pass forwards, so that they
form from twelve to twenty fine filaments as they reach the eyeball. They are dis-
Fig. 156.— NERVES OF THE ORBIT FROM THE
OUTER, SIDE. (From Sappey, after Hirscli-
feldandLeveille.) f
The external rectus muscle has been divided
and turned down : 1, optic nerve ; "2, trunk of
the third nerve ; 3, its upper division passing
into the levator palpebrre and superior rectus ;
4, its long lower branch to the inferior oblique
muscle ; 5, the sixth nerve joined by twigs from
the sympathetic ; 6, Gasserian ganglion ; 7,
ophthalmic nerve ; 8, its nasal branch ; 9, ciliary
ganglion ; 10, its short, 11, its long, and 12, its
sympathetic root ; 13, short ciliary nerves ;
14, supraorbital nerve.
posed in two bundles, springing from the upper and lower angles of the ganglion,
and being placed, the one set above, the other below the optic nerve. The lower set
is the more numerous, and is accompanied by the long ciliary nerves (from the
nasal), with which one or more of these branches are joined. Having entered the
eyeball by apertures in the back part of the sclerotic coat, the nerves are lodged in
grooves on its inner surface, and are finally distributed to the ciliary muscle, the
iris and the cornea (see the anatomy of the eye).
Varieties.— Additional roots to the ciliary ganglion have been observed by many
anatomists, derived from the upper division of the third nerve, from the fourth nerve, from
the lachrymal nerve, from the spheno-palatine ganglion, or from the sixth nerve.
Absence of the long root is recorded : in this case it is probable that the corresponding*
fibres pass directly from the nasal by the long ciliary nerves to the eyeball.
The sympathetic root may be represented by several fine filaments proceeding from the
cavernous plexus : according to Reichart this is the normal arrangement, the majority of the
filaments accompanying the third nerve.
II.— SUPERIOR MAXILLARY NERVE.
The superior maxillary nerve, or second division of the fifth (n. mazilfaris), is
intermediate in size between the ophthalmic and the inferior maxillary trunks.
It commences at the middle of the Gasserian ganglion, and, passing horizontally
forwards, soon leaves the skull by the foramen rotundum of the sphenoid bone. The
nerve then crosses the spheno-maxillary fossa, and, taking the name of infraor~bital>
enters the infraorbital canal of the upper maxilla, by which it is conducted to the
face. After emerging from the infraorbital foramen, it terminates beneath the
elevator of the upper lip in branches, which spread out to the side of the nose, the
lower eyelid, and the upper lip.
THE SUPERIOR MAXILLARY NERVE.
239
BRANCHES. — Near its origin a fine recurrent branch (n. meninyeus medius) passes
to the dura mater and middle meningeal artery. In the spheno-maxillary fossa an
orbital or temporo-malar branch ascends from the superior maxillary nerve to the
Fig. 157. — SUPERIOR MAXILLARY
NEIIVE AND SOME OF THE ORBITAL
NERVES. (From Sappey, after
Hirschfeld and Leveilk'. ) I
1, Gasserian ganglion ; 2, lachry-
mal nerve ; 3, trunk of the superior
maxillary nerve ; 4, its orbital branch ;
6, origin of its malar twig ; 7, its
temporal twig, joined by 5. the com-
municating branch from the lachrymal
nerve ; 8, spheno-palatine ganglion ;
9, Yidian nerve : 10, its upper branch
or great superficial petrosal nerve
proceeding to join 11, the facial
nerve ; 12, its lower branch or great
deep petrosal nerve joining the sympa-
thetic; 13, 14, posterior dental nerves;
16, terminal branches of the infra-
orbital nerve in the face ; 16, a branch
of the facial uniting with some of
the twigs of the infraorbital.
orbit, and two spheuo-palatine branches descend to join Meckel's ganglion ; while
the nerve is in contact with the upper maxilla, it furnishes the superior dental or
alveolar branches ; and on the face are the terminal branches already indicated.
Fig. 158. — PLAN OF THE SUPERIOR MAXILLARY NERVE. (G. D. T.j
Orbital branch. — The orbital or temporo-malar branch (n. zygcmaticus}, a
small cutaneous nerve, enters the orbit by the spheno-maxillary fissure, and imme-
diately divides into two branches (temporal and malar), which pierce the malar bone,
and are distributed to the temple and the prominent part of the cheek.
(a) The temporal branch (r. zygomaticotemporatts) is directed upwards in a
groove on the outer wall of the orbit, and leaves this cavity by the temporal canal
Q2
240
THE CRANIAL NERVES.
in the malar bone. While still in the orbit, it is joined by a communicating filament
(in some cases by two filaments) from the . lachrymal nerve. The nerve is then
inclined upwards in the temporal fossa between the bone and the temporal muscle,
and perforating the aponeurosis over the muscle nearly an inch above the zygoma,
ends in cutaneous filaments over the fore part of the temporal region. The
cutaneous ramifications are united with the facial nerve, and sometimes with the
auriculo-temporal branch of the third division of the fifth.
(#) The malar branch (r. zygomalicofacialis) lies at first in the loose fat in the
lower angle of the orbit, and is continued to the face through the malar canal of the
malar bone, where it is frequently divided into two filaments. It is distributed to
the skin over the malar bone, after forming a communication with the facial nerve.
Varieties. — The temporo -malar nerve is subject to frequent deviations from the arrange-
ment above described. Thus, either branch may be smaller than usual, or even absent, in
which case the other division of the nerve may be distributed over a larger area, or the
temporal branch may be reinforced or replaced by the lachrymal nerve, the malar branch by
the infraorbital nerve. The temporal branch, instead of perforating the malar bone
frequently passes into the temporal fossa through the anterior end of the spheno-maxillary
fissure.
The superior dental or alveolar nerves are, as a rule, three in number,
anterior, middle, and posterior, but the middle is sometimes conjoined with the
anterior, while the posterior is frequently represented by two separate offsets.
Fig. 159. — DEEP VIEW OF THE
SUPERIOR MAXILLARY
SERVE AND THE SPHF.XO-
PALATINE GANGLION, &C,
(From Sappey, after
Hirschfeld and Leveille.)
I
1, superior maxillary
nerve ; 2, posterior superior
dental ; 3, middle superior
dental ; 4, anterior superior
dental ; 5, superior dental
plexus ; 6, spheno-palatine
ganglion ; 7, Vidian nerve ;
8, its great superficial petrosal
branch ; 9, its great deep
petrosal branch ; 10, a part
of the sixth nerve, receiving
twigs from the carotid plexus
of the sympathetic ; 11, superior cervical sympathetic ganglion ; 12, its ascending branch ; 13, facial
nerve; 14, glosso-pharyngeal nerve ; 15, its tympanic branch ; 16, carotico-tympanic twig joining the
sympathetic ; 17, filament to the fenestra rotunda ; 18, filament to the Eustachian tube ; 19, filament
to the fenestra ovalis ; 20, small superficial petrosal nerve.
The posterior superior dental nerve arises from the superior maxillary trunk before
it enters the infraorbital groove, and immediately divides into two branches (often
separate at their origin), which descend with the posterior dental artery on the
zygomatic surface of the upper jaw. They send small external filaments to the gum
and the adjacent part of the mucous membrane of the cheek, and then enter the
posterior dental canals to terminate in offsets to the molar teeth and the lining
membrane of the antrum.
Variety. — The posterior dental nerve has been seen in a few instances of large size, and
replacing the buccal nerve, which was absent as a branch of the inferior maxillary, in the
supply of the cheek.
THE SUPERIOR MAXILLARY NERVE.
The middle superior dental nerve leaves the superior maxillary in the hinder part
of the infraorbital canal, and is directed downwards and forwards in a special canal
in the outer wall of the antrum to the bicuspid teeth.
The anterior superior dental nerve is the largest of the three. Arising near the
infraorbital foramen, it descends in its canal in the front wall of the antrum, and
divides into dental branches for the incisor and canine teeth, and a nasal branch,
which supplies the pituitary membrane in the fore part of the inferior meatus and
the adjoining part of the floor of the nasal fossa.
The three dental nerves communicate so as to form loops with one another while
they are contained in their bony canals, and from these loops other branches spring,
which join again and give rise to a plexus (superior dental plexus) from which the
minute terminal filaments proceed to the teeth and gum.
Facial branches. — The facial branches are divisible into palpebral, nasal, and
labial sets.
The inferior palpebral branches, generally an inner and an outer, ascend from
the termination of the infraorbital nerve to supply the skin and conjunctiva of the
lower eyelid in its whole breadth.
The lateral nasal branches, two or three in number, are directed inwards between
the fibres of the levator labii superioris alaeque nasi muscle to the skin of the side of
the nose.
The superior labial branches, the largest of the terminal offsets of the superior
maxillary nerve, and three or four in number, pass downwards between the elevator
muscles of the upper lip and of the angle of the mouth. Ramifying as they descend,
and giving off branches to supply the integument of the fore part of the cheek,
they end in the skin and mucous membrane of the upper lip.
Below the orbit, the terminal branches of the superior maxillary nerve are joined
by considerable branches of the facial nerve, the union between the two being named
the infraorbital plexus.
Spheno-Falatiue Ganglion.
The spheno-palatine ganglion, also named MeckeVs or the nasal ganglion, is
deeply placed in the spheno-maxillary fossa, close to the spheno-palatine foramen.
It receives the two spheno-palatine branches which descend together from the
superior maxillary nerve as it crosses the top of the fossa. It is of a reddish-grey
colour, triangular in form, and convex on the outer surface, and measures from
before back about 5 mm. The grey or ganglionic substance contains multipolar
nerve-cells, and does not involve all the fibres of the spheno-palatine branches of the
upper maxillary nerve, but is placed at the back part, at the point of junction of the
Vidian nerve, so that many of the fibres of the spheno-palatine nerves proceeding
to the nose and palate pass to their destination without being incorporated with the
ganglionic mass.
Branches proceed from the ganglion upwards to the orbit, downwards to the
palate, inwards to the nose, and backwards through the Yidian and pterygo-palatine
canals.
ASCENDING BRANCHES. — These are two or three very small twigs, which reach
the orbit by the spheno-maxillary fissure, and are distributed to the periosteum and,
according to Luschka, to the mucous membrane of the posterior ethmoidal and
sphenoidal sinuses.
Bock and Valentin describe a branch ascending- from the gang-lion to the sixth nerve ;
Tiedemaim, one to the lower angie of the ciliary gang-lion. Hirzel and Arnold traced fila-
ments to the optic nerve or its sheath.
THE CRANIAL NERVES.
DESCENDING BRANCHES. — These are three in number — the large, the small, and
the external palatine nerves, and are in great part continued directly from the
spheno-palatine branches of the superior maxillary.
(a) The large or anterior palatine nerve descends in the palato-maxillary canal,
and divides in the roof of the mouth into branches which are received into grooves
in the hard palate, and extend forwards nearly to the incisor teeth. In the mouth
it supplies the inner side of the gum, the glands, and the mucous membrane of the
hard palate, and joins in front with the naso-palatine nerve. While in its canal,
the large palatine nerve gives off one or two inferior nasal branches, which supply '
the mucous membrane over the greater part of the inferior turbinate bone, together
with the adjoining middle and inferior meatuses of the nose.
(#) The small or posterior palatine nerve enters the lesser palatine canal, and
is conducted to the soft palate, the tonsil, and the uvula. It has been thought
to convey motor fibres from the facial nerve to the levator palati and azygos uvulas
muscles.
(c) The external palatine nerve, the smallest of the series, courses through the
external palatine canal between the maxilla and the tuberosity of the palate bone,
Fig. 160. — XERVES OF THE NOSE
AND THE SPHEXO-PALATIXE
GANGLION FROM THE INNER
SIDE. (From Sappey, after
Hirschfeld and Leveille. ) 3
1, network of the external
branches of the olfactory nerve :
the area of distribution is repre-
sented somewhat too large ; 2,
nasal nerve, giving its external
branch to the outer wall of the
nose ; the septal branch is cut
short ; 3, spheno-palatine ganglion ;
4. ramification of the large pala-
tine nerve ; 5, small, and 6, ex-
ternal palatine nerve : 7, inferior
nasal branch ; 8, superior nasal
branch ; 9, naso-palatine nerve
cut short ; 10, Vidian nerve ; 11.
great superficial petrosal nerve ;
12, great deep petrosal nerve ; 13,
the sympathetic nerves ascending
on the internal carotid artery.
to be distributed to the tonsil and the outer part of the soft palate. This nerve is
occasionally wanting.
INTERNAL BRANCHES. — These consist of the naso-palatine, and the upper nasal
branches, which ramify in the lining membrane of the nasal fossae and adjoining
sinuses.
The upper nasal are very small branches, and enter the back part of the nasal
fossa by the spheno-palatine foramen. Some are prolonged to the upper and pos-
terior part of the septum, and the remainder ramify in the membrane covering the
upper two spongy bones, and in that lining the posterior ethmoidal cells.
The naso-palatine nerve (fig. 144, 3), long and slender, leaves the inner side of
the ganglion with the preceding branches, and after crossing the roof of the nasal
fossa is directed downwards and forwards, in a slight groove on the vomer, towards
the anterior palatine canal. The nerves of opposite sides descend to the palate
through the median subdivisions of the canal, called the foramina of Scarpa, the
nerve of the right side usually behind that of the left (see Osteology, p. 53). In
the lower common foramen the two naso-palatine nerves are connected with each
other in a fine plexus ; and they end in several filaments, which are distributed to
THE SPHENO-PALATINE GANGLION. 243
the mucous membrane behind the incisor teeth, and communicate with the great
palatine nerve. In its course along the septum, small filaments are furnished from
the naso-palatine nerve to the pituitary membrane.
POSTERIOR BRANCHES. — The branches directed backwards from the spheno-
palatine ganglion are the Vidian and pharyngeal nerves.
The Vidian nerve, arising from the back part of the ganglion, which seems to be
prolonged into it, passes backwards through the Vidian canal to the foramen lacerum,
where it divides into thQ great superficial and the great deep petrosal nerves. While
in its canal, the Vidian nerve gives some small nasal branches, which supply the
membrane of the back part of the roof of the nose and septum, as well as the mem-
brane covering the end of the Eusbachian tube ; and it is joined by the sphenoidal
filament from the otic ganglion (p. 249).
The large superficial petrosal nerve (fig. 159,8), entering the cranium on the
outer side of the carotid artery and beneath the Gasserian ganglion, is directed
backwards in a groove on the petrous portion of the temporal bone to the hiatus
Fallopii, and is thus conducted to the aqueductus Fallopii, where it joins the
geniculate ganglion of the facial nerve.
The large deep petrdsal nerve (fig. 159, 9), shorter than the other, is of a reddish
colour and softer texture : it is directed backwards, and on the outer side of the
carotid artery ends in the filaments of the sympathetic surrounding that vessel.
In accordance with the view taken of the ganglia connected with the fifth nerve
(p. 237), the superficial and deep petrosal parts of the Vidian nerve may be regarded
as the motor and sympathetic roots respectively of the spheno-palatine ganglion, the
spheno-palatine nerves constituting its sensory root. The ganglion may also receive
fibres from the glosso-pharyngeal uerve, conveyed to it through the small and large
deep petrosal nerves (p. 260, and fig. 170) : this connection is sometimes described
as a second sensory root.
The pharyngeal nerve is small, and springs from the back of the ganglion, often
in common with the Vidian nerve. It enters the pterygo-palatine canal with an
artery, and is lost in the lining membrane of the pharynx behind the Eustachian
tube.
SUMMARY. — The superior maxillary nerve, with Meckel's ganglion, supplies the
integument of the cheek and the fore part of the temple, the lower eyelid, the side
of the nose, and the upper lip ; the upper teeth ; the lining membrane of the nose ;
the mucous membrane of the upper part of the pharynx, of the antrum of Highmore,
and of the posterior ethmoidal cells ; the soft palate, tonsil, and uvula, and the
glandular and mucous structures of the roof of the mouth.
III.— INFERIOR MAXILLARY NERVE.
The lower maxillary nerve (n. mandibularis), the third and largest division of the
fifth, is made up of two portions of unequal size, the larger being derived from the
Gasserian ganglion, and the smaller being the slender motor root of the fifth nerve.
These two parts leave the skull by the foramen ovale in the sphenoid bone, and
unite immediately after their exit. Three or four mm. below the base of the skull,
and under cover of wthe external pterygoid muscle, the nerve separates into two
primary divisions, one of which is higher in position and smaller than the other.
The small, anterior, or upper portion (n. masticatorius) receives the greater part
of the fibres of the motor root, and breaks up into temporal, masseteric, external
pterygoid, and buccal branches, of which the last alone is a sensory nerve. The
large, posterior, or lower portion is chiefly sensory, and divides into auriculo-
temporal, lingual, and inferior dental nerves ; it likewise supplies through the last-
244
THE CRANIAL NERVES.
mentioned branch the mylo-hyoid muscle and the anterior belly of the digastric.
The branch to the internal pterygoid muscle, with which also are connected those
proceeding through the otic ganglion to the tensors of the palate and tympanum, is
sometimes counted as a part of the larger division, but is more correctly regarded
as arising from the undivided trunk.
The short trunk of the nerve also gives off, as it issues from the foramen ovale,
a slender recurrent branch (n. spinosus), which passes backwards into the skull
through the foramen spinosum with the middle meningeal artery, and divides like
that vessel into two branches. The anterior of these sends its filaments into the
Fig. 161. — PLAN OF THE INFERIOR. MAXILLARY NERVE. (GK D. T.)
great wing of the sphenoid bone, while the posterior traverses the petro-squamous
fissure, and is distributed to the mucous lining of the mastoid cells (Luschka).
From the sheath which the inferior maxillary nerve receives from the dura mater in its
passage through the foramen ovale tubular prolongations are continued on the several offsets
of the trunk. Those containing the. masseteric and auriculo-temporal nerves are of consider-
able strength, and become blended with the capsule of the temporo-maxillary articulation in
front and on the inner side respectively, so that they are exposed to a certain degree of
traction during the movements of the lower jaw. (E. Fawcett, Journ. Anat., xxvii, 1893,
p. 179.)
Varieties. — One or more of the branches of the superior division of the nerve may arise
separately from the main trunk.
There is not unfrequently a small fibrous band {pti>ry<jo-splu'noiclal ligam-f-nt') extending
from the root of the external pterygoid plate to a spot on the great wing of the sphenoid a
little in front of the foramen spinosum, and lying in the angle between the two divisions of
the inferior maxillary nerve. In rare cases this band is replaced by bone, so that the small
part of the nerve passes out through a special foramen on the under side of the great wing of
the sphenoid, just external to the foramen ovale. (Hyrtl," " Ueb. d. Porus crotaphitico-
buccinatorius," Wiener Sitzungsber., 1862 ; A. v. Brunn, " Das Foramen pterygo- spinosum
THE INFERIOR MAXILLARY NERVE.
245
und d. Poms crotaphitico-buccinatorius," Anat. Anz., vi, 1891 ; U. G-rosse, " Ueb. d. Foramen
pterygo-spinosum u. d. Foramen crotaphitico-buccinatorium." Anat. Anz., viii, 1893 ; J. Yule
Mackay, in Report of Committee of Collective Investigation of Anat. Soc., Journ. Anat.,
xxviii, 1893, p. 07.)
The deep temporal nerves (figs. 152 and 1G2) are usually three in number,
but are subject to considerable variety in their arrangement. The anterior is given
off by the buccal nerve after it has perforated the external pterygoid, and ascends
Fig. 162. — VIEW OP THE BRANCHES OP THE INFERIOR MAXILLARY NERVE PROM THE OUTER SIDE.
(From Sappey, after Hirschfeld and Leveille. ) |
The zygoma and part of the ramus of the lower jaw have been removed ; the dental canal has been
opened up ; the lower part of the temporal muscle has been taken away, and the masseter muscle turned
down : 1, masseteric nerve ; 2, posterior deep temporal nerve ; 3, buccal nerve ; 4, branch of the facial ;
5, anterior deep temporal nerve ; 6, filaments given by the buccal to the external pterygoid muscle ; 7,
middle deep temporal nerve ; 8, auriculo-temporal nerve ; 9, its temporal branches ; 10, its branches
to the meatus and auricle ; 11, its union with the facial ; 12, lingual nerve ; 13, mylo-hyoid nerve ;
14, inferior dental nerve ; 15, its twigs to the teeth ; 16, mental branch ; 17, branch of the facial
uniting with the mental.
to supply the foremost part of the temporal muscle. The middle passes outwards
above the external pterygoid and turns upwards close to the bone to enter the deep
surface of the muscle. The posterior is generally conjoined with the masseteric
nerve, and, taking a course similar to the middle branch, ramifies in the hinder part
of the muscle. The number of these nerves is frequently reduced by the union of
the middle with either of the other branches.
The masseteric nerve likewise passes above the external pterygoid, and is
directed nearly horizontally outwards at the posterior border of the temporal
muscle, and through the sigmoid notch of the lower jaw, to the masseter, which it
246 THE CRANIAL NERVES.
enters at the hinder part of its deep surface. It also gives a filament or two to the
articulation of the jaw.
The external pterygoid nerve generally arises in common with the buccal
branch, and penetrates the inner surface of its muscle.
The buccal nerve, which differs from the foregoing branches in being entirely
a sensory nerve, is usually conjoined at its origin with the anterior deep temporal
and the external pterygoid nerves. It passes forwards between the heads of the
external pterygoid, and then descends in close contact with the inner side (occa-
sionally perforating some of the fibres) of the temporal muscle at its insertion, to
the surface of the buccinator muscle. Here it divides into several branches which
join in a plexus round the facial vein with the buccal branches of the facial nerve,
and are finally distributed to the skin and mucous membrane of the cheek, extend-
ing as far forwards as the angle of the mouth.
Varieties. — The buccal nerve is occasionally replaced by a branch of the superior
maxillary (p. 240). It has been seen by Turner arising from the inferior dental nerve in the
dental canal, and issuing by a small foramen in the alveolar border of the lower jaw, close to
the ramus. Gaillet describes it in one case as arising directly from the Gasserian ganglion,
and passing from the cranium through a special aperture between the round and oval
foramina.
The internal pterygoid nerve (fig. 164, 13) is closely connected at its origin
with the otic ganglion, and descends to the inner or deep surface of its muscle,
being separated from the lingual and inferior dental nerves by the pterygo-spinous
ligament when that band is present (see Osteology, p. 47). From this nerve mainly,
as it passes the otic ganglion, arise the small branches to the tensor palati and tensor
tympani muscles.
Auricula-temporal nerve. — The auriculo-temporal nerve takes its origin close
to the foramen ovale, usually by two roots which embrace the middle meningeal
artery. It is directed at first backwards, beneath the external pterygoid muscle, to
the inner side of the neck of the lower jaw ; then changing its course, it turns up-
wards between the ear and the temporo-maxillary articulation, under cover of the
upper end of the parotid gland ; and finally, emerging from beneath the latter, it
ascends over the base of the zygoma in company with the superficial temporal artery,
behind which it is placed, to terminate on the side of the head as the superficial
temporal nerve.
Branches. — (a) Communicating branches. — The roots of the auriculo-temporal
nerve are joined, close to their origin, by slender filaments from the otic ganglion ;
and from the trunk of the nerve, as it turns upwards, one or two considerable
branches are sent forwards round the commencement of the superficial temporal
artery to the temporo-facial division of the facial nerve.
(&) The articular branches are one or two fine twigs to the hinder part of the
temporo-maxillary articulation.
(c) The nerves of the external auditory meatus are two in number, upper and
lower, and enter the canal between the osseous and cartilaginous parts of its wall.
They supply the skin of the meatus, and the upper one sends a filament to the
membrana tympani.
(d) Parotid branches pass from the nerve, or from its connecting branches with
the facial, to the gland.
(e) The anterior auricular nerves are usually two in number, and supply the skin
of the tragus and of the upper and fore part of the pinna.
(/) The superficial temporal nerve divides into slender branches which supply
the skin over the greater part of the temporal region, the anterior ones forming
communications with the temporal branches of the facial nerve (fig. 171, 18).
THE INFERIOR DENTAL AND LINGUAL NERVES. 247
Inferior dental nerve. — The inferior dental or mandibular nerve (n. alveolaris
inferior} is the largest of the branches of the lower maxillary nerve. It descends
under cover of the external pterygoid muscle, behind and to the outer side of the
lingual nerve, and, passing between the ramus of the jaw and the internal lateral
ligament of the temporo-maxillary articulation, enters the inferior dental canal.
In company with the dental artery, it proceeds along this canal, and supplies
branches to the teeth. At the mental foramen it bifurcates ; one part, the incisor
branch, being continued onwards within the bone towards the middle line, while the
other, the much larger mental branch, escapes by the foramen to the face.
AVhen about to enter the foramen on the inner surface of the ramus of the jaw,
the inferior dental nerve gives off the slender mylo-hyoid branch.
Branches. — (a) The mylo-hyoid branch descends in the groove on the inner side
of the ramus of the lower jaw to the under surface of the mylo-hyoid muscle, to
which and to the anterior belly of the digastric it is distributed. The fibres of this
nerve may be traced back within the sheath of the inferior dental to the motor root
of the inferior maxillary nerve.
(b) The dental branches supply the molar and bicuspid teeth, together with the
adjoining part of the gum. They form by their communications a fine inferior
dental plexus, resembling that formed by the corresponding nerves in the upper jaw.
(c) The incisor branch continues the direction of the trunk of the nerve, and
supplies filaments to the canine and incisor teeth.
(d) The mental or labial nerve, emerging from the bone by the mental foramen,
divides beneath the depressor anguli oris into three parts, an inferior, which descends
to the integument of the chin, and two superior, which ascend to the skin and
mucous membrane of the lower lip. All three communicate freely with the
mandibular branch of the facial nerve.
Varieties. — The inferior dental and lingual nerves have been observed to form a single
trunk as far as the dental foramen. On the other hand, they are often separated by an
accessory ligament stretched between the external pterygoid plate and the spine of the
sphenoid, to the outer side of the pterygo-spinous ligament (see v. Brunn, op. cit. p. 244).
The inferior dental nerve is occasionally perforated by the internal maxillary artery. It
sometimes has one or two accessory roots from other divisions of the inferior maxillary. The
most common of these is one which arises from the G-asserian ganglion and remains separate
until after it enters the dental canal (lesser inferior dental nerve, Sapolini).
The mylo-hyoid nerve frequently (constantly, Sappey) gives off a small branch, which
pierces the mylo-hyoid muscle and joins the lingual nerve. Branches are also described as
passing from the mylo-hyoid nerve to the depressor anguli oris and platysma myoides muscles
(Herile), to the integument below the chin (Krause, Schwalbe, and others), and to the sub-
maxillary gland (Meckel, Henle, Curnow).
Lingual nerve. — The lingual branch descends under cover of the external
pterygoid muscle, lying to the inner side and in front of the dental nerve, and
generally united to that by a cord which may cross over the internal maxillary
artery. Near its origin, it is joined at an acute angle by the clwrda tympani, a
small branch which is given off by the facial nerve, and descends from the inner
end of the Glaserian fissure. It then passes between the internal pterygoid muscle
and the ramus of the lower jaw, and is inclined obliquely inwards to the side of the
tongue, over the upper constrictor of the pharynx (where this muscle is attached to
the jaw), and above the deep portion of the submaxillary gland. Lastly, the nerve
crosses below "VVharton's duct, and is continued along the side of the tongue to the
apex, lying immediately beneath the mucous membrane.
Branches. — (a) Communicating brandies. — In addition to the cord above men-
tioned passing from the inferior dental to the lingual nerve, and the connection with
the facial nerve through the chorda tympani, the lingual nerve gives off branches to
248
THE CRANIAL NERVES.
the submaxillary ganglion at the place where it is in contact with the submaxillary
gland, and a little farther forwards one or two filaments descend over the fore part
of the hyo-glossus muscle to join in loops with similar branches of the hypoglossal
nerve.
(b) Branches to the mucous membrane of the mouth are given from the nerve at
the side of the tongue, and supply also the gum. Some delicate filaments are like-
wise distributed to the sublingual gland.
(c) The lingual or terminal Ranches perforate the muscular structure of the
tongue, and divide into filaments which are directed upwards to the mucous mem-
brane of the anterior two-thirds of the organ, where they terminate mainly in the
conical and fungiform papillae. Microscopic ganglia are found in their ultimate
ramifications.
Submaxillary Ganglion.
The submaxillary or lingual ganglion (fig. 181, 7) is placed above the deep
portion of the submaxillary gland, and is connected by anterior and posterior fila-
ments with the lingual nerve, from which it thus appears to be suspended by a loop.
It is somewhat larger than the ciliary ganglion, and triangular or fusiform in
shape. The cells of the ganglion are multipolar. Its hinder part receives branches
Fig. 163. — SUBMAXILLARY AND SUBLINGUAL
GANGLIA OF AN INFANT. (Rauber.) ±
from nerves which may be regarded
as its roots, while from its fore and
lower parts proceed the branches for
distribution.
ROOTS OF THE GAXGLIOX. — The
pobterior connecting branch from
the lingual nerve, often broken up
into two or three filaments, conveys to the ganglion fibres from the chorda tympani
and the inferior maxillary nerve, and thus represents the motor and sensory roots of
the ganglion. The sympathetic root is formed by slender twigs from the plexus on
the facial artery.
BRANCHES. — Five or six small nerves descend from the ganglion to the sub-
maxillary gland, and others run forwards to the mucous membrane of the mouth
and Wharton's duct.' The anterior branch of communication with the lingual nerve
is probably composed of fibres which pass from the ganglion and are distributed with
the offsets of that nerve. There is also occasionally a small branch or two passing
to the hypoglossal nerve (Meckel, Bose).
A minute siiUingual ganglion is described by some anatomists on the filaments passing
from the lingual nerve to the sublingual gland (fig. 163 ; 181, 8) ; and small groups of nerve-
cells are also found in the adjoining part of the lingual trunk (Rauber;.
Otic Ganglion.
The otic ganglion, or ganglion of Arnold, of a reddish-grey colour, is oval in
shape, flattened from within out, and measures about 4 mm. in its longest (antero-
posterior) diameter. It is • situated immediately below the foramen ovale, on the
deep surface of the inferior maxillary nerve, covering, and not un frequently
surrounding, the origin of the internal pterygoid branch. Its inner surface is close
to the cartilaginous part of the Eustachian tube and the tensor palati muscle ;
THE OTIC GANGLION.
249
behind it is the middle meningeal artery. Its cells also belong to the multipolar
variety.
ROOTS. — The ganglion receives,. through its connection with the nerve to the
Fig. 164.— THE OTIC GANGLION AND ITS
CONNECTIONS KKOM THE INNER SIDE.
(From Sappey, after Arnold.) g
The temporal bone is divided so as to
show the inner surface of the membrana
tympani and the canal of the facial
nerve ; the foramen ovale is opened on
the inner side : 1, small root of the fifth
nerve, passing down on the inner side
of the Gasserian ganglion to unite with
the inferior maxillary division ; 2, inferior
dental nerve ; 3, mylo-hyoid branch,
seen also farther down emerging in front
of the internal pterygoid. muscle ; 4,
lingual ; 5, chorda tympani ; 6, facial
nerve in its canal ; 7, auriculo-temporal
nerve, enclosing in its loop of origin the
middle meningeal artery ; 8, otic gang-
lion ; 9, small superficial petrosal nerve ;
10, branch to the tensor tympani muscle ;
11, twig connecting the ganglion with the
auriculo-temporal nerve ; 12, twig to the
ganglion from the sympathetic on the
meningeal artery ; 13, nerve to the
internal pterygoid muscle ; 14, branch to the tensor palati muscle.
internal pterygoid, fibres from the inferior maxillary nerve, and these may be
regarded as constituting its motor and sensory roots (short root of Arnold) ; the
Fig. 165. — THE OTIC GANGLION, WITH ITS
ROOTS AND BRANCHES. (Rauber. ) |
• ;'!"
sympathetic root is a filament (or
two) passing forwards from the
plexus on the middle meningeal
artery. The ganglion is also
joined posteriorly by the small
superficial petrosal nerve (long
root, Arnold), which connects it
with, and probably conveys to it
fibres from, the facial and glosso-
pharyngeal nerves (p. 2GO) ; and
a slender sphenoidal filament
ascends from it to the Vidian
nerve.
BRANCHES. — (a) Two or more
pale branches pass backwards to
the roots of the auriculo-temporal
nerve, and convey secretory fibres
from the glosso-pharyngeai nerve
to the parotid gland.
(b) A communicating twig descends to the chorda tympani.
(c, d and e) Slender filaments pass from the ganglion to the nerves supplying the
internal pterygoid, tensor palati and tensor tympani muscles.
(/) A filament joins the buccal nerve (Rauber).
250 THE CRANIAL NERVES.
SUMMARY. — Cutaneous filaments of the inferior maxillary nerve ramify on the
side of the head and the external ear, in the external auditory canal, the lower lip,
and the lower part of the face ; sensory branches are supplied by it to the greater
part of the tongue ; and branches are furnished to the mucous membrane of the
mouth, the lower teeth and gums, the salivary glands, the articulation of the
lower jaw, the dura mater' and skull, and the mucous lining of the mastoid
cells.
This nerve supplies the muscles of mastication, viz., the masseter, temporal, and
two pterygoids ; also the mylo-hyoid, the anterior belly of the digastric, the tensor
palati and tensor tympani muscles.
VI.— ABDUCENT NERVE.
The sixth nerve (abducent nerve of the eyeball, external oculomotor) is distri-
buted solely to the external rectus muscle of the eye. Its fibres arise from a nucleus
placed close to the floor of the fourth ventricle immediately above the striae acusbicae,
beneath the eminentia teres. Leaving the inner side of the nucleus, they pass for-
wards and somewhat downwards through the lower part of the pons, and form a
Fig. 166. — PLAN OF THE ORIGIN AND COURSE WITHIX THE
PONS OF THE SIXTH AND SEVENTH NERVES.
The nerves and their nuclei are projected on to a sagittal
section of the pons near the median plane : VI, sixth nerve ;
N.VI, its nucleus ; VII, facial nerve ; Gr, its inner genu ;
N.VII, its nucleus ; S.O. , superior olive.
flattened band, which emerges in the depression
at the lower edge of that body immediately
external to the pyramid. One or two of the
innermost bundles frequently issue between the
fibres of the pyramid, or from the lower edge of
the pons.
The nerve speedily becomes rounded, and is directed upwards and forwards,
lying for a distance of about 15 mm. between the anterior surface of the pons and
the occipital bone. It then enters an aperture in the dura mater to the inner side
of and slightly below that of the fifth nerve (see Vol. II, fig. 182), and passing on
the outer side of the inferior petrosal sinus, it crosses over the apex of the petrous
bone, and beneath the petro-sphenoidal ligament (see Osteology, p. 43), to enter the
cavernous sinus. In that cavity the nerve is directed forwards along the outer side
of the internal carotid artery, and reaching the outer wall of the space anteriorly, it
then passes into the orbit through the sphenoidal fissure, and between the heads
of the external rectus, to which muscle it is distributed on its ocular surface
(fig. 149, 6 ; 156, 5). As the nerve enters the orbit, it is placed below the
other nerves passing through the sphenoidal fissure, but above the ophthalmic
veins.
While contained in the cavernous sinus, the sixth nerve is joined by filaments
from the carotid plexus of the sympathetic, and as it enters the orbit it receives a
small filament from the ophthalmic nerve.
The number of fibres in the sixth nerve has been estimated at 2,000 to 2.500 by Rosenthal,
3.600 by Tergast. They are mostly large, but there are some of medium size ; fine fibres are
scanty.
Variety. — Absence of the sixth nerve upon one side is recorded, its place being supplied
by a branch of the third nerve (Generali).
THE FACIAL NERVE.
251
VII.— FACIAL NERVE.
The nucleus of the seventh or facial nerve is situated in the formatio reticularis
of the lower part of the pons, about on the same level as the nucleus of the sixth
nerve, but farther from the floor of the fourth ventricle. The fibres leave the back
of the nucleus, and are directed at first dorso-mesially towards the lower end of the
Fig. 167. — PLAN OF THE ORIGINS OP THE SIXTH AND SEVENTH
CRANIAL NERVES. (Adapted from Schwalbe. )
The outline represents a transverse section of the lower
part of the pons, on to which the course of the facial nerve is
projected : VI, sixth nerve ; N.VI, its nucleus ; VII, facial
nerve ; VII. A, the ascending portion of its root, supposed to be
seen in optical section : N.VII, its nucleus ; SO, superior
olive ; A.V, ascending or bul bar root of fifth nerve ; VIII. M,
mesial root of auditory nerve.
abducent nucleus. Here they are collected into a
well-marked bundle, which ascends for a short
distance close beneath the floor of the ventricle,
then bends sharply downwards and outwards over
the upper end of the abducent nucleus (inner genu
of ihe facial nerve], and finally runs forwards and
outwards through the lower part of the pons, to
emerge at the upper end of the medulla oblongata in the depression between^ the
olivary and restiform bodies. Those fibres of the nerve, however, which supply
the frontalis, orbicularis palpebrarum and corrugator supercilii muscles (ocular
facial) probably arise from the oculomotor nucleus, and descend by the posterior
Fig. 168. — THE FACIAL NERVE IN ITS CANAL,
WITH ITS CONNECTING BRANCHES, &C.
(From Sappey, after Hirschfeld and Le-
veille.) |
The mastoid and a part of the petrous bone
have been divided nearly vertically, and the
canal of the facial nerve opened in its whole
extent from the internal meatus to the stylo-
mastoid foramen ; the Vidian canal has also been
opened from the outer side : 1, facial nerve in
the first horizontal part of its course ; 2, its
second part turning backwards ; 3, its vertical
portion ; 4, the nerve at its exit from the stylo-
ma'stoid foramen ; 5, geniculate ganglion ; 6,
large superficial petrosal nerve ; 7, spheno-
palatine ganglion ; 8, small superficial petrosal
nerve ; 9, chorda tympani ; 10, posterior auricu-
lar branch cut short ; 11, branch to the digastric
muscle ; 12, branch to the stylo-hyoid muscle ;
13, twig uniting with the glosso-pharyngeal nerve (14 and 15)
longitudinal bundle to join the issuing portion of the root ; and it is possible that
the fibres for the orbicularis oris are derived from the hypoglossal nucleus.
At its superficial origin the facial nerve rests against, and commonly adheres for
a short distance to, the lower border of the pons just where the latter is passing into
the middle peduncle of the cerebellum, and immediately below the fifth nerve. To
its outer side is the auditory nerve, and between the two is a slender fasciculus
(fig. 140, between vn and Vin) known as the pars or portio intermedia of
Wrisberg (n. intermedius), which joins the facial nerve in the auditory canal.
252
THE CRANIAL NERVES.
The fibres of this part have been traced centrally to the upper end of the glosso-
pharyngeal nucleus (Duval). It is frequently connected more or less closely at its
emergence with one or both of the nerves between which it lies, and in many cases
a few of its fibres pass distally into the auditory nerve.
The fibres of the facial nerve are mostly of medium size, but the portio intermedia
consists almost wholly of very small fibres. Indications of a degenerated ganglion are found
in the facial nerve close to its exit from the bulb (Thomsen, Gaskell).
From its superficial origin, the facial nerve is directed outwards in company with
the auditory nerve to the internal auditory meatus. Here the facial lies in a groove
along the upper and fore part of the auditory nerve, and the portio intermedia is
placed between the two. At the bottom of the meatus the facial nerve enters the
Fig. 169. — GENICULATE GANGLION OF THE FACIAL NERVE
AND ITS CONNECTIONS FKCM ABOVE. (Bidder.)
The dissection is made in the middle fossa of the
skull on the right side, part of the temporal bone being
removed so as to open the internal auditory meatus,
hiatus Fallopii, and a part of the canal of the facial
nerve, together with the cavity of the tympanum ; a,
auricle ; b, middle fossa of the skull with the meningeal
artery ramifying in it ; 1, facial and auditory nerves in
the internal auditory meatus ; 2, large superficial
petrosal nerve ; 3, small superficial petrosal nerve lying
over the tensor tympani muscle ; 4, external superficial
petrosal nerve joining sympathetic twig on the meningeal
artery ; 5, facial and chorda tympani ; 6, nerves enter-
ing the jugular foramen.
aqueduct of Fallopius, and follows the wind-
ings of that canal through the temporal bone
to the lower surface of the skull. It passes
at first horizontally outwards for a short
distance, between the cochlea and vestibule,
to the inner wall of the tympanum, where it bends sharply backwards above the
fenestra ovalis, and then arches downwards behind the pyramid and the tympanic
cavity to issue by the stylo-mastoid foramen. At the place where it turns backwards
(outer genu ; genicul^m n. facial-is) f the nerve presents on its fore part a reddish
enlargement which contains unipolar nerve-cells, and is named the geniculate
ganglion (ganglion geniculi). This ganglion is mainly connected with the portio
intermedia, and the fibres which proceed from its cells (both proximally and distally)
are probably afferent. Below the skull, the facial trunk is continued downwards
and tor-wards through the substance of the parotid gland ; and a little behind the
ramus of the lower jaw it terminates by dividing into two parts, temper o-facial and
cervico-facial, from which numerous branches spread over the side of the head, the
face, and the upper part of the neck, communicating freely with one another, and
thus forming a radiating plexus to which the name of pes anserinus or p!r.riis
parotideus has been given.
BRANCHES. — A. Arising from the facial nerve during its course through the
temporal bone.
Communicating filaments with the auditory nerve. — These are one or
two slender twigs passing between the geniculate ganglion and the upper division of
the eighth nerve at the bottom of the internal auditory meatus, and probably con-
veying to the facial nerve fibres derived from the portio intermedia.
The large superficial petrosal nerve is directed forwards from the geniculate
ganglion, and issues by the hiatus Fallopii on the upper surface of the petrous
THE FACIAL NERVE.
253
portion of the temporal bone. Inclining downwards beneath the Gasserian ganglion,
the nerve enters the foramen lacerum, and is continued across the outer side of the
internal carotid artery to the posterior opening of the Vidian canal, where it unites
with the large deep petrosal nerve (derived from the sympathetic on the carotid
artery) to form the Yidian nerve joining the back of the spheno -palatine ganglion
(p. 243).
In addition to conveying fibres from the facial nerve (or portio intermedia) to the spheno-
palatine ganglion, the large superficial petrosal nerve contains others, derived presumably from
the fifth nerve, which run distally in the facial trunk. (See R. Penzo, " Ueb. d. Ganglion
geniculi u. d. mit demselben zusammenhangenden Nerven," Anatom. Anzeiger, viii, 1893. 738 ?
M. v. Lenhossek, ''Das Ganglion geniculi N. facialis u. seine Verbindungen," in ;'Beitrage zur
Histologie des Nervenystems," &c., 1894.)
portio intermedia
.'" geniculate ganglion
oerficial petrosal
lall superficial petrosal
small deep petrosal
/'' large deep petrosal
Vidian
ttylo-hyoid
from great
auricular
sup. maxillary
spheno-pala-
tine ganglion,
otic ganglion
lingual
from auriculo-
temporal
tcmporo-facial
— Tervico-faciai
Fig. 170. — PLAIT OF THE FACIAL NERVE, WITH SOME OF ITS COMMUNICATIONS. (Or. D. T.)
cli.ty., chorda tympani; its middle part is removed; ty., tympanic branch of the glosso-pharyngeal ;
$y., sympathetic on the internal carotid artery ; car.ty., carotico-tympanic nerve, passing between the
tympanic nerve and the sympathetic in the carotid canal.
Communication with the small superficial petrosal nerve —A minute
branch connects the geniculate ganglion with the small superficial petrosal nerve
passing from the tympanic plexus to the otic ganglion (p. 2 GO).
The external superficial petrosal nerve (Bidder) unites the geniculate
ganglion with the sympathetic filaments on the middle meningeal artery. This
nerve is not always present (Rauber).
A branch to the stapedius muscle is given off by the facial nerve as ifc
descends behind the pyramid.
Chorda tympani. — This branch, which according to many observers is in large
VOL, III. PT. 2.
254 THE CRANIAL NERVES.
part at least continuous with the portio intermedia, leaves the facial nerve at the
lower end of the aqueduct of Fallopius, and is directed upwards and forwards
through a small canal (iter chorda posterius) which opens on the posterior wall of
the tympanum, close to the attachment of the tympanic membrane. It then arches
forwards, being invested by the mucous lining of the cavity, across the upper part
of the membrane and over the inner side of the handle of the malleus, above the
insertion of the tensor tympani muscle. Finally, leaving the cavity by an aperture
(Her chordce anterius] at the inner end of the Glaserian fissure, the nerve inclines
downwards on the mesial side of the internal lateral ligament of the jaw, and unites
at an acute angle with the lingual nerve, in which its fibres are continued to the
submaxillary ganglion and the tongue. Before joining the lingual nerve, the chorda
receives a communicating filament from the otic ganglion.
A communication with the auricular branch of the pneumo-gastric
nerve is generally present, in the form of a twig leaving the facial nerve close
above the stylo-mastoid foramen (see p. 265).
B. Arising from the facial nerve below the base of the skull.
The posterior auricular nerve arises close to the stylo-mastoid foramen, and
turns upwards between the ear and the mastoid process, where it divides into
auricular and occipital branches.
The auricular branch ascends behind the ear and is distributed to the retrahens
auriculam and the small muscles on the cranial surface of the pinna. A twig is
sometimes continued upwards to the attollens muscle.
The occipital branch is directed backwards close to the bone, and supplies the
posterior part of the occipito-frontalis muscle.
The posterior auricular nerve receives communications from the great auricular
and small occipital nerves of the cervical plexus, as well as from the auricular branch
of the pneumo-gastric, and certain filaments which may sometimes be followed
from its branches to the skin are probably composed of fibres derived from these
nerves.
The digastric branch arises close below the preceding nerve, and divides into
two or three filaments which enter the posterior belly of the digastric muscle ; one
of these sometimes passes through or above the digastric, and joins the glosso
pharyngeal nerve near the base of the skull.
The stylo-hyoid branch, long and slender, arises in common with thewiigastric
branch, and inclines forwards to enter the stylo-hyoid muscle on its posterior aspect.
TEMPORO-FACIAL DIVISION. — The temporo-facial, the larger of the two primary
divisions of the facial nerve, is directed forwards through the upper part of the
parotid gland, crossing over the external carotid artery and the temporo-maxillary
vein. It receives one or two considerable offsets from the auriculo-temporal nerve
(p. 246), and speedily divides into a number of branches which form, by their com-
munications with one another and with branches of the fifth nerve, a network over
the side of the face, extending as high as the temple and as low as the mouth. Its
ramifications are arranged in temporal, malar, and infraorbital sets.
The temporal branches ascend over the zygoma and supply the attrahens and
attollens auriculam muscles, the frontalis, the upper part of the orbicularis palpe-
brarum, and the corrugator supercilii. One or two filaments pass to the auricle, and
are distributed to the small muscles on its outer surface. These branches form
communications with the auriculo-temporal nerve, the temporal branch of the
superior maxillary, and the supraorbital and lachrymal branches of the ophthalmic
nerve.
The malar branches cross the malar bone to reach the outer side of the orbit
and supply the orbicular muscle. Some filaments are distributed to both the upper
BRANCHES OF FACIAL NERVE.
255
and lower eyelids : those in the upper lid join filaments from the lachrymal and
supraorbital nerves, and those in the lower lid are connected with filaments from
the superior maxillary nerve. Filaments from this part of the facial also communi-
cate with the malar branch of the upper maxillary nerve.
The infraorbital branches (superior bucco-labial), of larger size than the
Fig. 171.— SUPERFICIAL DISTRIBUTION OF THE FACIAL, TRIGEMINAL, AND OTHER NERVES OF THE
HEAD. (From Sappey, after Hirschfeld and Leveille.) |
«, Facial Nerve. — 1, trunk of the facial nerve after its exit from the stylo-ma.itoid foramen ;
posterior auricular branch ; 3, filament of the great auricular nerve uniting with the foregoing ; 4,
occipital branch ; 5, auricular branch ; 6, twig to the superior auricular muscle ; 7, nerve to the
digastric ; 8, that to the stylo-hyoid muscle ; 9, superior or temporo-facial division of the nerve ; 10,
11, temporal branches ; 12, malar ; 13, 14, infraorbital ; 15, inferior or cervico-facial division of the
nerve ; 16, mandibular, and above this the buccal branches ; 17, cervical branch.
6, Fifth Nerve. — 18, auriculo-temporal uniting with the facial, giving anterior auricular and parotid
branches, and ascending to the temporal region ; 19, 20, supraorbital ; 21, lachrymal ; 22, infra-
trochlear ; 23, malar twig of the temporo-malar ; 24, superficial branch of the nasal ; 25, infraorbital ;
26, buccal, uniting with branches of the facial ; 27, mental.
c, Cervical Nerves.— 28, great occipital ; 29, great auricular ; 30, 31, small occipital ; 32, superficial
cervical.
others, are almost horizontal in direction, and are distributed between the orbit
and mouth. They supply the buccinator and orbicularis oris muscles, the zygo -
matici, the elevators of the upper lip and angle of the mouth, and the muscles of
the nose. Beneath the elevator of the upper lip these nerves are united in a plexus
with the terminal branches of the superior maxillary nerve ; on the side of the nose
they communicate with the nasal, and at the inner angle of the orbit with the infra-
trochlear nerve. The lower branches of this set are connected with those of the
cervico-facial division.
R 2
256 THE CRANIAL NERVES.
CERVICO-FACIAL DIVISION. — This division of the facial nerve is directed obliquely
through the parotid gland towards the angle of the lower jaw, and gives branches to
the face below those of the preceding division, and to the upper part of the neck.
The branches are named buccal, mandibular, and cervical. In the gland, this divi-
sion of the facial nerve is joined by filaments of the great auricular nerve of the
cervical plexus, and offsets from it penetrate the substance of the gland.
The buccal branches (inferior bucco-labial) are directed across the masseter
muscle to the angle of the mouth ; supplying the buccinator and sphincter muscles,
they communicate with the temporo-facial division, and on the buccinator muscle
join with filaments of the buccal branch of the inferior maxillary nerve.
The mandibular branch (supramaxillary), sometimes double, runs forwards
beneath the depressor anguli or is, and, after communicating with the mental branch
of the inferior dental nerve, supplies the muscles of the lower lip. One superficial
branch is continued along the margin of the lower jaw to the chin.
The cervical branch (inframaxillary) perforates the deep cervical fascia and
divides into slender offsets, which form arches beneath the platysma as low as the
hyoid bone. They supply the platysma, and form one or two loops of communica-
tion with the upper division of the superficial cervical nerve.
SUMMARY. — The facial nerve is the principal motor nerve of the head, supplying
all the superficial, and some of the deep muscles. Its superficial offsets are distri-
buted to the muscles of the scalp, the muscles of the external ear, nose, mouth, and
eyelids (with the exception of the levator palpebrae superioris), and to the cutaneous
muscle of the neck (platysma). Of the deep muscles, it supplies the stapedius, stylo-
hyoid, and posterior belly of the digastric (according to some also the levator palati
and azygos uvulas muscles through the large superficial petrosal nerve). It also
furnishes, through the chorda tympani, secretory and vaso-dilator fibres for the
submaxillary and sublingual glands ; and the same nerve would appear to contain
the taste-fibres from the fore part of the tongue.
The facial nerve is freely connected with the three divisions of the fifth nerve ;
and it also has communications with the spheno-palatine, submaxillary and otic
ganglia, with the auditory, glosso-pharyngeal and pneumo-gastric nerves (through
the auricular branch of the latter), and with parts of the sympathetic and spinal
nerves.
Filaments which may be traced from the branches of the facial nerve to the skin
of the face and neck are doubtless derived from the communications with sensory
nerves, especially the auriculo-temporal, great auricular and superficial cervical.
VIII.— AUDITORY NERVE.
The eighth or auditory nerve (n. acusticus) makes its appearance on the outer side
of the facial nerve, and is closely adherent for a short distance to the lower border
of the middle peduncle of the cerebellum. It begins by two roots, the one of which,
the mesial or anterior (radix vestibularis], passes obliquely backwards on the inner
side of the restiform body to the dorsal auditory nucleus in the floor of the fourth
ventricle, while the other, the lateral or posterior (radix cochlearis), passes round the
outer side of the restiform body, where it is somewhat enlarged and contains
numerous nerve-cells (ganglion of the lateral root, ganglion radicis cochlearis), and
appears to be continued into the striae medullares.
The fibres of the auditory nerve, both central and peripheral, have their origin
in the cells of the several portions of the acoustic ganglion (vestibular ganglion,
spiral ganglion of the cochlea, and perhaps also the ganglion of the lateral root),
which is the equivalent of an intervertebral ganglion ; and the auditory nerve in
the meatus corresponds therefore to the posterior root of a spinal nerve. The
THE AUDITORY NERVE.
257
fibres of the mesial root pass mainly to the dorsal auditory nucleus, but some turn
inwards to the raphe of the bulb, and others may ascend to the cerebellum either
directly or with the intervention of a special nucleus (Bechterew). The fibres of
the lateral root end in large part in the accessory or ventral auditory nucleus, which
is placed between the two roots in front of the restiform body, and in the ganglion
Fig. 172. — PLAN OP THE ROOTS OP THE TO CEREBELLUM
AUDITORY NERVE. (G. D. T. )
The outline represents a section at the
junction of the bulb with the pons : VIII. M. ,
mesial root, VIII. L., lateral root of the
auditory nerve ; N.VIII. ACC. , accessory
nucleus ; G.L.R. , ganglion of lateral root ;
N.VIII.D., dorsal nucleus of the auditory
nerve; A.V, ascending or bulbar root of
the fifth nerve.
of the lateral root ; but a smaller
number are continued into the
medullary striae and trapezium.1
The two roots unite as they leave
the medulla oblongata, and the nerve
is directed outwards to the internal
auditory meatus, in company with
the facial nerve, which rests in a
groove along its upper and fore part,
and the auditory artery, which,
together with the portio intermedia
of the facial nerve, is placed between
the two trunks. In the meatus, the nerve divides into an upper smaller and a lower
larger part, the fibres of which are continuous with the mesial and lateral roots
respectively. The upper or vestilular portion (n. vestibuli), passing above the crista
falciformis, divides again into three branches, which are distributed to the utricle and
Fig. 173.— THE AUDITORY NERVE OF THE RIGHT SIDE IN THE IN-
TERNAL AUDITORY MEATUS, SEEN FROM ABOVE. (Schwalbe.) f
The meatus has been opened from above, and the facial nerve
removed together with the portio intermedia. The left side of the
figure corresponds to the anterior wall of the meatus. 1, superior
division ; 2, utricular nerve ; 3, common stem of the superior and
external ampullary nerves ; 4, posterior branch of the lower division ;
5, saccular nerve ; 6, pcst^rior ampullary nerve; 7, cochlear nerve;
8, gangliform enlargement of superior division ; 9, crista falciformis.
—I
the ampullae of the superior and external semicircular ^..-
canals. The tower portion gives off a small posterior branch
(middle branch of Schwalbe),which furnishes the nerves of
the saccule and posterior semicircular canal, and is then V-
continued as the cochlear nerve, the subdivisions of
which enter the apertures in the fossa below the fore part of the crista falci-
formis. On the vestibular division of the nerve, in the superior fossa at the
bottom of the auditory meatus, is a ganglionic enlargement (intumescmtia ganglio-
formis Scarpce, vestibular ganglion), which is continued below into the saccular
nerve ; and there are said to be two small swellings on the posterior ampullary nerve
in its canal (Corti). The corresponding ganglion of the cochlear nerve is contained
1 See H. Held, "Die centrale Gehbrleitung," Archiv f. Anat, 1893.
258
THE CRANIAL NERVES.
in the bony wall of the cochlea, and is called the spiral ganglion. The cells in these
ganglia are bipolar. (See the anatomy of the ear.)
The auditory nerve often receives some of the fibres of the portio intermedia,
and its upper division is connected at the bottom of the internal auditory meatus
with the geniculate ganglion of the facial nerve (see p. 252).
The branches of the auditory nerve, together with the apertures by which they leave the
nieatus, are shown in the following table : —
Utricular nerve . . . ^
Superior ampullary nerve
External ampullary nerve
Saccular nerve .
Posterior ampuliary nerve
Superior division or vesti-
bular nerve
Inferior division
Posterior
branch
> Area cribrosa superior.
Cochlear nerve
. Area cribrosa media.
. Foramen singulare.
( Tractus spiralis foraminu-
. < lentus and foramen cen-
( trale cochleae.
IX.— GLOSSO-PHARYNGEAL NERVE.
The ninth or glosso-pharyngeal nerve emerges from the upper part of the
medulla oblongata, in the groove between the olivary and restiform bodies, by five
Fig. 174. — PLAN OF THE ORIGIN OF THE GLOSSO-PHARYNGEAL
NERVE. (After Obersteiner. )
The outline represents a transverse section of the upper
end of the bulb : IX, roots of the glosso-pharyngeal nerve ;
F.S. , funiculus solitarius ; N.IX, glosso-pharyngeal nucleus ;
N.AM., nucleus ambiguus ; A.V, ascending or bulbar root of
the fifth nerve.
or six filaments arranged in a vertical line com-
mencing immediately below the facial nerve.
From this spot the rootlets of the nerve pass
backwards and inwards through the bulb to the
special nucleus beneath the inferior fovea in the
floor of the fourth ventricle ; some of the fibres
turn downwards into the funiculus solitarius, and
others, probably efferent, bend forwards to the upper prolongation of the accessory
vagal nucleus (nucleus ambiguus).
The glosso-pharyngeal is composed almost entirely of very fine fibres, but mixed with
these there are a few of medium size.
From its superficial origin, the glosso-pharyngeal nerve is directed outwards in
front of the flocculus to the middle compartment of the jugular foramen, through
which it passes in company with the pneumo-gastric and spinal accessory nerves,
but in a separate tube of dura mater. In the foramen, where it is placed external
to and somewhat in front of the other nerves, it is lodged in a groove, occasionally
a canal, in the lower border of the petrous portion of the temporal bone, and it pre-
sents, successively, two ganglionic enlargements — the jugular ganglion and the
petrosal ganglion, containing unipolar nerve-cells, like those of the spinal ganglia.
After leaving the skull, the glosso-pharyngeal nerve appears between the internal
carotid artery and the jugular vein, and is directed downwards over the carotid
artery and beneath the styloid process and the muscles connected with it, to the
hinder border of the stylo-pharyngeus ; then curving gradually forwards, it crosses
THE GLOSSO-PHARYNGEAL NERVE.
259
over the outer surface of the latter muscle, and passes beneath the hyo-glossus to
end in branches for the hinder part of the tongue (fig. 179, 16).
The jugular ganglion (g. superius) is situated at the upper part of the osseous
groove in which the nerve lies during its passage through the jugular foramen. It is
Fig. 175. — DIAGRAMMATIC SKETCH FROM BEHIND OF
THE ROOTS OF THE NINTH, TKNTH, AND ELEVENTH
NERVES, WITH THEIR GANGLIA AND COMMUNICA-
TIONS. (Bendz.)
A, part of the cerebellum above the fourth ven-
tricle ; B, medulla oblongata ; C, spinal cord; 1,
glosso-pharyngeal nerve ; 2, pneumo-gastric ; 3, 3,
0, spinal accessory ; 4, jugular ganglion of the
glosso-pharyngeal ; 5, petrosal ganglion ; 6, tym-
panic branch ; 7, ganglion of the root of the
pneumo-gastric ; 8, auricular branch ; 9, ganglion
of the trunk of the pneumo-gastric ; 10, branch
from the upper ganglion to the petrosal ganglion of
the glosso-pharyngeal ; 11, inner portion of the
spinal accessory ; 12, outer portion ; 13, pharyngeal
branch of the pneumo-gastric ; 14, 14, superior
laryngeal branch ; 15, twigs connected with the
sympathetic ; 16, internal part of the spinal acces-
sory prolonged with the pneumo-gastric.
from 1 to 2 mm. in length, and it includes
only the lower filaments of the nerve, the
upper ones forming a separate fasciculus
which passes over the ganglion, and joins the trunk of the nerve below it. This
ganglion is not always to be distinguished, and it is regarded by Henle and others as
Fig. 176. — THE TYMPANIC BRANCH OF THE GLOSSO-
PHARYNGEAL NERVE, AND ITS CONNECTIONS.
(Breschet.)
A, squamous part of the left temporal bone ; B,
petrous part ; C, inferior maxillary nerve ; D,
internal carotid artery ; a, tensor tympani muscle :
1, sympathetic plexus ; 2, otic ganglion ; 3, glosso-
pharyngeal nerve ; 4, tympanic nerve ; 5, 5, caro-
tico-tympanic twigs ; 6, twig to fenestra rotunda ;
7, twig to fenestra ovalis ; 8, junction with the
facial nerve ; 9, small superficial petrosal nerve ;
10, twig from the otic ganglion to the tensor tym-
pani muscle ; 11, facial nerve ; 12, chorda tympani ;
13, petrosal ganglion of the glosso-pharyngeal ; 14,
small deep petrosal nerve.
resulting, when present, from the more or
less complete separation of a part of the
petrosal ganglion.
The petrosal ganglion is contained
in a small depression at the lower end of
the groove in the petrous part of the
temporal bone, and measures from 4 to 5 mm. in length. From it arise the small
branches by which the glosso-pharyngeal is connected with other nerves at the base
of the skull ; these are the tympanic nerve, and the branches of communication
with the pneumo-gastric and sympathetic.
BRANCHES. — A. Connecting branches and tympanic branch.
One filament unites the petrosal ganglion of the glosso-pharyngeal nerve with
the upper cervical ganglion of the sympathetic ; a second passes to the auricular
360
THE CRANIAL NERVES.
branch of the pneumo-gastric ; and a third, which however is not constant, joins
the ganglion of the root of the pneumo-gastric nerve.
The glosso-pharyngeal nerve is also joined below the petrosal ganglion, in many
cases, by a communicating branch from the facial nerve (p. 254).
The tympanic branch (nerve of Jacobson) ascends from the petrosal ganglion,
in company with the tympanic branch of the ascending pharyngeal artery, through
a small canal, the orifice of which is seen on the ridge of bone between the jugular
fossa and the carotid foramen. Having gained the inner wall of the tympanum, the
nerve runs upwards and forwards in a groove on the surface of the promontory, and,
after giving (or receiving) several branches, leaves the cavity at its upper and fore
part, where it becomes the small superficial petrosal nerve. The latter traverses a
small canal, which crosses beneath the upper end of the canal of the tensor tympani
muscle, and emerges on the upper surface of the petrous portion of the temporal
bone, immediately external to the hiatus Fallopii. Then inclining downwards, the
Fig. 177. — THE TYMPANIC NERVE OF THE LEFT SIDE IN ITS CONNEC-
TION WITH THE FACIAL. (KraUSC.) f
1, facial nerve, proximal end ; 2, geniculate ganglion ; 3, facial
nerve, distal end ; 4, nerve to fenestra ovalis ; 5, ganglion-cells in
tympanic nerve ; 6, nerve of fenestra rotunda ; 7, tympanic nerve from
glosso-pharyngeal ; 8, small deep petrosal nerve ; 9, nerve to Eustachian
tube ; 10, filament to geuiculate ganglion ; 11, small superficial petro-
sal nerve ; 12, petrosal branch of middle meningeal artery ; 13, large
superficial petrosal nerve ; 14, Pacinian corpuscles in the dura mater.
nerve passes from the skull through the fissure between
the petrous and the great wing of the sphenoid, or
occasionally through a small aperture in the latter bone,
and terminates in the otic ganglion. As it lies in its
canal, the small superficial petrosal nerve is joined by a
filament of communication from the geniculate ganglion
of the facial nerve, or from the large superficial petrosal
nerve close to that ganglion.
The branches of the tympanic nerve are partly dis-
tributed to the mucous lining of the middle ear, and
partly form communications with other nerves, giving
rise to what is called the tympanic plexus. Of the former
set, the principal branches are — one directed forwards to the Eustachian tube, and
two backwards to the neighbourhood of the fenestra rotunda and fenestra ovalis,
and to the mastoid cells. The communicating branches are, in addition to the
small superficial petrosal nerve with its filament of union with the facial, one or two
twigs (carotico-tympanic) which pass downwards and forwards through the anterior
wall of the tympanum to the carotid canal and join the sympathetic on the carotid
artery, and the small deep petrosal nerve which runs forwards in a minute canal in
the substance of the processus cochleariformis and enters the foramen lacerum,
where it joins the carotid plexus of the sympathetic, or sometimes one of the large
petrosal nerves (figs. 165, 170).
The tympanic nerve while in its canal is surrounded by a small fusiform mass of soft
vascular tissue which has been called the tympanic gland (Krause) ; and as it lies in the
tympanum it contains numerous nerve-cells in irregular groups.
B. Branches distributed in the neck.
Pharyngeal branches. — The largest of these (carotid branch, pharyngeal
division of the glosso-pharyngeal nerve — Henle) descends along the internal carotid
THE GLOSSOPHARYNGEAL KERVE. 261
artery and unites with the pharyngeal branch of the vagus to form the pharyngeal
plexus (p. 2C5) ; this branch is sometimes divided into two or even three parts.
One or two smaller twigs pass inwards through the superior constrictor muscle, and
supply the mucous membrane of the upper part of the pharynx.
A muscular branch is furnished to the stylo-pharyngeus, and sends also fila-
ments through the muscle to the mucous membrane of the pharynx.
Tonsillitic branches. — Slender filaments pass from the glosso -pharyngeal
nerve, as it approaches the base of the tongue, to the tonsil, over which they form
a sort of plexus (circulus tonsillaris), to the soft palate, and to the pillars of the
fauces.
Lingual branches. — The glosso-pharyngeal nerve divides as it passes beneath
the hyo-glossus muscle into two parts. One turns to the upper surface of the tongue
and subdivides into many branches, which supply the circumvallate papillae and the
mucous membrane over the posterior third of the organ, the hindmost filaments
reaching the anterior surface of the epiglottis. The other is smaller, and is distri-
buted to the mucous membrane of the side of the tongue, extending to about the
middle of its length, where it forms a communication with the lingual nerve.
Beneath the mucous membrane the terminal filaments are united in a plexus which
contains microscopic ganglia.
Variety. — In one case a branch from the glosso-pharyngeal supplied the mylo-hyoid
muscle and the anterior belly of the digastric, the normal mylo-hyoid nerve being wanting
(Guy's Hosp. Reports, vol. xiv, p. 453).
SUMMARY. — The glosso-pharyngeal nerve distributes branches to the mucous
membrane of the tongue, pharynx and middle ear, as well as to the stylo-pharyngeus
muscle, and possibly also to the middle constrictor of the pharynx. By its small
superficial petrosal branch it furnishes secretory and vaso-dilator fibres (through
the otic ganglion and the auriculo-temporal nerve) to the parotid gland. It is
connected with the following nerves, viz., the inferior maxillary division of the fifth
(through the otic ganglion), the facial, the pneumo-gastric (its trunk and branches),
and the sympathetic.
X.— PNEUMO-GASTRIC NERVE.
The tenth or pneumo-gastric nerve (nervus vagus, par vagum) is much larger
than the glosso-pharyngeal, and has the longest course of all the cranial nerves,
extending through the neck and thorax to the upper part of the abdomen. It arises
from the medulla oblongata immediately in front of the restiform body, by twelve or
fifteen filaments beginning close below, and continuing the line of, the roots of the
glosso-pharyngeal nerve. Its central connections are similar to those of the glosso-
pharyngeal, the roots passing backwards towards the floor of the fourth ventricle,
where the greater part of the fibres enter the vagal nucleus beneath the ala cinerea,
while a smaller number pass into the funiculus solitarius, and a third set, believed to
be efferent, spring from the accessory vagal nucleus.
The fibres of the vagal roots are mostly small. In the trunk of the nerve there are
also numerous fibres of medium size, but these are probably derived in large part from the
bulbar portion of the spinal accessory nerve, which joins the vagus close below the skull.
Many of the larger fibres are continued into the pharyngeal and inferior laryngeal branches,
which are in great measure distributed to striped muscles.
The roots of the vagus form at first a flat band, which is directed outwards
below the flocculus to the middle compartment of the jugular foramen. Here the
nerve is contained in the same sheath of dura mater and arachnoid as the spinal
262
THE CRANIAL NERVES.
accessory nerve, and its filaments unite in a small gang-Home enlargement which is
known as the ganglion of the root of the pneumo-gastric. After its passage through
the foramen, it is joined by the accessory part of the spinal accessory nerve, and a
second ganglion is formed upon it, the ganglion of the trunk of the nerve. Several
communications are at the same time established with surrounding nerves.
The upper ganglion or ganglion of the root of the pneumo-gastric nerve
i ganglion jugular e), situated in the jugular foramen, is of a greyish colour, nearly
spherical, and about 4 mm. in diameter. It has filaments connecting it with other
nerves, viz., with the facial, the petrosal ganglion of the glosso-pharyngeal, the spinal
accessory, and the sympathetic.
The lower ganglion or ganglion of the trunk of the pneumo-gastric nerve
(cervical ganglion, ganglion nodoswri) is placed below the base of the skull, about
1 cm. beyond the upper ganglion. It is of a flattened cylindrical form and reddish
colour, and measures from 15 to 20 mm. in length and 4 in breadth. The
nX't
C.r.
Fig. 178. — SECTION OF THE BULB AT ABOUT THE
MIDDLE OP THE OLIVE. (Schwalbe. )
The full description of this figure will be found
at p. 54 of parti. The following numbers refer
to the vagus and hypoglossal nerves and their
connections : n X, n X', two parts of the vagal
nucleus; f.s., funiculus solitarius ; n. am,
nucleus ambiguus or accessory vagal nucleus ;
X, bundle of vagus emerging between the resti-
form body and the olive ; n. XII, hypoglossal
nucleus ; XII, bundle of hypoglossal nerve
emerging between the olive and the pyramid.
accessory part of the spinal accessory
nerve runs over the surface of the
ganglion, and is in part continued
directly into the pharyngeal and
superior laryngeal branches of the
vagus ; some of the accessory fibres,
however, become incorporated with the
main trunk, and enter the inferior
laryngeal and cardiac branches. The
lower ganglion communicates with the hypoglossal, the spinal, and the sympathetic
nerves.
The nerve-cells in both ganglia of the vagus belong to the unipolar or spinal
type.
The pneumo-gastric nerve descends in the neck between, and concealed by, the
internal jugular vein and the internal carotid artery, and afterwards similarly between
the vein and the common carotid artery, being enclosed along with them in the
sheath of the vessels. In their passage into and through the thorax, the nerves are
disposed differently on the right and left sides.
On the right side the nerve crosses over the first part of the right subclavian
artery at the root of the neck, and its recurrent laryngeal branch turns backwards
and upwards round that vessel. The nerve then enters the thorax behind the right
innominate vein, and descends on the side of the trachea to the back of the root of
the lung, where it spreads out in the posterior pulmonary plexus. It emerges from
this plexus in the form of two cords, which are directed to the oesophagus, and by
their union and subdivision on it form, with similar branches of the left nerve, the
oesophageal plexus. Xear the lower part of the thorax, the branches of the nerve,
which have thus interchanged fibres writh the nerve of the left side, are gathered
THE PNEUMO-GASTRIC NERVE.
263
again into a single trunk, which, descending through the diaphragm along the back
of the oesophagus, is finally divided between the posterior surface of the stomach and
the solar plexus.
On the left side the pneumo-gastric nerve, entering the thorax between the left
carotid and subclavian arteries and behind the left innominate vein, crosses over the
Fig. 179. — THE DISTRIBUTION AND CONNECTIONS OF THE PNEUMO-GASTRIC NERVE ON THE LEFT SIDE IN THE
NECK AND UPPER PART OF THE THORAX. (From Sappey, after Hirschfeld and Leveille".) £
1, pneumo-gastric nerve ; 2, ganglion of its trunk ; 3, accessory part of the spinal accessory ; 4, union
of the pneumo-gastric with the hypoglossal ; 5, pharyngeal branch of the pneumo-gastric ; 6, superior
laryngeal nerve ; 7, external laryngeal ; 8, communication of the external laryngeal nerve with the
superior cardiac branch of the sympathetic ; 9, inferior or recurrent laryngeal ; 10, superior, and 11,
inferior cervical cardiac branches ; 12, 13, posterior pulmonary plexus ; 11, lingual branch of the inferior
maxillary nerve ; 15, distal part of the hypoglossal nerve ; 16, glosso-pharyngeal nerve ; 17, spinal acces-
sory nerve, uniting by its inner branch with the pneumo-gastric, and by its outer passing into the sterno-
mastoid muscle ; 18, second cervical nerve ; 19, third ; 20, fourth; 21, origin of the phrenic nerve ;
22, 23, fifth, sixth, seventh, and eighth cervical nerves, forming with the first dorsal the brachial
plexus ; 24, superior cervical ganglion of the sympathetic ; 25, middle cervical ganglion ; 26, inferior
cervical ganglion united with the first dorsal ganglion ; 27, 28, 29, 30, second, third, fourth, and fifth
dorsal ganglia.
arch of the aorta, below which its recurrent laryngeal branch turns inwards and up-
wards. It then passes behind the root of the left lung, forming, like its fellow, a
264.
THE CRANIAL NERVES.
posterior pulmonary plexus, whence it descends along the oesophagus, and takes part
in the formation of the oesophageal plexus. Inferiorly, it forms a single trunk in
front of the oesophagus, and is spread out on the anterior surface of the stomach.
There are various circumstances in the distribution of the pneumo-gastric nerves which at
first sight appear anomalous, but which are explained by reference to the process of develop-
ment. The recurrent direction of the inferior laryngeal branches arises from the extreme
shortness or rather absence of the neck in the embryo at first, and from the primitive arterial
arches having- originally occupied a position at a higher level than the parts in which those
branches are ultimately distributed, and having dragged them down as it were in the descent
of the heart from the neck to the thorax. The recurrent direction may therefore be accepted
as evidence of the development of those nerves before the occurrence of that descent. The
passage of one recurrent laryngeal nerve round the subclavian artery, and of the other round
the aorta, arises from the originally symmetrical disposition in which the innominate and sub-
clavian arteries on the right side, a,nd the arch of the aorta on the left, are derived from cor-
responding arches. The supply of the back of the stomach by the right pneumo-gastric nerve,
and of the front by the left nerve, is connected with the originally symmetrical condition of the
alimentary canal, and the turning over of the stomach on its right side in its subsequent
growth.
BRANCHES. — Some of the branches of the pneumo-gastric serve to connect this
with other nerves, but the larger number are distributed to various parts of the cir-
Fig. 180. — DIAGRAM OF THE ROOTS AND COMMUNI-
CATING BRANCHES OP THE PNEUMO-GASTRIC AND
NEIGHBOURING NERVES. (From Sappey, after
Hirschfeld and Leveille.)
1, facial nerve ; 2, glosso-pharyngeal with the
petrosal ganglion ; 2', connection of the digastric
branch of the facial nerve with the glosso-pharyngeal
nerve ; 3, pneumo- gastric, with its two ganglia ;
4, spinal accessory ; 5, hypoglossal ; 6, superior
cervical ganglion of sympathetic ; 7, 7, loop of union
between the first two cervical nerves ; 8, carotid
branch of sympathetic ; 9, nerve of Jacobson (tym-
panic), given off from the petrosal ganglion ; 10,
its cavotico-tympanic filaments ; 11, twig to Eusta-
chian tube ; 12, twig to fenestva ovalis ; 13, twig to
fenestra rotunda ; 14, small supei'ficial petrosal
nerve ; 15, large superficial petrosal nerve ; 1(5, otic
ganglion ; 17, auricular branch of pneumo-gastric ;
18, connection of spinal accessory with pneumo-
gastric ; 19, union of hypoglossal with first cervical
nerve ; 20, union between the sterno-mastoid branch
of the spinal accessory and that of the second
cervical nerve ; 21, pharyngeal plexus ; 22, superior
laryngeal nerve ; 23, external laryngeal ; 24, middle
cervical ganglion of sympathetic.
culatory, respiratory and digestive systems.
The special connecting branches arise
from the two ganglia of the nerve. The
branches of distribution arise from the
nerve in the several stages of its course
as follows : — In the jugular foramen, one
small branch is given to the dura mater, and another to the ear ; in the neck,
branches are furnished successively to the pharynx, the larynx, and the heart ; in the
thorax, additional branches are supplied to the heart, as well as offsets to the peri-
cardium, lungs and oesophagus ; and in the abdomen, its terminal branches are dis-
tributed to the stomach, liver, and other organs.
A. Branches of communication.
The upper ganglion of the pneumo-gastric nerve receives a twig from the
superior cervical ganglion of the sympathetic ; one or two filaments pass between it
THE PNEUMO-GASTKIC NERVE. 265
and the spinal accessory nerve ; and there is sometimes a filament connecting it with
the petrosal ganglion of the glosso-pharyngeal.
The lower ganglion of the pneumo-gastric forms connections with the hypo-
glossal nerve, with the superior cervical ganglion of the sympathetic, and with the
loop between the first two cervical nerves.
B. Branches of distribution.
The recurrent or meningeal branch, arises from the upper ganglion of the
pneumo-gastric, and passes backwards through the jugular foramen to be distributed
to the dura mater in the posterior fossa of the base of the skull.
The auricular branch (nerve of Arnold) is given off from the ganglion of the
root, and, after receiving a filament from the petrosal ganglion of the glosso-pharyn-
geal nerve, runs backwards along the outer boundary of the jugular foramen to an
opening near the root of the styloid process. It then traverses the substance of the
temporal bone, crosses the acqueduct of Fallopiuson its inner side about 4 mm. from
the lower end, forming here a communication with the facial nerve, and finally
emerges between the external auditory meatus and the mastoid process, where it
divides into two parts, the one of which joins the posterior auricular nerve, while the
other is distributed to the skin of the back of the pinna, and the lower and back part
of the auditory canal.
Varieties. — In rare instances, absence of the auricular branch has been observed, or of the
communication with the facial nerve. The auricular branch occasionally passes entirely into
the facial trunk, and in that case its fibres are probably conveyed to the external ear through
the posterior auricular nerve.
The pharyngeal branch, often represented by two or even more offsets, and
composed mainly of fibres prolonged from the accessory part of the spinal
accessory nerve, leaves the upper part of the ganglion of the trunk of the
vagus. It courses inwards over the internal carotid artery, and divides into
branches which, conjointly with those derived from the glosso-pharyngeal and
the sympathetic, form the pharyngeal plexus. This plexus often contains one or
more small ganglia, and from it filaments pass to the muscles and mucous mem-
brane of the pharynx. The motor fibres are conveyed to the plexus by the pharyn-
geal branch of the vagus, but they are probably derived from the bulbar part of the
spinal accessory nerve (see p. 270) ; the levator palati and azygos uvulae muscles are
also supplied by a branch from this source.1 One slender branch (lingual branch of
the vagus — Luschka) descends from the pharyngeal plexus, receiving its fibres from
the pharyngeal branches of both the glosso-pharyngeal and pneumo-gastric nerves,
and joins the hypoglossal nerve as that turns round the occipital artery.
Superior laryngeal nerve. — This branch springs from the middle of the
ganglion of the trunk of the vagus, and inclines forwards on the inner side of the
internal carotid artery towards the larynx. It is joined by filaments from the upper
cervical ganglion of the sympathetic and from the pharyngeal plexus, and speedily
divides into two branches which are distinguished as external and internal laryngeal.
The external laryngeal branch, the smaller of the two, runs downwards and for-
wards beneath the depressor muscles of the hyoid bone to the crico-thyroid muscle
in which it ends. It receives a filament from the upper cervical ganglion of the
sympathetic, and it gives off twigs to the inferior constrictor muscle of the pharynx,
as well as generally a cardiac branch which joins the superior cardiac branch of the
sympathetic.
The internal laryngeal branch is continued to the interval between the hyoid
1 The middle constrictor of the pharynx would appear in the monkey to be partly supplied by glosso-
pharyngeal fibres (Beevor & Horsley, op. cit. on p. 270).
£66 THE CRANIAL NERVES.
bone and the thyroid cartilage, where it perforates the thyro-hyoid membrane with
the laryngeal branch of the superior thyroid artery, and breaks up into numerous
diverging branches which supply the mucous membrane of the greater part of the
larynx. Some of these ascend in the ary-epi glottic fold to the base of the tongue and
the epiglottis ; while others pass downwards to the false vocal cord, and also to the
part of the pharyngeal mucous membrane covering the back of the larynx. One
long branch descends beneath the ala of the thyroid cartilage, and joins at the lower
part of the larynx a similar offset ascending from the recurrent laryngeal nerve.
Varieties. — The superior laryngeal nerre may pass on the outer side of the internal carotid
artery. The external laryngeal branch often arises separately from the main trunk. Offsets
of the external laryngeal nerve have been described by different anatomists as passing to the
pharyngeal plexus, to the thyroid body, to the sterno-hyoid, sterno-thyroid, and thyro-hyoid
muscles, to the lateral crico-arytenoid muscle, and to the mucous membrane of the true vocal
cord and lower part of the larynx. The internal laryngeal IrancJi has been seen piercing the
thyroid cartilage.
A middle laryngeal nerve is described by S. Exner as a slender offset from the pharyn-
geal plexus (in the rabbit and dog directly from the pharyngeal branch of the vagus), which
is distributed to the crico-thyroid muscle, and to the mucous membrane of the lower part of the
larynx by means of twigs which perforate the crico-thyroid membrane. (i; Die Innervation
des Kehlkopfes." Wiener Sitzungsber., 1884.)
Inferior laryngeal nerve. — The inferior or recurrent laryngeal nerve of the
right side arises at the root of the neck, and turns backwards below the subclavian
Fig. 181. — VlEW OF THE DISTRIBUTION AND CONNECTIONS OF THE PNEUMO-GASTRIC AND SYMPATHETIC
NERVES ON THE RIGHT SIDE. (Hirschfekl and Leveille. )
a, lachrymal gland ; 6, sublingual gland ; c, submaxillary gland and facial artery ; d, thyroid body ;
c, trachea, below which is the right bronchus cut across ; /, resophagus ; g, stomach, divided near the
pylorus ; i. transverse colon ; r, the diaphragm.
A, heart ; B, aorta, drawn forwards to show the cardiac plexus ; C, innominate artery ; D, subcla-
vian ; E, inferior thyroid ; F, a detached part of the external carotid, upon which runs a nervous plexus ;
G, internal carotid emerging from its canal superiorly ; H, descending thoracic aorta ; K, intercostal
vein ; L, pulmonary artery ; M, superior vena cava ; 0, intercostal artery.
1, ciliary nerves ; 2, branch of third nerve to inferior oblique muscle ; 3, 3, 3, the three divisions of
the fifth nerve ; 4, ciliary ganglion ; 5, spheno-palatine ; 6, otic ; 7, submaxillary ; 8, sublingual ; 9, sixth
nerve ; 10, facial in its canal, uniting with the spheno-palatine and otic ganglia ; 11, glosso-pharyngeal ;
12, right pneumo-gastric ; 13, left pneumo-gastric spreading on the anterior surface of the stomach ; 14,
spinal accessory ; 15, hypoglossal ; 16, 16, nerves of cervical plexus ; 17, middle trunk of brachial plexus ;
18, intercostal nerve ; 19, lumbar nerve ; 21, superior cervical ganglion ; 22, tympanic nerve ; 23,
large superficial petrosal nerve ; 24, cavernous plexus ; 25, sympathetic root of ciliary ganglion ; 26, fila-
ment to pituitary body ; 27, union of sympathetic with upper cervical nerves ; 28, pneumo-gastric nerve ;
29, superior laryngeal nerve ; 30, pharyngeal plexus ; 31, cord of sympathetic ; 32, superior cardiac
nerve ; 33, middle cervical ganglion ; 34, twig connecting the ganglion with, 35, the recurrent ; 36,
middle cardiac nerve ; 37, cord of sympathetic ; 38, inferior cervical ganglion ; 39, the line from this
number crosses the nerves proceeding from the brachial plexus ; 40, sympathetic twigs surrounding the
axillary artery ; 41, branch of union with the first intercostal nerve ; the line from the letter e, pointing to
the trachea, crosses the superior, middle, and inferior cardiac nerves ; 42, cardiac plexus ; 43, 44, right
and left coronary plexuses ; 45, 46, thoracic portion of the sympathetic cord ; 47, great splanchnic
nerve ; 48, semilunar ganglion ; 49, lesser splanchnic ; 50, solar plexus ; 51, union with the pneumo-
gastric rerve ; 52, diaphragmatic plexus ; 53, gastric plexus ; 54, hepatic ; 55, splenic ; 56, superior
mesenteric ; 57, renal plexus ; 58, first lumbar sympathetic ganglion.
artery ; the nerve of the left side arises in the upper part of the thorax, and is re-
flected round the arch of the aorta immediately beyond the attachment of the liga-
mentum arteriosum. Each nerve ascends in the neck behind the common carotid
artery, crossing either in front of or behind the inferior thyroid artery (see Yol. II,
p. 424), and lying in the groove between the trachea and oesophagus, to the lower
border of the cricoid cartilage, where it enters the larynx beneath the inferior con-
strictor muscle. Under cover of the ala of the thyroid cartilage, the nerve divides
into branches which supply all the intrinsic muscles of the larynx, with the exception
of the crico-thyroid. It likewise gives a few offsets to the mucous membrane below
THE PNEUMO-GASTRIC NERVE.
267
Fig. 181
268 THE CRANIAL NERVES.
the rima glottidis, and a connecting filament which joins the long branch of the
upper laryngeal nerve beneath the hinder part of the thyroid cartilage : through this
communication sensory fibres are probably conveyed to the inferior laryngeal
nerve.1
The recurrent nei've also furnishes branches to the cardiac plexus, and twigs of
communication with the inferior cervical ganglion of the sympathetic, as it turns
round the large artery ; tracheal and oesophageal branches as it ascends in the neck ;
and lastly, offsets to the inferior constrictor of the pharynx as it passes beneath that
muscle.
Varieties. — In cases of dorsal origin of the right subclavian artery the inferior laryn-
geal nerve does not turn round that vessel, but passes inwards more directly to the larynx (see
Vol. II, p. 386). This nerve has been seen furnishing twigs to the crico-thyroid muscle.
Cardiac branches. — Branches to the heart are given off by the pneumo-gastric
nerve both in the neck and in the thorax.
The cervical cardiac branches arise at both the upper and the lower part of the
neck. The upper branches, one or t\vo, are small, and join the cardiac nerves of the
sympathetic. The lower, a single branch, arises as the pneumo-gastric nerve is about
to enter the chest. On. the right side this branch lies by the side of the innominate
artery, and joins one of the cardiac nerves destined for the deep cardiac plexus : it
gives some filaments to the coats of the aorta. The branch of the left side crosses
the arch of the aorta, and ends in the superficial cardiac plexus.
The thoracic cardiac branches of the right side leave the trunk of the pneumo-
gastric as this nerve lies by the side of the trachea, and some are also derived from
the first part of the recurrent branch ; they pass inwards on the air-tube, and end
in the deep cardiac plexus. The corresponding branches of the left side usually
come entirely from the recurrent laryngeal nerve.
The depressor nerve of the rabbit would appear to be represented in man in many cases by
a slender branch which arises from the vagus in common with or just below the superior laryn-
geal nerve, or perhaps has a double origin, and either descends to the cardiac plexus in con-
junction with the superior cardiac nerve of the sympathetic (seldom independently), or rejoins
the vagus trunk from 1 to 3 cm. below its origin. In cases where this branch is not to be re-
cognised the fibres are probably contained in the vagus trunk as far as the lower part of the
neck. It is thought by Finkelstein and Alpiger that depressor fibres run in the cardiac offset
of the external laryngeal nerve. (A. Kreidmann, i; Anatomische Untersuchungen liber den
Nervus depressor beim Menschen und Hunde," Arch. f. Anat.. 1878 ; A. Finkelstein. " Der
Nervus depressor beim Menschen. Kaninchen, Hunde," &c., Arch. f. Anat., 1880 ; A. Viti. '• Re-
cherches de morphologic sur le nerf depresseur chez 1'homme et chez les autres mammiferes,"
Arch. ital. de Biol., v, 1884 ; G. Bekesy. " Beitrage zur Anatomie der Herznerven," 1888 ;
M. Alpiger, '; Anatomische Studie liber das gegenseitige Verhalten der Vagus- und Sympathi-
cusaste im G-ebiete des Kehlkopfes," Langenbeck's Archiv, xl, 1890.)
Pulmonary branches. — Two sets of pulmonary branches are distributed from
the pneumo-gastric nerve to the lung ; and they reach the root of the lung, one on
its fore part, the other on its posterior aspect. The anterior pulmonary nerves, two
or three in number, are of small size. They join with filaments of the sympathetic
ramifying on the pulmonary artery, and with these nerves constitute the anterior
pulmonary plexus. Behind the root of the lung the pneumo-gastric nerve becomes
flattened, and gives several branches of much larger size than the anterior branches,
which, with filaments derived from the second, third, and fourth thoracic ganglia of
the sympathetic, form the posterior pulmonary plexus. Offsets from this plexus
1 Howell and Huber, " Physiology of the communicating branch between the superior and the
inferior laryngeal nerves," Journ. of Physiology, xii, 1891.
THE PNEUMO-GASTBIC NERVE. £69
extend along the ramifications of the air-tube through the substance of the lung,
where they are beset with minute ganglia.
The anterior and posterior pulmonary plexuses of the two sides communicate with
one another in an open network across the front and back respectively of the lower
end of the trachea, and through these networks fibres are conveyed from both
pneumo-gastric nerves into each lung.
CEsophageal branches. — The oesophagus within the thorax receives branches
from the pneumo-gastric nerves, both above and below the pulmonary branches.
The lower branches are the larger, and are derived from the oesophageal plexus,
formed by connecting cords between the nerves of the right and left sides, while
they lie in contact with the oesophagus.
Fericardial branches. — Either vagus may furnish a filament to the upper and
fore part of the pericardium. Other twigs pass regularly to the back of the pericar-
dium from the oesophageal plexus, and often from the posterior pulmonary plexuses
(Zuckerkandl).
Gastric branches. — The branches distributed to the stomach (gastric nerves}
are terminal branches of both pneumo-gastric nerves. The nerve of the left side,
on arriving in front of the oesophagus, opposite the cardiac orifice of the stomach,
divides into many branches : the largest of these extend over the fore part of the
stomach ; others lie along its small curvature, and unite with branches of the right
nerve and the gastric plexus of the sympathetic ; and some filaments are continued
between the layers of the small omentum to the hepatic plexus. The right pneumo-
gastric nerve descends on the back of the gullet to the stomach, and distributes
branches to the posterior surface of the organ : a large portion of this nerve passes
to the solar, splenic and left renal plexuses of the sympathetic.
SUMMARY. — The pneumo-gastric nerves convey motor fibres to the voluntary
muscles of the soft palate (with the exception of the tensor palati), pharynx and
larynx, these being in part at least derived originally from the spinal accessory, to
the unstriped muscle of the alimentary canal — oesophagus, stomach and intestine (with
the exception of the rectum), and of the air-passages — trachea, bronchi, and their
divisions in the lungs. Sensory fibres are furnished to the pharynx, oesophagus and
stomach, to the larynx, trachea and bronchial ramifications, as well as to the dura
mater, the external ear, and the pericardium. The vagi also supply nerves to the
heart, both efferent (inhibitory — also received from the spinal accessory) and
afferent (depressor), and possibly inhibitory dilator fibres to the vessels of the intes-
tine. Lastly, pneumo-gastric fibres pass, either directly or through the solar plexus
and its offsets, to the liver, pancreas, spleen, kidneys and suprarenal bodies. Each
pneumo-gastric nerve is connected with the following cranial nerves — the spinal
accessory, glosso-pharyngeal, facial, and hypoglossal ; also with some spinal nerves ;
and with the sympathetic in the neck, thorax and abdomen.
XI.— SPINAL ACCESSORY NERVE.
The eleventh or spinal accessory nerve (spinal nerve accessory to the vagus) con-
sists of two parts, the one of which (bulbar or accessory) joins the trunk of the
pneumo-gastric, while the other (spinal) is distributed to the sterno-mastoid and tra-
pezius muscles. Its fibres spring from a continuous column of cells extending from
the level of the lower third of the olive to the fifth cervical nerve, in the bulb placed
dorso-laterally to the hypoglossal nucleus, and in the spinal cord forming a part of the
ventro-lateral group of the anterior horn. From this nucleus the fibres are directed
at first dorsally for a short distance, and then turn outwards through the lateral
region of the bulb or cord to emerge in a series of filaments from the side of the
VOL. III. PT. 2. S
270 THE CRANIAL NERVES.
medulla oblongata below the pneumo-gastric nerve, and from the lateral column of
the spinal cord as low down as the fifth or sixth cervical nerve. The filaments
arising from the medulla oblongata form the small bulbar portion of the nerve. The
lowest spinal filaments are attached to the middle of the lateral column ; the highest
ones arise close to the posterior nerve-roots, with the upper one or two of which they
are frequently connected.
According to Holl the association of the dorsal root of the first cervical nerve with the
spinal accessory is only apparent, the two being merely bound together by connective tissue,
and not interchanging any fibres. Kazzander found, however, in many cases a common
origin of rootlets of the accessory and first cervical nerves, or a passage of filaments between
the two, and less frequently a communication with the second cervical nerve. In one case
also there was a small ganglion on the highest root of the bulbar portion of the spinal acces-
sory nerve. (M. Holl, "Ueb. d. Nerv. accessorius Willisii." Arch. f. Anat., 1878; J. Kaz-
zander. " Ueb. d. N. accessorius Willisii u. seine Beziehungen zu d. oberen Cervicalnerven," &c.r
Arch. f. Anat., 1891.)
In the bulbar portion of the eleventh nerve fine fibres predominate, although there are some
of medium and large size. The spinal portion of the nerve consists almost wholly of large
fibres, and fine fibres are absent.
The bulbar portion is directed outwards with the pneumo-gastric nerve : the
spinal part ascends between the ligamentum denticulatum and the posterior
Fig. 182. — SECTION OF' UPPER END OF SPINAL CORD, SHOWING ORIGIN
OF SPINAL ACCESSORY NERVE. (After Lockhart Clarke. )
/, anterior, fp, posterior median fissure ; p, end of decussation of
pyramids ; Cla, GIp, anterior and posterior roots of first cervical
nerve ; XI, root of spinal accessory nerve ; c, central canal.
roots of the cervical nerves, passes into the skull
through the foramen magnum, and immediately bends
outwards to enter the middle compartment of the
jugular foramen, where the nerve is contained in the
same sheath of dura mater as the vagus (see Vol. II, fig. 182). In the foramen,
the two parts of the nerve interchange fibres, and they are sometimes intimately
united so as to form a single trunk for a short distance. The accessory part is
also connected by one or two filaments with the ganglion of the root of the pneumo-
gastric.
Below the skull, the internal, bulbar, accessory or vagal portion passes
over the surface of the lower ganglion of the vagus, and sends its fibres into the
pharyngeal and superior laryngeal branches, and into the trunk of that nerve belcw
the ganglion in the manner already described.
The bulbar portion of the spinal accessory nerve contains the inhibitory fibres which pass
by the vagus to the heart, and, as has been shown for the monkey by the experiments of Beevor
and Horsley and of Rethi, the motor fibres of the levator palati and azygos uvulae, as well as,
in part at least, of the constrictor muscles of the pharynx. It is generally stated also that the
motor fibres of the laryngeal muscles are derived from the same source, but this view is not
confirmed by recent observations of Grossmann, Gra bower and Navratil. (Beevor and
Horsley, "Note on some of the Motor Functions of certain Cranial Nerves (V., VII., IX., X.,
XI., XII.), and of the three first Cervical Nerves, in the Monkey," Proc. Roy. Soc., 1888 ;
L. Rethi, "Die Nervenwurzeln der Rachen- und Gaumenmuskeln," and "Der periphere
Verlauf der motorischen Rachen- und Gaumennerven," Wiener Sitzungsber., 1892 and 1893 ;
M. Grossmann, " Ueber die Athembewegungen des Kehlkopfes, II. Die Wurzelfasern der
Kehlkopfn erven," Wiener Sitaungsber.. 1889 ; Grabower, "Das Wurzelgebiet der motorischen
Kehlkopfnerven," Centralbl. f. Physiol., iii, 1890; E. v. Navratil. '• Thierversuche iiber die
Kehlkopfinnervation und iibei den N. accessorius Willisii." Ungar. Arch. f. Med., ii, 1894.)
THE HYPOGLOSSAL NERVE 271
The external or spinal portion (fig. 183, 5), after issuing from the jugular
foramen, is directed backwards either across the front of or behind the internal
jugular vein, and perforates the sterno-mastoid muscle, supplying this with branches,
and joining amongst the fleshy fibres with the nerve furnished to the muscle from
the cervical plexus. Descending in the next place obliquely across the posterior
triangular space of the neck behind the sterno-mastoid, the nerve passes beneath the
trapezius muscle. Here it forms a kind of plexus with branches of the third and
fourth cervical nerves, and distributes filaments to the trapezius, which extend
nearly to the lower border of the muscle.
Varieties. — The lower limit of the origin of the spinal part of the nerve was found by
Holl to range from the third to the seventh cervical nerve, but in the greater number of
cases it corresponded to the fifth or sixth nerve. It was seen by Sommering opposite the first
dorsal nerve. The spinal part of the nerve in one case pierced the dura mater below the first
cervical nerve, and re-entered the spinal theca higher up (Holl). The external portion of the
spinal accessory nerve sometimes passes beneath the sterno-mastoid without piercing the
muscle. In one instance this nerve has been seen terminating- in the sterno-mastoid muscle,
the trapezius being- supplied entirely by the third and fourth cervical nerves (Cumow). In
rare cases it has been observed sending a branch to join the descending cervical nerve.
XII.— HYPOGLOSSAL NERVE.
The hypoglossal or twelfth cranial nerve arises from a nucleus placed ventro-
laterally to the central canal in the lower part of the medulla oblongata, and extend-
ing upwards beneath the trigonum hypoglossi of the fourth ventricle (fig. 178, n.
xn). Thence the fibres pass obliquely forwards and outwards, between the anterior
and lateral areas of the bulb, and form a series of from ten to fifteen fine roots which
emerge along the groove separating the pyramid from the olivary body. The fila-
ments are directed outwards above (or behind) the vertebral artery, and are usually
collected into two bundles which perforate the dura mater separately opposite the
anterior condylar foramen, and are united into a single trunk as they pass through
that opening.
As it leaves the anterior condylar foramen the nerve is very deeply placed on the
inner side of the deep cervical vessels and the pneumo-gastric nerve. Winding
round the lower ganglion of the last, to which it is closely bound by connective
tissue, the hypoglossal nerve descends, inclining at the same time gradually forwards
between the internal carotid artery and jugular vein, to the lower border of the
digastric muscle. At this level it curves forwards round the commencement of the
occipital artery, the sterno-mastoid branch of which turns downwards over the nerve,
and is thence directed forwards above the hyoid bone to the under part of the tongue.
In the latter part of its course, it passes beneath the tendon of the digastric, the
lower end of the stylo-hyoid, and the mylo-hyoid muscles ; it crosses the external
carotid and the lingual arteries ; and it rests upon the hyo-glossus muscle, being-
accompanied by the ranine vein of the tongue. At the anterior border of the hyo-
glossus it is connected with the lingual branch of the fifth nerve, and then penetrates
the fibres of the genio-glossus muscle, dividing into branches which are distributed
to the muscular substance of the tongue.
BRANCHES. — While passing through the anterior condylar foramen, the hypoglossal
nerve gives off one or two minute recurrent twigs which ramify in the dura mater
around the foramen magnum, and in the diploe of the occipital bone. They were
thought by Luschka to be formed by recurrent fibres derived from the lingual nerve,
but it is possible that they consist of fibres which ascend from the communication
with the first cervical nerve, or from the sympathetic (Rudinger). The branches
arising from the nerve in the neck are partly filaments of communication with other
S 2
THE CRANIAL SERVES.
nerves, but mainly offsets of distribution to muscles connected with the hyoid bone
and larynx, and to the muscles of the tongue.
A. Branches of communication.
- Close below the skull the hypoglossal nerve is united by a filament with the
superior cervical ganglion of the sympathetic, by one or more twigs with the loop
between the first and second cervical nerves, and with the ganglion of the trunk of the
vagus by fibres which pass between the two nerves where they are in close connection
with one another.
As the nerve turns round the occipital artery, it is joined by the small lingual
branch of the vagus (p. 265) ; and in the • submaxillary region, it is connected with
Fig. 183. — VIEW OP THE DISTRIBUTION OP THE SPINAL ACCESSORY AND HYPOGLOSSAL NERVES. (From
Sappey, after Hirschfeld and Leveille.) |
1, lingual nerve ; 2, pneumo-gastric nerve ; 3, superior laryngeal (represented too large) ; 4, external
laryngeal branch ; 5, spinal accessory ; 6, second cervical ; 7, third ; 8, fourth ; 9, origin of phrenic
nerve ; 10, nerve to subclavius ; 11, external anterior thoracic nerve : 12, hypoglossal nerve ; 13,
descending cervical nerve ; 14, communicating cervical nerve ; 15, 16, 18, 19, branches from the plexiform
union of these nerves to the sterno-hyoid, sterno-thyroid and omo-hyoid muscles ; 17, branch to the
anterior belly of the omo-hyoid muscle ; 20, branch, to the thyro-hyoid muscle; 21, communicating
twigs from the hypoglossal to the lingual nerve ; 22, terminal branches of the hypoglossal nerve.
the lingual branch of the fifth nerve by one or two slender loops over the fore part
of the hyo-glossus muscle.
B. Branches of distribution*
Vascular branches. — These are one or two slender twigs which leave '''the
hypoglossal nerve close below the skull and pass to the mesial aspect of the internal
THE HYPOGLOSSAL NERVE.
273
jugular vein, where they are often, joined by filaments from the superior cervical
ganglion of the sympathetic (Luschka).
The descending cervical nerve (r. descendens hypoylossi) consists mainly of
fibres which pass to the hypoglossal from the first and second cervical nerves in the
communication below the skull. Leaving the trunk as it turns round the occipital
artery, or a little higher up, the descending nerve runs downwards on the surface of
the common carotid artery, inclining gradually from the outer to the inner side, and
Fig. 184. — PLAN OF THK CONNECTIONS
OK THE HYPOGLOSSAL WITH THE
CERVfCAL NERVES, AND THE FOR-
MATION OF THE ANSA CERVICALIS.
( After Holl.)
being placed generally within,
but sometimes on the front of,
the carotid sheath. After
having given off a branch to
the anterior belly of the omo-
hyoid muscle, it joins about
the middle of the neck in a
loop (ansa cervicalis) with
the communicating cervical
branches from the second and
third cervical nerves. The
concavity of the loop is turned
upwards, and the connection
between the nerves is fre-
quently effected by two or
more interlacing filaments
which form a small plexus.
From this interlacement of the
nerves, offsets are continued
backwards to the posterior
belly of the omo-hyoid, and
downwards to the sterno-hyoid
and sterno-thyroid muscles.
Muscular branches. —
The branch to the thyro-hyoid
muscle is a separate twig also
composed of fibres proceeding
from the cervical nerves, and
leaving the hypoglossal trunk
as it approaches the hyoid bone.
As it lies beneath the mylo-hyoid, the nerve gives offsets to the styloglossus, hyo-
glossus and genio-hyoid muscles, and the terminal branches, penetrating the genio-
glossus, supply that muscle and' the intrinsic muscles of the tongue. According to
Holl the nerve to the genio-hyoid is of cervical origin.
The fibres proceeding from the first and second cervical nerves do not become mingled with
those of the hypoglossal trunk, but for the most part form a small cord which can be
separated from the latter by removing the common sheath, and followed down into the
descending1 cervical nerve. A minute funiculus runs proximally with the hypoglossal nerve,
and others pass on the deep aspect of the trunk to the recti antici. The descending cervical nerve
THE SPINAL NE LIVES.
also contains fibres which pass upwards from the communicating branches and run peripherally
to enter the nerves of the thyro-hyoid and genio-hyoid muscles. (See M. Holl. " Beobachtungen
iiber die Anastomosen des Nervus hypoglossus," Zeitschr. f. Anat. u. Entw., 1876.)
The spinal origin of the nerves of the infrahyoid muscles has also been demonstrated ex-
perimentally in the monkey by Beevor and Horsley, who found that stimulation of the hypo-
glossal roots within the skull produced no effect on these muscles, while they were called into
action by stimulating the first and second cervical nerves. The sterno-hyoid and sterno -thyroid
were supplied mainly from the first nerve, and the omo-hyoid from the second (<>/>. fit. on
p. 270).
The fibres of the hypoglossal nerve are of medium size, resembling in this respect those of
the facial nerve, and being smaller than those of most of the motor nerves passing to
voluntary muscles (Gaskell).
Varieties. — In one instance, recorded by Riidinger, the hypoglossal nerve was found
taking its superficial origin from the posterior surface of the medulla oblongata. The vertebral
artery is not unfrequently found passing forwards between, very rarely above, the roots of the
nerve. The right and left nerves are occasionally united by a cross branch or loop in the sub-
stance of the genio-hyoid, or between that and the genio-glossus muscle. In rare cases, the
twelfth nerve gives filaments to the mylo-hyoid, to the digastric, or to the stylo-hyoid muscle.
The descending cervical nerve sometimes appears to be derived either altogether from the
pneumo-gastric or from both the pneumo-gastric and hypoglossal nerves, but it can always be
shown by dissection that these varieties of origin are only apparent, resulting from the tem-
porary adhesion of the filaments of this branch to those of the pneumo-gastric. A filament is
occasionally continued from the descending cervical nerve into the thorax, where it joins the
phrenic or the cardiac nerves ; in the latter case it is probably composed of fibres from the
vagus or the sympathetic, which have joined the hypoglossal or the descending nerve. This
nerve has also been seen sending a branch to the sterno-mastoid muscle.
In some animals the twelfth nerve possesses a posterior root furnished with a ganglion, like
a spinal nerve. A similar condition has been met with in a few instances in man.
SUMMARY. — The hypoglossal nerve proper supplies only the muscles of the tongue,
with the exception of the palato-glossus and the pharyngeo-glossus. Fibres derived
from- the first three cervical nerves, which are associated with the hypoglossal for a
part of their course are distributed to the infrahyoid muscles and the genio-hyoid.
Others of uncertain origin pass to the skull and dura mater, and to the internal
jugular vein. The hypoglossal forms connections with the pneumo-gastric, lingual,
upper three cervical nerves, and sympathetic.
SPINAL NERVES.
The spinal nerves are characterised by their origin from the spinal cord, and
their direct transmission outwards from the spinal canal in the intervals between
the vertebrae. There are, in all, thirty-one pairs of these nerves, and, according to
the region in which they issue from the spinal canal, they are named cervical,
dorsal or thoracic, lumbar, sacral, and coccygeal.
By universal usage each pair of nerves in the dorsal, lumbar and sacral regions is
named in correspondence with the vertebra below which it emerges. Of the eight
pairs of nerves between the cranium and the first dorsal nerve, the uppermost is
placed above the atlas, and the second and following nerves below the seven cervical
vertebrae in succession. These eight pairs are usually reckoned as eight cervical
nerves, but the first is also distinguished by the name of suboccipital nerve. The
nerves of the thirty-first pair emerge from the lower end of the sacral canal, pass
below the first vertebra of the coccyx, and are named coccygeal.
Varieties. — The spinal nerves necessarily vary in number with any deviation from the
usual number of the segments of the vertebral column. Sometimes an additional coccygeal
nerve exists. Among seven cases which were examined by Schlemm two coccygeal nerves
were found on each side in one instance, and on one side in another case. According to
Rauber vestiges of these, and also of a third pair of coccygeal nerves, are normally present in
the bundles of medullated fibres contained in the filum terminale (see Part I, p. 6). On the
other hand, the coccygeal nerve often appears to be wanting, being united to the filum termi-
nale (Rauber, Kadyi).
ORIGIN OF THE SPINAL NERVES.
275
THE ROOTS OF THE SPINAL NERVES.
Each spinal nerve springs from the spinal cord by two roots which approach one
another as they quit the spinal canal, and join in the corresponding intervertebral
Fig. 185. — DIAGRAMMATIC OUTLINE OP THE ROOTS AND FIRST
PART OF THE SPINAL NERVES, TOGETHER WITH THE SYMPA-
THETIC TRUNK OF ONE SIDE. (Allen Thomson.) £
The view is taken from before. In the upper part of the
figure the pons Varolii and medulla oblongata are represented,
and from V to XII, the roots of the several cranial nerves from
the trifacial to the hypoglossal are indicated. On thf left side
0 1, is placed opposite the first cervical nerve ; and the numbers
2 to 8, following below indicate the corresponding cervical
nerves ; Br, brachial plexus ; D 1 , is placed opposite the inter-
costal part of the first dorsal nerve, and the numbers 2, to 12,
following mark the corresponding dorsal nerves ; L 1, the first
lumbar nerve, and the numbers 2, to 5, following the remaining
lumbar nevves ; Cr, the anterior crural, and o, the obturator
nerve ; S 1, the first sacral, and the following numbers 2, to 5,
the remaining sacral nerves ; 6, the coccygeal nerve ; Sc, great
sciatic nerve ; x x , the filum terminale of the cord.
On the left side of the figure the following letters indicate
parts of the sympathetic nerve, viz., a, the superior cervical
ganglion communicating with the upper cervical spinal nerves
and continued below into the sympathetic cord ; b, the middle
cervical ganglion ; c, d, the lower cervical ganglion united with
the first dorsal ; d', the eleventh dorsal ganglion ; from the
sixth to the ninth dorsal ganglion the origins of the great
splanchnic nerve are shown ; I, the highest lumbar ganglion ;
s s, the upper sacral ganglion. In the whole extent of the
sympathetic cord, the twigs of union with the spinal nerves are
shown.
foramen into a single cord ; and each cord so
formed separates immediately into two divisions,
one of which is destined for parts in front of the
spine, the other for parts behind it.
General arrangement. — The roots of the
nerves arise on each side of the spinal cord by two
nearly continuous series of filaments (flla radicu-
laria), the anterior of which emerge from the
antero-lateral column opposite the anterior cornu
of the grey matter, while the posterior are attached
in a narrower line along the postero-lateral sulcus
of the cord. The filaments composing a single
nerve-root vary in number from five to ten, and
converge from above downwards as they pass from
the cord to the dura mater, where each root enters
a special aperture.
The posterior roots of the nerves are dis-
tinguished from the anterior roots by their greater
size, which is due to their constituent filaments
being both more numerous and individually larger
than those of the anterior roots. Each posterior
root is farther marked by a ganglion (interverte-
bral or spinal), of a size proportionate to that of
the nerve on which it is formed. The cells of
these ganglia are unipolar, and give origin to the
afferent fibres of the spinal nerves, both central and
peripheral. •-•- s c
276
THE SPINAL NERVES.
The ganglia are in general placed in the intervertebral foramina, immediately
beyond the spots at which the roots perforate the dura mater lining the spinal canal.
The first and second cervical nerves, however, which do not pass through inter-
vertebral foramina, have their ganglia in the corresponding position as they lie over
the neural arches of the vertebras. The ganglia of the sacral nerves are contained
in the spinal canal, that of the last nerve being occasionally at some distance from
the point at which the nerve issues. The ganglion of the coccygeal nerve is placed
in the canal within the sac of the dura mater, and at a variable distance from the
origin of the nerve.
The filaments of the posterior root of the nerve are collected into two bundles as
they approach the ganglion, and the inner extremity of the oval-shaped ganglion is
usually bilobate, the lobes corresponding to the two bundles of filaments.
The anterior roots of the spinal nerves are smaller than the posterior, and are
devoid of ganglia, their fibres arising from the cells of the grey matter of the spinal
Fig. 186. — DIFFERENT VIEWS OF A POR-
TION OF THE SPINAL COUI) FROM THE
CERVICAL REGION WITH THE ROOTS
OF THE NERVES. Slightly enlarged.
(Allen Thomson. )
In A, the anterior surface of the speci-
men is shown, the anterior nerve-root of
the right side being divided ; in B, a
view of the right side is given ; in C, the
upper surface is shown ; in D, the nerve-
roots and ganglion are shown from below :
1, anterior median fissure ; 2, posterior
median furrow and septum ; 3, origin
of the anterior nerve- roots ; 4, postero-
lateral groove, into which the filaments
of the posterior root are seen to sink ; 5,
anterior root passing over the ganglion ;
5', in A, the anterior root divided ; 6,
posterior root, the fibres of which enter
6', the ganglion ; 7, the antei-ior, and
7', the posterior primary division of the
nerve, each of which is seen in A and D
to be derived in part from the anterior
and in part from the posterior root.
cord, and mainly from those of the anterior cornu. Their filaments also tend to be
collected into two bundles near the intervertebral foramen.
Both anterior and posterior roots of all the spinal nerves contain fibres of very various
sizes — large, medium (10 /ti to 5 /z), and fine, but the proportion in which the different groups
occur is not the same throughout. The anterior roots of the cervical, lumbar, and sacral
nerves consist mainly of large and medium-sized fibres, fine fibres being present only in small
number, generally not exceeding- one-sixth of the whole. Those of the dorsal nerves, however,
as well as the coccygeal. show a preponderance of fine fibres, which are about three times as
numerous as the larger ones. The finest fibres (2'6 p. and less) are abundant in the anterior
roots of the dorsal nerves, but rare in the other regions, except in the last two sacral and the
coccygeal nerves. In the posterior roots the small fibres are about equal in number to the
medium-sized and large fibres together ; and. fibres of the largest size (above 20 /u). which are
frequent in the anterior roots, are here scanty. (E. Siemerling, Neurol. Centralbl., 1886, and
'• Anatomische Untersuchungen iiber die menschlichen Ruckenniarkswurzeln," Berlin, 1887.)
Varieties. — The posterior root of the first cervical nerve is sometimes wanting (8 percent.,
Kazzander) ; or it may arise partly or wholly from, or in common with, the spinal accessory
nerve (see p. 270). A defect in the roots of the thoracic nerves is said to be very common by
Adamkiewicz. who found in sixteen spinal cords only three with the full number of thoracic
roots ; in three there was absence of both anterior and posterior roots of one nerve, in three
absence of a posterior root only, and in seven absence of one anterior root (Virchow's Archiv.
Ixxxviii, 1882). Communications between the root-filaments (especially the posterior) of
adjoining nerves are frequently met with. Small detached portions of the intervertebral
ROOTS OF THE SPIXAL NERVES.
277
ganglia (fjanfjlici nlx-rrantin of Hyrbl) are sometimes found on the posterior roots of the upper
cervical nerves. The ganglia of the lumbar and upper sacral nerves are often double, there
being- a distinct swelling on each of the bundles of the posterior root. The ganglion of the
suboccipital nerve may be situated within the dural sheath, or be wanting (9 per cent.r
Kazzander). but in such cases there are probably nerve-cells interspersed in the posterior root.
According to Rattone there are regularly scattered nerve-cells along the posterior roots of all
the spinal nerves (Internat. Monatschr. f. Anat. u. Hist., i, 1884).
Size. — The roots of the upper cervical nerves are smaller than those of the lower
nerves, the first being much the smallest, and the sixth the largest. The posterior
roots of these nerves, with the exception of the first in which the anterior root is
larger than the posterior, exceed the anterior in size more than in the other spinal
nerves, and they are likewise composed of filaments which are considerably larger
than those of the anterior roots.
The roots of the dorsal nerves, exception being made of the first, which resembles
the lowest cervical nerves and is associated with them in a part of its distribution,
are of small size, and vary but slightly, or not at all, from the second to the last.
The filaments of both roots are thinly strewed over the spinal cord, and are slender,
those of the posterior exceeding"] in thickness those of the anterior root in only a
small degree.
The roots of the lower lumbar, and of the upper sacral nerves, are the largest of
all the spinal nerves ; those of the lowest sacral and of the coccygeal nerve are, on
the other hand, the smallest. All these nerves are crowded together upon the
lower end of the cord. Of these nerves the anterior roots are the smaller, but the
disproportion between the anterior and posterior roots is not so great as in the
cervical nerves.
Length. — The place at which the roots of the upper cervical nerves are
connected with the spinal cord being nearly opposite the foramina by which they
respectively leave the canal, these roots are comparatively short. But the distance
between the two points referred to is gradually augmented from nerve to nerve
downwards, so that the place of origin of the lower cervical nerves is the depth of
at least one vertebra, and that of the lower dorsal nerves about the depth of three
vertebrse, above the foramina by which they respectively emerge from the canal.
Moreover, as the spinal cord extends no farther than the first lumbar vertebra, the
length of the roots of the lumbar, sacral and coccygeal nerves increases rapidly
from nerve to nerve, and in each case may be estimated by the distance of the
foramen of exit from the extremity of the cord. Owing to their length, and the
appearance they present in connection with the spinal cord, the aggregation of the
roots of the nerves last referred to has been named the cauda equina.
A. diagram showing the level at which the several roots arise from the cord in relation to
the spines of the vertebrae, as determined by R. W. Reid, is given on p. 4 of Part I. of this
volume. The absolute length of certain of the nerve-roots in a subject of 18 years of age.
whose spinal cord was 41 cm. long, is shown in the following table, taken from Testut : —
RIGHT SIDE. LEFT SIDE.
3rd cervical nerve .
18 mm. ... 17 inm.
5th ,. „
. 25 , . . . 25 „
1st dorsal nerve
. 33 ,
. 32 „
5th ,
. 47 .
. 47
10th ,
» •
. 68 ,
. 68
12th ,
»?
. Ill .
. 110
1st lun
ibar nerve .
. 114 ,
. 114
2nd
, „
. 138 .
. 134
3rd
»
. 151 .
. 151
4th
163 164
6th
> :> •
.181 180
1st sacral nerve
. 188 ., . . . 188
5th
. 280 ,. . . . 280
278 THE SPINAL NERVES.
Direction. — The first cervical nerve is directed horizontally outwards. The
roots of the lower cervical and dorsal nerves at first descend over the spinal cord,
held in contact with it by the arachnoid, till they arrive opposite the several
intervertebral foramina, where they are directed horizontally outwards. The nerves
of the cauda equina run in the direction of the spinal canal.
Division of the nerves. — The two roots of each of the spinal nerves unite
immediately beyond the ganglion, and the trunk thus formed separates, as already
mentioned, into two divisions, an anterior or ventral and a posterior or dorsal,
which are called primary branches or divisions, and each of which contains fibres
proceeding from both the anterior and posterior roots.
Fig. 187. — PLAN OP THE MODE OP BRANCHING OF A SPINAL NERVE.
Before dividing in the manner above described each spinal nerve gives off a small
recurrent or meningeal branch, which is joined by a filament from the com-
municating cord between the anterior division of the nerve and the sympathetic,
and then runs inwards through the intervertebral foramen to the spinal canal,
where it is distributed to the vertebrae and ligaments, to the blood-vessels of the
canal, and to the dura mater (Luschka, Riidinger).
POSTERIOR PRIMARY DIVISIONS OP THE SPINAL NERVES.
The posterior divisions of the spinal nerves are, with few exceptions, smaller
than those given to the fore part of the body. Springing from the trunk which
results from the union of the roots of the nerve in the intervertebral foramen, or
frequently by separate fasciculi from the two roots, each turns backwards at once,
and soon divides into two parts, distinguished as external and internal, distributed
to the muscles and the integument behind the spine. The first cervical, the fourth
and fifth sacral, and the coccygeal are the only nerves the posterior divisions of
which do not separate into external and internal branches.
SUBOCCIPITAL NERVE. — The posterior division of the first cervical or suboccipital
nerve, slightly larger than the anterior, emerges over the arch of the atlas, between
this and the vertebral artery, and enters the space bounded by the larger rectus
and the two oblique muscles, where it divides into branches for the surrounding
muscles.
(a) One branch descends to the inferior oblique, and gives a filament, through
or over the fibres of that muscle, to join the second cervical nerve.
(£) Another ascends over the rectus posticus major muscle, supplying it and the
smaller rectus.
(c) A third enters the superior oblique muscle.
(d) A fourth sinks into the complexus, where that muscle covers the nerve and
its branches.
Variety. — A cutaneous branch is occasionally given to the back of the head : it accompanies
the occipital artery, and is connected beneath the integument with the great and small occipital
nerves.
POSTERIOR PRIMARY DIVISIONS.
279
Pig. 188. — SUPERFICIAL AND DEEP DISTRIBUTION OP THE POSTERIOR PRIMARY DIVISIONS OP THE SPINAL
NERVES. (After Hirschfeld and Leveille. ) i
On the left side the cutaneous branches are shown lying upon the superficial muscles; on the
right side, these muscles having been removed, the splenius and complexus have been divided in the
neck, and the erector spinse separated and partially removed in the back, so as to expose the deep
portions of the nerves.
a, a, small occipital nerve from the cervical plexus ; 1, muscular branches of the first cervical nerve
and union by a loop with the second ; 2, placed on the rectus capitis posticus major, marks the great
occipital nerve passing round the inferior oblique muscle and piercing the complexus ; the external
branch is seen to the outside ; 2', cranial distribution of the great occipital ; 3, external branch of the
posterior primary division of the third nerve ; 3', its internal branch, or third occipital nerve ; 4', 5',
6', 7', 8', cutaneous offsets from the internal branches of the cervical nerves on the left side ; the external
branches of these nerves proceeding to muscles are displayed on the right side ; d 1 to d 6, and thence
280 THE SPINAL NERVES.
to d 12, external muscular branches of the posterior primary divisions of the twelve dorsal nerves on the
right side ; d 1', to d 6', the internal cutaneous branches of the six upper dorsal nerves on the left side ;
d 7' to d-12', cutaneous branches of the six lower dorsal nerves from the external branches; I, I,
external branches of the posterior primary divisions of several lumbar nerves on the right side piercing
the muscles, the lower descending over the gluteal region ; I', I', the same more superficially on the left
side (the cutaneous branches of the lower dorsal and upper lumbar nerves are represented as piercing
the latissimus too high) : s, s, on the right side, the issue and union by loops of the posterior primary
divisions of four sacral nerves ; s', s', on the left side, cutaneous filaments from the internal branches
of the lower lumbar and upper sacral nerves.
CERVICAL NERVES (excepting the siiboccipital}. — The external branches give
only muscular offsets?, and are distributed to the splenius and the slender muscles
prolonged to the neck from the erector spinse, viz., the cervicalis ascendens, and
the transversalis cervicis with the trachelo-mastoid. That of the second nerve is
the largest of the series of external branches of the cervical nerves, and is often
united to the corresponding branch of the third.
The internal branches, larger than the external, are differently disposed at the
upper and the lower parts of the neck. That of the second cervical nerve is named,
from its size and destination, the great occipital, and requires separate notice. The
rest are directed inwards to the spinous processes of the vertebrae. Those derived
from the third, fourth, and fifth nerves pass over the semispinalis and beneath the
complexus, giving offsets to those muscles and to the multifidus, and, having
reached the spines of the vertebrse, pierce the splenius and trapezius, to be dis-
tributed in the integument over the latter muscle. From the cutaneous branch of
the third nerve an offset passes upwards to the integument on the lower part of
the occiput, lying at the inner side of the great occipital nerve ; this is sometimes
called the third occipital nerve.
Between the inner branches of the first three or four cervical nerves, beneath the corn-
plexus, there are frequently communicating loops ; this communication has been designated
by Cruveilhier the posterior cervical plexus.
The internal branches from the lowest three cervical nerves are placed beneath
the semispinalis muscle, and end in the muscular structure, without furnishing any
offset to the skin. These three nerves are the smallest of the series.
The great occipital nerve is directed upwards across the inferior oblique muscle,
and is transmitted to the surface through the complexus and trapezius muscles,
giving twigs to the complexus. Ascending with the occipital artery, it divides into
branches which radiate over the back of the head, the most external communicating
with the small occipital nerve.
Varieties. — The great occipital nerve occasionally sends a branch to the auricle, or replaces,
to a greater or less extent, the small occipital nerve (p. 286). The external division of the
second nerve is said to give off a cutaneous branch sometimes, or a twig to the superior
oblique. Either the sixth or the eighth cervical nerve may furnish a cutaneous branch. On
the other hand, the cutaneous branch of the fifth is sometimes wanting.
DORSAL NERVES. — The external branches increase in size from above down-
wards. They are directed through or beneath the longissimus dorsi to the space
between that muscle and the ilio-costalis or accessorius, and supply the several
divisions of the erector spinae. The lower five or six nerves give cutaneous twigs,
which are transmitted to the integument in a line with the angles of the ribs.
The internal branches of the upper six or seven dorsal nerves pass backwards
in the interval between the multifidus spinse and the semispinalis muscle ; they
supply the transverso-spinales muscles, and become cutaneous by the side of the
spinous processes of the vertebras. The cutaneous branch of the second nerve, and
sometimes others, extend outwards over the scapula. The internal branches of the
POSTERIOR PRIMARY DIVISIONS. 281
lower dorsal nerves are placed between the multifidus spinae and longissimus dorsi,
and end in the multifidus without giving branches to the integument. Where
cutaneous nerves are supplied by the internal branches, there are generally none
from the external branches of the same nerves, and vice versa.
The cutaneous offsets of the dorsal nerves run obliquely downwards in their passage
between and through the muscles, so that they become superficial and are distributed to the
skin at a level below that of the vertebra to which they correspond (see fig-. 189). This
descent is but slight in the case of the upper branches, which are derived from the internal
divisions of the nerves, and which in their subcutaneous course are directed nearly horizontally
outwards, but it becomes progressively greater in the lower branches, proceeding- from the
outer divisions, and the offset of the twelfth dorsal only makes its appearance a little distance
above the iliac crest. There is considerable variety in the size and in the extent of distribution
of the several nerves, which often differ on the two sides of the body ; and twigs from one or
two of the lowest dorsal nerves frequently pass over the iliac crest to the skin of the buttock.
(See Wardrop Griffith and Oliver, "On the Distribution of the Cutaneous Nerves of the Trunk,"
Proc. Anatom. Soc., 1890, in Journ. Anat., xxiv.)
Varieties. — The cutaneous offset of the first dorsal nerve is sometimes absent. There are
not unfrequently cutaneous branches from both divisions of the middle (sixth, seventh, and
eighth) dorsal nerves.
LUMBAR NERVES. — The external branches enter the erector spinae, and give
branches to that muscle. From the upper three, cutaneous nerves are supplied ;
and from the last, a filament descends to the corresponding branch of the first
sacral nerve. The cutaneous nerves given from the external branches of the first
three lumbar nerves (nn. clunium superiores) pierce the fleshy part of the ilio-
costalis and the aponeurosis of the latissimus dorsi : they cross the iliac crest near
the edge of the erector spinse, and terminate in the integument of the gluteal region.
One or more of the filaments may be traced as far as the great trochanter of the
femur.
The internal branches wind backwards in grooves close below the mamillary
processes of the vertebrae, and sink into the multifidus spinse muscle.
SACRAL NERVES. — The posterior divisions of these nerves, except the last, issue
from the sacrum, through its posterior foramina. The first three are' covered at
their exit from the bone by the multifidus spinae muscle, and bifurcate like the
posterior trunks of the other spinal nerves ; but the remaining two, which continue
below that muscle, are not thus divided.
The internal branches of the first three sacral nerves are small, and are lost in
the multifidus spinae muscle.
The external branches of the same nerves are united with one another, and
with the last lumbar and fourth sacral nerves, so as to form a series of anastomotic
loops on the upper part of the sacrum. From these, branches are then directed
outwards to the cutaneous or posterior surface of the great sacro-sciatic ligament,
where, covered by the gluteus maximus muscle, they form a second series of loops,
and end as cutaneous nerves (nn. clunium medii). The latter pierce the great
gluteus muscle in a line drawn from the posterior superior iliac spine to the tip of
the coccyx. They are commonly two in number — one is near the lower part of the
sacrum, the other by the side of the coccyx. All are directed outwards over the
great gluteal muscle.
In six dissections by Ellis the above arrangement was found to be the most frequent. The
variations to which it is liable are these : — the first nerve may not take part in the formation
of the second series of loops, and the fourth may be associated with them. From the first
three sacral nerves filaments are given to the sacro-iliac articulation (Luschka, Rudinger).
Small cutaneous twigs from the internal branches of the lower lumbar and upper sacral nerves
are described by many anatomists (fig. 188, .s-V).
The posterior divisions of the last two sacral nerves are smaller than those above
them, and are not divided into external and internal branches. They are connected
282
THE SPINAL NERVES
Fig. 189.
ANTERIOR PRIMARY DIVISIONS OF CERVICAL NERVES. 283
with each other by a loop on the back of the sacrum, and the lowest is joined in a
similar manner with the coccygeal nerve ; one or two filaments from these sacral
nerves are distributed in the neighbourhood of the coccyx.
COCCYGEAL NERVE. — The posterior division of the coccygeal nerve is very small,
and separates from the anterior primary portion of the nerve in the sacral canal.
It is joined by a communicating filament from the last sacral nerve, and ends in
the integument over the posterior surface of the coccyx.
ANTERIOR PRIMARY DIVISIONS OF THE SPINAL NERVES.
The anterior primary divisions of the spinal nerves are distributed to the parts
of the body situated in front of the vertebral column, including the limbs. They
are, for the most part, considerably larger than the posterior divisions, and each
is connected by one or two slender filaments with the sympathetic. Those of the
cervical, lumbar, and sacral nerves form plexuses of various forms ; but those of
the dorsal nerves remain for the most part separate from one another.
CERVICAL NEKVES.
The anterior divisions of the upper four cervical nerves form the cervical plexus.
The first emerges between the rectus lateralis and rectus anticus minor muscles ;
and the others, having passed behind the vertebral artery and between the two
intertransverse muscles, appear at the side of the neck between the scalenus medius
and rectus anticus major muscles. They are each united by a communicating filament
Fig. 189.— CUTANEOUS DISTRIBUTION OF THE POSTERIOR PRIMARY BRANCHES OF THE SPINAL
NERVES. (GK D. T.)
On the right side the nerves are shown lying on the superficial muscles ; on the left side the limit of
the skin-area supplied by these nerves is indicated by the dotted line. 7 c, seventh cervical spine ; 6 c?,
sixth dorsal ; 12 d, twelfth dorsal ; 5 I, fifth lumbar.
The nerves are indicated as follows : — C II, great occipital, from second cervical ; III to V, third to
fifth cervical ; D I, first dorsal ; II to XII, second to twelfth dorsal ; three cutaneous branches are given
by the sixth dorsal, two from the internal, and one from the external division ; L, lumbar ; S, upper
sacral ; C, lower sacral and coccygeal ; A S C, anterior divisions of the last sacral and coccygeal ; P C,
perforating cutaneous ; S S, small sciatic
to the first cervical ganglion of the sympathetic nerve, or to the cord connecting that
ganglion with the second.
The anterior divisions of the lower four cervical nerves, larger than the upper
four, appear between the anterior and middle scaleni muscles, and, together with
the larger part of the first dorsal, go to form the brachial plexus. They are each
connected by a filament with one of the two lower cervical ganglia of the sympathetic,
and with the plexus on the vertebral artery.
The anterior divisions of the first and second nerves require a notice separately
from the description of the nerves of the cervical plexus.
SUBOCCIPITAL NERVE.
The anterior primary division of the first nerve runs forwards in a groove on the
outer side of the upper articular process of the atlas, and bends downwards in front
of the transverse process of that vertebra to join the second nerve. In this course
forwards it lies beneath the vertebral artery, and on the inner side of the rectus
lateralis muscle, to which it gives a branch. As it crosses the inner side of the
foramen in the transverse process of the atlas, the nerve is joined by a filament
from the sympathetic on the vertebral artery. From the loop which it makes in
front of the transverse process, twigs are supplied to the two anterior recti muscles,
and one or two larger branches pass to the hypoglossal trunk, in connection with
which most of the fibres pass down into the descending cervical nerve (p. 273).
284
THE SPINAL NERVES.
The loop is also united by short filaments to the superior cervical ganglion of the
sympathetic and to the trunk-ganglion of the vagus.
Filaments of this nerve are distributed to the articulation of the occipital bone with the
atlas, and, according to Valentin, also to the mastoid process of the temporal bone.
SECOND CERVICAL NERVE
The anterior division of the second cervical nerve, beginning between the arches
of the first two vertebrae, is directed forwards between their transverse processes,
R.A.M*.
l(/9 SUPRACUAVICUUAR
Fig. 190. — PLAN OF THE CERVICAL PLEXUS AND ITS CONNECTIONS. (Gr. D. T.)
I to V, anterior divisions of the first to fifth cervical nerves ; Sy, communicating branches to the
upper cervical ganglion of the sympathetic ; branches to muscles are indicated as follows : — R. L. ,
rectus lateralis ; R.A.Mi., rectus anticus minor ; R.A.Ma., rectus anticus major ; L.C., longus colli ;
St.M., sterno-mastoid ; Sc.A., scalenus anticus ; Sc.M., scalenus medius ; L.S., leva tor scapulae.
passing round the outer side of the vertebral artery, and beneath the posterior
intertransverse and other muscles fixed to those processes. In front of the
THE CERVICAL PLEXUS.
285
intertransverse muscles, the nerve divides into an ascending part, which joins the
first cervical nerve, and a descending part to the third.
CERVICAL PLEXUS.
The cervical plexus is formed by the anterior divisions of the upper four cervical
nerves, and distributes branches to some of the muscles of the neck, and 4to a
Fig. 191.— THK SUPERFICIAL BRANCHES OF THE CERVICAL PLEXUS.
andLeveille.) J
(From Sappey, after Hirschfeld
1, superficial cervical nerve (represented too large) ; 2, its inferior branch ; 3, its superior branoh ; 4,
its union with the facial ; 5, great auricular nerve ; 6, one of its facial branches ; 7, its branch to the
lobule ; 8, twig which pierces the auricle to pass to its outer surface ; 9, branch to the deep surface of
the pinna; 10, its union with the posterior auricular of the facial nerve ; 11, small occipital nerve ;
12, its branch which unites with the great occipital nerve ; 13, a mastoid branch arising separately from
the plexus ; 14, twigs from this to the back of the neck ; 15, inner, 16, 17. middle, 18, outer branches
of the supraclavicular nerves ; 19, branch of the cervical nerves passing into the trapezius muscle ; 20,
spinal accessory distributed to the same and receiving a uniting branch from the cervical nerves ; 21,
branch to the levator scapulae ; 22, trunk of the facial nerve ; 23, its posterior auricular branch passing
into the occipital and postei'ior and superior auricular muscles ; 24, its cervical branch ; 25, great
occipital nerve.
portion of the integument of the head, neck, and chest. It is placed opposite
the first four vertebrae, beneath the sterno-mastoid muscle, and rests against
the middle scalenus muscle and the levator anguli scapulae. The disposition
VOL. III. PT. 2. T
286 THE SPINAL NERVES.
of the nerves in the plexus is as follows : — Each nerve, except the first, divides into
an ascending and a descending part ; and these are united in communicating loops
with the contiguous nerves. From the union of the second and third nerves,
superficial branches are supplied to the head and neck ; and from the junction of
the third with the fourth, arise some of the cutaneous nerves of the shoulder and
chest. Muscular and communicating branches spring from the same nerves.
The BRANCHES of the plexus may be divided into two sets — a superficial and
deep ; the superficial consisting of those which perforate the cervical fascia and
supply the integument ; the deep comprising branches which are distributed for
the most part to the muscles. The superficial nerves may be subdivided into
ascending and descending ; the deep nerves into an internal and an external series.
SUPERFICIAL ASCENDING BRANCHES.
Small occipital nerve. — The small occipital nerve varies in size, and is
occasionally double. It springs from the second and third (sometimes only the
second) cervical nerves, and is directed almost vertically to the head along the
posterior border of the sterno-mastoid muscle, giving off in its course twigs to the
skin over the upper portion of the posterior triangular space. Having perforated
the deep fascia near the cranium, the small occipital nerve ascends to the scalp
between the ear and the great occipital nerve, and ends in cutaneous filaments
which extend upwards to somewhat above the level of the ear. It communicates
with branches from the great occipital, great auricular and posterior auricular nerves,
and it supplies an auricular branch which is distributed to the upper part of the ear
on its inner aspect.
Varieties. — The small occipital nerve is sometimes directed backwards across the posterior
triangle of the neck, and perforates the trapezius muscle close to its upper border, before
ascending1 to the head. The auricular branch is occasionally derived from the great occipital
nerve. The small occipital is sometimes much reduced in size and distributed solely to the
skin of the neck, its place on the head being- taken by branches of the great occipital nerve.
Great auricular nerve. — Arising from the second and third cervical nerves,
this, the largest of the ascending branches of the plexus, winds round the hinder
border of the sterno-mastoid, and is directed obliquely upwards between the platysma
myoides muscle and the deep fascia of the neck towards the lobule of the ear. A
little below the latter the nerve gives a few small offsets to the face, and then ends
in auricular and mastoid branches.
(a) The auricular branches are directed to the back of the auricle, on which they
ramify, and are connected with twigs derived from the posterior auricular branch
of the facial nerve. One offset reaches the outer surface of the ear by a fissure
between the antihelix and the concha. A few filaments are supplied likewise to the
outer part of the lobule.
(#) The mastoid branch ramifies in the integument over the upper end of the
sterno-mastoid muscle and the mastoid process, and communicates with the
posterior auricular and small occipital nerves.
(c) The facial branches are distributed to the integument of the face over the
parotid gland. Some slender filaments penetrate into the substance of the gland,
and communicate with the lower division of the facial nerve.
Varieties. — The great auricular nerve may arise solely from the third, or from the third and
fourth cervical nerves (Henle). The mastoid branch is often a separate offset of the plexus,
ascending between the great auricular and small occipital nerves (fig. 191, 13).
Superficial cervical nerve (n. subcutaneus colli). — This nerve takes origin,
usually in common with the great auricular, from the second and third cervical
THE CERVICAL PLEXUS. 287
nerves, turns forwards over the sterno-mastoid muscle about the middle, and after
perforating the cervical fascia, divides beneath the platysma myoides into two
branches, which are distributed to the anterior part of the neck.
(a) The upper branch is the larger, and gives an ascending twig which accom-
panies the external jugular vein, and communicates freely with the cervical branch
of the facial nerve ; it is then transmitted through the platysma to the surface,
and ramifies in the integument of the upper half of the front of the neck, filaments
reaching as high as the lower maxilla.
(b) The lower branch, sometimes represented by two or three smaller offsets,
likewise pierces the platysma and is distributed below the preceding, its filaments
extending in front as low as the sternum.
Varieties. — The superficial cervical nerve also may arise from the third only, or from the
third and fourth cervical nerves. It is sometimes represented by two or more branches arising
separately from the plexus.
SUPERFICIAL DESCENDING BRANCHES.
Supraclavicular nerves. — The descending series of the superficial nerves are
thus named. They arise together from the third and fourth cervical nerves, and
descend in the interval between the sterno-mastoid and the trapezius muscles. As
they approach the clavicle, they are three or more in number, and are recognized
as internal, middle, and external.
(a) The internal branch (suprasternal), which is much smaller than the rest,
ramifies over and below the inner third of the clavicle, and terminates near the
sternum. From it one or two filaments are furnished to the sterno-clavicular
articulation (Riidinger, Hepburn).
(b) The middle branch, generally divided into two or three parts, and crossing
the clavicle in the interval between the sterno-nlastoidand trapezius muscles, distributes
some twigs over the fore part of the deltoid, and others over the pectoral muscle as
low as the third rib. The latter join the small anterior cutaneous branches of
some of the upper intercostal nerves.
(c) The external or posterior branch (supra-acromial) is directed outwards across
the clavicular attachment of the trapezius muscle, and ramifies over the acromion
and in the integument of the outer and back part of the shoulder.
Filaments from these nerves supply the skin over the lower part of the posterior
triangular space, and one or two twigs pass backwards over the trapezius to the
integument above the spine of the scapula.
Variety. — One of the middle branches of the supraclavicular nerves occasionally perforates
the clavicle on its way downwards.
DEEP BRANCHES : INTERNAL SERIES.
Connecting branches. — The cervical plexus is connected near the base of the
skull with the pneumo-gastric, hypoglossal, and sympathetic nerves, by means of
filaments intervening between those nerves and the loop formed by the first two
cervical nerves in front of the atlas (p. 283).
Muscular branches. — Branches to the pre vertebral muscles proceed from the
cervical nerves close to the vertebrae, including the loop between the first two of
these nerves ; and from the fourth nerve a twig is frequently given to the upper
part of the scalenus anticus.
Two communicating cervical branches, one from the second, the other
from the third cervical nerve, descend over or under the internal jugular vein to
join the descending cervical nerve in the ansa cervicalis, from which the infrahyoid
muscles are supplied (p. 273).
T 2
THE SPINAL NERVES.
Variety. — In some cases there is also a communicating- branch from the fourth nerve
(fig. 183).
Phrenic nerve. — The diaphragmatic or phrenic nerve (fig. 183, 9 ; 193, 3)
passes down through the lower part of the neck and the thorax to its destination.
It arises mainly from the fourth cervical nerve, but it also receives, in the majority
of instances, an additional root from either the third or the fifth nerve. While
descending in the neck, the nerve inclines inwards over the anterior scalenus
muscle ; and near the chest it is joined by a filament from the middle or lower
cervical ganglion of the sympathetic.
At the root of the neck each phrenic nerve is placed between the subclavian
artery and vein, and crosses over the internal mammary artery from without
inwards and backwards. It then takes a nearly vertical course, in front of the
root of the lung on each side, and along the side of the pericardium — between
this and the mediastinal part of the pleura. Near the diaphragm it divides into
branches, which pass separately through the muscle, and then diverging from each
other, are distributed on the under surface.
The right nerve has a more direct course than the left, and lies at first along the
outer side of the right innominate vein and the superior vena cava.
The left nerve is somewhat longer than the right, in consequence of the oblique
position of the heart and pericardium round which it winds, and also because the
diaphragm is lower on this than on the opposite side. It passes into the thorax
between the left innominate vein and subclavian artery, and then crosses in front
of the left vagus and over the left side of the arch of the aorta before reaching the
pericardium.
Besides the terminal branches supplied to the diaphragm, each phrenic nerve
gives on its way through the thora.x filaments to the pleura and pericardium.
Luschka describes also twigs from the lower part of the nerve to the peritoneum,
and on the right side to the inferior cava and the right auricle of the heart.
One or two filaments of the nerve of the right side join in a small ganglion with
branches to the diaphragm which are derived from the solar plexus of the
sympathetic ; and from the ganglion twigs are given to the suprarenal capsule, the
hepatic plexus, and the lower vena cava. On the left side there is a junction
between the phrenic and the sympathetic nerves near the oesophageal and aortic
openings in the diaphragm, but without the appearance of a ganglion.
According to the observations of Pansini in animals (Arch. ital. de Biologic, x, 1888) the
terminal ramifications of the phrenic nerves form in the diaphragm a complicated plexus, in
which the three last intercostal nerves also take part, and which contains microscopic ganglia.
On sensory fibres in the phrenic nerve, see J. Ferguson, in " Brain," 1891.
Varieties. — The phrenic may receive an accessory root from the second or the sixth cervical
nerve (rarely), from the descend ens cervicis or the ansa cervicalis, or from the nerve to the
subclavius (frequently). The last may be of considerable size ; and in some instances the
whole nerve has been found arising in this way and descending in front of the third part of
the subclavian artery and the subclavian vein to the thorax. The accettory phrenic nerve is a
filament arising from the fifth, or more rarely the fifth and sixth cervical nerves, and passing
either in front of or behind the subclavian vein to join the trunk at the root of the neck or at
a variable level in the thorax. The phrenic nerve, having a normal origin, has been observed
in different cases lying along the outer border of, or piercing, the scalenus anticus, crossing in
front of the subclavian vein, and passing through a ring formed by that vessel. It occasionally
gives a branch to the scalenus anticus.
DEEP BRANCHES : EXTERNAL SERIES.
Muscular branches. — The sterno-mastoid receives a branch from the second
cervical nerve. Two branches proceed from the third and fourth nerves to the
levator anguli scapulae ; and from the same nerves, as they leave the spinal canal,
THE CERVICAL AND BRACHIAL PLEXUSES. 289
branches are given to the middle scalenus muscle. Farther, the trapezius receives
one or more considerable branches which arise from the third and fourth cervical
trunks in common with the supraclavicular nerves.
Communications with the spinal accessory nerve. — In the substance of
the sterno-mastoid muscle, this nerve is connected with the branch of the cervical
plexus furnished to that muscle. It is also connected with the branches distributed
to the trapezius — the union between the nerves being beneath the muscle, and
having the appearance of a plexus ; and with another branch of the cervical plexus
in the interval between the two muscles.
SUMMARY OF THE CERVICAL PLEXUS. — From the cervical plexus cutaneous
nerves are distributed to the side of the head, to part of the ear and face, to the
anterior two-thirds or more of the neck, and to the upper part of the chest and
shoulder. The muscles supplied with nerves from the plexus are the sterno-mastoid,
the trapezius, and the int'rahyoid muscles, the anterior and lateral recti capitis, the
longuscolli, the levator anguli scapulae, the scalenus medius and anticus in part, and
the diaphragm. By means of its branches the plexus communicates with the
pneumo-gastric, spinal accessory, hypoglossal, and sympathetic nerves.
BRACHIAL PLEXUS.
This large plexus, from which the nerves of the upper limb are supplied-, is
formed by the union of the anterior trunks of the four lower cervical and the
greater part of the first dorsal nerves. It also receives in many cases a fasciculus
from the lowest of the nerves (fourth) which go to form the cervical plexus, or a
filament from the second dorsal nerve : these two roots may co-exist. The plexus
extends from the lower part of the neck to the axillary space, and terminates
opposite the coracoid process of the scapula in large nerves for the supply of the
limb.
The cervical or supraclavicular portion of the plexus, emerging from the cleft
between the scalenus anticus and medius, lies in the lower part of the posterior
triangular space, above and behind the third part of the subclavian artery : it is
crossed by the posterior belly of the omo-hyoid muscle, and is often pierced by the
transverse cervical or posterior scapular artery. After passing behind the clavicle,
the axillary or infraclavicular portion of the plexus is placed to the acromial side of
the axillary vessels, being enclosed in the axillary sheath, and covered by the
pectoralis major and subclavius muscles ; and at its termination it lies between the
pectoralis minor and subscapularis muscles.
The manner in which the nerves are disposed in the plexus is liable to some
variation, but the following may be regarded as the typical arrangement, from which
the different forms met with may in most cases be readily derived. The fifth and
sixth cervical join together at the outer border of the scalenus medius to form an
upper trunk ; similarly the eighth cervical and first dorsal unite together between
the scaleni muscles to form a lower trunk ; while the seventh cervical remains single,
forming a middle trunk.
Soon after passing the outer border of the scaleni muscles, each primary trunk
divides into an anterior and a posterior branch. The posterior branch of the lower
trunk, however, is much smaller than the others, and in most instances is derived
solely from the eighth cervical nerve. The anterior branches of the upper and
middle trunks unite together to form what is called the upper or outer cord of the
plexus ; the large anterior branch of the lower trunk forms by itself the lower or
inner cord of the plexus ; and the posterior branches of all three trunks unite
together to form the middle or posterior cord. The cords thus formed lie at first in
a single bundle on the outer side of the first part of the axillary artery, but lower
290
THE SPINAL NERVES.
down they are placed, the first on the outer side, the second on the inner side, and
the third behind that vessel in its second part, whence they are continued into the
principal nerves for the arm.
Varieties. — Deviations from the arrangement above described, depending* upon alterations
in the level at which the several portions of the plexus separate and unite, are often met with.
The seventh cervical nerve is sometimes divided into three branches, one passing- to each of
the three cords of the plexus. The posterior cord has been observed arising* from the sixth,
seventh, and eighth, and in one case only from the seventh and eighth cervical nerves
(Turner). Cases are recorded in which the plexus consisted of only two cords, the larger one
representing- either the inner and outer, or the posterior and inner cords of the normal
arrangement.
The fifth cervical nerve is not unfrequently, the sixth more rarely, directed outwards
through the fibres of the scalenus anticus ; the fifth nerve may even pass altogether in front
of that muscle.
BRANCHES. — The nerves proceeding from the brachial plexus are usually divided
into two classes, viz., A, those that are given off from its supraclavicular part, and
w
musculo-spiral ;
humeral nerve.
circumflex ; i,i, intercostal nerves ;
Fig. 192. — PLAN OF THE CERVICAL AND
BRACHIAL PLEXUSES. (Allen Thom-
son). i
The nerves are separated from the
spinal cord at their origin and are sup-
posed to be viewed from before : CI, the
first cervical or suboccipital nerve, and
the Roman numbers in succession from
II, to VIII, the corresponding cervical
nerves ; DI, the first, and II, and III,
the second and third dorsal nerves ; the
origin of the posterior piimary branch is
shown in all the nerves ; of these p 2,
indicates the great occipital from the
second, and p 3, the smallest occipital
nerve from the third. Cervical plexus :
1, anterior primary branch of the first
cervical nerve and loop of union with the
second nerve ; 2, small occipital nerve ;
3, great auricular nerve ; 3', superficial
cervical nerve : 3 n, communicating
branches to the ansa cervicalis from the
second and third ; 3 s, communicating to
the spinal accessory from the third and
fourth nerves ; 4, supraclavicular nerves ;
4', phrenic nerve. Brachial plexus :
V, to VIII', and D', the five roots of the
brachial plexi>s ; 5, tbe rhomboid nerve ;
5', suprascapular ; 5", posterior thoracic ;
6, nerve to the subclavius muscle ; 7, 7,
inner and outer anterior thoracic nerves ;
8, 8', 8", subscapular nerves. In the
larger nerves proceeding to the shoulder
and arm from the plexus, those of the
anterior divisions are represented of a
lighter shade, those belonging to the
posterior division darker ; ec, external
cutaneous or musculo-cutaneous ; m,
median ; n, ulnar ; ic, internal cu-
taneous ; w, nerve of Wrisberg ; r,
lateral branch of the same ; ih, intercosto-
so arise before the formation of the three cords of the plexus ; and B, those arising
below the clavicle from the outer, inner, and posterior cords.
To the former (supraclavicular) group belong some small muscular nerves to the
scaleni and longus colli muscles the nerve to the rhomboid muscles, the posterior
THE BRACHIAL PLEXUS.
291
thoracic nerve for the serratus magnus muscle, the suprascapular nerve, the nerve
to the subclavius, and sometimes a branch to join the phrenic nerve.
The nerves given off below the clavicle are derived from the three great cords of
the plexus in the following manner : —
From the upper or outer cord,— the external of the two anterior thoracic nerves,
the nerve to the coraco-brachialis, the musculo-cutaneous, aud the outer head of the
median.
From the lower or inner cord,— the inner of the two anterior thoracic nerves,
the nerve of Wrisberg or small internal cutaneous, the internal cutaneous, the ulnar,
and the inner head of the median.
From the posterior cord, — the three subscapular nerves, the circumflex, and the
musculo-spiral.
The following table shows the spinal nerves from which the several offsets of the plexus
are commonly derived.1 + signifies that the branch in question receives fibres from the
spinal nerve in whose column the sign is placed ; + ? signifies that there is most frequently
a root from that spinal nerve, but it may be wanting ; ? signifies that the corresponding root
is not unfrequently present, although exceptional. The rarer forms of variation are not taken
into account : —
C. V.
C. VI.
C. VII.
C. VIII.
D. 1.
A. SUPRACLAVICULAR BRANCHES.
a. To trunk-muscles.
To longus colli .....
+ ?
+ ?
+ ?
+ ?
To scaleni ......
+
+
?
To phrenic nerve ....
?
b. To limb- muscles.
To rhomboidei . ...
-f
Posterior thoracic ....
+
+
+ ?
Suprascapular ... . .
+
+ ?
To subclavius .....
+
1
B. INPRACLAVICULAR BRANCHES.
a. From outer cord.
~_
External anterior thoracic . . .
+ ?
+
+
To coraco-brachialis ....
+
Musculo-cutaneous . . .
+
+
Outer head of median
+
+
6. From inner cord.
Internal anterior thoracic . . .
-f-
_|-
Nerve of Wrisberg ....
+
Internal cutaneous . . . .
+
+
Ulnar ......
•t
_j_
_i_
Inner head of median . . . .
f
+
+
c. From posterior cord.
« Upper subscapular ....
+
+
Middle or long subscapular .
?
+
?
Lower subscapular ....
+ ?
+
?
Circumflex . . . ...
+
+ 1
Musculo-spiral ....
?
+
+
+
A. — BRANCHES ABOVE THE CLAVICLE.
Small muscular branches. — The branches for the scaleni and longus colli
muscles spring in an irregular manner from the lower cervical nerves close to their
place of emergence from the intervertebral foramina.
Branch to the phrenic nerve. — This small branch is, when present, an
offset from the fifth cervical nerve ; it usually joins the phrenic nerve on the
anterior scalenus muscle.
1 See W. P. Herringham,
1886.
The Minute Anatomy of the Brachial Plexus," Proc. Roy. Soc., xli,
292 THE SPINAL NERVES.
Varieties. — The communicating branch to the phrenic nerve has been seen to pass down
into the thorax over the subclavian artery, and even over the vein, before joining- with the
trunk. A second filament to the, phrenic, from the sixth nerve, is rarely met with.
The branch for the rhomboid muscles (n. dorsal-is scapula) arises in
common with the highest root of the posterior thoracic nerve from the fifth nerve
Fig. 193. — DEEP DISSECTION OF THE AXILLA, SHOWING THE BRACHIAL PLEXUS AND NEIGHBOURING
NERVES. (From Sappey, after Hirscbfeld and Leveille.) £.
The clavicle has been sawn through near its sternal end, and is turned aside with the muscles
attached to it ; the subclavius and the greater and lesser pectoral muscles have been removed from the
front of the axilla. 1, ansa cervicalis ; 2, pneumo-gastric ; 3, phrenic, passing down to the inner side
of the scalenus anticus muscle ; 4, anterior primary division of the fifth cervical nerve ; 5, 6, 7, the
same of the sixth, seventh, and eighth cervical nerves ; 8, the same of the first dorsal 'nerve ; 9, 9,
nerve to the subclavius muscle, communicating with the phrenic nerve ; 10, posterior thoracic nerve
distributed to the serratus magnus ; 11, external anterior thoracic nerve, passing into the great pectoral
muscle; 13, internal anterior thoracic, distributed to the lesser pectoral ; 14, twig of communication
between these two nerves ; 12, suprascapular nerve, passing through the suprascapular notch ; 15,
upper subscapular nerve ; 16, lower subscapular nerve ; 17, long subscapular nerve ; 18, 21, small
internal cutaneous nerve ; 19, union of this with the second and third intercostal nerves ; 20, lateral
branch of the second intercostal ; 22, internal cutaneous nerve ; 23, ulnar nerve to the inside of
the axillary artery, passing behind the vein, and having, in this case, a root from the outer cord of
the plexus ; 24, median nerve immediately below the place where its two roots embrace the artery,
which is divided above this place ; 25, musculo-cutaneous nerve, passing into the coraco-brachialis
muscle, to which it is giving a branch ; 26, musculo-spiral nerve, passing behind the divided axillary
artery.
close to the vertebrae, and is directed backwards to the base of the scapula through
the fibres of the middle scalenus, and beneath the levator anguli scapulae, to the
deep surface of the rhomboid muscles, in which it terminates. It gives one or two
branches to the levator scapulae, and sometimes a twig to the highest digitation of
the serratus posticus superior (Rielander).
THK BKACHIAL PLEXUS.
293
The posterior thoracic nerve (n. thoracalis longus] usually arises by three
roots from the fifth, sixth, and seventh cervical nerves. The upper and middle roots
perforate the scalenus rnedius and join either in the substance or on the surface of
that muscle : the lower root passes in front of the scalenus medius and joins the
trunk opposite or below the first rib. The nerve descends behind the brachial
plexus and the first part of the axillary artery, on the outer surface of the serratus
inagnus, nearly to the lower border of that muscle, supplying it with numerous
branches. The fibres derived from the several roots are distributed to the slips of
the muscle in order from above downwards.
Varieties. — The root from the seventh nerve is sometimes wanting1. In three instances
the nerve was found by Lucas receiving a fourth root from the eighth cervical nerve. The
root from the fifth nerve sometimes remains separate, being- distributed only to the upper
division of the muscle.
The suprascapular nerve arises from the trunk formed by the union of the
fifth and sixth cervical nerves, but its fibres are derived mainly from the fifth nerve.
It passes outwards and backwards beneath the trapezius and omo-hyoid muscles to
Fig. 194. — DISTRIBUTION OP THE SUPRA-
SCAPULAR AND CIRCUMFLEX NERVES.
(Hirschfeld and Leveille. ) ^
a, scalenus medixis and posticus muscles ;
b, levator anguli scapulae ; c, acroraion ; d,
deltoid muscle, of which the back part has
been removed ; e, rhomboid muscles ; /,
teres major ; g, latissimus dorsi ; 1, the
bra hial plexus, seen from behind ; ]', nerve
to the rhomboid muscles ; 2, placed on the
clavicle, the suprascapular nerve ; 3, its
branches to the supraspinatus muscle ; 4,
branch to the infraspinatus ; 5, the circum-
flex nerve, passing out of the quadrangular
interval ; 6, its branch to the teres minor
muscle; 7, branches to the deltoid; 8,
cutaneous branch.
the uppf r border of the scapula, where it enters the supraspinous fossa through the
suprascapular notch, below the ligament of the same name. In the supraspinous
fossa, the nerve supplies branches to the supraspinatus muscle, and a slender
articular filament to the shoulder-joint ; and it then descends through the great
scapular notch to the lower fossa, where it ends in the infraspinatus muscle,
furnishing sometimes a second twig to the articulation of the shoulder.
Varieties. — The suprascapular nerve is sometimes derived eolely from the fifth nerve ; or
it may receive a few fibres from the fourth nerve. It has been seen dividing1 into two parts,
the one of which passes through the suprascapular notch, while the other pierces the bone
just below the notch. Very rarely a branch is given to the upper part of the subscapularis
muscle, or to the teres miuor. Filaments to the acromio-clavicular articulation have been
noticed by Riidinger, and to the periosteum and substance of the scapula by Swan and Ellis.
The nerve of the subclavius muscle, a slender branch given off from the
front of the upper trunk of the plexus, is also derived mainly or wholly from the
fifth cervical nerve. It descends over the third part of the subclavian artery and
behind the clavicle to the posterior surface of its muscle.
Varieties. — The nerve to the subclavius often sends a branch inwards to join the phrenic
nerve either at the root of the neck (fig. 193) or, less frequently, in the thorax. A
communicating twig to the external anterior thoracic nerve, and a branch to the clavicular
head of the sterno-mastoid have also been observed (Turner).
294 THE SPINAL NERVES.
B. — BRANCHES BELOW THE CLAVICLE.
Anterior thoracic nerves. — The anterior thoracic nerves, two in number,
supply the pectoral muscles.
The external, or more superficial branch, arising from the outer cord under cover
of the clavicle, is derived from the sixth and seventh nerves, very frequently also the
fifth. It crosses inwards over the axillary artery, and, after giving off a branch to
join the inner nerve, terminates in the great pectoral muscle.
The internal, or deeper branch, springing from the inner cord, mostly receives
fibres from both the last cervical and first dorsal nerves. It comes forwards between
the axillary artery and vein, and is joined by the communicating branch from the
external nerve, with which it forms a plexiform loop embracing the axillary artery.
From this loop offsets proceed to the small and to the lower part of the large
pectoral muscles.
Varieties. — The internal branch occasionally has no fibres from the first dorsal nerve.
Cutaneous filaments from the anterior thoracic nerves to the mammary region and to the arm
have been described by various observers. The external branch is said to supply twigs
sometimes to the clavicular part of the deltoid ; and, according to Bock and Valentin, a
filament is given to the acromio-clavicular articulation.
Subscapular nerves. — The subscapular nerves are usually three in number,
and supply the muscles forming the posterior wall of the axilla.
The upper nerve, the smallest of the three, is derived from the fifth and sixth
cervical nerves, and penetrates the upper part of the subscapularis muscle. This
branch is often double.
The middle or long subscapular nerve (n. thoraco dor sails) is the largest of the
three, and obtains its fibres mainly from the seventh, to a less extent in many cases
also from the sixth or eighth cervical nerves. It descends in company with the
subscapular artery to enter the deep surface of the latissimus dorsi muscle.
The lower subscapular nerve is derived from the fifth and sixth, or less frequently
the sixth and seventh cervical nerves. It gives one or two branches to the lower
part of the subscapularis, and ends in the teres major muscle.
Varieties. — The upper nerve occasionally proceeds from the fifth or sixth cervical nerve
alone. The most frequent origin of the long subscapular ncrrc is from the seventh alo.ie, or
from the seventh and eighth nerves ; it rarely receives fibres from the fifth. The lower nrrcc
seldom proceeds from the fifth or sixth nerve alone, or from the fifth, sixth, and seventh
nerves. The branches to the lower part of the subscapularis and the teres major muscles are
sometimes independent offsets of the brachial plexus. The nerve to the teres major is
occasionally given off by the commencement of the circumflex nerve.
Circumflex nerve. — The circumflex nerve (n. axillaris), one of the terminal
branches of the posterior cord of the plexus, obtains its fibres from the fifth and
sixth cervical nerves. It is placed at first behind the axillary artery, resting on the
subscapularis muscle, at the lower border of which it turns backwards with the
posterior circumflex vessels. It then appears at the back of the shoulder in the
quadrilateral space between the two teres muscles (fig. 194), external to the long
head of the triceps, and divides into branches, which are distributed to the deltoid
and teres minor muscles, the integument of the shoulder, and the shoulder-joint.
(a) The upper branch winds round the upper part of the shaft of the humerus,
extending nearly as far as the anterior border of the deltoid muscle, to which it is
distributed. One or two cutaneous filaments penetrate between the muscular fibres,
and are bent downwards to supply the integument over the lower part of the muscle.
(b) The lower branch supplies offsets to the back part of the deltoid, and
THE CIRCUMFLEX NERVE.
295
furnishes the nerve to the teres minor, on which there is often a small reddish
enlargement. It then turns round the posterior border of the deltoid below the
Fig. 195. — DISTRIBUTION OP THE POSTERIOR CUTANEOUS NERVES OF THE
SHOULDER AND ARM (Hirsclifelcl and Leveille. ) I
1, supra -acromia) branches of the cervical plexus descending on the
deltoid muscle ; 2, ascending and 2', descending cutaneous branches of
the circumflex nerve ; 3, inferior external cutaneous of the musculo-
spiral nerve ; 4, posterior cutaneous branches of the musculo-cutaneous
nerve to the forearm ; 5, 6, internal cutaneous of the musculo- spiral ;
7, nerve of Wrisberg ; 8, 9, posterior branches of the internal cutaneous
nerve.
middle, and ramifies in the integument over the lower two-
thirds of that muscle, and over the adjacent part of the
triceps (n. cutaneus Irachii lateralis).
(c) One or two articular filaments for the shoulder-
joint arise near the commencement of the nerve, and
enter the capsular ligament below the subscapular muscle.
Rauber describes a filament of the upper branch as ascending
in the bicipital groove to be distributed to the upper extremity of
the humerus and the capsule of the shoulder- joint.
Varieties. — The circumflex nerve is occasionally derived wholly
from the fifth cervical ; and the contribution from the sixth
nerve is often very small. It has been seen to perforate the lower
part of the subscapularis muscle (Macalister, Bubenik), to which
it often furnishes a branch. Branches to the long- head of the
triceps and to the infraspinatus are also mentioned.
Internal cutaneous nerve. — The internal cutaneous
nerve (n. cutaneus antibrachii medialis) is composed of fibres
proceeding from the first dorsal, and usually also from the
eighth cervical nerve. After leaving the inner cord of
the plexus, it is placed at first to the inner side of the
axillary artery, and then descends superficially between the brachial artery and the
basilic vein to rather below the middle of the arm, where it becomes subcutaneous.
As it pierces the fascia it is divided into two parts, one destined for the anterior,
the other for the posterior surface of the forearm.
(a) The anterior division crosses at the bend of the elbow behind (less frequently
over) the median-basilic vein, and distributes filaments in front of the forearm, as
far as the wrist ; one of these may be joined with a cutaneous branch of the ulnar
nerve (fig. 197, 14).
(b) The posterior division, smaller than the anterior, inclines to the inner side
of the basilic vein, and sends its branches obliquely backwards round the inner
margin of the forearm to supply the skin about as far as the subcutaneous border of
the ulna. Above the elbow this division is connected with the small internal
cutaneous nerve ; in the forearm it communicates with the anterior part of the
internal cutaneous, and near the wrist sometimes with the dorsal branch of the
ulnar nerve.
(c) One or more branches to the integument of tlie arm pierce the fascia near the
axilla, and reach to the elbow, or nearly so, distributing filaments outwards over the
biceps muscle.
Varieties. — The posterior division of the internal cutaneous nerve has been seen arising
separately from the posterior branch of the lower trunk of the brachial plexus (G-. Elliot
Smith, Journ. Anat.. xxix, 85). Cases are recorded in which the posterior division is joined,
296
THE SPINAL NERVES.
or replaced to a greater or less extent, by a branch of the ulnar nerve. In one instance the
posterior branch was large and extended to the hand, taking the place of the absent dorsal
branch of the iilnar nerve (Gr. D. T.).
Fig. 196. — ANTERIOR CUTANEOUS NERVES OF THE SHOULDER AND ARM. (From Sappey, after
Hirschf eld and Leveille. ) 1
1, 1, supraclavicular nerves from the cervical plexus ; 2, 2, 2, cutaneous branches of the circumflex
nerve ; 3, 4, upper branches of the internal cutaneous nerve ; 5, upper external cutaneous branch of
the musculo-spiral ; 6, internal cutaneous nerve piercing the deep fascia ; 7, its posterior branch ; 8,
communicating twig with one of the anterior branches ; 9, 10, anterior branches of this nerve, some
turning round the median basilic and ulnar veins ; 11, musculo- cutaneous nerve descending
(exceptionally) over the median- cephalic vein ; 12, lower external cutaneous branch of the musculo-
spiral nerve.
Fig. 197. — ANTERIOR CUTANEOUS NERVES OF THE FOREARM AND HAND. (From Sappey, after Hirschf eld
and Leveille.) i
9, 10, 13, distribution of the anterior division of the internal cutaneous nerve ; 14, union of one of
these with a twig of the ulnar nerve ; 12, lower external cutaneous branch of the musculo-spiral nerve ;
11, 15, distribution of the external cutaneous nerve ; 16, union of one of its branches with 17, the
radial nerve ; 18, palmar cutaneous branch of the median nerve ; 19, 20, internal and external
digital branches to the thumb from the median nerve; 21, external digital to the index finger;
22, 23, digital branches to the index, middle, and ring fingers ; 24, 25, digital branches from the ulnar
nerve to the ring and little fingers.
Small internal cutaneous nerve.— The small internal cutaneous nerve or
nerve of Wrisberg (n. cutaneus brachn medialis), derived from the first dorsal nerve,
commonly arises from the inner cord of the brachial plexus in union with the large
internal cutaneous nerve. In the axilla it lies at first behind the axillary vein, but
it soon appears on the inner side of that vessel, and communicates with the
intercosto-humeral nerve. It then descends along the inner side of the basilic vein
THE MUSOULO-CUTANEOUS NERVE. 297
to about the middle of the arm, where it pierces the fascia, and its filaments are
thence continued to the interval between the internal condyle of the humerus and
the olecranon.
Varieties. — The small internal cutaneous may receive fibres from the eighth cervical
(rarely) or the second dorsal nerve. The connection iriHi flic fateroosto-kufaeral nerve
presents much variety in different cases : — in some, there are two or more intercommunications. '
forming a kind of plexus on the posterior boundary of the axillary space ; in others the
intercosto-humeral nerve is of larger size than usual, and takes the place of the nerve of
Wrisberg, only receiving in the axilla a small filament from the brachial plexus, and this
small communicating filament represents in such cases the nerve of Wrisberg. It sometimes
communicates also with the lateral cutaneous branch of the third intercostal nerve. Absence
of the nerve of Wrisberg is noted.
The nerve to the coraco-brachialis is a small branch formed by fibres
derived from the seventh cervical nerve. In the infant it is a separate offset from
the outer cord of the plexus, but in the adult it is commonly more or less closely
united to the trunk of the mnsculo-cutaneous nerve, from which it separates before
that nerve enters the muscle (Herring-ham). It is often represented by two
filaments.
Musculo cutaneous nerve. — The musculo-cutaneous or external cutaneous
nerve, derived from the fifth and sixth cervical nerves, is deeply placed between the
muscles as far as the elbow, and below that point is immediately under 'the
integument. Arising from the outer cord of the brachial plexus opposite the small
pectoral muscle, it perforates the coraco-brachialis, and, passing obliquely across the
arm between the biceps and brachialis anticus muscles, reaches the outer side of the
biceps a little above the elbow. Here it perforates the fascia, and, passing behind
the median-cephalic vein, divides into two branches which supply the integument
on the outer side of the forearm, one on the anterior, the other on the posterior
aspect.
A. Branches in the arm.
In addition to the one or two twigs to the coraco-brachialis which may be given
off from this nerve near its origin (see above), the musculo-cutaneous furnishes the
following offsets in the deep part of its course : —
(a) Branches to the biceps and brachialis anticus muscles, which arise after the
nerve has pierced the coraco-brachialis.
(b) A slender branch to the humerus, entering the bone with the medullary
artery.
(c) An articular filament to the elbow-joint.
The nerve to the humerus is described by Rauber and others as arising from the nerve
before it enters the coraco-brachialis, and descending along the brachial artery, to which it
supplies filaments ; but Testut states that in all the cases in which he found this branch it
was given off by the nerve to the brachialis anticus. An articular filament may proceed from
the nerve to the biceps (Cruveilhier) or from that to the brachialis anticus (Riidinger) ;
Testut traced a twig from the latter source to the periosteum about the coronoid fossa. A
vascular branch to the lower part of the brachial artery from the nerve of tho brachialis
anticus is described by Swan and Testut.
B. Branches in the forearm.
(a) The anterior branch descends near the radial border of the forearm. It is
placed in front of the radial artery near the wrist, and distributes its terminal offsets
over the thenar eminence. One or two filaments pierce the fascia and run on the
artery to the articulations of the wrist. This part of the nerve is connected above
the wrist with a branch of the radial nerve.
(b) The posterior branch is directed outwards to the back of the forearm, and
298
THE SPINAL NERVES.
ramifies in the integument of the lower two-thirds, extending as far as or somewhat
beyond the wrist. It communicates with a branch of the radial nerve, and with
the lower external cutaneous branch of the musculo-spiral nerve.
Varieties. — The musculo-cutaneous nerve proper occasionally receives fibres from the
seventh cervical nerve.
In some cases the constituent fibres of the nerve remain adherent to the outer head and
10
Fig. 198. — DEEP VIEW OF THE ANTERIOR NERVES OF THE SHOULDER AND ARM.
Hirschfeld and Leveille.) |
(From Sappey, after
1, musculo-cutaneous nerve, giving off 2, the branch to the coraco-brachialis muscle ; 3, branch to
the biceps, represented incorrectly as given off before the nerve pierces the coraco-brachialis ; 4, branch
to brachialis anticus ; 5, communicating branch from the median to the musculo-cutaneous nerve (an
infrequent variety) ; 6, continuation of the nerve to its cutaneous distribution ; 7, musculo-spiral nerve
in the interval between the brachialis anticus and supinator longus muscles ; 8, inferior external
cutaneous branch of the musculo-spiral ; 9, the large and small internal cutaneous nerves divided ; 10,
anterior branch of the internal cutaneous • 11, median nerve; to the inner side of this the ulnar nerve
is crossed by the line from 11.
Fig. 199. — DEEP VIEW OF THE ANTERIOR NERVES OF THE FOREARM AND HAND.
Hirschfeld and Leveille.) |
(From Sappev, after
12, median nerve ; 13, its branch to the pronator teres ; 14, branch to the superficial fle>or muscles,
which have been removed ; 15, branch to the flexor profundus digitorum ; 16, branch to the flexor
longus pollicis ; 17, anterior interosseous nerve ; 18, palmar cutaneous branch cut short ; 19, branch to
short muscles of thumb ; 20, 21, digital branches to thumb ; 22, 23, 24, third, fourth, and fifth
digital branches ; 25, branch given by ulnar nerve to flexor carpi ulnaris ; 26, branch to flexor profundus
digitorum ; 27, cutaneous twig ; 28, dorsal branch of .ulnar ; 29, superficial palmar portion ; 30, 31,
digital branches to ring and little fingers ; 32, deep palmar branch ; 33, its branch to short muscles of
little finger ; 34, 35, 36, twigs given by deep branch of ulnar to third and fourth lumbricales, all the
interosseous muscles, and the adductors of the thumb.
THE MUSCULO-CUTANEOUS NERVE. 299
trunk of the median for a variable distance in the upper part of the arm, the musculo-
cutaneous or its several branches then being1 given off from the median tru..k, and pissing
outwards to the interval between the biceps and brachialis anticus muscles : this is a common
arrangement in lower mammals. In other cases (2 per cent., Testut ; 8 per cent., Villar) only
a part of the fibres take this course, so that a communicating branch runs from the median to
the musculo-cutaneous (fig. 11)8. 5) ; or the muscular part of the nerve perforates the coraco-
brachialis and the cutaneous part is given off from the median (Schwalbe) ; or the median
furnishes only the muscular branches (Villar). Much more frequently (36 per cent.. Testut)
some of the median fibres are associated with the musculo-cutaneous in its passage through
the coraco-brachialis. a communicating branch then passing from the latter nerve to the
median. Very rarely the whole outer cord of the plexus pierces the coraco-brachialis, and
then divides into musculo-cutaneous and outer head of the median. (Testut, " Recheiches
anatomiques sur 1'anastomose du nerf musculo-cutane avec le nerf median," Journ. de 1 Anat.,
188:5 ; and " Memoire sur la portion brachiale du nerf musculo-cutaue," Internat. Monatschr.
f. Anat., 1884; F. Villar, •' Quelques recherches sur les anastomoses des nerfs du membre
superieur." Bull. Soc. Anat. de Paiis. 188S.)
Sometimes the musculo-cutaneous nerve does not perforate the coraco-brrchialis, in which
case it may pass eirher behind that muscle, or between the coraco-brachialis and the short
head of the biceps. The nerve has also been seen perforating the short head of the biceps, or
the brachialis anticus, as well as the coraco-brachialis.
In rare cases a branch is given to the pronator teres muscle. The terminal porlion of the
nerve is not unfrequently continued on the back of the hand to the skin over the first
metacarpal bone and the adjoining interosseous space. Hepburn found the musculo-cutaneous
supplying the back' of the thumb in a case in which the radial nerve was wanting ; and H.
Virchow and Th. Kolliker describe a case in which it gave the dorsal digital nerves to both
sides of the ring and the radial side of the little fingers.
SUMMARY. — The musculo-cutaneous nerve supplies the biceps and brachialis
anticus muscles, the integument on the outer side of the forearm, the humerus, and
the elbow and wrist-joints. Communications are established between it and the
radial and the lower external cutaneous branch of the musculo-spiral.
Ulnar nerve. — The ulnar nerve, the largest branch of the inner cord of the
brachial plexus, receives its fibres from the last cervical and first dorsal nerves.
From its origin, where it is placed between the axillary artery and vein, it descends
on the inner side of the main artery of the limb as far as the middle of the arm, and
thence with the inferior profunda artery along the back of the internal inter-
muscular septum, being often lodged in a grcove in the substance of the inner head
of the triceps muscle, to the interval between the olecranon and the inner condyle of
the humerus. In the arm it is covered only by the fascia, and it may be felt
through the integument a little above the elbow. It next passes between the two
heads of the flexor carpi ulnaris muscle, under cover of which it is continued with a
straight course as far as the wrist, resting on the flexor profundus digitorum. The
nerve meets the ulnar vessels somewhat above the middle of the forearm, and from
this point it remains in contact with them on their inner side. Above the wrist it
gives off a large dorsal branch to the hand, and the trunk then runs over the front
of the annular ligament, being placed between the ulnar artery and the pisiform
bone, to terminate as it enters the palm by dividing into superficial and deep parts.
The ulnar nerve usually gives off no branches in the upper arm.
A. Branches in the forearm.
(a) Articular filaments are given to the elbow-joint as the nerve passes
behind it.
(b) Muscular branches (Sc,ld) arise from the nerve near the elbow, and pass to
the flexor carpi ulnaris and the inner half of the flexor profundus digitorum muscles.
(c) Cutaneous branches. — These two small nerves arise about the middle of the
forearm by a common trunk. One pierces the fascia, and turning downwards, joins
a branch of the internal cutaneous nerve : this branch is often absent. The second,
a palmar branch, lies on the ulnar artery, which it accompanies to the hand. This
little nerve gives filaments around the vessel, and ramifies in the integument of the
300 THE SPINAL NERVES.
inner part of the palm, joining in some cases with other cutaneous offsets of the
ulnar or median nerve.
(d) Dorsal branch to the hand. — This large offset (8 c). leaving the trunk of the
ulnar nerve two or three inches above the wrist, winds backwards beneath the flexor
carpi ulnaris, gives a twig over the back of the wrist which usually joins in a loop with
an offset of the radial nerve, and then divides into branches : one of these ramifies
on the inner side of the little finger ; another divides to supply the contiguous sides
of that finger and the ring finger ; a third supplies in part the contiguous sides of
the ring and middle fingers, and usually communicates with the branch of the radial
passing to the same interspace ; while a fourth is distributed to the skin of the
metarcarpal region of the hand, often extending to the base of the index finger
(fig. 201 A). The dorsal digital branches on the little finger reach as far as the
nail ; on the ring finger they do not usually reach beyond the second phalanx. On
the sides of the fingers they form communications with the corresponding volar
digital nerves.
B. Branches in the palm.
(a) The niperfiaalpartot the ulnar nerve (1 d, or 8 c, 1 d) supplies filaments to the
palmaris brevis muscle and the integument of the hypothenar eminence, and divides
into two digital branches. One of these passes to the ulnar side of the little finger ;
the other is connected in the palm of the hand with the innermost digital branch of
the median nerve, and at the cleft between the little and ring fingers, divides into the
collateral nerves for these fingers. From the communicating branch with the
median nerve filaments are sent to the skin and vessels of the palm. The terminal
disposition of the digital branches on the fingers is the same as that of the median
nerve, to be presently described.
(b) The deep part (8 c) sinks backwards with the deep branch of the ulnar artery
between the abductor and flexor brevis minimi digiti muscles, and passing to the
inner side of and below the hook of the unciform bone (which it sometimes grooves1),
through the cleft in the opponens minimi digiti muscle (Vol. II, p. 238), follows the
course of the deep palmar arch across the hand. It supplies the short muscles of
the little finger as it passes between them ; as it lies over the metacarpal bones it
distributes branches to the interosseous muscles and the inner two lumbricales ; and
at the outer side of the palm it terminates in offsets to the adductores pollicis and
the abductor indicis muscles. Articular filaments pass upwards to the wrist, and
others descend to the metacarpo-phalangeal articulations (Riidinger). Rauber also
describes small perforating branches, which accompany the superior perforating
arteries in the interosseous spaces, and join the terminal filaments of the posterior
interosseous nerve.
Varieties. — The ulnar nerve not unfrequently has an additional root from the seventh
cervical nerve. It is rarely derived wholly from the eighth nerve, or from the seventh and
eighth cervical. In a few instances the nerve has been seen descending in front of the inner
condyle instead of behind. Cases are also recorded in which the ulnar nerve slipped forwards
over the internal condyle when the elbow was bent. A branch may pass from tLe ulnar nerve
in the arm to reinforce the internal cutaneous (p. 295). A communication between the ulnar
and median nerves in the arm was seen by Villar, and also a communication with the
musculo-spiral (Bull. Soc. Anat. Paris, 1888, 613). A branch from the median to join the
ulnar in the forearm is of frequent occurrence (p. 302). When the occasional epitrochleo-
anconeus muscle (Vol. II, p. 225) is present, it receives a branch from the ulnar nerve.
Filaments of the ulnar nerve have been found passing- to the inner part of the triceps, or to
the flexor sublimis digitorum, and from the deep part to the second (H. St. John Brooks,
Testut), or to the first lumbricalis (J. T. Wilson), or to the outer head of the flexor brevis
pollicis (normal according to Swan and Brooks). The dorsal branch may be smaller than
1 W. Anderson, "A Note on the Course and Relations of the Deep Branch of the Ulnar Nerve,"
Proc. Auat. Soc., Feb. 6, 1894.
THE MEDIAN NERVE. 301
usual, or even absent, in £which case the deficiency is generally compensated by the radial
nerve (p. 306). in rare cases by the lower external cutaneous of the musculo-spiral (p. 304), or
by the internal cutaneous (p. 296). Its area of digital distribution is seldom increased, but it
was found by Hepburn supplying1 all four finders in a case of absence of the radial nerve.
Its filaments often reach to the radial side of the second metacarpal bone, and in one instance
they were followed by Zander to the back of the first phalanx of the thumb.
SUMMARY. — The ulnar nerve gives cutaneous filaments to the lower part of the
forearm (to a small extent), and to the inner part of the hand on its palmar and
dorsal aspects. It supplies the following muscles, viz., the ulnar flexor of the carpus,
the deep flexor of the fingers (its inner half), the short muscles of the little finger
with the palmaris brevis, the interosseous muscles of the hand, the inner two
lumbricales, and the adductores pollicis. Lastly, it contributes to the nervous
supply of the joints of the elbow, wrist, and hand.
Median nerve. — The median nerve, composed of fibres proceeding from the
lower three cervical and the first dorsal nerves, arises by two roots or heads, one from
the outer, the other from the inner cord of the brachial plexus. Commencing by
the union of these roots in front or on the outer side of the axillary artery, the
nerve descends in contact with the brachial artery, lying on its antero-lateral aspect
as far as the middle of the arm, then gradually passes inwards over it, and near the
elbow gains the inner side of the vessel. Sinking into the hollow at the bend of the
elbow, the nerve passes beneath the superficial portion of the pronator teres, but over
the deep slip of that muscle, by which it is separated from the ulnar artery, and
continues straight down the front of the forearm between the flexor sublimis and
flexor profundus digitorum muscles. Arrived near the wrist it lies beneath the
fascia, between the tendons of the flexor sublimis and palmaris longus internally
and that of the flexor carpi radialis externally. It then enters the palm behind the
annular ligament, and rests on the flexor tendons. Somewhat enlarged, and of a
slightly reddish colour, it here separates into two parts of nearly equal size. One of
these (the external) supplies some of the short muscles of the thumb, and gives
digital branches to the thumb and the index finger ; the second portion supplies the
middle finger, and in part the index and ring fingers.
The median nerve usually gives no branch in the upper arm.
A. Branches in the forearm.
(a) Articular Iranches. — These are one or two filaments to the front of the
elbow-joint (Riidinger).
(1) Muscular Iranches arise either together or separately in the neighbourhood
of the elbow and pass to the pronator teres (6 c\ flexor carpi radialis (6 c), palmaris
longus and the condylo-ulnar head of the flexor sublimis digitorum (7, 8 c, Id). A
separate offset enters the radial head of the flexor sublimis, and a third branch
supplying the index finger belly of the same muscle is given off by the trunk at a
lower level in the forearm.
(c) Anterior interosseous nerve (7, 8 c, 1 d or 8 c, 1 d).— This is the longest branch
of the median nerve, and it supplies the deeper muscles of the front of the forearm.
Leaving the main trunk a little below the elbow, it runs downwards with the artery
of the same name on the interosseous membrane to the deep surface of the pronator
quadratus muscle, in which it ends. It distributes branches to the flexor longus
pollicis and the outer half of the flexor profundus digitorum, between which it lies ;
a slender branch is given off to the interosseous membrane, along or in which it
descends, dividing into two, and supplying filaments to the membrane, to the
anterior interosseous vessels, to the shafts of the radius and ulna with the medullary
arteries, and to the periosteum ; and from the lower end of the nerve a twig is con-
tinued to the front of the wrist-joint. Small Pacinian bodies are found on the
branches passing to the bone and periosteum (Rauber).
VOL, III., PT. 2. U
302 THE SPINAL NERVES.
(d) The palmar cutaneous branch arises a variable distance above the wrist, and
pierces the fascia of the forearm between the tendons of the flexor carpi radialis and
palmaris longus, close to the annular ligament, to terminate in the integument of
the palm, where it communicates with the palmar cutaneous branch of the ulnar
nerve. Some filaments are distributed over the thenar eminence, and form com-
munications with twigs of the radial or external cutaneous nerve.
B. Branches in the hand.
(a) Branch to muscles of the thumb. — This short nerve (6 c), arching outwards
immediately below the annular ligament, subdivides into branches for the abductor,
the opponens, and the outer head of the flexor brevis pollicis muscles.
(#) Digital nerves. — These are five in number, and belong to the thumb, and the
fingers as far as the outer side of the ring-finger. They lie at first beneath the
superficial palmar arch and its digital branches, but as they approach the clefts between
the fingers, they are close to the integument in the intervals between the longi-
tudinal divisions of the palmar fascia, and on the fingers the nerves lie in front of
the vessels.
The first and second nerves lie along the sides of the thumb ; and the former (the
outer one) is connected with the radial nerve over the border of the thumb.
The third, destined for the radial side of the index finger, gives a branch to the
first or most external lumbricalis muscle.
The fourth supplies the second lumbricalis, and divides into collateral branches
for the adjacent sides of the index and middle fingers.
The fifth, the most internal of the digital nerves, is connected by a cross branch
with the ulnar nerve, and divides to supply the adjacent sides of the ring and
middle fingers. It often gives a branch to the third lumbricalis, which then has a
double supply.
Each digital nerve divides at the end of the finger into two branches, one of
which supplies the ball on the fore part of the finger, while the other ramifies in the
pulp beneath the nail. Branches pass from each nerve forwards and backwards to
the integument of the finger ; those passing backwards join the dorsal collateral
nerve, and supply mainly the integument over the second and third phalanges of the
middle three digits. Filaments are also furnished to the articulations of the fingers.
The volar digital branches of the median and ulnar nerves are beset with numerous
Pacinian corpuscles both in the palm and on the fingers : the number of these
bodies varies from 60 to 100 in each digit.
Varieties. — Occasionally the median nerve does not receive any fibres from the first
dorsal nerve.
Either of the heads of the nerve may be double. The level at which the two heads join is
very variable : they have been found separate to the middle of the arm, and in one case
nearly as far as the elbow (Testut). Calori saw the two heads embracing the axillary vein as
well as the artery. The inner head may cross behind, instead of in front of, the axillary
artery. The whole nerve is often found passing- behind the brachial artery (Vol. II. p. 441).
The outer head has been seen by Turner passing behind the axillary artery, so that the trunk
of the nerve lay altogether to the inner side of the brachial artery ; and in another case
recorded by the same anatomist the outer head separated from the musculo-cutaneous in the
middle of the arm and crossed behind the brachial artery to join the inner head. Gruber and
Walsh have described cases in which the nerve entered the forearm over the pronator teres
muscle. It has also been seen running down the forearm superficial to the flexor sublimis
digitorum (G. D. T.). The nerve has been found split for a certain distance in the forearm,
the cleft giving passage to the ulnar artery (Testut) or a branch of that vessel (Mauclaire). or
to the superficial long head of the flexor longus pollicis (Davies-Colley, Taylor and Dalton,
J. W. Williams), or to a supernumerary long palmar muscle (Reid and Taylor).
The frequent communication between the median and musculo-cutaneous nerves in the
arm has already been referred to (p. 299). One instance is recorded of a connection between
the median and ulnar nerves in the arm (p. 300). A communication between these nerves in
the upper part of the forearm is present in the proportion of one in four or five limbs, usually
THE MEDIAN NERVE. 303
in the form of a branch leaving- the median in common either with the muscular offsets at the
elbow or with the anterior interosseous nerve, and passing- with or near the ulnar artery to
join the ulnar nerve about the middle of the forearm : less frequently the connection is by
means of a loop or small plexus, from which twigs are given off to the flexor profundus
digitorum muscle : this communication between the median and ulnar nerves in the upper
part of the forearm is normal in most apes (Hepburn, Hofer). and in lower mammals
(Bardeleben). A communication in the lower part of the forearm is rare. In two cases a
branch was seen passing from the median nerve at the elbow, over the superficial muscles, to
join the ulnar (T. J. Jeans). Very seldom a branch runs from the ulnar to the median trunk
or to its anterior interosseous branch. The communicating branch between the median and
ulnar nerves in the palm is commonly directed from the ulnar to the median, but it may run
in the opposite direction, or the communication may be looped or plexiform in arrangement.
Absence of the communication has been noted. In two cases described by Klint the anterior
interosseous nerve received a branch from the musculo-spiral (posterior interosseous ?) through
the interosseous membrane. A communication between the anterior and posterior interosseous
nerves at the lower end of the interosseous space is noticed by Martin and Rauber. (F. Curtis,
" Recherches anatomiques sur Tanastomose du Median et du Cubital a 1'avant-bras," Intemat.
Monatschr. f. Anat. u. Hist., iii, 1886 ; Third Annual Report of Committee of Collective
Investigation of the Anat. Soc., by Arthur Thomson, Journ. Anat., xxvii, 1892.)
The digital nerves in the palm are often pierced by the corresponding arteries. Four cases
are recorded by Gruber in which the nerve supplying the adjacent sides of the middle and ring
fingers arose from the trunk in the forearm. A branch from the median nerve to the abductor
indicis muscle was observed by Brooks.
SUMMARY. — The median nerve gives cutaneous branches to the palm, and to
three and a half fingers. It supplies the pronator muscles, the flexors of the carpus
and the long flexors of the fingers (except the ulnar flexor of the carpus, and part
of the deep flexor of the fingers), likewise the outer set of the short muscles of the
thumb, and two lumbricales. Articular filaments are also given to the joints of the
elbow, wrist, and fingers.
A great similarity will be observed in the distribution of the median and ulnar
nerves. Neither gives any offset in the arm. Together they supply all the muscles
of the front of the forearm and in the hand, and together they supply the skin of
the palmar surface of the hand, and impart tactile sensibility to all the fingers.
Musculo-spiral nerve. — The musculo-spiral nerve (n. radialis of French and
German writers), the largest offset from the brachial plexus, is derived from the
sixth, seventh, and eighth cervical nerves, in some cases also from the fifth. It
occupies chiefly the back part of the limb, and supplies nerves to the extensor
muscles, as well as to the skin.
Arising behind the axillary vessels from the posterior cord of the brachial plexus,
of which it is the principal continuation and the only branch prolonged into, the
arm, it soon turns backwards with the superior profunda artery between the long
and internal heads of the triceps, and runs beneath the external head of that muscle,
in the hinder part of the spiral groove of the humerus, to the outer side of the arm.
It then pierces the external intermuscular septum, and descends in the interval
between the supinator longus and brachialis anticus muscles nearly to the level of
the outer condyle of the humerus, where it ends by dividing into the radial and
posterior interosseous nerves. Of these, the radial is altogether a cutaneous nerve,
while the posterior interosseous is the muscular nerve of the back of the forearm.
The branches of the musculo-spiral nerve may be classified according as they
arise on the inner side of the humerus, behind that bone, or on the outer side.
A. Internal branches.
(a) Muscular branches for the long and inner heads of the triceps (7, 8 c). That for
the inner head gives two or three filaments to the upper part of the muscle, and then
descends by the side of the ulnar nerve, to which it is often closely adherent for a
part of its course, and enters the lower short fibres of the head. This long filament
is named by Krause the ulnar collateral branch.
u 2
304 THE SPINAL NERVES.
(&) The internal cutaneous branch of the musculo-spiral nerve (n. cutaneus
brachii posterior) (8 c), often united in origin with the preceding, winds backwards
beneath the intercosto-humeral nerve, and extends, supplying filaments to the skin
over the long head of the triceps, nearly as far as the olecranon. This nerve is
accompanied by a small cutaneous artery.
B. Posterior branches.
These consist of a fasciculus of muscular branches (7, 8 c) which supply the outer
and inner heads of the triceps muscle and the anconeus. The branch of the anconeus
is slender, and remarkable for its length ; it descends in the substance of the inner
head of the triceps to reach its destination.
C. External branches.
(a) The external cutaneous branches, two in number, arise before the nerve
pierces the external intermuscular septum, and become superficial just below the
middle of the arm, between the outer head of the triceps and the brachialis anticus
muscles.
The upper branch (6 c), the smaller of the two, is directed downwards to the fore
part of the elbow, along the cephalic vein, and distributes filaments to the lower
half of the arm on its outer and anterior aspect. The lower branch (n. cutaneus
antibrachii dorsalis) (6 c, or 6, 7 c, or 7 c, or 7, 8 c) descends in the interval between
the external condyle and the olecranon, and reaches as far as the wrist, distributing
its offsets to the lower half of the arm, and to the forearm, on their posterior
aspect. It is connected near the wrist with a branch of the external cutaneous
nerve, and often with the dorsal branch of the ulnar nerve. In some cases this
branch is prolonged to the back of the hand (fig. 201, A).
(b) Muscular branches are furnished to the supinator longus (6 c), extensor carpi
radialis longior (6, 7 c) (the extensor carpi radialis brevior usually receiving its nerve
from the posterior interosseous), and frequently a small twig to the outer part of the
brachialis anticus (6 c), as the nerve lies between those muscles. Together with these
branches articular filaments are given to the outer part of the elbow-joint.
According to Rauber a branch of the musculo-spiral nerve is given regularly to the periosteum
on the back of the humerus ; and in some cases it also furnishes the nerve to the shaft of that
bone, when the principal medullary artery is derived from the superior profunda. Filaments
are described as passing to the elbow-joint also from the ulnar collateral nerve, and from the
branch to the anconeus.
Varieties. — The musculo-spiral nerve has been seen passing backwards through the
quadrilateral space between the teres muscles with the circumflex nerve (Guy's Hosp. Rep.,
xliv). A communication with the ulnar nerve in the arm is recorded by Villar (p. 300). The
lower external cutaneous branch was traced by Brooks in one case to the first phalanx of the
ring and the second phalanx of the little fingers ; and it has been observed furnishing the
dorsal digital nerves of the little and the ulnar half of the ring fingers in the place of the
ulnar nerve (Gruber, Gegenbaur).
Radial nerve. — The radial nerve (ramus superficialis n. radialis) receives its
fibres from the sixth cervical nerve, sometimes also the fifth or seventh. Continuing
straight down from the musculo-spiral nerve, it lies a little to the outer side of the
radial artery along the anterior border of the extensor radialis brevior, under cover
of the supinator longus, and resting on the supinator brevis, the insertion of the
pronator teres, and the radius. About three inches above the wrist the nerve turns
backwards beneath the tendon of the supinator longus and becomes subcutaneous.
It then divides into two branches, which ramify on the back of the hand in the
following manner : —
(a) The external portion passes to the radial side of the thumb, and is joined
by an offset of the external cutaneous nerve. It distributes filaments over the thenar
eminence.
THE RADIAL NERVE. 305
(b) The internal portion communicates with the posterior branch of the
musculo-cutaneous nerve in the forearm, sends an offset to the back of the wrist,
which usually joins in an arch with the dorsal branch of the ulnar nerve, and
then divides into four branches for the thumb and the outer two fingers. One
Fig. 2'JO. VlKW OK THE RADIAL SIDE OF THE FOREARM, SHOWING THE
FINAL DISTRIBUTION OF THE MUSCULO-SPIRAL NERVE. (Hirschfeld and
Leveille.) J
The supinator longus and the radial extensoi-s have been divided, and
their upper parts removed ; the extensor coimnunis digitorum is pulled
backwards, and the supinator bi-evis has been partially dissected to show
the posterior interosseous nerve passing through it.
1, on the tendon of the biceps muscle, the musculo-cutaneous nerve ;
1', near the wrist, the lower part of this nerve and its plexus of union
with the radial nerve ; 2, trunk of the musculo-spiral nerve in the
interval between the. brachialis anticus, on which the number is placed, and
the supinator longus muscles ; 2', its muscular twigs to the long supinator
and long radial extensor ; 2", the posterior interosseous nerve passing
through the substance of the supinator brevis ; 3, placed upon the cut
lower portion of the supinator longus, and lower down, the radial nerve ;
4, the external digital nerve of the thumb ; 5, digital nerves of the
forefinger and thumb arising in common ; 6, the same of the fore and
middle fingers ; 7, twig of union with the dorsal branch of the ulnar
nerve ; 8, placed upon the common extensor of the fingers, the muscular
branches of the posterior interosseous nerve to the long extensor muscles ;
9, upon the extensor longus pollicifc, the branches to the short extensoi
muscles.
of these supplies the ulnar side of the thumb, the second
passes to the radial side of the index finger, the third
divides for the adjacent sides of the index and middle
fingers, and the fourth is directed to the interspace
between the middle and ring fingers. In their course these
branches supply twigs to the skin of the outer part of the
back of the hand ; and the innermost one crosses, and
usually communicates with the outer branches of the dorsal
uluar nerve.
The distance to which the branches of the radial nerve
extend varies in the several digits. On the thumb they
reach to the nail, on the index finger to the second
phalanx, and on the middle finger only to the first phalanx, while from the inner-
most branch filaments pass to the root of the ring finger.
From the dorsal digital nerves twigs are said to be given to the carpo-metacarpal,
metacarpo-phalangeal, and first interphalangeal articulations ; and according to Hedon
filaments pass forwards through the interosseous spaces to the skin of the palm. Lejars
describes an offset from the outer division of the radial nerve to the abductor pollicis muscle
(Bull. Soc. Anat. Paris, 1890, 433)
Varieties. — The area of distribution of the radial and ulnar nerves, and the degree to
which they overlap on the back of the hand, as well as the extent of the dorsal nerves on the
three middle fingers, are subject to much variability. From observations in man and
mammals Hedon and Zander conclude that the primitive arrangement is that in which the
radial nerve supplies three and a half digits and the ulnar one and a half, all the digital
branches extending to the nail. The reduction of the dorsal nerves on the three middle
fingers appears to be an arrangement peculiar to man, in whom however the nerves are not
unfrequently continued to the nail in the index and ring fingers, but very rarely in the
middle finger. (H. St. John Brooks, '; On the distribution of the cutaneous nerves on the
dorsum of the human hand/1 Internat. Monatschr. f. Anat. u. Phys., v. 1888 : E. Hedon.
'• Etude critique sur rinnervation de la face dorsale de la main," Internat. Monatschr. f. Anat.
u. Phys.. vi. 1889 ; R. Zander. •• Ueber die sensibeln Xerven auf der Riickenflache der Hand
bei Saugetieren und beim Menschen.'' Anat. Anz.. iv. 1889.)
306
THE SPINAL NERVES.
Occasionally the radial nerve supplies the whole of the back of the hand and fingers. Its
outer division often gives a branch to the palm. Absence of the radial nerve was met with
by Hepburn, the musculo-cutaneous supplying the thumb, and the ulnar nerve all the four
fingers (Journ. Anat., xxi, 511).
A.
RADIAL-
Fig. 201. — DORSAL CUTANEOUS NERVES OP THE HAND. (A, after Brooks ; B, after Hedon.)
The radial nerve is shown in blue, the branches of the ulnar in red. offsets of the musculo-cutaneous,
musculo-spiral and median in black. The two figures illustrate variations in the cutaneous supply. In
A, the radial and ulnar nerves overlap to a considerable extent, and the lower external cutaneous of the
musculo-spiral extends to the back of the hand. In B, the overlapping of the radial and ulnar nerves
is slight, and the musculo-cutaneous is prolonged independently into the hand.
Posterior interosseous nerve. — This nerve (r. profundus n. radialis), the
larger of the two divisions of the musculo-spiral, is composed of fibres derived from
the sixth and seventh, sometimes also the eighth, cervical nerves. It winds to the
back of the forearm round the outer side of the radius, traversing the cleft in the
supinator brevis muscle, and is prolonged between the deep and superficial layers of
the extensor muscles to somewhat below the middle of the forearm, where it sinks
beneath the long extensor of the thumb, and reaches the lower part of the
interosseous membrane.
Much diminished in size by the separation of numerous branches for the
muscles, the nerve lies at the back of the wrist beneath the tendons of the extensor
indicis and the common extensor of the fingers, and forms here a small enlargement,
from which filaments are given to the adjoining ligaments arid articulations.
Branches. — (a) Muscular branches.— Before the nerve passes to the back of the
forearm it gives offsets to the extensor carpi radialis brevior (6, 7 c) and the supinator
brev»s (6 c) muscles. After perforating the supinator brevis, it supplies branches (7 c)
ANTERIOR PRIMARY DIVISIONS OF DORSAL NERVES. 307
to the extensor communis digitorum, extensor minimi digiti, extensor carpi ulnaris,
the three extensors of the thumb, and the extensor indicis.
(&) Articular branches. — From the terminal enlargement of the nerve fine twigs
proceed to the articulations of the wrist, and, according to Rlidinger and Rauber,
other filaments descend on the back of the hand to the metacarpo-phalangeal
articulations.
Varieties. — The posterior interosseous nerve may pass over, instead of perforating, the
supinator brevis muscle (Luschka, Krause). A branch to the anconeus muscle is described by
the same anatomists. There may be a communication between the anterior and posterior
interosseous nerves at the lower part of the interosseous space (p. 303). In two cases, recorded
by Turner and Schwalbe, the posterior interosseous nerve passed down to supply the adjacent
sides of the index and middle fingers ; a similar condition has been found in the chimpanzee,
orang and gibbon (Westling, Hepburn, Hofer).
SUMMARY. — The musculo-spiral nerve supplies the extensor muscles of the
elbow-joint, and frequently sends a filament to the brachialis anticus. which,
however, receives its principal supply from another source. Before separating
into its two large divisions, the nerve gives branches to two muscles of the
forearm, viz., the long supinator, and the long radial extensor of the carpus.
The posterior interosseous division distributes nerves to the remaining muscles on
the outer and back part of the forearm, except the anconeus (previously supplied),
viz., to the short supinator and the extensors.
Cutaneous nerves are distributed, from the trunk of the nerve and its radial
division, to the upper arm, to the forearm, and to the hand — on the posterior and
outer aspect of each. Articular branches are furnished to the elbow, wrist,
metacarpo-phalangeal, and first interphalangeal joints.
DOESAL NERVES.
The anterior divisions of the twelve dorsal or thoracic nerves are distributed
almost entirely to the walls of the thorax and abdomen. The exceptions are the
first, the greater part of which joins the brachial plexus, and the second and
twelfth, which send cutaneous offsets to the arm and hip respectively. Close to the
intervertebral foramina, these nerves are connected to the gangliated cord of the
sympathetic by very short communicating branches ; they are then directed trans-
versely outwards to their destination without forming any plexus, and in this
respect they differ from the anterior primary divisions of the other spinal nerves.
The smaller part of the first, and the trunks of the succeeding ten nerves pass
forwards in the intercostal spaces, and are thence termed intercostal nerves. Of
these, the upper six are confined to the parietes of the thorax, while the lower
five are continued anteriorly from the intercostal spaces into the wall of the
abdomen. The twelfth nerve, sometimes distinguished as the subcostal nerve,
is placed below the last rib, and is therefore contained altogether in the abdominal
wall.
FIRST DORSAL NERVE.
The anterior division of the first dorsal nerve divides into two parts, the larger
of which ascends over the neck of the first rib to enter into the brachial plexus.
The remaining portion of the nerve is continued as the first intercostal, a small
branch which lies at first under cover of the first rib, and then courses along the
first intercostal space, in the manner of the other intercostal nerves, but has usually
no lateral cutaneous branch, and may also want the anterior cutaneous.
Variety.— The first dorsal nerve frequently receives a connecting twig which passes up-
wards in front of the neck of the second rib from the second nerve. This branch was found
by Cunningham in twenty-seven out of thirty-seven dissections ; it was of variable size, but
308
THE SPINAL NERVES.
generally very small, and it sometimes joined only one. in other cases both, of the divisions of
the first nerve (Journ. Anat., xi, 539).
UPPER OR PECTORAL INTERCOSTAL NERVES.
In their course to the fore part of the chest, these nerves accompany the inter-
costal blood-vessels. From the intervertebral foramina they are directed outwards in
front of the superior costo-transverse ligaments, the levatores costarum and the
external intercostal muscles, being covered anteriorly, as far as the angles of the ribs,
only by the pleura and the thin layer of connective tissue known as the endothoracic
fascia. Gaining the upper part of the corresponding intercostal spaces, where they
are placed below the intercostal vessels, the nerves next run between the external and
internal intercostal muscles, and soon give off the large lateral cutaneous branches,
Fig. 202. — PLAN OP AN UPPER DORSAL NERVE.
(G. D. T.)
which accompany the prolongations of
the trunks for a short distance, and
then bend outwards through the ex-
ternal intercostal muscles about mid-
way between the spine and the sternum.
The nerves themselves, much reduced
in size, are now continued forwards
amid the fibres of the internal
intercostal muscles as far as the costal
cartilages, where they again come into
close relation with the pleura. In
approaching the sternum they cross in
front of the internal mammary vessels
and the triangularis sterni ; and finally
they pierce the internal intercostal
muscles and the greater pectoral, to
end in the integument of the breast,
receiving the name of the anterior
cutaneous nerves of the thorax.
BRANCHES. — Muscular branches are furnished by the intercostal nerves in the
first part of their course to the levatores costarum, and, from the upper four nerves,
to the serratus posticus superior. Several twigs enter the intercostal muscles with
which the nerves are in relation. At the fore part of the chest the triaogularis
sterni is supplied by offsets of these nerves from the second or third to the sixth ;
and from the fifth and sixth nerves branches pass to the upper end of the rectus
abdominis.
Minute subcostal branches perforate the internal intercostal muscles to reach
the inner surface of the ribs, where they are distributed to the. periosteum and bone,
as well as probably to the costal pleura (Testut) ; and, according to Luschka, fine
sternal twigs are given off at the anterior ends of the intercostal spaces to the
back of the sternum.
The lateral cutaneous nerves of the thorax pierce the external intercostal
and serratus magnus muscles, in a line a little behind the pectoral border of the
axilla. The first intercostal usually gives no lateral branch, or only a slender twig
to the axilla, but when that of the second nerve is unusually small, it may be supple-
mented by a branch of the first. The branch from the second intercostal is named
mtercosto-humeral, and requires separate description. Each of the remaining latera
THE UPPER INTERCOSTAL NERVES.
309
cutaneous nerves divides into two branches, which reach the integument at a short
distance from each other, and are named anterior and posterior.
Fig. 203. — VIEW OF THE ANTERIOR DIVISIONS ov THE DORSAL AND SOME OF THK OTHER SPINAL
NERVES FROM BEFORE. (HirscMeld and Leveille.) J
The pectoralis major and minor muscles have been removed ; on the right side the rectus abdominis
and internal oblique muscles are shown ; on the left side the anterior part of the rectus is cut away,
and the transversalis is exposed.
1, median and other nerves of the brachial plexus ; 2, nerve of Wrisberg ; 3, intercosto-humei-al ;
4, intercostal nerves continued forwards to 4', their anterior cutaneous twigs ; 5, lateral cutaneous branches
of these nerves ; 6, lateral cutaneous branch of the last dorsal nerve ; 7, iliac branch of the ilio-
hypogastric nerve; 8, hypogastric branch of the same; 9, ilio-inguinal ; 10, middle cutaneous of
the thigh.
310 THE SPINAL NERVES.
The anterior branches are continued forwards over the border of the great
pectoral muscle. In the female their terminal ramifications supply the skin over the
mamma, and some filaments enter the substance of the gland. From the lowest two
nerves twigs are supplied to the upper digitations of the external oblique muscle
of the abdomen.
The posterior branches turn backwards to the integument over the scapula and
the latissimus dorsi muscle. The branch from the third nerve ramifies in the axilla,
and a few filaments often reach the arm.
The intercosto-humeral nerve (n. mtercosto-brachialis), the lateral cutaneous
branch of the second intercostal nerve, corresponds with the posterior of the two
divisions of the succeeding lateral cutaneous branches, the anterior being commonly
wanting. It crosses the axillary space to reach the arm, and is connected in the
axilla with an offset of the nerve of Wrisberg (p. 296). Penetrating the fascia, it
becomes subcutaneous, and ramifies in the integument of the upper half of the arm
on the inner and posterior aspect ; a few filaments reach the integument over
the scapula. The branches of this nerve cross over the internal cutaneous offset of
the musculo-spiral, and a communication is established between the two nerves.
The size of the intercosto-humeral nerve, and the extent of its distribution, are in
inverse proportion to the size of the other cutaneous nerves of the upper arm,
especially the nerve of Wrisberg.
The anterior cutaneous nerves of the thorax, which are the terminal twigs
of the intercostal nerves, are reflected outwards in the integument over the great
pectoral muscle. One or two of the upper branches may be connected with
the supraclavicular nerves. In the female, those from the second, third, and fourth
nerves are distributed over the mammary gland.
Varieties. — At the hinder part or side of the chest some of the adjacent intercostal
nerves are occasionally connected by filaments which cross the inner surfaces of the ribs,
passing from one intercostal space to join the nerve in the interval next below. A twig' from
the second intercostal nerve to the pectoralis major has been described by Swan and M. Flesch ;
one to the pectoralis minor by Brooks.
LOWER OR ABDOMINAL INTERCOSTAL NERVES.
The lower intercostal nerves in the first part of their course have relations like
those of the upper nerves already described. Lying between the external and
internal intercostal muscles, they give off the lateral cutaneous branches, and at the
fore part of the intercostal spaces they penetrate the internal intercostal muscles.
They then pass between the slips of origin of the diaphragm, the seventh, eighth,
and ninth nerves each crossing behind the cartilage of the rib below, and enter the
abdominal wall. Here they are continued between the internal oblique and
transversalis muscles as far as the outer edge of the rectus, diverging from one
another as they pass inwards, in consequence of the increasing obliquity of the
lower nerves. Finally, perforating the posterior layer of the sheath of the rectus,
they turn forwards through the substance of that muscle and the anterior layer of its
sheath to end in small cutaneous branches (anterior cutaneous nerves) . While between
the abdominal muscles the lower three or four nerves are united by loops of com-
munication, and sometimes form a small plexus.
BRANCHES. — Muscular branches are given to the levatores costarum, to the
serratus posticus inferior (from the ninth, tenth, and eleventh nerves), to the
subsostal and intercostal muscles, and to the abdominal muscles with which
the nerves are in contact. Filaments are also described as passing from these nerves
to the costal portion of the diaphragm (Baur, Swan, Luschka).
The lateral cutaneous nerves of the abdomen pass to the integument through
the external intercostal and external oblique muscles, in a line with the corresponding
THE LAST DORSAL NERVE. 311
nerves on the thorax, and divide in the same manner into anterior and posterior
branches.
The anterior IrancJws are the larger. They supply the digitations of the external
oblique muscle, and are then directed inwards, the lower nerves also inclining
downwards, in the superficial fascia, with small cutaneous arteries, nearly to the
edge of the rectus muscle.
The posterior branches bend backwards over the latissimus dorsi.
The anterior cutaneous nerves of the abdomen are uncertain in number
and position. There are generally two or three twigs from each nerve, and some of
them perforate the rectus near its outer border, but the greater number issue near
the linea alba. The branches of the seventh nerve emerge near the lower end of the
ensiform process, and those of the tenth usually supply the skin about the
umbilicus.
LAST DOBSAL NERVE.
The anterior primary division of the last dorsal nerve is directed outwards in
company with the abdominal branch of the first lumbar artery along the lower border
of the twelfth rib. It passes beneath the external arched ligament of the diaphragm,
across the front of the quadratus lumborum, and at the outer border of the latter
muscle it perforates the posterior aponeurosis of the transversalis (middle layer of
the lumbar fascia), to follow a course similar to that of the lower intercostal nerves
in the abdominal wall. It is usually connected near its origin with the first
lumbar nerve by means of a small cord, which descends on or through the substance
of the quadratus lumborum muscle. It supplies branches to the quadratus
lumborum (frequently), internal oblique, transversalis, rectus, and pyramidalis
muscles, as well as lateral and anterior cutaneous branches ; and it sometimes com-
municates in the abdominal wall with the ilio-hypogastric nerve. Its anterior
cutaneous twigs are distributed below a point midway between the umbilicus and
pubis.
The lateral cutaneous branch of the last dorsal nerve is usually of considerable
size. It pierces the internal oblique muscle, gives a branch to the lowest slip of the
external oblique, and then emerging through the latter muscle a variable distance
(from one to three inches) above the iliac crest, is directed downwards to the
integument of the fore part of the gluteal region, some filaments reaching as far as
the great trochanter.
Varieties. — In some cases the lateral cutaneous branch of the last dorsal nerve is small,
and is distributed entirely to the skin above the iliac crest, its place over the hip being taken
by the iliac branch of the ilio-hypogastric nerve. Complete absence of this branch was
observed by M. Griffin four times in fifty cases (" Some Varieties of the Last Dorsal and First
Lumbar Nerves," Journ. Anat., xxvi, 1891).
LUMBAR NEEVES.
The anterior divisions of the lumbar nerves increase in size from the first to the
fifth. The upper three and the greater part of the fourth enter the lumbar plexus ;
the smaller part of the fourth and the fifth pass down to the sacral plexus. On
leaving the inter vertebral foramina, the nerves are connected by filaments with the
cord of the sympathetic, these filaments being longer than those connected with
other spinal nerves, in consequence of the position of the lumbar sympathetic
ganglia on the fore part of the bodies of the vertebrae. In the same situation
small twigs are furnished to the quadratus lumborum muscle from the first and,
sometimes, the second nerve, and to the psoas from the second and third nerves.
312
THE SPINAL NERVES.
LUMBAR PLEXUS.
The lumbar plexus is formed by the anterior primary divisions of the upper four
lumbar nerves. It is placed in the substance of the psoas muscle, in front of the
transverse processes of the corresponding vertebrae. Above, the plexus is narrow,
and is usually connected with the last dorsal nerve by a small offset from that nerve,
DXTT
IV
V
CJ
Fig. 204. — DIAGRAM OF THE LUMBAR AND
SACRAL PLEXUSES WITH THE PRINCIPAL
NERVES ARISING FROM THKM. (Allei)
Thomson.) %
DXII, the divided roots of the last dorsal
nerve ; LI, to V, the roots of the five
lumbar nerves ; the loops uniting the an-
terior primary divisions of these nerves
together, and the first with the twelfth
dorsal, are shown ; SI, to V, and CI, the
sacral and coccygeal nerves ; p, placed on
some of the nerves, marks the posterior
primary divisions cut short ; p, p', the
plexus formed by the union of the posterior
branches of the third, fourth, and fifth sacral
and the coccygeal nerves ; d, anterior divi-
sion of the last dorsal nerve, from which
d' the lateral cutaneous branch arises ; 1,1',
ilio-hypogastric nerve, dividing into its two
branches ; the ilio-inguinal nerve is seen
below these, without a number ; 2, genito-
crural ; 2', external cutaneous of the thigh ;
ql, branches to quadratus lumborum ; %.s,
branches to the psoas muscle ; a; anterior
crural nerve ; il, branches to the iliacus ;
ob, obturator nerve ; ob', accessory obturator ;
IV, V, loop from the fourth and fifth
lumbar, forming the lumbo-sacral cord ;
3, superior gluteal nerve ; sc, great sciatic
nerve, continued from the sacral plexus ;
4, small sciatic nerve rising from the plexus
posteriorly ; 4', inferior gluteal nerve ; 5,
inferior pudendal ; 5', posterior cutaneous of
the thigh and leg ; 6, 6, branch to the
obturator internus and gemellus superior ;
b", (>', branch to the gemellus inferior,
quadratus femoris and hip-joint ; 7, twigs to
the pyriformis ; 8, pudic nerve ; 9, visceral
branches ; 9', twig to the levator ani ; 10,
perforating cutaneous nerve; 11, coccygeal
branches.
named dor so-lumbar ; below, it is
wider, and is joined to the sacral
plexus by means of a branch passing
from the fourth lumbar nerve to the
fifth.
The nerves entering the lumbar
plexus do not form an interlace-
ment, as in the brachial plexus, but the several nerves of distribution proceeding
from the plexus for the most part arise by two or more roots from a corre-
sponding number of spinal nerves, so as to produce the appearance of a series
of loops. The usual arrangement may be thus stated : — The first lumbar nerve,
having been joined by the branch from the last dorsal, gives off the ilio-
hypogastric and ilio-inguinal nerves, and sends downwards a communicating
branch to the second nerve. The fibres of the dorso-lurnbar cord enter chiefly
the ilio-hypogastric nerve, but some may pass also to the ilio-inguinal. The
THE LUMBAR PLEXUS.
313
descending branch of the first nerve contributes to the genito-crural, often
to the anterior crural, and occasionally to the obturator nerve. The second
lumbar nerve furnishes the greater part of the genito-crural and external cutaneous
nerves, and gives a connecting branch to the third, from which some of the
fibres of the anterior crural and obturator nerves are derived. From the third
nerve three branches proceed ; the largest part enters the anterior crural nerve ; a
small branch, dorsally placed, joins the external cutaneous ; and the third, arising
from the ventral aspect of the trunk, passes to the obturator nerve. The fourth
nerve also gives three branches, of which the anterior and posterior serve to
complete the obturator and anterior crural nerves respectively, while the third,
placed below the others, descends to join the fifth lumbar nerve, thus forming the
Iwnbo-sacral cord, which enters into the sacral plexus.
The BRANCHES of the lumbar plexus form two sets, which are distributed, one to
the lower part of the wall of the abdomen, the other to the fore part and inner side
of the lower limb. In the former set are the ilio-hypogastric and ilio-inguinal
nerves, and part of the genito-crural ; and to the latter belong the remaining part
of the genito-crural nerve, the external cutaneous, the obturator, and the anterior
crural nerves.
Varieties of the lumbar plexus. — In the normal condition, the first three lumbar nerves
enter wholly into the lumbar plexus, and the fifth lumbar nerve into the sacral plexus, while
the fourth — the nervus fur calls of v. Jhering — is divided between the two plexuses. The
proportion of the fourth nerve, which descends to the sacral plexus, is normally less than one-
half, but it varies in different cases from one-twentieth to nine-tenths (Eisler). When the
sacral division of this nerve is very large it may be joined by a branch from the third lumbar
nerve ; and conversely, when the sacral division of the fourth nerve is very small, the fifth
lumbar nerve may send an offset to the lumbar plexus, where it contributes to the formation
of the anterior crural and obturator nerves, or, perhaps, only to the former. In these cases
there are, therefore, two furcal nerves, viz., 3 I and 4 I, or 4 1 and 5 1 respectively. Farther, the
sacral branch of the fourth lumbar nerve may be wanting, and then the fifth lumbar is the
sole furcal nerve. A series may thus be traced in which the furcal nerves are progressively,
from above downwards, 3 and 4 I, 4 I, 4 and 5 Z, and 5 I. At the same time, the nerves given off to
the limb from the lumbar and sacral plexuses are found to vary in their origin to some extent,
having a tendency to arise higher or lower, according to the position of the furcal nerve or
nerves. In the slighter degrees of variation this is shown by a difference in the size of the
contributing roots, so that a given trunk will derive a larger share of its fibres from an upper,
and a smaller share from a lower spinal nerve, or vice versa ; but in the more marked degrees
the origin may be shifted upwards or downwards to the extent of one spinal nerve. There
are thus to be distinguished two extreme forms of plexus (fig. 205), which may be called Ugh
and low (the " anterior " and "posterior " forms of Langley, " prefixed " and " postfixed types "
of Sherrington), and between which the normal or average plexus is placed, as is shown, for
the lumbar plexus only, in the following table, wherein the order of the nerves in each case
indicates the size of the roots in descending series, and the roots enclosed in parentheses are
inconstant : —
High form.
Normal form.
Low form.
External cutaneous ...
2, (1)1
3, 2, 4, 1 1
2, 31
3, 4, 2 I
3, 2Z
4, 3, 5, 21
Anterior crural
Furcal nerves
(very rarely 3, 2, 1 I)
3, 2, 4, 11, (12 d)
3 and 4 1
(or 4 I with large sacral division)
4, 3, 2, 1 I
41
4, 3, 5, 2 1
4 and 5 1, or 51
Forms intermediate to these also occur : and the relations of the several offsets of the
plexus to one another sometimes vary to a limited extent : that is, one nerve may have a high
origin, while the others belong to the normal form, or vice versa. Variations are more
frequent and extensive in the downward direction than the opposite. In some instances the
extreme forms are associated with irregularities of the vertebral column (see Vol. II, p. 12),
314
THE SPINAL NERVES.
the low form of plexus with an additional moveable vertebra, and the high form with assimi-
lation of the fifth lumbar vetebra to the sacrum, but this is not always the case. The upper
three offsets of the lumbar plexus, not being1 true limb-nerves, do not vary so much in their
PUOJ
Fig. 205. — EXTREME FORMS OF LUMBAR AND SACRAL PLEXUSES. (From Eisler.)
A. High form of plexus : ventral aspect. From a subject in which the fifth lumbar vertebra was
assimilated to the sacrum, and articulated on both sides with the ilium.
B. Low form of plexus : dorsal aspect. From a subject in which there were thirteen dorsal and
five lumbar vertebrae.
origin, although they also are affected at times by the general form of the plexus ; on the
other hand, it may happen with a low form of plexus that the ilio-hypogastric and ilio-
inguinal nerves receive an additional root from the twelfth dorsal (Paterson) . (J. N. Langley
(lumbar plexus of cat), Journ. Phys.. xii. 349, xv. 210. and xvii. 296 ; C. S. Sherrington (cat and
monkey), Journ. Phys.. xiii. 639 ; P. Eisler. " Der Plexus lumbosacralis des Menschen,"
Halle, 1892 ; A. M. Paterson, " The Origin and Distribution of the Nerves to the Lower Limb,"
Journ. Anat., xxviii, 84).
Ilio-hypogastric and ilio-iiiguinal nerves. — These nerves are the upper
two branches of the lumbar plexus. They are both derived mainly from the first
lumbar nerve, and have a nearly similar course and distribution, corresponding
together to the anterior (intercostal) division of a dorsal nerve. They pass
forwards between and through the broad muscles of the abdomen, furnish a
lateral cutaneous branch to the integument of the hip, and becoming subcutaneous
anteriorly, end in the integument of the lowest part of the abdomen and scrotum in
the male, or labium pudendi in the female, as well as the adjacent part of the
BRANCHES OF LUMBAR PLEXUS. 315
thigh. The extent of distribution of the one is inversely proportional to that of the
other.
The ilio-hypogastric nerve, the highest and largest of the branches proceed-
ing from the first lumbar nerve, usually receives fibres also from the last dorsal
nerve through the dorse-lumbar cord. Issuing from the upper part of the psoas
muscle at the outer border, it runs obliquely over the quadratus lumborum to the
iliac crest, and there perforating the transverse muscle of the abdomen, gets between
that muscle and the internal oblique, and divides into an iliac and a hypogastric
branch.
(a) The iliac branch (ramus cutancus lateralis) pierces the internal oblique
muscle, and then emerges through the external oblique close to the iliac crest about
the junction of its middle and anterior thirds, to be distributed to the integument
over the gluteus medius and tensor vaginae femoris muscles.
(b) The hypogastric or abdominal branch passes on between the transversalis and
internal oblique muscles, to both of which it supplies twigs, and is connected with
the ilio-inguinal nerve near the iliac crest. It then perforates the internal oblique
muscle, and, piercing the aponeurosis of the external oblique a little above the
external abdominal ring, is distributed to the skin of the abdomen above the pubis
(r. cutaneus anterior).
Varieties. — The ilio-hypogastric nerve is occasionally derived from the last dorsal, and it
may even receive a root from the eleventh dorsal nerve (fig-. 205, A). The iliac branch varies
in size inversely with the lateral cutaneous of the twelfth dorsal, and it is sometimes altogether
wanting-. The hypogastric branch is not unfrequently joined with the last dorsal nerve
between the muscles. In some cases this branch supplies the pyramidalis muscle.
The ilio-inguinal nerve, smaller than the preceding, is also derived from the
first lumbar nerve, and sometimes receives an accession from the dorso-lurnbar cord.
Appearing from beneath the outer border of the psoas muscle below the ilio-hypo-
gastric nerve, it is directed obliquely downwards and outwards over the quadratus
lumborum and iliacus to the fore part of the iliac crest, where it perforates the
transversalis, and communicates with the ilio-hypogastric nerve between the
muscles. Then piercing the internal oblique muscle, it descends in the inguinal
canal, and emerging at the external abdominal ring on the outer side of the
spermatic cord, divides into branches which are distributed to the skin of the pubic
region and root of the penis and scrotum in the male, or labium pudendi in the
female (nn. scrotales s. labiales anteriores), and of the adjacent upper and inner
part of the thigh. In its progress this nerve may furnish branches to the internal
oblique and transversalis muscles.
Varieties. — The ilio-hypogastric and ilio-inguinal nerves often arise by a common trunk,
which divides after perforating the transversalis muscle. The ilio-inguinal nerve is occasion-
ally derived from the last dorsal nerve (fig. 205, A). On the other hand, it may spring from
the loop between the first and second lumbar nerves, or even entirely from the latter nerve.
It is sometimes small, and ends near the iliac crest by joining the ilio-hypogastric nerve,
which in that case gives off an inguinal branch having a similar course and distribution to the
ilio-inguinal nerve. The ilio-inguinal nerve may be absent, its place being taken by the
genital, rarely by the crural, branch of the genito-crural. In some cases the nerve has an
iliac or lateral branch, which is distributed to the skin in the neighbourhood of the anterior
superior iliac spine. The ilio-inguinal nerve may also replace to a greater or less extent the
genital branch of the genito-crural. or (very rarely) the external cutaneous -nerve (M. Griffin).
Genito-crural nerve. — The genito-crural nerve (n. geniiofemoralis) belongs
partly to the external genital organs and partly to the thigh. It is derived chiefly
from the second lumbar nerve, but receives also a few fibres from the connecting
cord between that and the first nerve. The nerve descends obliquely through the
psoas muscle, from which it emerges near the inner border, about on a level with
316
THE SPINAL NERVES.
the disc between the third and fourth lumbar vertebrae, and then lying on the fascia
covering the anterior surface of that muscle divides at a variable height into an
internal or genital, and an external or crural branch. It often bifurcates close to
Fig. 206. — VIEW FROM BEFORE OF THE ANTERIOR BRANCHES OF THE LUMBAR AND SACRAL NERVES
WITH THE PLEXUSES. (From Sappey, after Hirschfeld and Leveille.) £
1, lumbar part of the sympathetic cord ; 2, 2', anterior primary division of the twelfth dorsal nerve ;
3, first lumbar ; 4, 4', ilio-hypogastric branch of this nerve ; 5, 5', ilio-inguinal branch ; 6, second
lumbar nerve ; 7, 7', genito-crural nerve ; 8, 8', external cutaneous nerve of the thigh ; 9, third
lumbar nerve ; 10, fourth ; 11, fifth ; 12, lumbo-sacral cord ; 13, iliac branch of the ilio-hypogastric ;
14, its abdominal branch ; 15, ilio-inguinal nerve ; 16, external cutaneous nerve of the right side passing
out of the abdomen under Poupart's ligament ; 17, 17, 17, cutaneous ramifications of this nerve ;
17', the same nerve exposed on the left side ; 18, 18', genital branch of the geuito-crural ; 19, 19, its
crural branch on the right side ; 19', the same on the left side exposed as it descends in front of the femoral
artery ; 20, 20', anterior crural nerve ; 21, 21', obturator nerve ; 22, left sacral plexus ; 23, aortic
plexus of the sympathetic, connected with the other preaortic plexuses and the lumbar ganglia.
its origin from the plexus, in which case its two branches perforate the psoas
muscle in different places.
(a) The genital 'branch (n. spermaticus externus) lies upon or near the external
iliac artery, and sends a filament along that vessel ; then perforating the trans-
versalis fascia (or passing through the deep abdominal ring) it traverses the
inguinal canal with the spermatic cord, supplies the cremaster muscle, and sends
filaments to the skin of the scrotum and adjoining corner of the thigh. In
the female it accompanies the round ligament of the uterus to the skin of the
groin.
(b) The crural branch (n. lumboinguinalis) descends upon the psoas muscle
beneath Poupart's ligament into the thigh. Immediately below that ligament, and
THE EXTERNAL CUTANEOUS NERVE. 317
at the outer side of the femoral artery, it pierces the fascia lata, and supplies the
skin on the upper part of the thigh, communicating with the middle cutaneous
branch of the anterior crural nerve. While it is passing beneath Poupart's
ligament, some filaments are prolonged from this nerve on the femoral artery.
Varieties. — The two divisions of the genito-crural nerve often arise independently from
the lumbar plexus (fig-. 205). The genital branch is occasionally derived from the last dorsal
and first lumbar nerves (fig-. 205, A). Either branch may proceed wholly from the first or the
second lumbar nerve (fig. 205, B). Absence of either division, or more rarely of the whole
nerve, may occur : in such cases the fibres usually forming the genital branch are associated
with the ilio-inguinal nerve, and those belonging to the crural division with the external
cutaneous or anterior crural nerve. Conversely, the genital branch may reinforce or replace
the ilio-inguinal nerve, and the crural branch the external or middle cutaneous. The genital
branch often gives filaments to the lower fibres of the internal oblique and transversalis
muscles.
External cutaneous nerve. — This nerve (n. cufaneus femoris lateralis),
arising from the second and third lumbar nerves, emerges from the outer
border of the psoas muscle, and crosses the iliacus below the ilio-inguinal nerve,
where it is placed beneath the iliac fascia. It passes under Poupart's ligament,
and enters the thigh immediately below the anterior superior iliac spine, where it
divides into an anterior and a posterior branch distributed to the integument of the
outer side of the hip and thigh (fig. 208, 1).
(a) The posterior branch perforates the fascia lata and subdivides into two or
three others, which turn backwards and supply the skin upon the outer surface of
the limb, from the upper border of the hip-bone nearly to the middle of the thigh.
The highest among them are crossed by the cutaneous branches from the last dorsal
nerve.
(Z>) The anterior branch, the continuation of the nerve, is at first contained in a
canal formed in the substance of the fascia lata ; but, about four inches below
Poupart's ligament, it enters the subcutaneous fatty tissua, and is distributed along
the outer part of the front of the thigh, ending near the knee. The principal offsets
spring from its outer side. In some cases, this branch reaches quite down to the
knee, and takes part there in the formation of the patellar plexus.
Varieties. — In the normal form of lumbar plexus the external cutaneous nerve is derived
mainly from the second lumbar nerve, and receives only a small root from the third. In the
high form of plexus it arises entirely from the second lumbar nerve, or from the second and
first ; while in the low form its chief root is furnished by the third nerve. The external
cutaneous nerve often accompanies, or is united with, the anterior crural trunk to below
Poupart's ligament. The posterior branch is sometimes replaced by an offset of the genito-
crural nerve. In one instance the place of the external cutaneous nerve was taken by a
branch of the ilio-inguinal (M. Griffin).
Obturator nerve. — The obturator nerve arises from the lumbar plexus generally
by three roots, which proceed from the second, third and fourth lumbar nerves, and
of which that from the third is the largest, while the root from the second nerve is
often very small. Having emerged from the inner border of the psoas muscle,
opposite to the brim of the pelvis, it runs along the side of the pelvic cavity, above
the obturator vessels, as far as the opening in the upper part of the thyroid foramen,
through which it escapes from the pelvis into the thigh. In the foramen, it divides
into an anterior and a posterior branch, which are separated from one another by
some fibres of the obturator externus, and lower down by the short adductor
muscle.
A. The anterior or superficial portion communicates with the accessory obturator
nerve, when this is present, and descends over the upper border of the obturator
VOL. III., PT. 2. X
318
THE SPINAL NERVES.
externus and in front of the adductor brevis, but behind the pectineus and adductor
longus muscles. It gives branches as follows : —
(a) An articular branch to the hip-joint arises in the thyroid foramen.
(ft). Muscular branches are given to the gracilis and adductor longus muscles, and
generally also to the adductor brevis.
(c) The terminal twig turns outwards upon the femoral artery, and surrounds
that vessel with small filaments.
(d) An offset at the lower border of the adductor longus communicates beneath
the sartorius with the internal cutaneous branch of the anterior crural nerve, and
with a branch of the internal saphenous nerve, forming a sort of plexus.
B. The posterior or deep part of the obturator nerve, having perforated the upper
Fig. 207.— THE LUMBAR PLEXUS FROM BEFORE. WITH THE
DISTRIBUTION OF SOME OF ITS NERVES. (Slightly
altered from Schmidt.) i
«, last rib ; b, quadratus lumborum muscle ; c,
oblique and ti-ansverse muscles, cut near the crest of
the iliimi and turned down : d, pubis ; c, adductor
brevis muscle ; /, pectineus divided and turned out-
wards ; <j. adductor longus ; 1, ilio-hypogastric nerve ;
2, ilio-inguinal ; 3, external cutaneous ; 4, anterior
crural ; 5, accessory obturator ; 6, obturator, united
with the accessory by a loop round the pubis ; 7, genito-
crural in two branches cut short near their origin \
8, 8, lumbar portion of the gangliated' sympathetic
cord.
fibres of the obturator externus muscle,,
crosses behind the short adductor to the fore-
part of the adductor magnus, where it divides
into several branches, all of which end in
those muscles, excepting one which is pro-
longed downwards to the knee-joint.
(a) The muscular branches supply the
external obturator and the great adductor
muscle, with the short adductor also when
this muscle receives no branch from the
anterior division of the nerve.
(b) The articular branch for the knee
rests at first on the adductor magnus, but
perforates the lower fibres of that muscle,,
and thus reaches the upper part of the
popliteal space. Supported by the popliteal artery, and sending filaments around
that vessel, the nerve then descends to the back of the knee-joint, and enters the
articulation through the posterior ligament. This branch is often wanting.
Varieties. — The obturator nerve sometimes has an additional root from the first or the
fifth lumbar nerve. In extreme cases of the hig-h form of the plexus it may arise from the-
upper three lumbar nerves. The root from the second nerve is rarely wanting- (Eisler). It
occasionally gives a branch to the pectineus muscle. A branch to the obturator internus is
described by Krause. Eisler traced filaments to the obturator artery and the periosteum on
the back of the pubis.
Occasional cutaneous nerve. — In some instances the communicating1 branch described
above is larg-er than usual, and descends along- the posterior border of the sartorius to the
inner side of the knee, where it perforates the fascia, communicates with the internal
saphenous nerve, and extends down the inner side of the limb, supplying' the skin as low as
the middle of the leg1.
When this cutaneous branch of the obturator nerve is present, the internal cutaneous
branch of the anterior crural nerve is small, the size of the two nerves bearing an inverse
proportion to each other.
THE ANTERIOR CRURAL NERVE. 319
Accessory obturator nerve. — This slender nerve is pi'esent in one out of every three or
four bodies (29 per cent., Eisler). It arises from the third and fourth lumbar nerves (rarely
also from the fifth, sometimes only from the third), between the roots of the obturator and
anterior crural nerves, bein^- associated at its origin more closely with the latter, but it is often
bound up for a short distance with the obturator nerve, of which it then appears to be a
branch. It descends beneath the iliac fascia along- the inner border of the psoas muscle,
crosses over the superior ramus of the pubis, and passing behind the pectineus muscle, ends by
dividing into branches. Of these, one joins the superficial part of the obturator nerve ; another
enters the pectineus on its under surface : and a third passes to the hip-joint. Throug-h the
communication with the obturator nerve fibres may also pass to the adductor long-us, gracilis,
and adductor brevis muscles, rarely to the skin of the inner side of the thi^h. The accessory
nerve is sometimes very small, and ends in filaments which perforate the capsule of the joint.
(See A. M. Paterson, ''The pectineus muscle and its nerve-supply," Journ. Anat., xxvi, 1891,
and op. cit. ,v., Journ. Anat., xxviii, 95 ; P. Eisler. " Der Plexus lumbosacralis," 1892).
SUMMARY. — The obturator nerve and accessory obturator supply the three
adductor muscles of the thigh, with the gracilis and obturator externus, and in
some cases, the pectineus. They also give branches to the hip and knee-joints; and
occasionally a cutaneous branch descends to the inner side of the thigh, and to the
inner and upper part of the leg.
Anterior crural or femoral nerve. — This, the largest nerve arising from
the lumbar plexus, is derived principally from the third and fourth lumbar nerves,
but in part also from the second and first. Emerging from the outer border of the
psoas muscle near its lower part, it descends into the thigh in the groove between
that muscle and the iliacus, and therefore to the outer side of the femoral blood-
vessels. Below Pouparb's ligament, the nerve becomes flattened out and divides into
two parts, one of which is mainly cutaneous, while the other is distributed for the
most part to muscles.
A. Branches in the trwik. — The branches given from the anterior crural nerve
within the abdomen are few and of small size.
(a) The iliacus receives three or four small branches (2, 3 I), which are directed
outwards from the nerve to the muscle.
( b) The nerve of the femoral artery is a small branch which divides into numerous
filaments upon the upper part of that vessel. It sometimes arises lower down than
usual, in the thigh. It may, on the other hand, be found to take origin above the
ordinary position from the third lumbar nerve. Beck and Rauber describe
filament passing from this nerve, in company with the medullary artery, to the
femur.
B. Terminal branches. — From the principal or terminal divisions of the nerve
the remaining branches take their rise as follows.
From the superficial or anterior division cutaneous branches are given to the
fore part of the thigh, and to the inner side of the leg ; they are the middle and
internal cutaneous nerves. Two muscles, the sartorius and the pectineus, receive
their nerves from this group.
From the deep or posterior division branches proceed to supply the extensor
muscle of the knee, and also one cutaneous nerve, the internal saphenous.
(a) Middle cutaneous nerve. — The middle cutaneous nerve ( 2, 3 /) either pierces the
fascia lata in two parts about four inches below Poupart's ligament, or as one trunk
which soon divides into two branches. These branches descend on the fore part of
the thigh to the front and inner side of the patella. After or before the nerve has
become subcutaneous, it communicates with the crural branch of the genito-crural
nerve, and also with the internal cutaneous.
This nerve, or the outermost of its branches, frequently pierces the upper part of
the sartorius muscle.
(b) Internal cutaneous nerve. — The internal cutaneous nerve (2, 3 /) gives branches
x 2
320
THE SPINAL NERVES.
to the skin on the inner side of the thigh, and the upper part of the leg ; but the
extent to which it reaches varies with the presence or absence of the " occasional
cutaneous " branch of the obturator nerve.
Lying beneath the fascia lata, this nerve descends obliquely over the upper part
of the femoral artery. It divides either in front of that vessel, or at the inner side,
into two branches (one anterior, the other posterior), which pierce the fascia
separately. Before dividing, this nerve gives off two or three cutaneous twigs,
which accompany the upper part of the long saphenous vein. The highest of these
perforates the fascia near the saphenous opening, and reaches down to the middle of
Fig. 208. — CCTANKOUS NERVES OP TIIK ANTERIOR AND INNER
PART OF THE THIGH. (From Sappey, after Hirschfekl and
Leveilld.) i
1, external cutaneous nerve ; 2, 3. middle cutaneous, the
outer one passing through the sartorius muscle ; 4, filament to the
sartorius : 5, internal cutaneous nerve ; 6, its anterior division ;
7. one of its upper branches ; 8, a cutaneous twig from the
nerve to the pectineus ; 9, pateilar branch of the internal
saphenous nerve ; 10, continuation of the saphenous to the leg.
the thigh. Another, larger than the rest, passes
through the fascia about the middle of the thigh, and
extends to the knee. In some instances, these small
branches spring directly from the anterior crural
nerve; and one branch is frequently given off from
the nerve to the pectineus, joining in a loop on the
inner side of the femoral artery with a branch passing
in front of that vessel (fig. 208, 8 ; 209, 7).
The anterior branch, descending in a straight line
to ihe knee, perforates the fascia lata in the lower
part of the thigh ; it afterwards runs down near the
tendon of the adductor magnus, giving off filaments
on each side to the skin, and is finally directed over
the patella to the outer side of the knee. It com-
municates above the joint with a branch of the long
saphenous nerve ; and sometimes it takes the place of
the branch usually given by the latter to the integu-
ment over the patella.
The posterior or inner branch of the internal
cutaneous nerve, descending along the posterior
border of the sartorius muscle, perforates the fascia
lata at the inner side of the knee, and communicates
by a small branch with the internal saphenous
nerve, which here descends in front of it. It gives some cutaneous filaments to the
lower part of the thigh on the inner side, and is distributed to the skin upon the
inner side of the calf. While beneath the fascia, this branch of the internal
cutaneous nerve joins in an interlacement with offsets of the obturator and internal
saphenous nerves below the middle of the thigh ; and in the leg it communicates
again with branches of the saphenous nerve.
(c) The branch to the pectineus (2, 3 /) is usually associated at its origin with the
internal cutaneous nerve. It crosses inwards behind the femoral vessels, and enters
the muscle on its anterior aspect : this branch is occasionally double.
(d) The sartorius muscle receives two or three twigs (2, 3 /) which arise in
common with the middle cutaneous nerve, and enter the upper part of the muscle.
THE ANTERIOR CRURAL NERVE.
521
(e) The branch to the rectas femoris (3, 4 I) enters the posterior surface of its
muscle : from this nerve, and from some of the other muscular branches, twigs are
sent, in company with a branch of the external circumflex artery, to the hip-joint.
(/) The nerve to the vastm externus (3, 4 /), of considerable size, descends with
a large branch of the external circumflex artery along the anterior border of the
muscle, and sends a filament to the knee-joint.
(ff) Two or three branches (3, 4 /) penetrate the crureus muscle on its anterior
surface, and from the most internal of these a filament can be traced, under cover of
the anterior border of the vastus internus muscle, to the subcrnreus. the periosteum
of the lower end of the femur, and the synovial membrane of the knee-joint.
Fig. 209. — DEEP NERVES OP THE ANTERIOR AND INNER PART OF
THE THIGH. (From Sappey, after Hirschfeld and Leveille.) |
1, anterior crural nerve ; 2, branches to the iliacus muscle ;
3, branch to the lower part of the psoas ; 4, internal and middle
cutaneous nerves, divided to show the deeper branches ; 5, 6,
nerves to the pectineus ; 7, cutaneous filament from the last ; 8,
posterior branch of the internal cutaneous nerve ; 9, branch to the
rectus ; 10, branch to the vastus externus ; 11, branch to the
vastus internus ; 12, internal saphenous nerve ; 13, its patellar
branch ; 14, its continuation to the leg ; 15, obturator nerve ; 16,
branch to the adductor longus; 17, branch to the adductor brevis ;
18, branch to the gracilis ; from this a filament is prolonged
downwards, to unite with the plexus formed by the union of
branches from the internal cutaneous and internal saphenous
nerves ; 19, deep branch of the obturator nerve to the adductor
magnus ; 20, lumbo-sacral cord ; 21, its union with the first sacral
nerve ; 22, 22, lumbar and sacral parts of the sympathetic nerve ;
23, external cutaneous nerve.
(7^) The nerve of the vastus internus (3, 4 I) runs
downwards with the internal saphenous nerve beneath
the aponeurosis covering the femoral vessels, giving
several branches to the upper part of its muscle ; it
enters the latter about the middle of the thigh, and
from its lower end a considerable twig is continued
to the knee-joint, in company with the deep branch
of the anastomotic artery.
(i) Internal saphenous nerve. — The internal or
long saphenous (3, 4/) is the largest of the branches of
the anterior crural nerve. It is deeply placed as far as
the knee, but is subcutaneous in the rest of its extent.
In the thigh, it accompanies the femoral vessels,
lying at first to their outer side, but lower down
gradually crossing over the artery, and passing
beneath the same aponeurosis. When the vessels
pass through the opening in the adductor magnus muscle into the popliteal space,
the saphenous nerve separates from them, and is continued beneath the sartorius
muscle to the inner side of the knee ; here, having first given off', as it lies near thu
inner condyle of the femur, a branch which is distributed over the front of the patella,
it becomes subcutaneous by piercing the fascia at the lower border of the sartorius.
The nerve then accompanies the saphenous vein along the inner side of the leg,
and, passing in front of the inner ankle, terminates on the inner side of the meta-
tarsal region of the foot. In the leg it is connected with the posterior branch of the
internal cutaneous nerve.
The distribution of its branches is as follows : —
A communicating branch is given off about the middle of the thigh to join in the
322 THE SPINAL NERVES.
interlacement formed beneath the sartorius by this nerve and branches of the
obturator and internal cutaneous nerves.
The pateUar branch perforates the sartorius muscle and the fascia lata, and
spreads out over the front of the knee, where it forms, by uniting with branches of
the internal and middle (sometimes also the external) cutaneous nerves, a plexus
named i\\e patellar plexus.
Numerous branches are given off from the nerve to the skin of the leg, and the
larger of these turn forwards over the anterior border of the tibia. Its terminal
offsets on the inner side of the loot communicate with branches of the musculo-
cutaneous nerve.
Varieties. — In the high form of plexus the anterior crural may receive fibres from the
last dorsal nerve, in the low form from the fifth lumbar, the root at the opposite end of the
plexus being: correspondingly reduced. The nerve has been seen entering- the thigh between
the femoral artery and vein (Dubrueil). The several branches of the middle, or of the
internal, cutaneous nerve frequently arise independently from the anterior crural. The middle
or internal cutaneous nerve sometimes leaves the trunk of the anterior crural at a higher level
than usual, within the abdomen. The posterior branch of the internal cutaneous is sometimes
very small or absent, its place being supplied by the obturator or the internal saphenous nerve.
The anterior crural occasionally gives off the external cutaneous nerve of the thigh. The
internal saphenous nerve has been seen ending at the knee, its place in the leg being taken by
a branch of the internal popliteal nerve (Gr. H. Meyer). The patellar branch has been
observed arising from the nerve to the vastus internus (Guy's Hosp. Reports, 3rd ser.. xvi. 161).
The internal saphenous rarely furnishes the internal dorsal digital nerve of the great toe.
Branches of the anterior crural nerve to the tensor vaginae femoris and adductor longus are
described by several anatomists. Arthur Thomson found a branch passing behind the femoral
vessels to join the accessory obturator nerve and supply in part the latter muscle ( Journ. Anat..
xix, 331).
SUMMARY. — The anterior crural nerve is distributed to the skin upon the fore
part and inner side of the thigh, commencing below the termination of the ilio-
inguinal and genito-crural nerves. It furnishes also a cutaneous nerve to the inner
side of the leg and foot. All the muscles on the front of the thigh receive their
nerves from the anterior crural^ and the iliacus and pectineus are also supplied by
this nerve. Lastly, branches are given from the anterior crural nerve to the femoral
artery, to the thigh-bone, and to the hip and knee-joints.
FIFTH LUMBAR, NERVE.
The anterior branch of the fifth lumbar nerve, having received a fasciculus from
the nerve next above it, descends to join the first sacral nerve, and forms part of the
sacral plexus. The trunk resulting from the union of the fifth with a part of the
fourth nerve is named the lumbo-sacral cord, and gives origin to the greater part of
the superior gluteal nerve.
SACRAL AND COCCYGEAL NERVES.
The anterior divisions of the first four sacral nerves emerge from the spinal canal
by the anterior sacral foramina, and the fifth passes forwards between the sacrum and
coccyx.
The first two sacral nerves are large, and of nearly equal size ; the others diminish
rapidly, and the fifth is exceedingly slender. Like the anterior divisions of the
other spinal nerves, those of the sacral nerves communicate with the sympathetic :
the communicating cords are very short, as the sympathetic ganglia are close to the
inner margin of the foramina of the sacrum.
The first three nerves and part of the fourth contribute to form the sacral plexus.
The fifth has no share in the plexus, — it ends on the back of the coccyx. As the
description of the fourth and fifth sacral nerves and of the coccygeal will occupy
THE FOURTH AND FEFTH SACRAL NERVES. 323
only a short space, these three nerves may be noticed first, before the other nerves
and the numerous branches to which they give rise are described.
FOURTH SACRAL NERVE.
Only one part of the anterior division of this nerve joins the sacral plexus ; the
remainder, which is more than half the nerve, supplies branches to the viscera and
muscles of the pelvis, and sends downwards a connecting filament to the fifth
nerve.
(a) The visceral branches of the fourth sacral nerve are directed forwards to the
lower part of the bladder, and communicate freely with branches from the sympa-
thetic nerve. Offsets are distributed to the neighbouring viscera, according to the
sex (nn. hfemorrhoidales medii ; nn. resicales inferiores ; nn. vtujinales). They will
be described with the pelvic portion of the sympathetic nerve. These branches are
associated with others proceeding from the third sacral nerve, and they are some-
times derived mainly from the latter nerve. Sometimes filaments are added from
the second sacral nerve.
(Jb) Of the muscular branches, one supplies the levator ani, piercing that muscle
on its pelvic surface ; another enters the coccygeus ; while a third (hcemorrhoidal or
penneal branch} ends in the external sphincter muscle of the anus. The last branch,
after passing either through the coccygeus, or between it and the levator ani, reaches
the perineum, and gives filaments also to the integument between the anus and the
coccyx.
According1 to Eisler the nerve to the levator ani is derived from the third and fourth sacral
nerves, in some cases even from the second and third.
FIFTH SACRAL NERVE.
The anterior branch of this, the lowest sacral nerve, comes forwards through the
coccygeus muscle opposite the junction of the sacrum with the first coccygeal
vertebra : it then descends upon the coccygeus nearly to^the tip of the coccyx, where
it turns backwards through the fibres of that muscle, and ends in the integument
upon the posterior and lateral aspect of the bone (nn. ano-coccygei).
As soon as this nerve appears in front of the coccygeus muscle (in the pelvis) it
is joined by the descending filament from the fourth nerve, and lower down by the
small anterior division of the coccygeal nerve. It supplies filaments to the coccygeus
muscle.
COCCYGrEAL NERVE.
The anterior branch of the coccygeal, or, as it is sometimes named, the sixth
sacral nerve, is a very small filament. It escapes from the spinal canal by the
terminal opening, pierces the sacro-sciatic ligaments and the coccygeus muscle, and,
being joined upon the side of the coccyx with the filth sacral nerve, partakes in the
distribution of that nerve. The connection between the fourth and fifth sacral and
the coccygeal nerves is sometimes described as the coccygeal plexus.
SACRAL PLEXUS.
The lumbo-sacral cord (resulting as, before described from the junction of the
fifth and part of the fourth lumbar nerves), the anterior divisions of the first three
sacral nerves, and part of the fourth unite to form this plexus. Its construction is
simpler than that of the spinal nerve-plexuses already described, as the several
nerves unite without much interlacement into an upper large, and a lower small, cord
or band. The upper band is formed by the union of the lumbo-sacral cord with the
first and second, and the greater part of the third, sacral nerves, and is continued
324
THE SPINAL NERVES.
into the great sciatic nerve : the lower band, which has a more plexiform arrange-
ment, results mainly from the junction of the smaller part of the third sacral nerve
with the portion of the fourth nerve belonging to the plexus, and is prolonged into
Fig. 210. — THE SACRAL PLEXUS OF
THE RIGHT SIDE, FROM BEHIND.
(G. D. T.)
The peroneal and popliteal divisions
of the great sciatic nerve are separated
up to their origin. The dorsal offsets
of the plexus are represented light, and
the ventral offsets dark.
J-SACRAL CORD
S'JP.
GLUT.
the pudic nerve. The lower
band is, however, joined by a
small fasciculus from the second
sacral nerve, and according to
Eisler it receives fibres also from
the first sacral nerve. To the
place of union the nerves pro-
ceed in different directions, that
of the upper ones being obliquely
downwards, while that of the
lower is nearly horizontal ; and,
as a consequence of this difference,
they diminish in length from the
first to the last. The sacral plexus
rests on the anterior surface of
the pyriformis muscle, opposite
the side of the sacrum, and
escaping through the great sacro-
sciatic foramen, ends at the lower
border of the pyriformis in the
great sciatic and pudic nerves.
BRANCHES.— In addition to the terminal offsets, viz., the great sciatic and pudic
nerves, the sacral plexus gives origin to a number of collateral branches of smaller
size. These are the superior gluteal, inferior gluteal, small sciatic, and perforating
cutaneous nerves, and branches to the pyriformis, obturator intern us, gemelli, and
quadratus femoris muscles.
In the description of the sacral plexus a division is sometimes made into two subordinate
plexuses. The larger upper part, which ends in the great sciatic nerve and gives off the other
branches to the limb, is distinguished as the sciatic plexus {plexus iscMadiciis\ while the
smaller lower part, including the pudic nerve together with the visceral and muscular branches
of the third and fourth sacral nerves, is designated the pudic plexus (plexus pudendiut}.
In the usual condition the greater part of the sacral plexus is prolonged, as already stated,
into the great sciatic trunk, which divides at a variable level in the thigh into the internal
popliteal and external popliteal (or peroneal) nerves. But in many cases (1 in 5 or 6) these
nerves spring independently from the plexus, and the external popliteal division passes back-
wards through a cleft in the pyriformis muscle, the lower part of which is interposed between
the two nerves. In the normal arrangement also the two nerves can be readily separated up
to the pelvis by dissecting off the sheath of the great sciatic trunk, and it is then found that
the plexus and the nerves entering it are divided into ventral and dorsal portions, the internal
popliteal nerve being formed by the union of the ventral divisions of the lumbo-sacral cord
and the first three sacral nerves, while the external popliteal receives the dorsal divisions of
the lumbo-sacral cord and the first two sacral nerves. The collateral branches of the plexus
may also be divided in a corresponding manner according as they arise from the anterior or
BRANCHES OF THE SACRAL PLEXUS.
posterior divisions of the nerves, and thus the offsets of the plexus passing- to the limb may be
grouped as follows : —
Anterior or ventral nerve.*. l^oxterior or rfor.<ml tierces.
Nerve to quadratus f emoris. Superior gluteal.
Nerve to obturator internus. Inferior gluteal.
Internal popliteal. Nerves to pyriformis.
Small sciatic (perineal branch and inner External popliteal.
part of femoral division). Small sciatic (gluteal branches and outer
part of femoral division).
Perforating cutaneous.
Varieties of the sacral plexus. — The nerves proceeding from the sacral plexus vary in
their origin, like the offsets of the lumbar plexus, in accordance with the position of the
nernixfiircft.lix (see p. 313). The range of variation is shown in the following table, mainly
after Eisler : —
High form of plexus.
Normal form.
Low form.
Furcal nerves... -\
3 I and 4 I (or 4 1}
with large sacral >
41
4 I and 51 or 5
I
N. to quad, fern
N. to obt. int
Internal popliteal
Superior gluteal
division) )
4, 51
1 *, 5. 4 1, 2 s
Is, 5, 41, 2 s, (3 I)
5, 4 ', 1 s
4, 5 Z, 1 s
51, 1, 2s
1 «, .H 2s, 41, 3s
51, I s 41, (2 s)
Is, 51
2, 1, 3 s
2, 1 s, 5 1, 3 s, (4
511 2s
0
Inferior gluteal
N. to pyriformis
External popliteal . ...
51, Is, 41
(50, 1, 2s
5, 41, 1 s, (3 Z)
Is, 51, 2s
I, 2s
51, 1 s 41 2s
1, 2s, 51
2, 1, <3)s
1 2s 51 (3s]
Small sciatic
Pudic
1, 2s, 51
2, 3, 1 s, il
2, 3, 1 s
3. 4, 2. 1 s
2, 3, 4 s
3421s
(The relative size of the several roots is indicated by the order of the nerves, and those
included in parentheses are inconstant.)
A. — COLLATERAL BRANCHES.
Small muscular branches.— The pyriformis muscle is supplied by twigs arising
from the back of the first angl second sacral nerves.
The nerve of the quadratus f emoris muscle arises from the front of the upper part
of the plexus, receiving its fibres from the lumbo-sacral cord and first sacral nerve.
Concealed at first by the great sciatic nerve, it passes beneath the gemelli and the
tendon of the obturator internus — between those muscles and the capsule of the
hip-joint, — and reaches the deep (anterior) surface of the quadratus. It gives off a
branch to the inferior gemellus muscle, and another to the back part of the
hip-joint. A second filament frequently passes directly from the sacral plexus to the
articulation.
The nerve of the obturator internus muscle, derived from the fifth lumbar and upper
two sacral nerves, springs from the front of the plexus immediately below the fore-
going, with which it is usually connected at its origin. Appearing at t ie lower
border of the pyriformis to the inner side of the great sciatic nerve, it then turns
over the ischial spine on the outer side of the pudic vessels, and is directed forwards
through the small sacro-sciatic foramen to reach the inner surface of the obturator
muscle. This nerve furnishes a small offset to the superior gemellus.
Varieties. — Occasionally the branch to the superior gemellus is also given off by the nerve
to the quadratus ; or that muscle may be supplied from both sources. In one instance
J. T. Wilson found the nerve to the quadratus continued to the upper part of the adductor
magnus (Journ. Anat., xxiii, 354).
Superior gluteal nerve. — The superior gluteal nerve arises from the back of
the lumbo-sacral cord and first sacral nerve. It leaves the pelvis with the gluteal
326
THE SPINAL NERVES.
vessels through the great sacro-sciatic foramen above the pyriformis muscle, and
immediately divides into two branches, which run forwards between the glutens
medius and minimus, supplying those muscles and the tensor vaginas femoris.
(a) The upper branch is the smaller and more superficial ; it sends its offsets
solely to the glutens medius.
(b) The lower branch crosses the middle of the gluteus minimus muscle with the
lower branch of the gluteal artery ; it sends branches to both the gluteus medius
and minimus, and generally perforates the fore part of the latter muscle to reach the
deep surface of the tensor vaginas femoris, in which it ends.
Varieties. — The superior gluteal sometimes receives fibres also from the second sacral
nerve. A branch to the pyriformis muscle may be given off from the lowest root of this
nerve.
Fig. 211.— BRANCHES OF THE SACRAL PLEXUS IN THE
BUTTOCK. (Hirschfeld and Leveille.) i
a, great trochanter ; i, tensor vaginne femoris
muscle ; c, tendon of the obturator interims muscle ;
d, upper part of the vastus externus ; e, coccyx ;
/, gracilis muscle; between/and dr the adductor magnus,
semitendinosus, and biceps muscles, with the lower
end of the gluteus maximus ; 1, 1. upper branch of the
superior gluteal nerve ; 1', 1', inferior branch of the
same nerve ; 1", branch of the nerve to the tensor
vaginae femoris ; 2, 2, sacral plexus and great sciatic
nerve ; 2', muscular twig from the plexus to the pyri-
formis; 2" branch to the gemellus superior and obturator
internus; 3, small sciatic nerve, 3', 3', placed on the upper
and lower parts of the divided gluteus maximus, the
branches of the inferior gluteal nerve ; 3", the gluteal
cutaneous branches of the small sciatic nerve winding
round the lower border of the gluteus maximus ; 4, the
continuation of the small sciatic nerve as posterior
cutaneous nerve of the thigh ; 4', inferior pudendal
branch of the small sciatic ; 5, placed on the lower
part of the sacral plexus points to the origin of the pndic
nerve ; 6, its pei^neal division with its muscular
branches ; 6', internal superficial perineal branch ;
6", external superficial perineal ; -t- +, distribution of
these nerves and the inferior pudendal on the scrotum ;
7, dorsal nerve of the penis.
Inferior gluteal nerve. — The inferior gluteal nerve arises from the back of
the plexus, being formed of fibres which are derived from the lumbo-sacral cord, the
first and second sacral nerves. It usually sends a branch downwards to join the
commencement of the small sciatic nerve, and sometimes the two nerves are more
closely connected at their origins. The inferior gluteal nferve turns backwards at the
lower border of the pyriformis muscle, and immediately divides into a number of
branches which, diverging upwards and downwards, enter the deep surface of the
gluteus maximus muscle about midway between its origin and insertion.
Small sciatic nerve. — The small sciatic nerve (nervus cutaneus femoris
posterior) is entirely a sensory nerve, supplying the integument of the lower part of
the buttock, the back of the thigh, and the upper part of the back of the leg ; it also
furnishes one branch to the perineum — the inferior pudendal nerve.
The nerve takes its origin usually from the back of the upper three sacral nerves
by as many roots, the highest of which arises in common with a part of the inferior
gluteal nerve. Emerging below the -pyriformis muscle, it descends beneath the
gluteus maximus muscle, resting on the great sciatic nerve, and then along the back
of the thigh under cover of the fascia lata to a little beyond the knee. Here it
becomes subcutaneous, and its terminal ramifications are distributed to the skin of
THE SMALL SCIATIC NERVE.
the calf, one branch accompanying the short saphenous vein and forming a com
munication with the external saphenous nerve.
Fig. 212. — POSTERIOR CUTANEOUS NERVES OF THE HIP AND THIGH. (Hirschfeld and Leveille.) |
' a, gluteus maximus muscle, divided at its inferior part to show the small sciatic nerve ; b, b, fascia
lata ; c, d, part of the semitendinosus, biceps, and semimembranosus muscles exposed by the removal of
the fascia ; e, gasti'ocnemius ; /, coccyx ; g, internal saphenous vein ; 1, 2, 3, 3, posterior twigs of the
external cutaneous nerve of the thigh ; 4, small sciatic nerve ; 4', 4", its gluteal cutaneous branches ;
5, continuation of the small sciatic ; 5', 5', its inner and outer femoral cutaneous branches spreading on the
fascia of the thigh ; 6, 6, its terminal branches descending on the calf of the leg ; 7, internal and
external popliteal nerves, separating in the popliteal space ; 8, posterior divisions of the lower sacral and
coccygeal nerves ; 9, inferior pudendal nerve.
Fig. 213. — DEEP POSTERIOR NERVES OF THE HIP AND THIGH. (Hirschfeld and Leveille.) £
a, gluteus medius muscle ; b, gluteus maximus ; c, pyriformis ; d, placed on the great trochanter,
points to the tendon of the obturator internus ; e, upper part of the femoral head of the biceps ; /, semi-
tendinosus ; if, semimembranosus: h, gastrocnemius ; i, popliteal artery; 1, placed on the gluteus
minimus muscle, points to the superior gluteal nerve ; 2, 2, 2, ramifications of the inferior gluteal nerve ;
3, placed on the great sacro-sciatic ligament, points to the pudic nerve ; 3', its farther course ; 4, inferior
pudendal ; f>, placed on the upper divided part of the semitendinosus and biceps, points to the divided
small sciatic or posterior cutaneous nerve of the thigh ; 6, great soiatic nerve ; 6', 6', some of its
muscular branches to the hamstrings ; 7, internal popliteal nerve ; 7', its muscular or sural branches ;
8, external popliteal nerve ; 8', its external cutaneous branch ; 9, communicating tibial ; 9', communi-
cat'.ng peruneal branch to the external saphenous nerve.
Branches. — (a) The gluteal cutaneous branches (mi. clunium mferiores) are two or
three in number, and bend upwards over the lower border of the gluteus maximus
muscle, to be distributed to the skin of the lower and outer part of the gluteal
region.
328 THE SPINAL NERVES.
(b) The inferior pudendal nerve (rr. perineales] turns inwards below the ischial
tuberosity, giving offsets (sometimes separate branches of the nerve) to the skin ot
the upper and inner part of the thigh, and is continued forwards to the outer part of
the scrotum (or external labium pudendi), where its terminal filaments are
distributed, after forming communications with the external superficial perineal
branch of the pudic nerve.
(c) The femoral cutaneous branches are numerous, and arise from both sides of
the nervj while it lies beneath the fascia : they supply the skin of the back of the
thigh, the larger number passing to the inner side.
Varieties. —In cases of separate origin of the internal and external popliteal nerves
(p. 324), the small sciatic nerve also arises from the sacral plexus in two parts. The ventral
portion descends with the internal popliteal nerve below the pyrif ormis. and gives off the inferior
pudendal and inner femoral branches, while the dorsal portion passes through that muscle with
the external popliteal nerve, and furnishes the gluteal and outer femoral branches. The
inferior pudendal nerve sometimes pierces the great sacro-sciatic ligament. The small sciatic
may be joined on the back of the thigh by a branch of the great sciatic nerve (p. 331). In
some cases the small sciatic nerve ends behind the knee, its place in the leg being then taken
by a branch of the external popliteal (p. 336).
. The perforating cutaneous nerve (fig. 215, 10) is a slender branch which
arises most frequently from the second and third sacral nerves, and passes backwards
through the great sacro-sciatic ligament : it then turns upwards round the lower
border of the glutens maximus, and is distributed to the skin over the inner and
lower part of that muscle.
Varieties. — A perforating cutaneous nerve arising as above stated was found by Eisler 22
times in 34 plexuses : in three of these it was conjoined at its origin with the pudic nerve.
Instead of piercing the great sacro-sciatic ligament it may run with the pudic nerve between
the great and small ligaments, or it may pass between the great ligament and the gluteus
maximus muscle. In other cases a nerve having a similar distribution («. jwrfontHx <•!><•<• t/i/nix
major. Eisler) arises from the third and fourth (fig. 210), or fourth and fifth nerves (fig. 204.
10), and pierces the coccygeus muscle on its way backwards. Its place may also be supplied
by a branch of the small sciatic.
B. — TERMINAL BRANCHES.
Pudic nerve. — The pudic nerve (n. pudendus) is a short plexiform trunk, .which
is given off from the lower part of the sacral plexus, and distributes branches to the
perineum and external organs of generation. Its chief root is usually derived from
the third sacral nerve. To this are added others from the fourth and second nerves ;
and according to Eisler it also receives fibres from the first sacral nerve. The upper
roots spring from the front of the ventral divisions of the corresponding sacral
nerves. Passing out of the pelvis between the pyriformis and coccygeus muscles, it
turns forwards over the attachment of the small sacro-sciatic ligament to the ischial
spine, where it is placed on the inner side of the pudic vessels, to the small sacro-
sciatic foramen. Having thus arrived at the hinder part of the ischio-rectal fossa,
the trunk ends by dividing into the following three branches, viz., the inferior
hsemorrhoidal nerve, the perineal nerve, and the dorsal nerve of the penis, or clitoris,
according to the sex.
(a) The inferior hcemorrhoidal nerve (4, 3, (2) s) is sometimes derived separately
from the sacral plexus ; it inclines inwards towards the anus and divides into
numerous branches which supply the skin of the hinder part of the perineal space
and the external sphincter muscle. The most anterior branches form communica-
tions with the interior pudendal and superficial perineal nerves.
(b) The perineal nerve (3, 2, 4 s) is the largest of the three divisions of the pudic
nerve. It runs forwards along the outer wall of the ischio-rectal fossa, being con-
THE PUDIC NERVE.
329
tained in a special sheath of the obturator fascia below the pudic vessels, and breaks
up into superficial and deep branches.
The superficial 'perineal nerves are two in number, external and internal. The
external or posterior, which is the first to leave the perineal trunk, runs forwards
along the outer side of the perineal space to the scrotum, and sometimes gives a
branch to the adjacent part of the thigh. The iniernal or anterior branch is larger,
and runs forwards nearer the middle line, dividing into long slender offsets which
are distributed to the integument of the scrotum. The two branches communicate
freely together, and the external generally receives the connecting filaments from the
inferior pudendal and inferior haemorrhoidal nerves. The superficial perineal and
Fig. 214. — RIGHT SIDE OP THE INTERIOR OP
THE MALK PELVIS, WITH THE PRINCIPAL
NKRVES DISPLAYED. (Hhschfeld and Le-
veille.) i
The left wall has been removed as far as the
sacrum behind and the symphysis pubis in
front ; the viscera and the lower part of the
right levator ani have been removed ; a, lower
end of the aorta ; a', placed on the fifth lumbar
vertebra, between the two common iliac arteries,
of which the left is exit short ; b, right external
iliac vessels ; c, symphysis pubis ; d, the divided
pyriformis muscle, close to the left auricular
surface of the sacrum ; e, bulb of the urethra
covered by the bulbo-cavernosus muscle ; the
membranous part of the urethra cut short is
seen passing into it ; 1, on the crest of the
ilium, the external cutaneous nerve of the thigh
passing over the iliacus muscle ; 2, on the psoas
muscle, the genito-crural nerve ; 3, obturator
nerve ; 4, 4, on the lumbo-sacral cords ; that of
the right side points to the gluteal artery cut
short ; 4'. superior gluteal nerve ; 5, on the
right sacral plexus, points by four lines to the
anterior divisions of the four ' upper sacral
nerves, which, with the lumbo-sacral cord, form
the plexus ; 5', placed on the fifth piece of the
sacrum, points to the fifth sacral nerve ; 5",
visceral branches from the third and fourth sacral nerves ; 6, placed on the lower part of the coccyx,
below the coccygeal nerves ; 7, the nerve of the levator ani muscle ; 8, inferior hsemorrhoidal nerve ;
9, nerve of the obturator internus ; 10, pudic nerve : 10', muscular branches of the perineal nerve ;
10", superficial perineal nerves, and on the scrotum the distribution of these nerves and the inferior
pudendal nerve ; II, right dorsal nerve of the penis ; 11', the nerve on the left crus penis which is cut
short ; 12, small sciatic nerve; 12', its inferior pudendal branch. ; 13, on the transverse process of the
fifth lumbar vertebra, the lowest lumbar sympathetic ganglion ; 14, on the first piece of the sacrum, the
upper sacral sympathetic ganglia ; between 14 and 6, are seen the remaining ganglia and sympathetic
nervous cords, as well as their union with the sacral and coccygeal nerves, and at 6, the lowest ganglion
or ganglion impar.
inferior pudendal nerves are sometimes named from their distribution long scrotal
nerves (nn. scrotales poster iores).
In the female, both the superficial perineal branches terminate in the external
labium pudendi (nn. labiales posterior es).
The deep branches generally arise by a single trunk, and are distributed mainly
to the muscles of the perineum. They supply the fore part of the external sphincter
and levator ani muscles, the transversus perinei, ischio-cavernosus and bulbo-
cavernosus. One branch passes inwards through the bulbo-cavernosus muscle, and
divides into slender filaments which penetrate the corpus spongiosum and reach the
mucous membrane of the urethra.
(c) The dorsal nerve of the penis (2, 3, (1) s) is the deepest branch of the pudic
nerve, and accompanies the pudic artery in its course through the deep perineal
fascia (Vol. II, pp. 339 and 477), and between the layers of the suspensory liga-
330 THE SPINAL NERVES.
inent to the dorsum of the penis, alons; which it passes as far as the glans, where it
divides into filaments for the supply of that part. While passing through the deep
perineal fascia, it gives fine twigs for the supply of the constrictor urethras muscle ;
and on the dorsum of the penis, it is joined by branches of the sympathetic system,
and sends outwards numerous offsets to the integument on the upper surface and
sides of that organ. Some filaments also penetrate the corpus cavernosum.
In the female the dorsal nerve of the clitoris is much smaller than the correspond-
ing branch in the male ; it is similarly distributed.
Fig. 215. — DISSECTION OP THE PERINEUM OF THE MALE TO SHOW THE DISTRIBUTION OF THE PUDIC
AND OTHER NERVES. (Hirschfeld and Leveille. ) |
On the right side a part of the gluteus maximus muscle and the great sacro-sciatic ligament have been
removed : 1, great sciatic nerve of the right side ; 2, 2', on the right side, inferior gluteal nerve ; 2",
on the left side, gluteal cutaneous branches of the small sciatic ; 3, small sciatic nerve in the thigh ;
4, 4, inferior pudendal nerve ; 4', network of this and the superficial perineal nerves in the scrotum ;
5, right pudic nerve ; 6, superior branch or dorsal nerve to the penis : 7, external superficial perineal
branch ; 7', internal superficial perineal branch ; 8, deep or musculo-bulbal branches ; 9, inferior
hsemorrhoidal nerve ; 10, perforating cutaneous nerve.
Varieties. — In the high, form of plexus the pudic nerve may receive fibres from the fifth
lumbar (Eisler). Henle describes and figures a root to the pudic from the fifth sacral nerve,
but this was never met with by Eisler or Paterson. The inferior hsemorrhoidal nerve often
pierces the great or the small sacro-sciatic ligament on its way to the perineum (Eisler). The
external superficial perineal nerve may also pierce the great sacro-sciatic ligament.
SUMMARY. — The pudic nerve supplies the skin and muscles of the perineum, the
penis, and part of the scrotum in the male ; and the clitoris, labia, and other corre-
sponding parts in the female. It communicates with the inferior pudendal branch of
the small sciatic nerve.
Great sciatic nerve. — The great sciatic nerve (nervus ischiadicus'), the largest
nerve in the body, supplies the muscles at the back of the thigh, and by the branches
continued from it gives nerves to all the muscles below the knee and to the greater
part of the integument of the leg and foot. The several joints of the lower limb
receive filaments from it and its branches.
This large nerve is the continuation of the main part of the sacral plexus. It
extends from the lower border of the pyriformis muscle to somewhat below the
middle of the thigh, where it separates into two large divisions, named the internal
and external popliteal nerves. At first it lies in the hollow between the great
THE GREAT SCIATIC NERVE. 331
trochanterand the ischial tuberosity, covered by the gluteus maximus and resting on
the gemelli, obturator internus, and quadratus femoris muscles, in company with the-
small sciatic nerve and the sciatic artery, and receiving from that artery a branch
which runs for some distance in its substance. Lower down it rests on the
adductor magnus, and is covered behind by the loug head of the biceps muscle.
f Branches. — In its course downwards, the great sciatic nerve supplies offsets to
the hamstring muscles, viz., the semitendinosus, two heads of the biceps, and
semimembranosus. A branch is likewise given to the inner part of the adductor
magnus.
The branches of the great sciatic nerve to the muscles arising from the ischial tuberosity
are associated with its internal popliteal division, from which, however, they may be separated
up to their origin from the sacral plexus. They are then found to arise in the following^
order from above downwards : — the nerves to the adductor magnus (from 4 and 5 Z) and
semimembranosus (4, 5J and 1 *)> these being- commonly united in one cord ; two branches
for the semitendinosus (from 5 /, 1 and 2 xj, one supplying- the part of the muscle above, and
the other the part below the tendinous inscription ; and the nerve of the long head of the-
biceps (from 1, 2 and 3 *). The nerve of the short head of the biceps is united with the
external popliteal division, and according to Paterson may be followed up to 5 I, 1 and 2 s.
Varieties. — The bifurcation of the great sciatic nerve may take place at any point
intermediate between the sacral plexus and the lower part of the thigh ; and in some cases
the two popliteal nerves arise separately from the sacral plexus (see p. 324). Very rarely the
division takes place below the popliteal space (Henle). A branch of the great sciatic to join
the small sciatic on the back of the thigh is said to be normal by Krause, of frequent occurrence
by Henle. In one instance a nerve to the short head of the biceps arose directly from the
sacral plexus in union with the inferior gluteal nerve (G-. D. T.).
Internal popliteal nerve. — The internal popliteal (n. tibialis), the larger
of the two divisions of the great sciatic nerve, following the same direction as
the parent trunk, continues along the middle of the popliteal space to the lower
border of the popliteus muscle, beyond which point the continuation of the trunk
receives the name of posterior tibial. The internal popliteal nerve lies at first at
a considerable distance from tfye popliteal artery, at the outer side and nearer to
the surface ; but, from the km e-joint downwards, the nerve, continuing a straight
course, is close behind the artery, and then crosses it rather to the inner side.
Branches. — The internal popliteal nerve supplies branches to the knee-joint and to
the muscles of the calf of the leg, and also part of a cutaneous branch, the external
or short saphenous nerve. „
(a) The articular branches are given off from the upper part of the popliteal
trunk, and are generally three in number ; two of them accompany the upper and
lower articular arteries of the inner side of the knee-joint, the third follows the
middle or azygos artery. These nerves pierce the ligamentous tissue of the joint.
The upper one is often wanting.
(b) The muscular branches arise from the nerve while it is contained in the
popliteal space. They include two nerves to the gastrocnemius (1, 2 s) — one to each
head of the muscle ; a small nerve to the plantaris (4, 5 /, 1 s), derived either from
the branch to the outer head of the gastrocnemius, or directly from the main trunk ; a
considerable branch to the soleus (57, 1, 2 s), which enters the muscle on its posterior
aspect, close to the upper border ; and a nerve to the popliteus (4, 5 /, Is). The
last branch arises somewhat lower down, and is more deeply placed, than the others ;
it descends on the outer side of the popliteal vessels, gives off filaments to the
superior tibio-fibular articulation, to the tibia, and to the interosseous membrane,
and then turns beneath the lower border of its muscle, which it penetrates on the
deep or anterior surface. The branch to the tibia enters the shaft of the bone with
the medullary artery : that to the interosseous membrane is a long slender
3o~ THE SPINAL NERVES.
which, after supplying filaments to the anterior and posterior tibial arteries, is
•continued downwards in the membrane to end in the inferior tibio-fibular articu-
lation, and the periosteum of the lower part of the tibia ; small Pacinian corpuscles
occur on the filaments passing to the bone and ligaments.
(c) The cutaneous branch. — External or short saphenous nerve (n. suralis). — The
cutaneous branchof the internal popliteal nerve (tibial communicating nerve ; n. cutaneus
•sunv medialis) (1, 2 s) descends along the leg, in the furrow between the heads of the
Fi<:. 216. — POSTERIOR CUTANEOUS NERVES OF THE LEG.
after Hirschfeld and Leveille.)
(From Sappey,
1, internal popliteal nerve ; 2, branch to the inner head of the gastro-
cnemius muscle ; 3, 4, branches to the outer head and plantaris ; 5, tibial
communicating nerve ; 6, external popliteal nerve ; 7, lateral cutaneous
branch of the leg ; 8. peroneal communicating branch, descending to unite
with the tibial communicating in 9, the external saphenous nerve ; 10,
calcaneal branch from this nerve ; 11, calcaneal and plantar cutaneous
branches from the posterior tibial nerve ; 12, internal saphenous nerve ;
13, posterior branches of this nerve.
gastrocnemius muscle, to about midway between the knee and
the foot. Here it perforates the fascia, and a little lower down
is usually joined by a branch from the external popliteal nerve
(peroneal communicating}. After receiving this communicat-
ing branch, the external saphenous nerve descends beneath
the integument near the outer side of the tendo Achillis in
company with the short saphenous vein, and turns forwards
below the external malleolus to end in the skin on the outer
side of the little toe, forming also a communication on the
dorsum of the foot with the outer division of the musculo-
cutaneous nerve. While turning round the external malleolus,
the extern H! saphenous nerve gives off external calcaneal
branches to the skin on the outer side of the heel ; and
other filaments pass to the ankle-joint and the astragalo-
calcaneal articulation (Riidinger),
Varieties. — The union between the tibial communicating
nerve and the branch of the external popliteal nerve occurs
in some cases higher than usual, occasionally even at or close
to the popliteal space. It sometimes happens that the com-
munication between the nerves is altogether wanting ; in which
case the cutaneous nerve to .he foot is generally continued from
the branch of the internal popliteal nerve. The area of distribution of the external saphenous
nerve in the foot is often increased, so that it supplies in part or wholly the outer one and a
half, or even two and a half toes on their dorsal aspect : in these cases the peroneal communi-
cating branch is said to be of larger size than usual. Occasionally the external saphenous
nerve ends on the outer border of the foot, without reaching the toes.
Posterior tibial nerve. — The internal popliteal nerve receives the name of
posterior tibial at the lower margin of the popliteus muscle. It passes down the leg
with the posterior tibial artery, lying for a short distance on the inner side of the
vessel and afterwards on the outer side, the artery inclining inwards from its origin
while the nerve takes a straighter course. In the interval between the inner
malleolus and the heel, it divides into the two plantar nerves (internal and external).
The posterior tibial nerve, like the accompanying vessels, is covered at first by the
muscles of the calf of the leg, afterwards only by the integument and fascia, and it
rests upon the deep-seated muscles.
THE INTERNAL PLANTAR NERVE. 333
Branches. — The deep muscles on the back of the leg, the fibula, the integument
of the sole of the foot, and the ankle-joint receive branches from the posterior tibial
nerve in its course along the leg.
(a) The muscular branches (5 /, 1, 2 s) emanate from the upper part of the nerve
either separately or by a common trunk ; one is distributed to each of the deep
muscles, viz., the tibialis posticus, the flexor longus digitorum, and the flexor longus
hallucis ; and a second nerve is furnished to the soleus, piercing the deep surface
of the muscle.
(&) The fibular branch is a long slender offset which arises in common with the
nerves to the deep muscles, and descends, beset with numerous Pacinian corpuscles,
in the canal of the peroneal vessels as far as the ankle. It gives off filaments to the
vessels which it accompanies, to the shaft of the fibula with the medullary artery,
and to the periosteum covering that bone (Rauber).
(c) The calcaneo-plantar nerve (1, 2s) is given off by the posterior tibial in the
lower part of the leg, and becomes superficial by piercing the internal annular
ligament. It divides into internal calcaneal branches which ramify in the integu-
ment on the inner side of the heel, said. plantar cutaneous branches which supply the
skin of the inner and hinder part of the sole.
(a) One or two articular filaments pass from the posterior tibial nerve close
above its division to the inner side of the ankle-joint (Rudinger).
Internal plantar nerve. — The internal plantar (4, 5 /, Is), slightly the larger
of the two nerves to the sole of the foot into which the posterior tibial divides,
accompanies the internal or smaller plantar artery, and supplies nerves to both sides
of the inner three toes, and to one side of the fourth. From the point at which it
separates from the posterior tibial nerve, it is directed forwards under cover of the
first part of the abductor of the great toe ; then passing between that muscle and
the short flexor of the toes, it gives off the internal collateral branch for the great
toe, and divides about the middle of the foot into three digital branches. The
outermost of these branches communicates with the external plantar nerve. The
distribution of this nerve in the foot closely resembles that of the median nerve in
the hand.
Branches.— (a} Muscular branches are supplied to the abductor hallucis and flexor
brevis digitorum.
(b) An articular filament passes deeply between the abductor hallucis and the
tendons of the long flexors of the toes to supply the joints between the astragalus,
the navicular, and the inner two cuneiform bones (Rudinger).
(c) Small plantar cutaneous branches perforate the plantar fascia to ramify in the
integument of the sole of the foot.
(d) The digital branches are named numerically from within outwards : the
outer three pass from under cover of the plantar fascia near the clefts between the
toes. The first or innermost branch continues single, but the other three
bifurcate to supply the adjacent sides of two toes. They are distributed as follows : —
Theirs/ digital branch is destined for the inner side of the great toe ; it becomes
subcutaneous farther back than the others, and sends off a branch to the flexor brevis
hallucis muscle.
The second branch, having reached the interval between the first and second
metatarsal bones, furnishes a small twig to the first lumbricalis muscle, and bifurcates
behind the cleft between the great toe and the second to supply their contiguous
sides.
The third digital branch, corresponding with the second interosseous space,
divides in a manner similar to that of the second branch into two offsets for the sides
of the second and third toes.
VOL. III., PT. 2. Y
334
THE SPINAL NERVES.
The fourth digital branch, distributed to the adjacent sides of the third and
fourth toes, usually has a communication with the external plantar nerve.
Along the sides of the toes, cutaneous and articular filaments are given from these
digital nerves ; and, opposite the ungual phalanx, each sends a dorsal branch to the
pulp beneath the nail, and then runs on to the ball of the toe, where it is distributed
like the nerves of the fingers. Pacinian corpuscles are attached at intervals to these
nerves.
External plantar nerve. — The external plantar nerve (1, 2s) completes the
supply of digital nerves to the toes, furnishing branches to the little toe and half
the fourth ; it also gives a deep branch of considerable size, which is distributed to
several of the short muscles in the sole of the foot. There is thus a great resemblance
between the distribution of this nerve in the foot and that of the ulnar nerve in the
hand.
Fig. 217. — SUPERFICIAL AND DEEP DISTRIBUTION OK THE PLANTAR
NERVES. (After Hirschfeld and Leveille, slightly modified.)
(Allen Thomson.) ^
Parts of the flexor brevis digitoruin, abductor hallucis, abductor
minimi digiti, and the tendons of the flexor longus digitorum, together
with the lumbricales muscles, have been removed so as to bring into
view the adductor transversus and interosseous muscles in the middle
of the foot.
a, upon the posterior extremity of the flexor brevis digitorum, near
which, descending over the heel, are seen ramifications of the calcaneal
branch of the posterior tibial nerve ; b, abductor hallucis ; c, tendon
of the flexor longus digitorum, divided close to the place where it is
joined by the flexor accessorius ; d, abductor minimi digiti ; e, tendon
of the flexor longus hallucis between the two portions of the llexor
brevis hallucis ; 1, internal plantar nerve giving twigs to the abductor
hallucis, and 1', a branch to the flexor brevis digitorum, cut short ;
2, inner branch of the internal plantar nerve, giving branches to the
flexor brevis hallucis, and forming 2', the internal collateral nerve of
the great toe ; 3, continuation of the internal plantar nerve, dividing
into three branches, which form, 3', 3', 3', the plantar digital nerves
of the first and second, second and third, and third and fourth toes ;
4, external plantar nerve ; 4', its branch to the abductor minimi digiti ;
5, twig of union between the plantar nerves ; 6, superficial branch of
the external plantar nerve, dividing into 6', 6', the collateral digital
nerves of the fourth and fifth toes and the external nerve of the fifth ;
7, deep branch of the external plantar nerve.
The external plantar nerve runs obliquely forwards
towards the outer side of the foot, along with the external
plantar artery, between the flexor brevis digitorum and
the flexor accessorius, as far as the interval between the former muscle and the
abductor of the little toe. Here it divides into a superficial and a deep branch,
having previously furnished offsets to the abductor minimi digiti and the flexor
accessorius, as well as a filament through the last muscle to the calcaneo-cuboid
articulation (Riidinger).
(a) The superficial portion separates into two digital branches, which have the
same general arrangement as the digital branches of the internal plantar nerve. The
outermost of these is undivided, and runs along the outer side of the little toe : it is
smaller than the other, and pierces the plantar fascia farther back. The short flexor
muscle of the little toe, and sometimes one or both of the interosseous muscles of
the fourth space, receive branches from this nerve.
The larger digital branch usually communicates with the internal plantar nerve,
and bifurcates near the cleft between the fourth and fifth toes to supply one side of
each.
(I) The deep or muscular part of the external plantar nerve dips into the sole of
the foot with the external plantar artery, under cover of the tendons of the flexor
THE EXTERNAL PLANTAR NERVE.
335
muscles and the accessorius, and terminates in numerous branches for the following
muscles : — all the interosseous (dorsal and plantar) except occasionally one or both
of those in the fourth space, the outer three lumbricales, the adductor transversus
and adductor obliquus hallucis. This part of the nerve also furnishes articular
filaments to the tarso-metatarsal, and frequently to the metatarso-phalangeal joints,
us well as minute perforating branches, which pass upwards through the posterior
ends of the intermetatarsal spaces to join the interosseous branches of the anterior
tibial nerve (Riidinger).
Out of ten dissections by Brooks, the lumbricales were supplied as stated above in nine.
In the tenth case the first and second lumbricales received branches from both the internal and
Fig. 218. — CUTANEOUS NERVES OF OUTER SIDE OF THE
LEG AND FOOT. (From Sappey, after Hirschfeld
and Leveille. ) £-
1, external popliteal nerve ; 2, its lateral cutaneous
branch ; 3, pcroneal communicating branch which
unites with 4, the tibial communicating, in 5, the
external saphenous nerve ; 6, calcaneal branch of the
external saphenous ; 7, external dorsal digital branch
of the fifth toe ; 8, dorsal digital branch of the
fourth and fifth toes ; 9, 9, musculo-cutaneous nerve ;
10, 10, its two divisions ; 11, union with the external
saphenous ; 12, communication between its outer and
inner branches ; 13, anterior tibial nerve, shown by the
removal of a part of the muscles ; 14, its inner ter-
minal branch, emerging in the space between the first
and second toes, where it gives the collateral dorsal
digital branches to their adjacent sides ; 15, recurrent
articular nerve.
external plantar nerves (Journ. Anat.. xxi, 575).
The branch of the external plantar nerve to the
second lumbricalis runs forwards beneath the
adductor transversus hallucis, and then turns
backwards over that muscle to reach its destina-
tion. Cruveilhier describes the branch to the
third lumbricalis as piercing- the adductor trans-
versus hallucis. The deep part of the external
plantar nerve rarely gives a branch to the outer
head of the flexor brevis hallucis (normal accord-
ing1 to Henle and Schwalbe).
SUMMARY OF THE INTERNAL POPLITEAL
NERVE. — This nerve supplies all the muscles
of the back of the leg and sole of the foot,
the articulations of the kuee, ankle and foot,
the bones and vessels of the leg, and the in-
tegument of the plantar aspect of the toes,
the sole of the foot, and in part that of the
lower half of the back of the leg.
External popliteal or peroueal nerve (n.peronceus communis]. — This nerve
descends obliquely along the outer side of the popliteal space, lying close to the
biceps muscle. Continuing downwards over the outer part of the gastrocnemius
muscle (between it and the biceps) and below the head of the fibula, the nerve turns
round that bone and, passing between it and the peroneus longus muscle, divides
into the anterior tibial and the musculo-cutaneous nerves.
BRANCHES. — Some articular and cutaneous branches are derived from the external
popliteal nerve before its final division.
(a) The articular branches are conducted to the outer side of the capsular liga-
ment of the knee-joint by the upper and lower articular arteries of that side. They
Y 2
336 THE SPINAL NERVES.
sometimes arise together, and the upper one occasionally springs from the great
sciatic nerve before the bifurcation. From the lower branch a filament is given to
the superior tibio-fibular articulation (Eiidinger).
From the place of division of the external popliteal nerve, a branch (often double)
called the recurrent articular nerve ascends through the tibialis anticus with the
anterior tibial recurrent artery ; its fibres terminate mainly in that muscle, but fila-
ments may be traced to the superior tibio-fibular articulation, the periosteum over
the outer tuberosity of the tibia, and the fore part of the knee-joint.
(b) The cutaneous branches (5 /, 1, 2 s), generally two in number, supply the skin
on the back part and outer side of the leg.
The peroneal or fibular communicatiny branch, which usually joins the short
saphenous nerve below the middle of the back of the leg, is the largest of these
nerves. In some instances, it continues as a separate branch, and its cutaneous
filaments reach down to the heel or on to the outer side of the foot.
The lateral cutaneous branch of the leg (n. cutaneus sune laterals), often
arising in conjunction with the foregoing, extends along the outer side of the leg
to the middle or lower part, sending offsets both backwards and forwards.
In some cases there is another cutaneous branch which arises from the upper part of the
external popliteal nerve, and ramifies over the back of the calf, taking the place of the small
sciatic nerve below the knee.
Musculo -cutaneous nerve. — The musculo-cutaneous nerve (n.peronceussuper-
ficialis) (4, 5 /, Is) descends between the peronei muscles and the long extensor of
the toes, and reaches the surface by perforating the fascia in the lower part of the
leg on the anterior aspect. It then divides into two branches, distinguished as
external and internal, which proceed to the toes. The two branches sometimes
perforate the fascia at different spots.
Branches. — (a) Muscular branches are given to the peroneus longus and peroneus
brevis.
(b) Cutaneous branches given off near the primary division are distributed to the
lower part of the leg.
(c) The internal branch of , the musculo-cutaneous nerve, passing forwards along
the dorsum of the foot, furnishes one branch to the inner side of the great toe, and
another to the contiguous sides of the second and third toes. It also gives offsets
which extend over the inner ankle and side of the foot. This nerve communicates
with the long saphenous nerve on the inner side of the foot, and with the anterior
tibial nerve between the first and second toes.
(d) The external branch, smaller than the internal, descends over the foot
towards the fourth toe, tvhich, together with the contiguous borders of the third
and fifth toes, it supplies with branches. Cutaneous nerves, derived from this
branch, spread over the outer ankle and the outer side of the foot, where they are
connected with the short saphenous nerve.
The dorsal digital nerves are continued on to the last phalanges of the toes.
The number of toes supplied by each of the two divisions of the musculo-
cutaneous nerve is liable to vary ; together, these nerves commonly supply all the
toes. on the dorsal aspect, excepting the outer side of the little toe, which receives a
branch from the short saphenous nerve, and the adjacent sides of the great toe and
the second toe, to which the anterior tibial nerve is distributed : with this latter
branch, however, it generally communicates.
Varieties. — The external division of the musculo-cutaneous nerve is often reduced in size,
the deficiency being supplied by the external saphenous nerve. Less frequently the internal
branch is replaced to a greater or lets extent en the toes by the anterior tibial nerve. The
THE ANTERIOR TIBIAL NERVE.
337
number of toes supplied by the musculo-cutaneous nerve is seldom increased. (On variations
in the nerves of the dorsum of the foot, and their relative frequency, see the Second Annual
Report of the Committee of Collective Investigation of the Anat. Soc.. by Arthur Thomson ,
Joura. Anat., xxvi, 1891.)
Anterior tibial nerve. — The anterior tibial nerve (n. peroneus profundus)
(4, 5 /, 1 s\ commencing between the fibula and the peroneus longus, inclines
obliquely beneath the long extensor of the toes to the fore part of the interosseoua
membrane, and there comes into contact with the anterior tibial vessels ; with
these vessels it descends to the front of the ankle-joint, where it divides into an
external and an internal branch. The nerve reaches the anterior tibial artery about
Fig. 219. — DISTRIBUTION OP THE BRANCHES OP THE EXTERNAL
POPLITEAL NERVE ON THE FRONT OP THE LEG AND DORSUM OP
THE FOOT. (After Hirschfeld and Leveille.) 1
The upper part of the peroneus longus muscle has been removed, the
tibialis anticus, the long extensor of the great toe and the peroneus
longus are drawn apart in the leg by hooks marked a, b, and c, and
the tendons of the extensor muscles have been removed on the dorsum
of the foot ; 1, external popliteal or peroneal nerve, winding round the
outer part of the fibula ; 1', its recurrent articular branches exposed
by the dissection of the upper part of the tibialis anticus muscle ;
2, 2, musculo-cutaneous nerve ; 2' 2', twigs to the long and short
peroneal muscles ; 3, 3', internal branch of the musculo-cutaneous
nerve ; 4, 4', 4', its external branch ; 5, external saphenous nerve,
uniting at two places with the outer branch of the musculo-cutaneous ;
5', its branch to the outer side of the fifth toe ; 6, placed on the upper
part of the extensor longus digitorura, marks the anterior tibial nerve
passing beneath the muscle ; 6, placed farther down on the tendon of
the tibialis anticus, points to the nerve as it lies in front of the
anterior tibial artery ; 6', 6', its muscular branches in the leg ; 6", on
the tendon of the extensor longus hallucis, points to the anterior tibial
nerve after it has passed into the foot behind that tendon ; 7, its inner
branch, uniting with a twig of the musculo-cutaneous, and giving the
dorsal digital nerves to the adjacent sides of the first and second toes ;
8, distribution of its outer branch to the extensor brevis digitorum and
tarsal articulations.
the junction of the upper with the second fourth of the
leg, and is thence placed in front of the vessels as far as
the ankle, at which spot it is usually on their outer side.
Branches. — (a) Muscular branches. — In its course
along the leg, the anterior tibial nerve gives offsets to
the adjacent muscles, namely, the tibialis anticus, the
extensor longus digitorum, the extensor proprius hallucis,
and the peroneus tertius.
(b) An articular filament for the ankle-joint arises
from the lower part of the nerve.
(c) The external branch of the anterior tibial nerve
turns outwards over the tarsus beneath the short extensor of the toes ; and, having
become enlarged (like the posterior interosseous nerve on the wrist) breaks up into
branches which supply the short extensor muscle, and the articulations of the foot.
(d) The internal branch, continuing onwards in the direction of the anterior tibial
nerve, accompanies the dorsal artery of the foot to the first interosseous space, and
ends in two branches, which supply the integument on the neighbouring sides of the
great toe and the second toe on their dorsal aspect. It communicates with the
internal division of the musculo-cutaneous nerve.
From the internal branch one, and from the external two or three slender
interosseous branches are sent forwards to the intermetatarsal spaces, where they are
joined by the perforating twigs of the external plantar nerve (p. 385). They supply,
338 THE SPINAL NERVES.
filaments to the tarso-metatarsal articulations and the periosteum of the metatarsal
bones, and terminate in the metatarso-phaiangeal joints. The second and some-
times the first of these nerves give twigs also to the dorsal interosseous muscles
upon which they lie (Riidinger, Cunningham).
Varieties. — Occasionally the anterior tibial nerve supplies also the inner side of the great
toe, or the adjacent sides of the second and third toes. In one case the anterior tibial nerve sent
branches to the outer three and a half toes, the great toe and the inner half of the second being-
supplied by the musculo-cutaneous (F. T. Roberts. Liverpool Med. and Surg-. Reports, vi.
1867). Very rarely the digital branches are altogether wanting.
SUMMARY OF THE EXTERNAL POPLITEAL NERVE. — This nerve supplies, besides
articular branches to the knee, ankle, and foot, the muscles and integument of the
outer side and front of the leg and dorsum of the foot. It gives the peroneal
communicating branch to the short saphenous nerve, and communicates with the
long saphenous nerve.
SYNOPSIS OF THE SENSORY DISTRIBUTION OF THE
CEREBRO-SPINAL NERVES.
1. In the head. — The face, and head in front of tlie ear are supplied with
sensory nerves from the fifth cranial nerve. The ophthalmic division supplies
branches to the forehead, upper eyelid, and dorsum of the nose. The superior
maxillary division supplies the greater part of the cheek, the side of the nose, upper
lip, lower eyelid, and the region behind the eye over the fore part of the temporal
fascia. The inferior maxillary division supplies the chin and lower lip, the hinder
part of the cheek, the fore and upper parts of the pinna of the ear on its outer side,
and the integument in front of the ear and upwards on the side of the head.
The head behind the ear is mainly supplied by the great occipital branch of the
posterior division of the second spinal nerve, but above the occipital protuberance
there is also distributed the branch from the posterior division of the third spinal
nerve ; and in front of the area of the great occipital nerve is a space supplied by
anterior divisions of spinal nerves, viz., the back of the pinna of the ear, and the
lower part of its outer surface, together with the integument behind, and that
in front over the parotid gland, which are supplied by the great auricular nerve
(2, 3 c) ; while between the area of this nerve and the great occipital the small
occipital nerve (2, 3 c) reaches the scalp, and sends a branch to the upper part of
the pinna. The auricular branch of the pneumo-gastric nerve also is distributed on
the back of the ear.
Cavities of the head. — The mucous membrane of the nasal fossa is supplied by
the olfactory nerves and the first and second divisions of the fifth nerve. The
ramifications of the olfactory nerves are restricted to the small olfactory region at
the highest part of the cavity; the nasal branch of the ophthalmic division of the
fifth nerve supplies the anterior portion of the lining membrane; and the superior
maxillary serves all the remainder. The frontal sinus is supplied by the nasal nerve,
the ethmoidal cells and sphenoidal sinus by the nasal and superior maxillary, and the
maxillary antrum by the superior maxillary nerve.
In the mouth, the upper lip, the teeth of the upper jaw with the gum, and the
mucous membrane of the hard palate, are supplied by the superior maxillary nerve.
The lower lip and the inner surface of the cheek, the lower teeth and the gum, and
the greater part of the tongue in front of the anterior pillars of the fauces, together
with the mucous membrane of the alveolo-lingual sulcus, are supplied by the inferior
maxillary nerve. The taste-fibres of the fore part of the tongue probably run in the
chorda tympani; and the root of the tongue is supplied by the glosso-pharyngeal
DISTRIBUTION OF CEREBRO-SPINAL NERVES.
339
nerve. The soft palate receives branches from the superior maxillary and glosso-
pharyngeal nerves. The mucous membrane of the pharynx in its upper part,
including the mouth of the Eustachian tube, receives twigs of the superior maxillary
Fig. 220. — CUTANEOUS AREAS OP THE NERVES OF THE HEAD AND NECK. (Gr.D.T.)
The areas supplied by the branches of the first division of the fifth are enclosed by black lines ;
those supplied by the second division of the fifth and by branches of the cervical plexus by red lines :
and those supplied by the third division of the fifth and by the posterior primary divisions of the
cervical nerves by blue lines. S T, supratrochlear, I T, infratrochlear, and L, lachrymal branches of
the first division of the fifth. The hinder part of the cheek, on which the word "auriculo " is placed,
receives fibres of the auriculo-temporal nerve through the communication with the facial. The black
spots denote the points at which the respective nerves become superficial.
In this and similar figures the overlapping of adjacent nerves is indicated, so that along the boundary
of each area there is a region which is supplied by the two nerves. It is, however, to be remarked
that, owing to the difficulty of determining anatomically the precise extent of skin supplied by a branch
of nerve, and the great degree of individual variability in this respect, neither the extent of the several
areas nor the degree of overlapping are to be regarded otherwise than as approximate representations of
what appears to be the average condition.
340
CEREBRO-SPINAL NERVES.
C'«CUMFLEX
•5-6
..M E 0 I A N/ ,
\
Fig. 221.
SENSORY DISTRIBUTION. 341
nerve ; in the rest of its extent it is supplied by the glosso-pharyngeal and pneumo-
gastric nerves, mainly through the pharyngeal plexus, but in the neighbourhood of
the superior aperture of the larynx it receives filaments of the superior laryngeal
nerve. The larynx is supplied mostly by the superior laryngeal nerve, but in its
lowest part it receives fibres from the inferior laryngeal, which also supplies
the trachea. The sensory nerves of the (fsopliagus are probably derived from
the pneumo-gastric.
The mucous lining of the tympanic cavity and Eustachian tiibe are supplied
by the glosso-pharyngeal nerve, while to the mastoid cells filaments pass from the
same source, as well as from the inferior maxillary nerve (Luschka). The outer
surface of the tympanic membrane, like the skin of the external auditory meatus
generally, is supplied by the auriculo-temporal of the fifth and the auricular branch
of the pneumo-gastric nerves.
In the cranial cavity the dura mater receives branches from the three divisions of
the fifth, the pneumo-gastric, and the hypoglossal nerves.
2. In the trunk. — The posterior divisions of the spinal nerves supply an area
extending on the back from the vertex of the skull to the buttock. This
area is narrow in the neck ; it is expanded in the upper dorsal region, extending
over the back of the scapula; in the lower dorsal and lumbar regions its extent may
be marked by a line drawn from the lower angle of the scapula (the arm hanging
against the side) to the middle of the iliac crest ; and in the buttock its lower limit
is indicated by a line from the tip of the coccyx to the great trochanter (see fig. 189,
p. 282). The series of cutaneous branches is not continuous, there being gaps in
the lower cervical and lower lumbar regions, corresponding to the middle parts
of the brachial and lumbo-sacral plexuses ; that is, those spinal nerves which
contribute most largely to the supply of the limbs do not furnish dorsal cutaneous
offsets.
The area supplied by the cervical plexus, besides extending upwards, as already
mentioned, on the lateral part of the skull, stretches over the front and sides
of the neck, and the upper part of the shoulder and breast.
The area of the anterior divisions of the dorsal and first lumbar nerves meets
superiorly with that of the cervical plexus, and posteriorly with that of the posterior
divisions of the dorsal and lumbar nerves. It passes down over the haunch
and along by the outer part of Poupart's ligament, and includes part of the penis
and scrotum, and a small portion of the integument of the thigh internal to
the saphenous opening. This extensive area may be subdivided by a line passing
through the nipple downwards to the centre of Poupart's ligament into a mesial
region supplied by the anterior cutaneous branches of the nerves, and a larger
lateral region supplied by the lateral cutaneous branches. In the former region the
skin over the ensiform process is supplied by the sixth and seventh dorsal nerves, and
that around the umbilicus usually by the tenth dorsal nerve.
The root of the penis on its dorsal aspect and a part of the scrotum anteriorly are
Fig. 221. — CUTANEOUS AREAS OF THE NERVES OP THK UPPER LIMB. (Gr.D.T. )
A, anterior view ; B, posterior view.
The areas supplied by the circumflex and musculo-spiral nerves, derived from the posterior cord of
the brachial plexus, are circumscribed by red outlines ; those of the ulnar, internal cutaneous, and
nerve of Wrisberg (W), from the inner cord of the plexus, together with the intercosto-humeral nerve,
by blue lines ; and those of the mus3ulo-cutaneous from the outer cord of the plexus, with the median
derived from both outer and inner cords, by interrupted black lines. The lower limit of the supra-
clavicular nerves over the shoulder is also shown by a broken black line. The numerals following the
names of the nerves indicate the spinal nerves from which the latter arise ; 3, 4, 5, 6, 7, 8, the
corresponding cervical nerves ; 1, 2, the first and second dorsal nerves. The cutaneous branches of the
musculo-spiral are distinguished as follows : — I, internal cutaneous ; II, upper, and III, lower
external cutaneous.
342
CEREBRO-SPINAL NERVES.
POST.\
POST.
SACRAL"*!
2 /
Fig. 222. -CUTANEOUS AREAS OF THE NERVES OF THE LOWER LIMB. ((r.D.T.)
A, anterior view ; B, posterior view. For explanation, see opposite page.
SENSORY DISTRIBUTION. 343
supplied by the ilio-inguinal and geni to-crural nerves (1 /). The greater part of the
penis, the lower and hinder parts of the scrotum, and the perineum are supplied by
the pudic nerve (2, 3, 4 s), the scrotum also receiving branches from the inferior
pudendalof the small sciatic (2, 3 s). The branches to the penis are derived mainly
from the second sacral nerve, to a less extent from the third ; those to the scrotum
and fore part of the perineum chiefly from the third nerve, but in part also
from the second ; and those to the hinder part of the perineum from the fourth and
third sacral nerves (Paterson).
3. In the upper limb. — The shoulder, supplied superiorly by the descending
branches of the cervical plexus (3, 4 c), receives its cutaneous nerves inferiorly from
the circumflex nerve (5, 6 c).
The arm internally is supplied by the intercosto-humeral nerve (2 d) and
the nerve of Wrisberg (1 d). The inner and anterior part is supplied by the
Fig. 223. — NERVE-SUPPLY OP THE SKIN OP THE SOLE. (Gr.D.T.)
The areas enclosed by red lines are those supplied by the external cutaneous nerve, the middle and
internal cutaneotis, and the internal saphenous branches of the anterior crural nerve, the perforating
cutaneous nerve, and the lateral cutaneous, rnusculo-cutaneous, and anterior tibial branches of the
peroneal nerve, i.e., the dorsal offsets of the limb-plexus. Those enclosed in blue lines are supplied by
branches derived from the ventral offsets of the limb-plexus, viz., the calcaneo-plantar branch of the
posterior tibial and the plantar nerves. The area of the small sciatic is enclosed internally by a blue
and externally by a red line, corresponding to the double nature of the nerve (see p. 325). The area of
the inner side of the leg supplied by the obturator and internal cutaneous in common, and that supplied
by the external saphenous, are enclosed in interrupted black lines, the nerves concerned being derived
partly from dorsal and partly from ventral divisions.
internal cutaneous nerve (8 c, 1 d} and the posterior and outer parts by the circum-
flex (5, 6 c), and by the internal and external branches of the musculo-spiral nerve
(6, 7, 8 c}.
The forearm, anteriorly and on the outer side, is supplied by the musculo-
cutaneous (5, G c) ; on its outer and posterior aspect by the lower external cutaneous
branch of the musculo-spiral (6, 7, 8 c), and inferiorly by the radial branch (6, 7 c)
of the same nerve. On the inner side, both in front and behind, is the internal
cutaneous nerve (8 c, 1 d), and inferiorly are branches of the ulnar (8 c, 1 d).
On the lack of the hand are the radial and ulnar nerves, the radial (6, 7 c)
supplying about three fingers and a half or less, and the ulnar (8 c) one and a half
or more.
On the front of the hand, the median nerve (6, 7, 8 c, 1 d) supplies three fingers
and a half, and the ulnar ( 1 d, or 8 c, Id) one and a half. In the palm is a branch of
the median, and also a branch of the ulnar, given off above the wrist. On
the thenar eminence are branches of the musculo-cutaneous, median, and radial
nerves.
4. In the lower limb. — The buttock is supplied from above by the cutaneous
branches of the posterior divisions of the lumbar nerves, with the ilio-hypogastric (17)
344 CEREBRO-SPINAL NERVES.
and lateral branch of the last dorsal nerves ; internally by the posterior divisions of
the sacral nerves ; externally by the posterior branch of the external cutaneous
nerve (2, 3 7) proceeding from the front ; and inferiorly by the perforating
cutaneous nerve (2, 3 s) and branches of the small sciatic nerve (1, 2, 3 s) proceeding
from below.
The thigh is supplied externally by the external cutaneous nerve (2, 3 7) from the
lumbar plexus ; posteriorly, and in the upper half of its inner aspect, by the small
sciatic (1, 2, 3 s) ; anteriorly, and in the lower half of the inner aspect, by the middle
and internal cutaneous (2, 3 7) of the anterior crural, the latter being frequently
assisted by the obturator nerve (2, 3, 4 I).
The leg is supplied posteriorly by the small sciatic (1, 2, 3 s) and short saphenous
(1, 2 s) nerves; internally by the long saphenous (3, 4 /) and branches of the
internal cutaneous of the thigh (2, 3 7) (or obturator) ; and outside and in front by
cutaneous branches of the external popliteal nerve (5 7, 1, 2 s) and by its musculo-
cutaneous branch (4, 5 7, 1 s).
On the dorsum of the foot are the branches of the musculo -cutaneous (4, 5 7, 1 s),
supplying all the toes with the exception of the adjacent sides of the first and second,
which are supplied by the anterior tibial (4, 5 7, 1 s), and the outer side of the little
toe, which, with the outer margin of the foot, is supplied by the short saphenous
nerve (1, 2 s). The long saphenous (3, 4 7) is the cutaneous nerve of the inner side
of the foot.
The sole of the foot is supplied in its posterior part, together with the inner side
of the heel, by the calcaneo-plantar branch of the posterior tibial nerve (1, 2 s).
In front of this, the inner and larger part is supplied by the internal plantar
nerve (4, 5 7, 1 s), which extends ^to the inner three toes and a half, while the outer
part, with the remaining one toe and a half, is supplied by the external plantar
nerve (1, 2 s). Over the outer side of the heel, and along the outer margin of the
sole, are branches of the external saphenous nerve (1, 2 s).
CUTANEOUS DISTRIBUTION OF THE SPINAL NERVES TO THE TRUNK
AND LIMBS.
The manner in which the several spinal nerves are distributed to the skin has
been greatly elucidated by the experimental investigations of Sherrington, the
dissections of Herringham and Paterson, and the clinical and pathological
observations of Koss, Thorburn, Head, and others. From these it would appear
that in the trunk the branches of each dorsal (segmental) nerve are generally
distributed to a continuous area of skin, which has the form of a zone extending
horizontally or obliquely from the dorsal to the ventral median line (see fig. 225,
A, B, C). According to the observations of Head, the upper dorsal nerves
form exceptions to this statement, their zones being interrupted laterally by the
interposition of the upper limb, into which the middle portions of the first and
second nerves (corresponding to their lateral cutaneous offsets) are prolonged ; but
Sherrington found in the monkey that there was complete continuity between the
trunk and limb portions of the areas of these nerves. Inferiorly, the zone of the last
dorsal nerve is produced downwards over the hip ; and the first lumbar nerve, which
resembles a dorsal nerve in its distribution, also supplies a zone which is similarly
extended laterally over the hip, as well as ventrally to the penis, scrotum, and upper
part of the thigh ; while with the second lumbar nerve the series of limb-nerves
proper commences. These zones, moreover, overlap to a considerable extent, owing
partly to the communications established between the several trunks, as is especially
the case with the lower intercostal nerves (see p. 310), and partly to the crossing of
CUTANEOUS DISTRIBUTION OF SPINAL NERVES.
345
their terminal filaments, so that there is probably no spot of the skin which
is supplied only by one spinal nerve (Sherrington).
In the limbs, although the nerves have been mingled in the plexuses, there is a
similar principle to be recognized in their ultimate distribution, the fibres derived
from the several spinal nerves being supplied to definite continuous areas in
positions which are readily explained by reference to the mode of development of the
limb. Thus, the upper nerves are distributed along the preaxial side of the limb,
and the lower nerves along the postaxial side, while the intermediate nerves descend
along the centre of the limb, and supply only the more distal parts. The skin at the
root of the limb is not supplied by offsets of the limb-plexus, but by branches
of nerves which have been drawn out, as it were, with the skin of the adjoining
part of the trunk during the development of the limb.
dorsal or ventral, m&ckcttt tine,
Head
Fig. 224. --SCHEME OF THE SENSORY SPINAL SKIN-FIELDS OF THE HIND LIMB OF MONKEY (Macacus
rhesus). (Sherrington.)
10, 11, 12, areas of lower dorsal nerves ; 1 — 7, areas of lumbar nerves ; 8 — 11, areas of sacral and
caudal nerves. Of the seven lumbar nerves in this monkey, the second and seventh correspond
respectively to the first lumbar and first sacral nerves of man. The overlapping of the skin-fields is not
indicated. The arrangement is the same on the dorsal and ventral aspects.
Ths following rules have accordingly been formulated by Herringham from his
observations on the nerves of the upper limb, and have been confirmed by Paterson
for the lower limb : —
A. Of two spots on the skin, that -which is nearer the preaxial border tends to be
supplied by the higher nerve.
B. Of two spots in the preaxial area, Ihe lower tends to be supplied by the loiver
Fig. 225. — SEGMENTAL CUTANEOUS AREAS FROM THE FIRST DORSAL TO THE FOURTH SACRAL, AS
DETERMINED BY CLINICAL AND PATHOLOGICAL OBSERVATIONS IN MAN. (Head.)
On the right side of the figures the areas are marked by different colours and modes of shading; on
the leftside the " maximum spots " (seat of most marked tenderness and pain) of the areas are shown.
The several dorsal, lumbar and sacral areas are indicated each by the initial letter followed by a number.
In C, C 7 is the seventh cervical spine, 3 to 12 are the corresponding dorsal spines, and L 1 to 4 are
lumbar spines.
THE SPINAL NERVES.
•D.L
Fig. 225.
CUTANEOUS DISTRIBUTION TO TRUNK AND LIMBS.
347
Fig. 225.
348
THE SPINAL NERVES.
nerve, and of two spots in the postaxial area, ilw lower tends to be supplied by the hu
nerve.
CervS.
CutM
Fig. 226. — THE SEGMENTAL CUTANEOUS AREAS FROM THE THIRD CERVICAL TO THE FIRST DORSAL. (Head.)
la the upper limb, as is shown in fig. 221, the shoulder is supplied by offsets
of the cervical plexus, proceeding from the third and fourth cervical nerves;
the preaxial side of the limb, extending from the outer side of the shoulder to the
CUTANEOUS DISTRIBUTION TO TRUNK AND LIMBS.
349
thumb, is supplied by the fifth and sixth cervical nerves ; and the postaxial side,
from the little finger to the axilla, by the eighth cervical and first and second dorsal
nerves. The seventh cervical nerve does not become superficial on the ventral
aspect until the hand is reached, although on the dorsal aspect it appears earlier in
the lower external cutaneous branch of the musculo-spiral, but here it is probably
distributed to the lower part of the area of that nerve. The digits are supplied
by the sixth, seventh, and eighth cervical, and first dorsal nerves, in this order,
from the radial (preaxial) to the ulnar (postaxial) side.
In the lower limb (figs. 222 and 223) the skin of the hip receives its nerves from
the lateral cutaneous offsets of the last dorsal and first lumbar nerves, and from the
posterior primary divisions of the lumbar and sacral nerves, while the anterior
division of the first lumbar nerve reaches the upper part of the thigh in front. The
nerves of the preaxial and postaxial borders of the limb are not so readily traced as in
the case of the upper limb, owing to the displacement which has taken place with
the marked rotation of the lower limb during development, and the great extension
L.R
LM
Fig. 227. — THE SEGMENTAL CUTANEOUS AREAS FROM THE SECOND TO THK FIFTH LUMBAR. (Head.)
The second lumbar ai*ea is marked in cross lines, the third in vertical lines, the fourth with circles,
and the fifth with dots.
of the area supplied by dorsal branches of the limb-nerves, with a corresponding
reduction of the ventral area. The preaxial border may be represented by a line
following the course of the internal saphenous vein from the groin along the inner
border of the sartorius to the knee, and thence along the inner border of the tibia to
the ankle and inner border of the foot ; and the postaxial border by a line running
from the coccyx along the lower border of the gluteus maximus, thence down the
postero-lateral aspect of the thigh to the back of the head of the fibula, and descend-
ing along the leg over the external malleolus to the outer border of the foot (Paterson).
Along the preaxial border, as thus defined, are the second, third, and fourth lumbar
nerves, while along the postaxial border are found the first, second, and third sacral.
It will be observed that both of the lines are overstepped to some extent by nerves
of dorsal origin, and that the area supplied by ventral nerves is reduced to a strip
along the postero-internal part of the thigh, over but not completely covering the
hamstring and adductor muscles, and along the back of the leg, but spreading out
VOL. III., PT. 2. Z
<'KIM<;i',i;o-snN \l, \h.i;VKS.
in thi- fool, to the whole hivudtli of the solo. The lil'lh luml>;ir uer\e docs no!
hceome etilaneoiis on I he vein ral aspect mil d the sole is reached, hut in I he dorsal
nerves it, appears earlier in the lateral cutaneous hraneh ofilie peroneal. 'The toes
are supplied l>y the fourth and lil'lh luinhar, and I he first, and second sacral nerves,
in this order, from the preaxiul to the postaxial side.
The disposition ..I' (he cutaneous arras of I lie segment a 1 nerves in the Innli. as determined
1»V Sherriii» I on for I lie pelvic liniti ot' I lie monkey, is shown dia:1 ramniat iea 1 1 v in tiy.'J'JI. The
.e\ era I tie Ids are seen to lie arranged in^ regular order a Ion L; a line continued out wards from the
dorsal or vent ral median line of I lie t rim k, over t he correspond iny surface of I he limb, and form-
ing a kind of secondary axial line for the latter. The lields of I he preaxial nerves eoiist.il n I e
i de ccndm:' series almi" this line, the sixth Inmhar field spreads from the end of the axial
line to the extremity of the limit, and the lields of the postaxial nerves, less numerous
than the preavial, form an ascending series. The arranycment of the cutaneous nerves does
not a",ree with thai of the mol or ner\ es of I he limh, \\hich supply each a coiititrnoiis band
rn nn i n L; pa ral lei lo i he limit-axis from the I rnnk to I he free Itorder of I he limit. The in use I es
of a given part of the limb and the overlying integument are, therefore, not necessarily
supplied l>v t he same se^ineutal nerves ( SherriuL;'tou ).
I 'i". tires L'l'.'i. 'J'Ji'i ami !"_' 7 represent, (he •• se-.- mental areas" of tlu> skin oxer the trunk and
limits as determined hy Head from clinical observations. These areas are. however, not the
re;/ ions supplied by the respective posterior spinal nerve roots, but represent rat her the parts
of the skin in connection with the segments of the j^rey matter of the spinal eord by means
,if lib res subserving the sensations of pain, heat, and cold, but not. touch. They differ
--I rikin;1,! \ from the areas of the posterior nerve roots in not overlapping, except to a small
extenl in (he neck and upper limbs, whereas I he root areas overlap so much that there is no
loss of tactile sensation after division til a single posterior root. ( Sherrinv.ton, Head). II ma\
also be pointed out thai the areas as designated by Head do not always ai;rec with the distri-
bution of I he corresponding ner\e- as determined anatomically. Thus, the area marked 1> .'i
on the inner side of the arm corresponds rather to I he brachial (list rilmt i< -n of t he second
dorsal iierxe through its mlcrcosto- humeral branch and the communication with the nerve ol
\\rishep.'.. while the third dorsal nerye does not usually contribute largely to the supply of the
arm. Similarlv, I he areas marked I) II. I) !'_', and I/ I, would seem on anatomical ;• rounds, :>s
well as from observations in cases of injury, as shown by Thorburu. to correspond more
nearly to the twelfth dorsal and first and second lumbar nerves, it is therefore possible thai.
while the !',d ici a I a rran " • •men I anil distribution of the sey.'inental areas, as well as their
visceral associations, have been in principle correct ly IVCOL: n i /ed by Head, some modifications
in the details of limitation and enumeration of these areas mav be rendered necessary by more
extended ohservat ions.
SENSORY DISTRIBUTION OP THE SPINAL NERVES TO THE VISCERA.
There is strong reason for believing thai the tlioracie and abdominal viscera are supplied
\\ith sensory t-hres derived from the spinal nerves, and passing through the sympathetic. In
IliedoLT Kd;;vwort h has traced mednllatcd fibres of medium si/.e. which he regards as sensory.
Irotii the posterior roots of the spinal nerves into the s\ mpat het ic. and thence to the several
viscera : and his results are ^cncralh in close agreement with the inferences drawn
from clinical observations in man (Head), although their accuracy in some particulars is
disputed by l,ani;-ley. Kolliker also recoL>;ni/,cs mednllatcd sensory nerve libres passing without
interruption from the posterior roots of spinal nerves through the sympathetic to the
viscera. Indirect evidence as to the source of these fibres is furnished by the seat of
"referred pain' in alVcctiotis ol the several organs. Arrordin:; to the hypothesis of Ross.
the pain is referred in such cases to part s supplied hy somatic sensory libres having t heir origin
t rom the nerves in which the sensory fibres of the a Heeled \iscusare contained, owiniv
to dilVnsion of the irritation conveyed by the latter libres in the corresponding segment of the
grey matter of the spinal cord. The following table, taken from Head, shows the probable
origin of the sensory fibres of the different organs : —
Heart.-l. •_'. :i dorsal.
Lnnirs. 1. •_'. 3, I. I dot-sal.
Stomach. ('•. 7. *. !> dorsal. Cardiac end from ('•. 7. 1'yloric end from !>.
Intestines.— (n) Down to upper part of rectum, D. lo. n. 12 dorsal. (A) Rectum. •_'. ::. !
sacral.
Liver and ( iall-l'daddcr. (\\ .'), 7, S, «». 10 dorsal.
Kidney and Ureter.—10, 11, 12 dorsal. Upper part of ureter, 10 dorsal. At lower end ol
ureter. 1 lumbar tends to appear.
Bladder. — («) Mucous membrane and neck of bladder, (1), 2, 3, 4 sacral, (ft) Over-
distension and inett'ectual contract ion. 11. 1 L' dorsal, and 1 lumbar.
\n sci LAB DISTRIBUTION, 351
I'roslalr. 1(1. I I, ( 12) dor :i!.
I, 2, .'{ sarral, : ml .. lumltar.
Kpididyniis. II, I L' dorsal, and I lumbar
T««Ht,is. 10 dorsal.
Ovary. - 10 dorsal.
App.'iidayvs, \c. II and I "2 dorsal, I lumkir.
I'ti-rus. (11} In nmt rael.ion, |O. II, I'J dorsal, :uid I lumbar ( // ) O. ulrri, (I), 2, J{, -1
sacral ( .'. lnini.;if \ <-i \ rand y ).
LITERATURE OP THE DISTRIBUTION OF SENSORY NERVES.
Edtfeworth, p. H., (hi <i l«r<t< Jil>r«l ,SV //.w/-// Xi<i>j,/// <>f tin' Tln>,;i,-i,- m/,
.Iniiin. of l'liys;.y., xiii, |,S!)±
Head, H., (hi DithirbantW <>/' S< fixation, ///'/// r.,-/'"'""' /v/' '"' '"''' '" '/"' /'"'" "/ Vi
/)in('«m; I'.rain, |.;irls Ixiaixl Ixii, I Mil.",, and Ixvii, IS'.t).
Herrinsrham, W. P.. Tin- Mi, ml,- Aunt,,,,,,/ ,,/' //,, /Imr/u'nf /Vo-//x, I'ruc. Uoy. Soc,., di, 1H8C.
LanR-ley, J. N., ^// I lie. /an/tr .M«lnll,ii«l Fibrcn »/'lli< <s'//////»>///Y//r Xi/xtiM, .lourn. ul 1'liyHgy.,
Mackenzie, J., HOIIK' I'uiiilx l>«irin<j on //ir Awtri, tt.itin «/' A'« a. :<>, ii him-,1,,.. mnl Viwrul
l>ini'<im', I '.i-;i in, |iarl, Ixiii, IM'.C!.
Paterson, A. M., Tin <h-i</in <ni<l. l><ntril>ii<i<>ii <>ftlie Nerves to tli< Lmi;,- /t/Hifi, Journ. of Anal.,
\xviii, I.S1KI I.
Ross, J., On Ih, Myinritt,if DixtrilHitinii <>/' ^'imni-if />i'*<,rili-i:<<, liraiu, 1888, and in "ShidirH in
\iial,iiniy,'1 t.lic Owens < !oll<!«,'i), 18!)1.
Sherring-ton, C. S., A'./'y/r/1///// -iitx in i:.i-«iiiiii<iti«n «l lln /', ri/>/nr<i/ />/'.;// iliuliun ,,/' lli< I ''Hire* of
t/ir Po^erior Root H nffiinw Spinal AV/w/i, I'n.r. Roy. Hoc., Hi, 1W2, and JMiil. Tran , !
Starr, M.Allen, Ann'ii'-m .lonrn Mi'd. Sci., May, I SHH ; Aora/ A inrnt/ifnin. nan </it/t/< In Ih,
/h'<i!/in>nln <>f 1. 1: * '.an H of tin- L<,ir,r Xj,in<i/ (ford, llit(!rna.L .Imirn. nf Mcd. Sricncc, I HD2 ; l.nnd
.\nirnl liquid <tn <t </u itl< in //if /h'lii/iioxix nf Lixiniixof tin f '/'/>' f I'nrtiini <>/' tin ,^/iiiin/ ('nr/f, I'.iain,
part Ixvii, 1894.
Thorburn, W., A ('<>„<,•;/,„/;<>„ in //,, ,S'///7/r/-i/ uf II,, ,S/, //,,// t',,rt/, IHH!»; 77/r AV//.VI/V/ />//,,
'in/inn nf ^n/i/ti/ \<rr''n, P.rain, part: Ixiii, IMKI.
Voig-t, C. A., /frifr<it/f in- />> n/Kit" .\<-nr«[<i</i<, n'/,:,t il,r H,^ln; ilnm-
'•nl'/i <•/.;,• l/uiiiii ,ni </,<>• O/Hrjfdr/ic <b'n /tit iixr/i/ic/K'it, h'or/irrH, \\'I«-IHI I »• -nl .: > In 1 1 ten,
SYNOPSIS OF THE MUSCULAR DISTRIBUTION OF THE CEREBRO-
SPINAL NERVES.
J . To muscles of the head and fore part of the neck. — The muscles ofthfi orbil
arc mostly supplied by the third cranial nerve — the superior division of that nerve being
distributed to the levator |)al|>(-br;i! and the HUpcrior IVC,|,IIK inuscleH, and the inferior
division to the infi-rior :nid internal rec.ti and tlie inferior oblique. rrii(! Huperior
oblique muscle is Huj)plied by the fourth nerve, and the external rectus by the sixth ;
wliili UK- tensor tarsi has no special nerve apart from those of the orbieularin
pidpebrarinn, wliicli :..n: derived IVoin the fjw.i;!.!.
The Nii/t(r/iaa/. wmrlcs of I In- face, and scalp, which are associated in their action
as a tfronp of muscles of expression, together with the buccinator muscle, are supplied
by t he seventh cranial nerve, the retnihens auriculam and occipitalis muscles being
supplied by its posterior auricular branch.
The deep muscle of'thc f<m> employed in mastication, vi/., Uie temporal, masseter,
and two pterygoid muscles, are supplied by the inferior maxillary division of
the fifth cranial nerve.
M uncles above ike ////«•/>/ hone. — The mylo-hyoid muscle and anterior belly of the
digastric are supplied by a branch of the inferior maxillary division of the fifth cranial
nerve ; the posterior belly of the digastric muscle and the stylo-hyoid (together with
the Htapcdius muscle) are supplied l,y br-.m-lieH of the facial. The muscles of the
tongue receive their nervous supply from the hypoglossal nerve ; and the genio-
hyoid muscle is supplied (like the infrahyoid muscles) by the upper cervical nerves.
The mu8clct> ascmdiny to Ike kyoid bone and larynx, viz., the sterno-hyoid, omo-
hyoiil, and sterno-thyro-hyoid, are supplied from the upper cervical nerves through
their communications with the hypoglossal nerve and the ansa cervicalis.
z 2
352 CEREBRO -SPINAL NERVES.
The larynx, pharynx, and soft palate. — The crico-thyroid muscle is supplied by
the external laryngeal branch of the pneumo-gastric nerve, and the other intrinsic
muscles of the larynx by the recurrent laryngeal. The constrictors of the pharynx
are supplied mainly by the bulbar part of the spinal accessory nerve through the
pharyngeal branch of the vagus and the pharyngeal plexus ; and the levator palati,
azygos uvulse, palato-pharyngeus, and palato-glossus are innervated from the same
source. The stylo-pharyngeus, and possibly the middle constrictor in part, are
supplied by the glosso-pharyngeal. The tensor palati is supplied through the otic
ganglion by the inferior maxillary division of the fifth nerve (and the tensor tympaui
is supplied in the same way).
2. To muscles belonging exclusively to the trunk, and muscles
ascending to the skull. — All those muscles of the hack which act upon the spine
and head, viz., the splenius, complexus, erector spinae, and the muscles more deeply
placed, receive their supply from the posterior divisions of the spinal nerves.
The sterno-mastoid is supplied by the spinal accessory nerve and a twig of the
cervical plexus coming from the second cervical nerve.
The rectus capitis anticus minor and rectus capitis lateralis are supplied by the
first cervical nerve, the rectus capitis anticus major by the upper four cervical nerves ;
the longus colli and seal-mi receive twigs from nearly all the cervical nerves.
The muscles of the chest-ivall, viz., the intercostals, subcostals, levatores
costarum, serrati postici, and triangularis sterni, are supplied by the intercostal
nerves.
The obliqui, transver sails, and rectus of the abdomen are supplied by the lower
six to eight intercostal nerves ; and the internal oblique and transverse muscles also
get branches from the first lumbar nerve. The cremaster muscle is supplied by the
genital branch of the genito-crural nerve (1, 2 I).
The quadratus lumhorum receives small branches from the last dorsal and upper
one or two lumbar nerves.
The diaphragm receives the phrenic nerves from the fourth and fifth cervical
nerves, branches from the lower intercostal nerves, and likewise sympathetic filaments
from the plexuses round the phrenic arteries.
The muscles of the urethra and. penis are supplied by the pudic nerve (2, 3, 4 s),
the levator and sphincter ani by the pudic and the fourth sacral nerves ; and the
coccygeus muscle by the fourth and fifth sacral nerves.
3. To muscles attaching the upper limb to the trunk. — The trapezius and
the cleido-mastoid receive the distribution of the spinal accessory nerve, and, in union
with it, offsets from the cervical plexus.
The latissimus dor si receives the long subscapular nerve (7, 8 c).
The rhomhoidei are supplied by a branch from the fifth cervical nerve.
The levator anguli scapulae is supplied by branches from the third and fourth
cervical nerves, and partly also by the branch to the rhomboid muscles.
The serratus magnus has a special nerve, the posterior thoracic, derived from
the fifth, sixth, and usually the seventh cervical nerves.
The subctavius receives a branch from the place of union of the fifth and sixth
cervical nerves.
The pectorales are supplied by the anterior thoracic branches of the brachial
plexus, the larger muscle usually receiving fibres from the lower four cervical and
first dorsal nerves, and the smaller from the last two cervical and first dorsal.
4. To muscles of the upper limb. — Muscles of the shoulder. — The supra-
spinatus and infraspinatus are supplied by the suprascapular nerve (5, G c) ; the
subscapularis by the upper and lower subscapular nerves (5, K c) : the teres major
by the lower subscapular (5, 6 c) ; and the deltoid and teres minor by the circumflex
nerve (5, 6 c).
MUSCULAR DISTRIBUTION. 353
Posterior muscles of the arm and forearm. — The triceps (7, 8 f), anconeus
(7, 8 f), supinator longus (6 c), and extensor carpi radialis longior ((>, 7 c) are
supplied by direct branches of the musculo-spiral nerve ; while the extensor carpi
radialis brevior (6, 7 c), the supinator brevis ((> c), and the other extensor muscles in
the forearm (7 c) receive their branches from the posterior interosseous division of
that nerve.
Anterior muscles of the arm and forearm. — The coraco-brachialis is supplied by
the seventh cervical nerve, and the biceps and brachialis anticus by the fifth and
sixth cervical nerves through the musculo-cutaneous trunk ; the brachialis anticus
likewise receives a twig frequently from the musculo-spiral nerve (6 c). The
muscles of the front of the forearm are supplied by the median nerve, with the
exception of the flexor carpi ulnaris and the inner half of the flexor profundus
digitorum, which are supplied by the ulnar nerve. The offsets to the pronator tere.
and flexor carpi radialis are derived from the sixth cervical nerve, those to the flexor
sublimis digitorum from the seventh and eighth cervical and first dorsal nerves, and
those to the flexor carpi ulnaris, flexor longus pollicis, flexor profundus digitorum and
pronator quadratus from the eighth cervical and first dorsal nerves.
Muscles of the hand. — The abductor, opponens, and outer head of the flexor
brevis pollicis are supplied by a branch of the median nerve (6, or 6 and 7 c). The
lumbricales (7, 8 c, 1 d) receive their branches, the outer two from the median, and
the inner two from the ulnar nerve. All the other muscles are innervated through
the ulnar from the eighth cervical nerve.
5. To muscles of the lower limb. — Muscles of the hip. — The ilio-psoas is
supplied by the second and third lumbar nerves, the branches to the iliacus being
given off from the anterior crural. The gluteus medius and minimus and the tensor
vaginae femoris are innervated by the superior gluteal (4, 5 I, 1 s), and the gluteus
maximus by the inferior gluteal (5 I, 1, 2 s). The pyriformis (1, 2 s), quadratus
femoris and inferior gemellus (4, 5 /, 1 s), and obturator internus with the
superior gemellus (5 /, 1, 2 s), receive special branches from the sacral plexus.
The obturator externus is supplied by the obturator nerve (3, 4 I).
Muscles of the thigh. — The sartorius (2, 3 Z), pectineus (2, 3 /), and quadriceps
extensor cruris (3, 4 I) are supplied by the anterior crural nerve. The adductor
longus (2, 3 D, gracilis (2, 3, 4 /), adductor brevis (2, 3, 4 /), and adductor magnus
(3, 4 I) are supplied by the obturator nerve, but the adductor magnus likewise
receives a branch (4, 5 I) from the internal popliteal division of the great sciatic
nerve. The hamstring muscles are supplied by branches of the great sciatic nerve,
the semimembranosus (4, 5 /, 1 s), semitendinosus (5 I, 1, 2 s\ and long head of
the biceps (1, 2, 3 s), receiving their branches from its internal popliteal division,
and the short head of the biceps (5 /, 1, 2 s) from its external popliteal division.
Anterior muscles of the leg and foot. — The muscles in front of the leg, together
with the extensor brevis digitorum, are supplied by the anterior tibial nerve
(4, 5 ?, 1 s).
The peroneus longus and Irevis are supplied by the musculo-cutaneous
nerve (4, 5 Z, 1 s).
Posterior muscles of the leg. — The gastrocnemius (1, 2 5), plantaris (4, 5 Z, 1 *),
popliteus (4, 5 /, 1 s), and soleus (5 /, 1, 2 s) are supplied by the internal popliteal
nerve, the last muscle receiving also a second branch (1, 2 s) from the posterior
tibial nerve. The flexor longus digitorum (5 /, 1 s), tibialis posticus (5 /, 1 s), and
flexor longus hallucis (5 /, 1, 2 s) derive their nerves from the posterior tibial.
Plantar muscles. — The flexor brevis digitorum, the abductor and flexor brevis
hallucis, and the innermost lumbricalis are supplied by the internal plantar
nerve (5 ?, 1 s) ; all the others, including the flexor accessorius and interosseous
muscles, are supplied by the external plantar nerve (1, 2s).
354 THE SPINAL NERVES.
MUSCULAR DISTRIBUTION OF THE SPINAL NERVES.
The statements made in the foregoing synopsis, and in the following lists of the
muscles supplied by each spinal nerve, are based mainly upon dissections and
pathological observations in man, but in part also upon physiological experiments in
the monkey. Owing to the difficulties of these investigations, and the limited
number of observations that have as yet been made, there is still some uncertainty
as to the exact supply of some of the muscles of the limbs, where the nerves
are mingled in plexuses before passing to their distribution, and especially as to the
range of individual variations.
In the case of the short trunk-muscles, which are derived from a single
myomere, the nervous supply is single, coming from the nerve of that segment. In
more extended muscles, which are formed by the fusion of portions of several
segments, the nervous supply is correspondingly multiple, although there is at times
a reduction in the number of nerves in comparison with the segments from which
the muscle appears to have been derived, e.g., in the quadratus lumborum and
complexus. In the limbs the segmental arrangement of the muscles and nerves is
obscured ; but with regard to the general disposition it may be stated that most if
not all of the muscles are supplied from more than one spinal nerve, and that the
muscles on the preaxial side of the limb tend to be supplied by higher nerves than
those on the postaxial side.
From the lists it will be seen that muscles of different action are often supplied
from the same nerve-roots. Terrier and Yeo concluded from their experiments in
the monkey that the muscles called into action by the stimulation of a single nerve-
root entering into the brachial or crural plexus form a group executing some definite
co-ordinated movement of the limb, but Sherrington, in numerous observations on
the same animal, failed to find evidence of such an association. Risien Russell,
while supporting Ferrier and Yeo as to the co-ordination, also points out tha^ (in
the dog) when antagonistic muscles are represented in the same nerve-roots, one
group predominates in one root and the opposite group in another root. Similarly,
in man, at least for the larger joints of the limbs, the muscles producing the chief
movements in opposite directions are mainly represented at different levels. Thus,
the abductors of the shoulder are innervated mainly by the fifth cervical root, and
the adductors by the sixth and seventh ; the flexors of the elbow are supplied mainly
through the fifth and sixth cervical nerves, and the extensors through the seventh and
eighth ; the extensors of the wrist predominate in the seventh, and the flexors in
the eighth cervical and first dorsal nerves. So also in the lower limb, the flexors of
the hip are represented mainly in the second and third lumbar nerves, and the
extensors in the fifth lumbar and first and second sacral ; the adductors in the third
and fourth lumbar, and the abductors in the fifth lumbar and first sacral nerves ;
the flexors of the knee in the fifth lumbar and first and second sacral nerves, and the
extensors in the third and fourth lumbar.
TABLE OP THE MUSCLES SUPPLIED BY THE SEVERAL SPINAL NERVES.
NERVE. ANTERIOR DIVISION. POSTERIOR DIVISION.
1st cervical .-. Rectus lateralis, Rectus anticus minor and major, Rectiis posticus major and
Grenio-hyoid, Inf rahyoid muscles. minor, Obliquus superior
and inferior, Complexus.
2nd cervical . . Rectus anticus major, Longus colli, Sterno-cleido- Obliquus inferior, Com-
mastoid, Grenio-hyoid, Infrahyoid muscles. plexus, Splenius, Tra-
chelo-mastoid.
MUSCULAR DISTRIBUTION.
NERVE. ANTERIOR DIVISION.
3rd cervical . . Rectus anticus major, Longus colli, Infrahyoid
muscles, Scalenus medius, Levator scapulae,
(Sterno-cleido-mastoid),1 Trapezius, (Dia-
phragm).
4th cervical . . Rectus anticus major, Longus colli, Scalenus
medius (and anticus), Diaphragm, Levator
scapulae, Trapezius.
5th cervical . . Longus colli, Scaleni, (Diaphragm) . Levator sca-
pulae, Rhomboidei, Serratus magnus, Sub-
clavius, Supraspinatus, Infraspinatus, Teres
minor, Subscapularis, (Teres major), Deltoid,
(Pectoralis major), Biceps, Brachialis anticus.
(>th cervical . . Longus colli, Scaleni, (Subclavius), Serratus
magnus, (Supraspinatus, Infraspinatus, Teres
minor), Subscapularis, Teres major, Deltoid,
Pectoralis major. Biceps, Brachialis anticus,
Pronator teres, Flexor carpi radialis, Supi-
nator longus and brevis, Extensores carpi
radiales, Abductor, Opponens and Flexor
brevis pollicis.
7th cervical . . Longus colli. Scalenus medius,(Serratus magnus),
Pectoralis major and minor, Latissimus dorsi,
(Teres major), Coraco-brachialis, Triceps
brachii, Anconeus, Flexor sublimisdigitorum,
(Flexor profundus digitorum, Flexor longus
pollicis, Pronator quadratus), Extensores
radiales, Extensors of digits, Extensor carpi
ulnaris, (Abductor, Opponens and Flexor
brevis pollicis).
Sth cervical . . Longus colli, Pectoralis major and minor,
Latissimus dorsi, Triceps brachii, Anconeus,
Flexors of digits, Flexor carpi ulnaris, Pro-
nator quadratus, Adductores pollicis, Inter-
ossei, Abductor, Flexor brevis and Opponens
minimi digiti.
1st dorsal . . . Pectoralis major and minor, Flexors of digits,
Flexor carpi ulnaris, Pronator quadracus,
Intercostales. Levator costae, Serratus pos-
ticus superior.
2nd dorsal . . Intercostales, Levator costae, Serratus posticus
superior, (Triangularis sterni).
3rd dorsal . . ) Intercostales, Levatores costarum, Serratus
4th dorsal . . \ posticus superior, Triangularis sterni.
5th dorsal . . ) Intercostales, Levatores costarum, Triangularis
(5th dorsal . . ] stemi, Obliquus externus, Rectus abdo-
minis.
7th dorsal . . ) Intercostales, Levatores costarum, Subcostales,
Hth dorsal . . f Obliquus extern as, Obliquus internus,
Transversalis abdominis, Rectus abdominis.
J)th dorsal . . "i Intercostales, Levatores costarum, Subcostales,
10th dorsal . > Serratus posticus inferior. Obliquus externus,
llth dorsal . } Obliquus internus, Transversalis abdominis,
Rectus abdominis.
12th dorsal . . (Quadratus lumborum), Obliquus externus,
Obliquus internus, Transversalis abdominis,
Rectus abdominis, Pyramidalis.
1st lumbar . . Quadratus lumborum, (Obliquus internus,
Transversalis abdominis), Cremaster.
2nd lumbar . . (Quadratus lumborum), Cremaster, Psoas
magnus, (Psoas parvus), Iliacus, Pectineus,
Adductor longus, Adductor brevis, Gracilis,
Sartorius.
POSTERIOR DIVISION.
Complexus, Transverso-
spinales, Splenius, Erec-
tor spinae.
Transverso-spinales, Erec •
tor spinas.
1 Names enclosed in parentheses indicate that the muscles are not always supplied from the nerve-
root in question.
356
MUSCULAR DISTRIBUTION OF SPINAL NERVES.
NERVE.
3rd lumbar
ANTERIOR DIVISION.
POSTERIOR DIVISION.
Multifidus spinse, Erector
spinae.
Psoas magnus, Iliacus, Pectineus, Adductor
longus, Adductor brevis. Adductor magnus.
Gracilis, Obturator externus, Sartorius,
Quadriceps.
4th lumbar . . (Psoas magnus). Adductor brevis, Adductor
magnus, G-racilis, Obturator externus,
Quadriceps, Gluteus medius and minimus,
Tensor vaginae femoris, (Gluteus maximus, |
Obturator internus), Quadratus femoris, |
Semimembranosus, (Deep muscles of back of \
leg), Muscles of front and outer side of leg,
Extensor brevis digitorum.
5th lumbar . . (Quadriceps), Adductor magnus, Grluteus
maximus, medius and minimus, Tensor
vaginas femoris, (Pyriformis), Quadratus
femoris, Obturator internus, Hamstrings,
Muscles of leg (except gastrocnemius),
Extensor brevis digitorum, Inner muscles of
sole.
1st sacral . . . Gluteus maximus, medius and mini- \
mus, Tensor vagina3 femoris, Pyriformis,
Obturator internus, Quadratus femoris,
(Adductor magnus), Hamstrings, Muscles of
leg and foot.
2nd sacral . . . Gluteus maximus, (Gluteus medius and minimus,
Tensor vaginae femoris), Pyriformis, Obtu- '
rator internus, Semiteniinosus, Biceps, Multifidus spina?.
(Muscles of front of leg, Peronei), Gastro-
cnemius, Soleus, Flexor longus hallucis,
(Flexor longus digitorum, Tibialis posticus),
Outer muscles of sole, Perineal muscles.
3rd sacral . . . (Pyriformis), Biceps, long head, (Gastrocnemius.
Soleus, Muscles of sole), (Levator ani,
Coccygeus), Perineal muscles,
•ith sacral . . . Levator ani, Coccygeus, Perineal muscles.
5th sacral . . . (Coccygeus).
The unstriped muscles of the viscera and other parts are also under the influence of
fibres derived from the cerebro-spinal nerves. These will be referred to in the description of
the sympathetic.
/
LITERATURE OF THE MUSCULAR DISTRIBUTION OF SPINAL NERVES.
Beevor, C. E., and Horsley, V., Note on some of the Motor Functions of certain Cranial
Nerves, and of the three first Cervical Nerves, in the Monkey, Proc. Roy. Soc., 1888.
Bolk, L., Beziehungen zicischen Skelet, Muskulatur und Ncrvcn der Extremitaten, dargeleyt am
Beckengilrtel, an dessen Muskulatur, sowie am Plexus lumbo-sacralis, Morphol. Jahrb., xxi, 1894.
Eisler, P., Der Plexus lumbosacralis des Menschen, 1892.
Ferrier, D., and Yeo, GK F., The Functional Relations of the Motor Roots of the Brachial
and Lumbo-sacral Plexuses, Proc. Roy. Soc., 1881.
Forg-ue et Lanneg-race. Distribution des racines motrices dans les muscles des membres, and
Distribution Kpeciale des racines motrices du plexus lombo-sacre, Comptes rendus, 1884.
Growers, "W. R., Diseases of the Nervous System.
Herring-ham, W. P., The Minute Anatomy of the Brachial Plexus, Proc. Roy. Soc., 1886.
Paterson, A. M., The Origin and Distribution of the Nerves to the Lower Limb. Journ. of Anat.,
xxviii, 1893—4.
Huge, GK, Zeugnisse fur die metamere Verkilrzung des Rumpfes bei Saugethieren. Der
Musculus rectus thoraco-abdominalis der Primaten, Morphol. Jahrb., xix, 1892; Verschiebungcn in
den Endgebieten der Nerven des Plexus lumbalis der Primaten, Morphol. Jahrb., xx, 1893 (Nerves to
abdominal muscles).
Russell, J. S. Risien. An Experimental Investigation of the Nerve-roots which enter into the
Formation of the Brachial Plexus of the Dog, Phil. Trans., 1892.
Sherring-ton, C. S., Notes on the Arrangement of some Motor Fibres in the Lumlo-sacral Plexus.
Journ. of Physg., xiii, 1892.
Simon, A., Ueber die Bcziehungen bestimmter Muskeln zu bestimmten Abschnittcn der grauen
Substanz des Ruckenmarks, In. Diss., Strassburg, 1892.
Starr, M. Allen, American Journal of the Medical Sciences, May, 1888.
Thorburn, W. A Contribution to the Surgery of the Spinal Cord, 1889.
THE SYMPATHETIC NERVES.
35?
THE SYMPATHETIC NERVES.
The nerves of the sympathetic system are distributed to the internal viscera,
together with other glandular organs of the body, to the heart and blood-vessels.
Fig. 228. — DIAGRAMMATIC OUTLINE OF THE SYMPATHETIC CORD OF
ONE SIDE IN CONNECTION WITH THE SPINAL NERVES. (Allen
Thomson. )
The full description of this figure will be found at p. 275.
On the right side the following letters indicate parts of the
sympathetic nerves, viz., — a, superior cerviccil ganglion, com-
municating with the upper cervical spinal nerves, and continued
below into the great sympathetic cord ; b, middle cervical gang-
lion ; c, d, lower cervical ganglion united with the first dorsal ;
df, eleventh dorsal ganglion ; from the sixth to the ninth dorsal
ganglia the origins of the great splanchnic nerve are shown, and from
the tenth that of the small splanchnic nerve ; /, first lumbar
ganglion; ss, first sacral ganglion. In the whole extent of the sym-
pathetic cord the twigs of union with the spinal nerves are shown.
and to the unstriped muscles of the body generally.
Some organs, however, receive nerves also from the
cerebro-spinal system directly, as the lungs, the heart,
and the upper and lower parts of the alimentary
canal ; and those viscera which are not supplied
directly in this way receive fibres derived originally
from cerebro-spinal nerves through their sympathetic
plexuses.
This division of the nervous system consists of a
somewhat complicated collection of ganglia, cords and
plexuses, the parts of which may, for convenience, be
classified in two groups, viz., the principal gangliated
cords, and the great prevertebral plexuses, with the
nerves proceeding from them. The ganglia of union with
cranial nerves, viz., the ciliary, spheno-palatine, otic, and
submaxillary ganglia, which agree in their connections
and structure with the ganglia of the sympathetic
system, have already been described in connection
with the fifth nerve.
The foundation of the sympathetic is constituted
by medullated fibres, for the most part of very small
size (2'fyi and less), which pass by means of the white
rami communicantes from certain of the cerebro-spinal
nerves, into the cords and ganglia of the sympathetic.
Here some of the fibres terminate in arborisations
around the cells of the ganglia of the great sympa-
thetic cord (vertebral or lateral ganglia of Gaskell),
while others, which frequently run for a variable
distance either upwards or downwards in the cord,
pass by the rami efferentes to the prevertebral plexuses,
where they may end similarly in the ganglia of those
plexuses (prevertebral or collateral gang lia, Gaskell), or
they may be continued on to the secondary plexuses, to
break up in the ganglia close to or in the organs
supplied (terminal ganglia, Gaskell). Some of the
medullated fibres also pass through the several
plexuses to the viscera or other parts without being
358
THE SYMPATHEI1C NERVES.
interrupted in any of the ganglia above mentioned. From the cells of the ganglia
other fibres, in great part it' not entirely non-medullated, arise. These are the
proper sympathetic fibres. They run partly in the grey rami communicantes to the
spinal nerves, partly in the rami efferentes and the offsets of the collateral and
terminal ganglia to their ultimate distribution.
The great gangliated cords (trunci sympathies) are two in number, and
each consists of a series of ganglia (ganglia trunci sympat/iici), united by short
intervening cords, sometimes double. These gangliated cords are placed symmetri-
cally, partly in front, and partly on the side, of the vertebral column, extending
from the base of the skull to the coccyx. Superiorly they are connected with
Fig. 229. — SCHEME OF THE SYMPATHETIC CORD AND ITS CONNECTION*
WITH THE SPINAL NERVES. (Gr. D. T. )
Meclullated fibres passing into and through the sympathetic cord
are represented by continuous lines, pale fibres arising from the
sympathetic ganglia by dotted lines.
plexuses which enter the cranial cavity, while interiorly
they converge on the sacrum, and terminate in a loop on
the coccyx. The several portions of the cords are dis-
tinguished as cervical, dorsal or thoracic, lumbar, and
sacral, and in each of these parts the ganglia are equal
in number, or nearly so, to the vertebrae against which
they lie, except in the neck, where there are only three.
Connection of the gangliated cords with the
cerebro-spinal system. — The ganglia are severally
connected with the anterior primary divisions of the
spinal nerves in their neighbourhood by short filaments
called rami communicantes, which are of two kinds, white
and grey, the former consisting mainly of medullated
fibres, and the latter of pale fibres. In some cases these
are separate branches ; in others they are united in one
cord, which then consists of a white and a grey part.
As a rule, the communicating branches join the ganglia
of the sympathetic trunk, but sometimes they unite with
the part of the cord connecting adjacent ganglia.
White rami communicantes are composed, as
stated above, mainly of very fine medullated fibres passing
from the spinal nerves to the sympathetic cord. The
fibres proceed from both roots of the spinal nerves, but
to a greater extent from the anterior. It is probable that
the fibres derived from the posterior roots are for the
most part afferent, but it has been shown by v. Lenhossek and others in the chick
that the posterior roots also contain fibres which spring from cells of the spinal cord,
and are believed to enter the sympathetic (Kolliker). These fibres have, however,
as yet not been observed in mammals, and Sherrington in the cat and monkey failed
to find evidence of any fibres in the posterior roots arising from cells of the spinal
cord. Some of the medullated fibres are continued over the ganglia of the cord to
enter the efferent branches ; others end in the ganglia, often ascending or descending
for a considerable distance in the cord to reach ganglia at a higher or lower level
than that of the communicating branch by which they pass to the sympathetic.
The individual fibres also which terminate in the cord are not necessarily confined
to one ganglion. According to Langley and Anderson, a single fibre may send
KAMI COMMUNICANTES. 359
branches to several (about four) ganglia. In this way the fibres contained in one
communicating branch may have a wide distribution in the sympathetic.
White rami communicantes are not furnished by all the spinal nerves.
According to (laskell, by whose investigations the fundamental constitution of the
sympathetic and its relations to the cerebro-spinal nerves were first made clear, they
are found in the dog from the second dorsal to the second lumbar nerve inclusive ;
but Langley has shown that in the dog and cat white rami communicantes are
given off by the spinal nerves from the first dorsal to the fourth lumbar, and in the
rabbit from the first dorsal to the fifth lumbar inclusive. In man it is most
probable that they exist from the first dorsal to the first or second lumbar nerves,
perhaps also the third in some cases. The visceral branches of the second, third,
and fourth sacral nerves (pelvic splanchnic* of Gaskell) correspond to white
rami communicantes, although they do not join the sympathetic cord, but pass
directly to the prevertebral plexuses ; and in this group also are to be included the
visceral branches of the spinal accessory, vagus, glosso-pharyngeal, and facial nerves
(cervico-cranial rami viscerales, Gaskell), as well as the short root of the ciliary
ganglion from the third nerve.
The medullated fibres passing into the sympathetic system are classified by Kolliker as
follows : —
(«•) Sensory fibres which, when derived from spinal nerves, run in the posterior roots.
(&) Vaso- and viscero-constrictors, proceeding from certain cranial (IX, X, XI) and
spinal nerves, mainly from the anterior roots of the latter, but possibly also from the
posterior roots. These fibres all end in ganglia of the sympathetic, and their action
is transmitted through pale fibres springing from the cells of the ganglia.1
(c) "Vaso- dilators and viscero-inhibitory nerves, given off from the above-mentioned
cranial nerves, and the anterior roots of spinal nerves. They are continued as medullated
fibres, not forming any connection with nerve-cells, to their respective organs.
The existence of special trophic and secretory fibres in the sympathetic is as yet uncertain.
Grey rami communicantes are found passing between the sympathetic cord and
all the spinal nerves. Their pale fibres arise wholly from the nerve-cells of the ganglia
of the sympathetic cord, and for the most part from the cells of the ganglion with
which the branch is connected. Pale fibres arising from the cells of one ganglion,
and running along the cord to leave by the grey ramus of the next ganglion, only
occur exceptionally (Langley). On entering the anterior primary division of
a spinal nerve, the fibres of the grey ramus are directed both peripherally and
centrally. Of those passing centrally, some go off in the posterior primary division
of the nerve, others enter the sheath of the nerve, the surrounding tissue in
the inter vertebral foramen, and the dura mater, running up to the latter in
the posterior root. In the whole of the anterior root, and in the intradural portion
of the posterior root, there are no pale fibres (Gaskell). The fibres passing distally
in the anterior and posterior primary divisions of the spinal nerves have been
shown, by experiments on animals, to supply vaso-motor nerves to the arteries of the
body-wall and limbs, pile-motor fibres to the muscles of the hairs, and secretory
fibres to the sweat-glands.
Intermixed with the pale fibres in the grey rami communicantes there are also a
1 To this group must also be added the pilo-motor nerves, which have been shown by Langley
and Sherrington to have a similar arrangement, as well as probably the motor nerves of the sphincter
muscle of the iris, which pass from the third nerve through the ciliary ganglion. The lastr however,
present the peculiarity that the fibres of the short ciliary nerves arising from the cells of the ciliary
ganglion are medullated.
It may also be observed here that doubt is thrown by Langley upon the universal validity of the rule
that fibres passing from the cerebro-spinal nerves to the sympathetic are medullated until they reach the
ganglion in which they end, while the fibres arising from the ganglion-cells are always non-medullated.
He thinks that spinal fibres sometimes lose their medulla some distance before reaching the cells
amongst which they end, and on the other hand that fibres proceeding from sympathetic ganglion-cells
may in some cases be medullated, like the short ciliary nerves. He also considers it probable that a
given fibre in the sympathetic is interrupted by a nerve-cell in one ganglion only.
360
THE SYMPATHETIC NERVES.
few medullated fibres of varying size, even in regions where distinct white rami do
not exist (Langley).
.From each grey ramus a filament is given off to join the recurrent branch of
Fig. 230. — THE SUPERIOR CKK-
VICAL GANGLION OF THK
SYMPATHETIC, WITH I !'S
BRANCHES AND CONNEC-
TIONS. (Henle. )
1, styloid process ; '2,
uvula ; 3, great cornu of
liyoid bone, pushing up tlie
posterior wall of the pharynx ;
4, oesophagus ; 5, thyroid
body ; Sp, stylo-pharyngcns
in uscle.
Cc, common carotid artery '
Ci, internal carotid ; Ge, ex-
ternal carotid ; t su, superior
thyroid ; 1, lingual ; m e,
facial.
IX, gl osso-pharyngeal
nerve ; X, vagus ; XII, hypo-
glossal ; c1, first cervical ;
c'2, second cervical ; ph, pha-
ryngeal branch of vagus ; I r s,
superior laryngeal ; d h, de-
scending cervical nerve ;
G c s, superior cervical gang-
lion of sympathetic ; c i, as-
cending branch ; j, jugular
branch ; c d s. superior cardiac
the corresponding spinal
nerve, which is distribu-
ted in the interior of the
spinal canal (p. 278).
Other filaments pass over
the bodies of the verte-
bras, supplying the in-
tercostal and lumbar
arteries, the ligaments,
and the bones.
The portions of the
sympathetic cord inter-
vening between the
ganglia are composed
of a white and a grey
part, the former, which
is usually the larger,
consisting of medul-
lated fibres continued
from the white rami
communicantes, and the
latter of pale fibres,
which arise in the
ganglia and run along the cord before entering the efferent branches.
The rami etferentes are the branches proceeding from the gangliated cord to
the prevertebral plexuses, and likewise composed of medullated fibres of spinal
origin and pale fibres springing from the ganglia.
CERVICAL PART OF CORD. 361
The great prevertebral plexuses comprise three large aggregations of nerves,
or nerves and ganglia, situated in front of the spine, and occupying respectively the
thorax, the abdomen, and the pelvis. They are single and median, and are named
respectively the cardiac, the solar, and the hypogastric plexus. These plexuses
receive branches from the cerebro-spinal nerves, as well as from both the gangliated
cords above noticed, and they constitute centres from which the viscera are supplied
with nerves.
CERVICAL PART OF THE GANGLIATED CORD.
In the neck, the gangliated cord is deeply placed behind the great cervical blood-
vessels, being embedded in the fascia forming the back of the carotid sheath, and
resting on the muscles which immediately cover the fore part of the vertebral
column. It comprises three ganglia, the first of which is placed near the base of
the skull, the second in the lower part of the neck, and the third close to the head of
the first rib.
UPPER CERVICAL GANGLION.
This is the largest ganglion of the great sympathetic cord, 20 mm. or more long
and 4 — 6 mm. wide. It is continued superiorly into an ascending branch, and
tapers below into the connecting cord, so as to present usually a fusiform shape ; but
there is considerable variety in this respect in diiferent cases, the ganglion being
occasionally shorter and broader than usual, and sometimes constricted at intervals.
Ib has the reddish-grey colour characteristic of the ganglia of the sympathetic
system. It is placed on the rectus anticus major muscle opposite the second and
third cervical vertebrae, lying behind the internal carotid artery, and to the inner
side of the vagus nerve.
Connection with spinal nerves. — At its outer side, the superior cervical
ganglion is connected with the first four spinal nerves by means of slender cords,
which belong to the group of grey rami communicantes. The branches to the
third and fourth nerves often pierce the rectus anticus major muscle ; and they may
be given off from the upper part of the cord, instead of directly from the ganglion.
The circumstance of this ganglion being* connected with so many as four spinal nerves,
together with its occasionally constricted appearance, is favourable to the view that it may be
regarded as consisting of several ganglia which have coalesced.
The superior cervical ganglion is considered by Gaskell to be a distal or collateral ganglion
It receives its cerebro-spinal fibres, which constitute the cervical splanchnic* of Gaskell. from
the upper dorsal nerves, through the cervical part of the sympathetic cord.
Connection with cranial nerves. — Small twigs connect the ganglion or its
cranial cord with the lower ganglion of the pneumo-gastric, and with the twelfth
cranial nerve, near the base of the skull ; and another branch (n. jugularis], which
is directed upwards from the ganglion, divides at the base of the skull into two
filaments, one of which ends in the petrosal ganglion of the glosso-pharyngeal
nerve ; while the other, entering the jugular foramen, joins the ganglion of the root
of the pneumo-gastric.
From the lower part of the ganglion a filament sometimes runs forwards and downwards
to join the external laryngeal nerve. This branch is described as normal by many anatomists,
but according to Drobnik it is only exceptionally present.
Besides the branches connecting it with cranial and spinal nerves, the first
cervical ganglion gives off also the ascending branch, pharyngeal branches, the upper
cardiac nerve, and branches to blood-vessels, as well as two or three filaments which
pierce the prevertebral muscles to supply the upper cervical vertebra? and their
ligaments.
THE SYMPATHETIC NERVES.
1. ASCENDING BRANCH AND CRANIAL PLEXUSES. — The ascending or carotid
branch of the first cervical ganglion (n. caroticus internus) is soft in texture and of
a reddish-grey tint, seeming to be in some degree a prolongation of the ganglion
itself. In its course to the skull, it is concealed by the internal carotid artery,
with which it enters the carotid canal in the temporal bone, and it is then divided
into two parts, which are placed one on the outer, the other on the inner side of the
vessel.
The external division distributes filaments to the internal carotid artery, receives
one or two carotico-tympanic twigs from the tympanic branch of the glosso-
pharyngeal (p. 2 GO), and, after communicating by means of other filaments with the
internal division of the cord, forms the carotid plexus.
The internal division, rather the smaller of the two, supplies filaments to
the carotid artery, and goes to form the cavernous plexus. The terminal parts
of these divisions of the cranial cord are prolonged on the trunk of the internal
carotid, and extend to the cerebral and ophthalmic arteries, around which they form
secondary plexuses, those on the cerebral arteries ascending to the pia mater. One
minute plexus enters the eye-ball with the central artery of the retina.
Fig. 231. — CONNECTIONS OK
THE SYMPATHETIC NKRVK
THROUGH ITS CAROTID
BRANCH WITH SOME OK
THE CRANIAL NERVES.
(From Sappey, after
Hirschfeld and Leveille.)
The full description of this
ligure will be found at p. 240.
The following numbers refer to
sympathetic nerves and their
connections : 6, spheno-palatine
ganglion ; 7, Yidian nerve : 9,
large deep petrosal nerve ; 10,
a part of the sixth nerve
receiving twigs from the carotid
plexus of the sympathetic ; 11,
superior cervical sympathetic
ganglion : 12, its prolongation
15, tympanic nerve ; 16, t\vig uniting it to the sympathetic.
in the carotid branch
Carotid plexus. — The carotid plexus (plexus caroticus inlernus), situated on
the outer side of the internal carotid artery at its second bend (reckoning from
below), or between the second and third bends, joins the fifth and sixth cranial
nerves, and gives many filaments to the vessel on which it lies.
Branches. — (a) The connection with the sixth nerve is established by means
of one or two filaments of considerable size, which are supplied to that nerve where
it lies by the side of the internal carotid artery.
(V) The filaments connected with the Gasserian ganglion of the fifth nerve
proceed generally from the carotid plexus, but sometimes from the cavernous.
(c) The large deep petrosal nerve passes forwards from the outer side of the artery
to the posterior aperture of the Vidian canal, where it joins the large superficial
petrosal from the facial to form the Vidian nerve, which is continued to the spheno-
palatine ganglion (p. 243).
(d) The small deep petrosal nerve passes between the carotid plexus and the
tympanic plexus (p. 200).
Cavernous plexus. — The cavernous plexus, named from its position in the
sinus of the same name, is placed below and rather to the inner side of the highest
turn of the internal carotid artery. Besides giving branches on the artery, it
BRANCHES OF UPPER CERVICAL GANGLION. 3G3
communicates with the third, the fourth, and the ophthalmic division of the fifth
cranial nerves.
BRANCHES. — (a) The filament which joins the third nerve comes into connection
with it close to the point of division of that nerve.
(&) The branch to the fourth nerve, which may be derived from either the
cavernous or the carotid plexus, joins the nerve where it lies in the wall of
the cavernous sinus.
(c) The filaments connected with the ophthalmic trunk of the fifth nerve are
supplied to its inner surface.
(d) The sympathetic root of the ciliary ganglion passes from the cavernous
plexus into the orbit, either separately, or in connection with the nasal nerve, or,
according- to Reichart, with the third nerve (p. 238).
(e) Minute filaments are furnished to the pituitary body.
2. PHARYNGEAL NERVES AND PLEXUS. — These nerves arise from the fore part of
the ganglion, and are directed obliquely inwards to the side of the pharynx.
Opposite the middle constrictor muscle they unite with branches of the pneumo-
gastric and glosso-pharyngeal nerves ; and by their union with these nerves the
pharyngeal plexus is formed. Branches emanating from the plexus are distributed
to the muscles and mucous membrane of the pharynx (p. 265). One or two
filaments pass from these branches to the superior and external laryngeal nerves
(fig. 228).
3. UPPER CARDIAC NERVE. — Each of the cervical ganglia of the sympathetic
usually furnishes a cardiac branch, the three being named respectively the upper,
middle, and lower cardiac nerves.
These branches are continued singly, or in connection, to the large prevertebral
centre (cardiac plexus) of the thorax. Their size varies considerably, and where
one branch is smaller than common, another will be found to be increased in size,
as if to compensate for the defect. There are some differences in the disposition of
the nerves of the right and left sides.
The upper or superficial cardiac nerve of the right side proceeds generally
from two or more branches of the ganglion, with, in some instances, an offset from
the cord connecting the first two ganglia. In its course down the neck the nerve
lies in the back of the carotid sheath, along the front of the longus colli muscle ; it
crosses either in front of or, less frequently, behind the inferior thyroid artery, and is
placed in front of the recurrent laryngeal nerve. Entering the thorax, it passes in
some cases before, in others behind, the subclavian artery, and is directed along the
innominate artery to the back part of the arch of the aorta, where it ends in
the deep cardiac plexus, a few small filaments continuing also to the front of
the great vessel. Some branches accompany the inferior thyroid artery to be
distributed to the thyroid body.
In its course downwards this cardiac nerve is repeatedly connected with other
branches of the sympathetic, and with the pneumo-gastric nerve. Thus, about the
middle of the neck it is joined by one or more filaments from the external laryngeal
nerve ; and, rather lower down, by one or two filaments from the trunk of the
pneumo-gastric nerve (upper cervical cardiac branches) ; lastly, on entering the
chest, it joins with the recurrent laryngeal.
The upper cardiac nerve of the left side has, while in the neck, the same
course and relations as that of the right side. Within the chest it follows the left
carotid artery to the arch of the aorta, and usually crosses over that vessel to enter
the superficial cardiac plexus. In some cases, however, this nerve ends, either
wholly or in part, in the deep cardiac plexus, and it then descends behind the arch
of the aorta.
THE SYMPATHETIC NERVES,
Varieties. — The cardiac nerves vary greatly in their disposition, and in many cases it is
difficult, if not impossible, to recognize the arrangement which is described as typical. The
superior cardiac nerve of the right side, instead of passing to the thorax in the manner stated
above, may join the cardiac branch furnished from one of the other cervical ganglia. This
nerve is sometimes wanting, especially on the right side ; in such cases it appears to be
Fig. 232. — CONNECTIONS OP THE CERVICAL AND UPPER THORACIC SYMPATHETIC GANGLIA AM> XKRVES
ON THE LEFT SIDE. (From Sappey, after Hirschfeld and Leveille.)
The full description of this figure will be found at p. 263. The following numbers refer to the
sympathetic ganglia and nerves, and those immediately connected with them ; 5, pharyngeal plexus ;
12, 13, posterior pulmonary plexus ; and to the reader's left, above the pulmonary artery, the superficial
cardiac plexus ; 24, superior cervical ganglion of the sympathetic ; 25, middle cervical ganglion ;
26, conjoined inferior cervical and first thoracic ganglia ; 27, 28, 29, 30, second, third, fourth, and fifth
thoracic ganglia.
replaced by a larger superior cardiac offset from the vagus or its external laryiigeal branch
(M. Alpiger).
Drobnik describes a special yrctraclieal Iranc7i which is given off from the communication
between the superior cardiac nerve and the recurrent laryngeal ; it descends on the trachea,
and terminates partly in the pericardium, partly in the anterior pulmonary plexus.
4. BRANCHES TO BLOOD-VESSELS. — The nerves which ramify on the arteries
(nn. carotid externi] spring from the front of the ganglion, and twine round
the trunk of the external carotid artery (plexus caroticus externus). They are also
prolonged on the branches of the artery, forming upon them slender plexuses which
are named like the arteries they accompany. From the plexus on the facial artery
MIDDLE AND LOWER CERVICAL GANGLIA. 365
is derived the filament which forms the sympathetic root of the subinaxillaiy
ganglion ; and from that on the middle meningeal artery twigs are described as extend-
ing to the otic ganglion, as well as to the geniculate ganglion of the facial nerve
(external superficial petrosal nerve, p. 253). One filament descends from these
nerves to the carotid gland.
Microscopic ganglia are frequently met with in the vascular plexuses, and several larger
ones of more constant occurrence have been described. The most important of these is
the tciu/)or<il (/uixjlion, about 2 mm. in length, situated on the external carotid artery at the
place of origin of the posterior auricular branch ; it is said to receive a filament from
the stylo-hyoid branch of the facial nerve.
MIDDLE CERVICAL GANGLION.
The middle ganglion, much the smallest of the cervical ganglia, is placed on the
sympathetic cord at or near the spot where it crosses the inferior thyroid artery,
about opposite the sixth or seventh cervical vertebra. It is usually connected by grey
branches with the fifth and sixth spinal nerves, but in a somewhat variable
manner. It gives off thyroid branches and the middle cardiac nerve.
Thyroid branches. — From the inner side of the ganglion some twigs proceed
along the inferior thyroid artery to the thyroid body, where they join the recurrent
laryngeal and the external laryngeal nerves. While on the artery, these branches
communicate with the upper cardiac nerve.
The middle cardiac nerve (deep or great cardiac nerve) of the right side is
prolonged to the chest either in front of or behind the subclavian artery. In the
chest it lies on the trachea, where it is joined by filaments of the recurrent laryngeal
nerve, and it ends in the right side of the deep cardiac plexus. While in the neck,
this nerve communicates with the upper cardiac nerve and the recurrent branch of
the pneumo-gastric.
On the left side, the middle cardiac nerve enters the chest between the left carotid
and subclavian arteries, and joins the left side of the deep cardiac plexus.
Varieties. — The middle cervical ganglion is often absent, and in that case the middle
cardiac nerve is given off by the interganglionic cord. On the other hand, it is sometimes
double (fig. 233). The smaller upper portion (A) is the middle cervical ganglion of Arnold
and Luschka, the thyroid ganglion of Krause ; while the larger lower portion (B) is the
middle cervical ganglion of Swan and Krause, the inferior cervical ganglion of Arnold,
Luschka, and Riidinger. The single ganglion is more frequently in the latter situation.
This part of the cord is sometimes placed behind the inferior thyroid artery, or it may be
divided so that the artery is enclosed in a loop of the nerve.
LOWER CERVICAL GANGLION.
The lower cervical ganglion is irregular in shape, usually somewhat flattened
and round, or semilunar, and is frequently united to the first thoracic ganglion, the
common mass being described as the first thoracic ganglion by many authors. It lies
over the first costo-central articulation, in the lateral angle between the subclavian and
vertebral arteries. The connecting cord between the middle and lower cervical
ganglia usually passes behind the vertebral artery, but in some cases, especially on
the left side, the interganglionic cord forms a ring around the vessel. The two-
ganglia are also united by the ansa subclavia (see below).
The inferior cervical ganglion is connected to the lowest two cervical nerves by
grey communicating branches, and it gives off the lower cardiac nerve and offsets to
blood-vessels.
The lower cardiac nerve, issuing from the inferior cervical ganglion, or from
the first thoracic, inclines inwards on the right side, behind the subclavian artery
and terminates in the cardiac plexus behind the arch of the aorta. It communicates
VOL. III.. PT. 2. •*• A
366
THE SYMPATHETIC NERVES.
NF.
THYR.
with the middle cardiac and recurrent laryngeal nerves behind the subclavian
artery.
On the left side, the lower cardiac often becomes blended with the middle cardiac
nerve, and the cord resulting from their union terminates in the deep cardiac
plexus.
Branches to blood-vessels. — From the lowest cervical and first dorsal ganglia
slender grey branches ascend along the vertebral artery in its canal, forming
a plexus (plexus vertebmlis) round the vessel by their intercommunications, and
supplying it with offsets. This plexus is connected with the cervical spinal nerves
as they cross the vertebral artery, and its ultimate ramifications are continued on
the intracranial branches of the vertebral and basilar arteries.
"Fig. 233. — THK SYMPATHETIC AT THK
LOWER PART OF THK NECK. (Gr. D. T. )
A, B, middle cervical ganglion in two
pieces ; C, inferior cervical ganglion ;
D and E, first and second thoracic
ganglia.
a, vertebral offset of inferior cervical
ganglion ; b, branch which ascends
through the foramen in the transverse
process of the last cervical vertebra to
join the seventh nerve.
Below C are the origin of the inferior
cardiac nerve, and the termination of
the ansa subclavia. The arteries have
been drawn downwards and inwards in
order to display the nerves. The middle
cervical ganglion is, therefore, in a lower
position than natural ; and the com-
munication between the middle and lower
ganglia is directed more transversely
than would be the case if the parts Avere
in their natural place.
Ansa subclavia ( Vieussenii}. —
This name is given to a small
cord, often double, which passes
between the middle cervical and
the lower cervical, or first dorsal,
ganglia, in front of the sub-
clavian artery, forming a loop
around that vessel, and supplying it ^ith small offsets (plexus subclavms). From
the latter, filaments pass to the internal mammary artery, and in some cases
form a communication with the phrenic nerve.
A direct twig of communication to the phrenic nerve is often given off from the inferior
cervical ganglion, less frequently from the middle cervical ganglion.
The stellate ganglion of the dog and cat corresponds to the united lower cervical
and upper three or four thoracic ganglia of man. In the rabbit the name f/anf/llon stcU(ttnm
was used for the lower cervical ganglion, corresponding to the middle cervical ganglion
of man, by Ludwig and Thiry, whereas Cyon applied it to the first thoracic ganglion, which
corresponds to the lower cervical ganglion in man (Krause).
CONSTITUTION OF THE CERVICAL SYMPATHETIC.
The sets of fibres which have been recognized in the cervical sympathetic, and their
probable origin, are as follows : —
(a) Pupillo-dilator fibres, arising from the first, second, and third dorsal nerves. They
pass upwards in the ascending branch of the superior cervical ganglion, and thence to
the Gasserian ganglion, reaching the eyeball through the first division of the fifth and
the long ciliary nerves. (It is stated by many observers that pupillo-dilator fibres are
contained also in the seventh and eighth cervical nerves.)
MID.
CARD.
THORACIC PART OF CORD. 367
(V) Motor fibres to the involuntary muscle of the orbit and eyelids, from the highest
four or five dorsal nerves (Lang-ley).
(V) Vaso-motor fibres of the head. Vato-GOnstriotor fibres are given off in the dog1 and
cat chiefly by the second, third, and fourth dorsal nerves, in the rabbit by the dorsal
nerves from the second to the eighth (Langley). There is also some evidence as to the
existence of mso-dilator filnr*. but the origin of these has not been fully ascertained.
(d] Secretory fibres of the submaxillary gland, mainly from the second and third dorsal
nerves.
(^) Pilo-motor fibres of the face and neck, in the monkey arising from the second,
third, fourth, and fifth dorsal nerves (Sherrington).
In all the foregoing groups the fibres of spinal origin terminate, and fibres of sympathetic
origin arise, in the superior cervical ganglion.
(/) Accelerator fibres of heart, derived from the upper four or five dorsal nerves, but
chiefly from the second and third. The spinal fibres end and sympathetic fibres begin in the
middle and lower cervical (perhaps also the first thoracic) ganglia.
THORACIC PART OF THE GANGLIATED CORD.
In the thorax the gangliated cord is placed at the side of the spinal column, along
a line passing over the costo-central articulations. It is covered by the pleura, and
crosses the intercostal blood-vessels.
The ganglia are commonly eleven in number, seldom twelve. The first, when
distinct, is larger than the rest, and lies at the vertebral extremity of the first
intercostal space ; but it is often blended with the lower cervical ganglion. The
succeeding ganglia are small, oval or triangular in form, and correspond generally
to the heads of the ribs from the third to the eleventh ; while the last is placed
a little in front of the head of the twelfth rib, about the upper border of the last
dorsal vertebra.
Connection with spinal nerves. — The branches of connection between the
dorsal nerves and the ganglia of the sympathetic are usually two in number for each
ganglion, one of these being white and the other grey (p. 358).
BRANCHES OF THE GANGLIA.
The branches furnished by the upper four or five ganglia are small, and are dis-
tributed in great measure to the vertebrae and ligaments, and to the descending
thoracic aorta (fig. 232), on which they form, together with filaments proceeding
lower down from the great splanchnic nerve, a slender network (plexus aorticus
thoracalis). From the second, third, and fourth ganglia offsets pass also to the
posterior pulmonary plexus (p. 268).
The branches furnished by the loiver six or seven ganglia unite into three cords
on each side, which pass down to join plexuses in the abdomen, and are dis-
tinguished as the great, the small, and the smallest splanchnic nerves (abdominal
splanchnics of Gaskell).
The great splanchnic nerve is formed by the union of roots which are given
off by the thoracic ganglia from the fifth or sixth to the ninth or tenth inclusive.
The trunk thus constituted descends obliquely forwards over the bodies of the dorsal
vertebras, and after perforating the crus of the diaphragm terminates in the upper
part of the semilunar ganglion : some of the fibres may occasionally be followed to
the suprarenal body and the renal plexua This nerve is remarkable from its white
colour and firmness, due to its consisting in large part (four-fifths according to
Riidinger) of medullated fibres, which are continued directly from the spinal nerves ;
from the highest root they may be traced upwards along the sympathetic cord as far
as the third thoracic ganglion and nerve, or even higher.
In the chest the great splanchnic nerve is not unfrequently divided into parts,
and forms a plexus with the small splanchnic nerve. In many cases also a small
i. A 2
368
THE SYMPATHETIC NERVES.
Fig. 234. — DIAGRAMMATIC VIEW OF THE
SYMPATHETIC COKD OF THE RIGHT SIDE,
SHOWING ITS CONNECTIONS WITH THE
PRINCIPAL CEREBRO-SPINAL NERVES AND
THE MAIN PREAORTIC PLEXUSES. £
Cerebro- spinal Nerves. — VI, a portion of
the sixth cranial nerve as it passes through
the cavernous sinus, receiving two twigs from
the carotid plexus of the sympathetic nerve ;
0, ciliary ganglion, connected by a twig with
the cavernous plexus ; M, connection of the
spheno-palatine ganglion by the large deep
petrosal nerve with the caroti'l plexus ; C,
cervical plexus ; Br, brachial plexus ; I) 6,
sixth dorsal nerve ; I) 12, twelfth ; L3, third
lumbar nerve ; S 1, first sacral nerve ; S 3,
third ; S 5, fifth ; Cr, anterior crural nerve ;
Cr', great sciatic ; pn, pneumo-gastric nerve
in the lower part of the neck ; r, recurrent
nerve, winding round the subclavian artery.
Sympathetic Cord. — c, superior cervical
ganglion ; c', middle ; c", inferior ; from each
of these ganglia cardiac nerves (all deep on
this side) are seen descending to the cardiac
plexus ; d ], placed immediately below the
first dorsal sympathetic ganglion : d 6, is
opposite the sixth ; I 1, first lumbar gan-
glion ; c g, the terminal or coccygeal ganglion.
Preaortic and Visceral Plexuses. — pp,
pharyngeal plexus ; pi, posterior pulmonary
plexus, spreading from the pneumo-gastric on
the back of the right bronchus ; ca, on the
aorta, the cardiac plexus, towards which, in
addition to the cardiac nerves from the three
cervical sympathetic ganglia, other branches
are seen descending from the pneumo-gastric
and recurrent nerves ; co, right or posterior,
and co', left or anterior coronary plexus ;
o, cesophageal plexus in long meshes on the
gullet ; sp, great splanchnic nerve ; + , small
splanchnic ; + + , smallest splanchnic ; the
first and second of these are shown joining so,
the solar plexus ; the third descending to re,
the renal plexus ; connecting branches between
the solar plexus and the pneumo-gastric nerves
are also represented ; pn\ above the place
where the right pneumo-gastric passes to the
posterior surface of the stomach : pn' , the
left, distributed on the anterior surface of
the cardiac portion of the oi'gan ; from the
solar plexus large branches are seen surround-
ing the arteries of the cceliac axis, and de-
scending toms, the superior mesenteric plexus;
opposite to this is an indication of the supra-
renal plexus ; below re (the renal plexus), the
spermatic plexus is also indicated ; av, on the
front of the aorta, marks the aortic plexus,
formed by nerves descending from the solar
and superior mesenteric plexuses and from the
lumbar ganglia ; 'nil, the inferior mesenteric
plexus, surrounding the corresponding artery ;
hy, hypogastric plexus, placed between the
common iliac arteries, connected above with
the aortic plexus, receiving nerves from the
lower lumbar ganglia, and dividing below into
the right and left pelvic or inferior hypogas-
tric plexuses ; pi, right pelvic plexus ; from
this the nerves descending are joined by those
from the plexus on the superior hsemorrhoidal
vessels mi', by sympathetic nerves from the sacral ganglia, and by numerous visceral nerves from the
third and fourth sacral spinal nerves, and there aie thus formed the rectal, vesical, and other plexuses,
which ramify upon the viscera from behind forwards, and from below upwards, as towards ir, and v,
the rectum and bladder.
CONSTITUTION OF THORACIC CORD. 369
ganglion (splanchnic ganglion) is formed on it, usually confined to the inner part of
the nerve, over the last dorsal vertebra, or the last but one ; and when it presents a
plexiform arrangement, several small ganglia have been observed on its divisions.
According to Cunningham, the splanchnic ganglion is always present on the right
side.
From the great splanchnic nerve and the splanchnic ganglion filaments are given
to the front of the vertebrae and the aorta.
In eight instances out of a large number of bodies, Wrisberg observed a fourth splanchnic
nerve (ne.mis s/jf(irirhH/r><* .s-///;/r ///<.*). It is described as formed by offsets from the cardiac
nerves, and from the lower cervical as well as some of the upper thoracic ganglia.
The small splanchnic nerve springs from the ninth and tenth (sometimes the
tenth and eleventh) thoracic ganglia, or from the neighbouring part of the cord. It
passes along with the preceding nerve, or separately, through the diaphragm, and
ends in the lower part of the semilunar (or aortico-renal) ganglion. In the chest,
this nerve often communicates with the great splanchnic nerve ; and in some
instances it furnishes a branch to the renal plexus, especially if the lowest splanclinic
nerve is very small or wanting.
The smallest splanchnic nerve (nervus renalis posterior, Walter) arises from
the last thoracic ganglion, and communicates sometimes with the nerve last
described. After passing the diaphragm with the cord of the sympathetic, it ends
in the renal plexus. Its place is frequently supplied by a branch of the small
splanchnic nerve.
CONSTITUTION OP THE THORACIC PART OP THE SYMPATHETIC.
The thoracic portion of the gangliated cord receives most of the spinal fibres entering the
sympathetic system (/;/'. p. 359). Only a small part of these end in the thoracic ganglia ; the
greater number pass either upwards into the neck or downwards into the abdomen. The fibres
ascending to the neck arise from the upper dorsal nerves ; they include the pupillo-dilator
fibres, secretory fibres of the submaxillary gland, vaso-motor fibres of the head and neck,
accelerator fibres of the heart, and others, all of which have been referred to in connection
with the cervical sympathetic (p. 366). In addition to these, the following groups have been
demonstrated experimentally in the lower animals : —
(«) Vaso-constrictor fibres of the pulmonary vessels have been shown by Bradford and
Dean, in the dog, to pass out of the spinal cord by the thoracic nerves from the second to the
seventh (mainly, however, through the third, fourth, and fifth nerves), and to end in the
ganglion stellatum.
(b~) Vaso-constrictor fibres of the limbs are connected with the vertebral ganglia.
Those of the fore limb are given off by the dorsal nerves, in the dog from the third to the
eleventh (Bayliss and Bradford), in the cat from the fourth to the ninth (Langley). Those
of the hind limb are furnished, according to the same investigators, in the dog by the last
three (11, 12, 13) dorsal and first three lumbar nerves, and in the cat by the last two or three
dorsal and the first three or four lumbar nerves.
(r) Secretory fibres to the sweat-glands of the fore foot leave the dorsal nerves from
the third or fourth to the ninth, and pass to the ganglion stellatum ; while those of the hind
limb emerge by the last two dorsal and upper three lumbar nerves, and descend in the cord
to the lower lumbar and upper sacral ganglia— in the cat (Langley).
(d) Pilo-motor fibres in the cat pass from the lower nine or ten dorsal nerves, as well as
the upper three or four lumbar, to the vertebral ganglia (Langley).
The splanchnic nerves contain : —
(e) Viscero-inhibitory fibres of the stomach and intestine.— According to Langley
and Dickinson they end in the ganglia of the solar plexus.
(/) Vaso-motor nerves of the abdominal blood-vessels. — The existence of vaso-con-
strictor fibres for the arteries of the alimentary canal in the splanchnic nerves is well
established ; and, according to Langley and Dickinson, these nerves also contain the vaso-
dilator fibres of the same vessels : both sets of fibres end in the ganglia of the solar plexus.
Vaso-constrictor fibres of the portal vein and its tributaries were originally demonstrated by
Mall ; according to Bayliss and Starling, in the dog, they are given off by the dorsal nerves
from the third to the eleventh, but mainly from the fifth to the ninth. The nerves of the
renal blood-vessels, both constrictor and dilator, are derived in the dog from the dorsal nerves
from the sixth downwards, as well as (constrictors only) from the upper two lumbar nerves
370 THE SYMPATHETIC NERVES.
(Bradford) : the renal vaso-motor fibres probably end in the ganglia of the renal plexus
(Langley and Dickinson).
(</) Afferent fibres from the abdominal viscera.
The lowest part of the cord also contains : —
(//•) Some of the motor fibres of the circular muscle of the rectum, proceeding from the
lower dorsal nerves. Together with fibres from the upper one or two lumbar nerves, they
pass by the aortic plexus to the inferior mesenteric ganglion. Associated with these are the
inhibitory fibres of the longitudinal muscle of the rectum (Fellner).
LUMBAR PART OF THE GANGLIATED CORD.
In the lumbar region, the two gangliated cords approach one another more
nearly than in the thorax. They are placed on the front of the bodies of the
vertebras, each lying along the inner margin of the psoas muscle ; and that of the
right side is partly covered by the vena cava, that of the left by the aorta.
The ganglia are small, and of an oval shape. They are commonly four in
number, but occasionally their number is diminished, and they are then of larger
size.
Connection with spinal nerves. — In consequence of the greater distance at
which the lumbar ganglia are placed from the intervertebral foramina, the branches
of connection with the spinal nerves are longer than in other parts of the gangliated
cord. There are generally two connecting branches for each ganglion, but the
number is not so uniform as it is in the chest ; nor are those belonging to any one
ganglion connected always with the same spinal nerve. The connecting branches
accompany the lumbar arteries, and, as they cross the bodies of the vertebras, are
covered by the fibrous bands which give origin to the muscular fibres of the psoas.
BRANCHES. — The branches of these ganglia are uncertain in their number.
Some join the plexus on the aorta ; others descending go to form the hypogastric
plexus. Several filaments are distributed to the vertebrae and the ligaments con-
necting them,
CONSTITUTION OP THE LUMBAR PORTION OF THE SYMPATHETIC.
Spinal fibres pass into the sympathetic from the upper one or two lumbar nerves, and
others descend in the cord from the lower dorsal nerves. For the most part they form a
continuation of groups of fibres which have been noticed in the account of the thoracic
sympathetic (p. 369), including vaso-con stricter and secretory nerves of the hind limb, pilo-
motor fibres, vaso-constrictor fibres of the abdominal vessels, and motor fibres of the circular
muscle, with inhibitory fibres of the longitudinal muscle of the rectum.
Arising from the lumbar nerves only are the following : —
(«) Vase-motor nerves of the penis. — The raso-comtrictor fibres probably pass from the
upper lumbar nerves into the sympathetic cord, whence they are mainly continued by pale
fibres through grey rami communicantes to the pudic nerve ; but it is stated by Francois-
Franck that some constrictor fibres run through the inferior mesenteric ganglion to the
hypogastric plexus, and that these are accompanied by a part of the vaso-dilator fibres of
the penis.
(£>) Motor fibres to the bladder, passing by the aortic plexus to the inferior mesenteric
ganglion, and thence through the hypogastric and pelvic plexuses, to supply the circular
muscle, including the sphincter. Associated with these there are probably inhibitory fibres of
the longitudinal muscle.
(tf) Motor fibres to the uterus, taking a similar course to the foregoing.
(Motor fibres to the vas deferens in the male, or to the round ligament of the uterus in
the female, were found by Sherrington in the monkey leaving the cord by the anterior roots
of the second and third lumbar nerves (corresponding to the first and second lumbar of man),,
and passing to their destination through the genital branch of the genito-crural nerve.)
SACRAL PART OF THE GANGLIATED CORD.
Over the sacrum, the gangliated cord of the sympathetic nerve is much diminished
in size, and gives but few branches to the viscera. Its position on the front of the
sacrum is along the inner side of the anterior sacral foramina ; and like the two
SACEAL PART OF CORD.
371
series of those foramina, the right and left cords approach one another in their
progress downwards. The upper end of each is united to the last lumbar ganglion
by a single or a double intergauglionic cord ; and at the lower end they are
connected by means of a loop, in which a single median ganglion, ganglion impar or
coccygeal ganglion, placed on the fore part of the coccyx, is often found. The sacral
ganglia are usually four in number ; but the variation both in size and number is
more marked in these than in the thoracic or lumbar ganglia.
Variety. — In one instance the cord was found terminating at the second sacral nerve
(E. Fawcett, Journ. Anat., xxix, 329).
Connection with spinal nerves. — From the proximity of the sacral ganglia
to the spinal nerves at their emergence from the foramina, the communicating
Fig. 235. — SACRAL PORTION OF THE SYMPATHETIC CORDS
OP AN INFANT, SLIGHTLY ENLARGED. (Rauber.)
s 1 — s 4, sacral ganglia ; c, coccygeal ganglion,
showing indications of its origin by the fusion of
two ganglia, and sending downwards branches which
run with the middle sacral artery ; ri, interfunicular
branches uniting the ganglia of the two sides ; below
these is seen a small interfunicular ganglion.
branches are very short : there are often
two for one ganglion, and these are in
some cases connected with different sacral
nerves. The coccygeal nerve communi-
cates with the last sacral, or the coccygeal
ganglion.
BRANCHES. — The branches proceeding
from the sacral ganglia are much smaller
than those from other ganglia of the cord.
They are for the most part expended on the
front of the sacrum, and join the corre-
sponding branches from the opposite side.
Some filaments from one or two of the
upper ganglia enter the pelvic plexus,
while others go to form a plexus on the
middle sacral artery. From the loop con-
necting the two cords, filaments are given to the coccyx and to the ligaments about
it, and to the coccygeal gland.
CONSTITUTION OF THE SACRAL SYMPATHETIC.
There are no spinal fibres passing from the sacral nerves to the sympathetic cord, but the
latter contains medullated fibres which descend from the lumbar region and terminate in the
sacral ganglia. These fibres include vaso-constrictor and secretory fibres of the hind
limb, and the pilo-motor fibres of the hindmost part of the body and the tail in the cat
(Langley).
The visceral branches of the sacral nerves (pclriv xplanchnics, Graskell) are equivalent
to white rami communicantes (p. 359), but they pass directly into the pelvic plexuses, where
a few of the fibres may turn upwards to the inferior mesenteric ganglion,1 while the larger
number enter the plexuses of the pelvic viscera. They comprise : —
(Y/) Motor fibres to the longitudinal muscle, and inhibitory fibres to the circular
muscle of the rectum.
1 Fibres ascending to the inferior mesenteric ganglion are described by Graskell in the dog, but they
were not found by Langley in the cat.
372 THE SYMPATHETIC NERVES.
(I) The chief motor fibres of the bladder, distributed probably to the longitudinal
muscle.
(c) Motor fibres of the uterus.
((I) Vaso-dilator fibres of the penis (nrrri eriyentex).
(e) Secretory fibres of the prostate gland.
THE GREAT PLEXUSES OF THE SYMPATHETIC.
Under this head are included certain large plexuses of nerves placed farther
forwards in the visceral cavity than the gangliated cords, and furnishing branches
to the viscera. The principal of these plexuses are the cardiac, the solar, and
the hypogastric with the pelvic plexuses prolonged from it. They are composed of
assemblages of nerves, or of nerves and ganglia, and from them smaller plexuses are
derived.
CABDIAC PLEXUS.
This plexus receives the cardiac branches of the cervical ganglia and those of the
pneumo-gastric nerves, and from it proceed the nerves which supply the heart,
besides some offsets which contribute to the nervous supply of the lungs. It lies
against the aorta and pulmonary artery, where these vessels are in contact, and in its
network are distinguished two parts, the superficial and the deep cardiac plexuses,
the deep plexus being seen behind the vessels, and the superficial more in front, but
both being closely connected. The branches pass from these plexuses chiefly
forwards in two bundles, accompanying the coronary arteries.
Superficial cardiac plexus. — The superficial cardiac plexus (fig. 232) lies in
the concavity of the arch of the aorta, between the ligament of the ductus arteriosus
and the right branch of the pulmonary artery. In it the superficial or upper cardiac
nerve of the sympathetic of the left side terminates, either wholly or in part,
together with the lower cervical cardiac branch of the left pneumo-gastric nerve. In
the superficial plexus a small ganglion, the ganglion of Wrisberg, is frequently found
at the point of union of the nerves. Besides ending in the right coronary plexus,
the superficial cardiac plexus furnishes laterally filaments along the pulmonary artery
to the anterior pulmonary plexus of the left side.
Deep cardiac plexus. — The deep cardiac plexus, much larger than the
superficial one, is placed behind the arch of the aorta, between it and the end of the
trachea, and above the bifurcation of the pulmonary artery.
This plexus receives all the cardiac branches of the cervical ganglia of the
sympathetic nerve, except the upper cardiac nerve of the left side. It likewise
receives the cardiac nerves furnished by the vagus and by the recurrent laryngeal
branch of that nerve, with the exception of the left cervical cardiac nerves.
Of the branches from the right side of the plexus, the greater number descend
in front of the right pulmonary artery, and join branches from the superficial part in
the formation of the right coronary plexus ; others, passing behind the right
pulmonary artery, are distributed to the right auricle of the heart, and a few
filaments are continued into the left coronary plexus.
On the left side, a few branches pass forwards by the side of the ductus arteriosus
to join the superficial cardiac plexus, and others descend to the left auricle ; but the
great majority end in the left coronary plexus.
The deep cardiac plexus sends filaments to the anterior pulmonary plexus on each
side.
Coronary plexuses. — The right or posterior coronary plexus is derived from
both the superficial and deep cardiac plexuses, the filaments by which it arises
embracing the root of the aorta. It accompanies the right coronary artery on the
heart, sending its branches upwards and downwards to the auricle and ventricle.
CARDIAC PLEXUS. 373
The left or anterior coronary plexus is larger than the right, and is derived
mainly from the left half of the deep cardiac plexus. Being directed forwards
between the pulmonary artery and the left auricular appendage, it reaches the left
coronary artery, and subdivides into two principal portions which accompany the
primary divisions of that vessel.
Nervous filaments ramify in great number under the epicardium, especially on the
ventricular portion of the heart. They are not so easily distinguished in man as in
some animals. In the heart of the calf or the lamb they are distinctly seen without
dissection, running in lines which cross obliquely the muscular fibres. Microscopic
ganglia occur on the nerves of the auricles, and in the course of the coronary
plexuses, but they are absent from the offsets to the ventricular wall (see Vol. II,
Fig. 236. — DIAGRAMMATIC REPRESENTATION OP THE CARDIAC PLEXUS OP THE HUMAN EMBRYO.
(W. His, jun. )
a, aorta ; a', pulmonary artery ; b, atrium, with the orifices of the veins ; Au, auricle proper ;
v, ventricle ; vg, vagus ; sy, cord of sympathetic ; p, p, pericardium ; s, transverse sinus of peri-
cardium ; I, bulbar plexus ; II, atrial plexus ; III, intermediate plexus.
From the embryological investigations of W. His, jun., it appears that the ascending aorta,
the pulmonary trunk, and the ventricles of the heart are supplied by the upper cardiac nerves,
while the auricles receive branches arising- at a lower level. The earliest of the cardiac nerves
to be developed are branches from both vagus and sympathetic of each side to the arterial
bulb, which appear about the end of the fourth or the beginning of the fifth week of foetal
life, and make their way between the aorta and the pulmonary trunk, where they form the
bulbar plexus. In the seventh week other nerves are found passing from the vagi lower down
to the back of the auricles, and forming there the atrial plexus, which also receives
sympathetic branches through the following plexus. The bulbar anel atrial plexuses are
connected by branches which descend from the former behind the transverse sinus of the peri-
cardium, and are joined by offsets of both vagi, the left recurrent nerve, and the sympathetic
cords, the whole constituting the intermediate plexus. All of these branches contain numerous
ganglion-cells of sympathetic nature, which travel downwards with the growth of the nerves.
In the course of the third month the coronary nerves are developed from the bulbar plexus,
and offsets of the atrial plexus spread over the auricles. In the definitive state therefore the
bulbar plexus is represented by the superficial cardiac plexus and a part of the deep cardiac
plexus, with their coronary offsets, the intermediate plexus by the remainder of the deep
cardiac plexus, and the atrial plexus by the network on the auricles. The distribution of
the ganglia in the adult heart corresponds to the extent of these plexuses.
SOLAR OR EPIGASTRIC PLEXUS.
The solar or epigastric plexus (plexus cxliacus), the largest of the prevertebral
centres, is placed at the upper part of the abdomen, behind the stomach, and in
374
THE SYMPATHETIC NERVES.
front of the aorta and the pillars of the diaphragm. Surrounding the origin of the
cceliac axis and the superior mesenteric artery, it occupies the interval between the
suprarenal bodies, and extends downwards as far as the pancreas. The plexus
Fig. 237. — SOLAR AND AORTIC PLEXCSES, WITH THE LUMBAR PORTION OF THE SYMPATHETIC CORDS,
IN THEIR RELATIONS TO THE AORTA, &C. (GK D. T. )
C.A., coeliac axis, and S.M.A., superior mesenteric artery, both cut close to their origin ; surround-
ing them is the solar plexus ; on the aorta below the renal arteries is the aortic plexus ; s', great,
s", small, and s'", smallest splanchnic nerves ; A, phrenic ganglion ; B, semilunar ganglion ; C, aortico-
renal ganglion ; D, superior mesenteric ganglion ; E, spermatic ganglion ; F, inferior mesenteric
ganglion.
SOLAR PLEXUS. 375
consists of nervous cords, with several ganglia of various sizes connected with them.
The large and small splanchnic nerves on both sides, and some branches of the
pneumo-gastric, terminate in it. The branches given off from it are very
numerous, and accompany the arteries to the principal viscera of the abdomen,
constituting so many secondary plexuses on the vessels. Thus, diaphragmatic,
cceliac, mesenteric, and other plexuses are recognised, which follow the corresponding
arteries.
Semiluiiar ganglia. — The solar plexus contains, as already mentioned, several
ganglia (ganglia cvdiaca) ; and by the size of these bodies it is distinguished from
the other prevertebral plexuses. The two principal ganglionic masses, named
semilunar, though they have often little of the form the name implies, occupy the
upper and outer part of the plexus, one on each side, and are placed close to the
suprarenal bodies, by the side of the cceliac and the superior mesenteric arteries.
At the upper end, which is expanded, each ganglion receives the great splanchnic
nerve. The lower part of the ganglionic mass, lying over the root of the renal artery,
is commonly more or less detached from the rest, and is distinguished as the
aortico-renal ganglion ; it is joined by the small splanchnic nerve, and gives origin
to the greaterpart of the renal plexus. Another part, lying below and to the right
of the origin of the superior mesenteric artery, is named the superior mesenieric
ganglion.
Diaphragmatic or phrenic plexus. — The nerves composing this plexus are
derived from the upper part of the semilunar ganglion, and are larger on the right
than on the left side. Accompanying the arteries along the lower surface of the
diaphragm, the nerves sink into the substance of the muscle. They furnish some
filaments to the suprarenal body, and join with the spinal phrenic nerves.
At the right side, on the under surface of the diaphragm, and near the supra-
renal body, there is a small ganglion (diaphragmatic or phrenic ganglion), which
marks the junction between the phrenic nerves of the spinal and sympathetic
systems. From this small ganglion filaments are distributed to the vena cava, the
suprarenal body, and the hepatic plexus. On the left side the ganglion is wanting.
Suprarenal plexus. — The suprarenal nerves issue from the solar plexus and
the outer part of the semilunar ganglion, some filaments being added from the
diaphragmatic plexus and one of the splanchnic nerves. They are short, but
numerous in comparison with the size of the suprarenal body, which they enter on
its inner and posterior part. These nerves consist in great part of white fibres, and
are beset with minute ganglia.
Renal plexus. — The nerves forming the renal plexus emanate for the most part
from the aortico-renal ganglion, but some are added from the solar and aortic
plexuses. The renal plexus also receives the termination of the smallest, and some-
times filaments from the small splanchnic nerve, as well as a branch from the first
lumbar ganglion. The nerves of the plexus are mostly grey, and in their course
along the renal artery ganglia of different sizes (renal ganglia) are formed on them.
Lastly, dividing with the branching of the vessel, the nerves follow the renal arteries
into the substance of the kidney. On the right side some filaments are furnished to
the vena cava, behind which the plexus passes with the renal artery ; and on both
sides offsets pass to the spermatic plexus, and a filament to the ureter.
Spermatic plexus. — This small plexus commences in the renal, but receives in
its course along the spermatic artery an accession from the aortic plexus, in which
a small spermatic ganglion is often formed at the place where these branches arise.
Continuing downwards to the testis, the spermatic nerves are connected with others
which accompany the vas deferens and its artery from the pelvis.
In the female, the plexus, like the artery, is distributed to the ovary and the
uterus.
376 THE SYMPATHETIC NERVES.
Cceliac plexus. — This plexus is of large size, and is derived from the fore part
of the great epigastric plexus. It surrounds the coeliac axis in a kind of fenestrated
sheath, and subdivides, with the artery, into coronary, hepatic, and splenic plexuses,
the branches of which form communications corresponding with the arches of the
arterial anastomosis. The plexus receives on the left side a considerable offset from
the right pneumo-gastric nerve.
The coronary plexus is placed with its artery along the small curvature of the
stomach, and unites with the nerves which accompany the pyloric artery, as well as
with branches of the pneumo-gastric nerves. The nerves of this plexus enter the
coats of the stomach, after running a short distance beneath the peritoneum.
The hepatic plexus, the largest of the three divisions of the coeliac plexus, ascends
with the hepatic vessels and the bile duct, and, entering the substance of the liver,
ramifies on the branches of the portal vein and the hepatic artery. Offsets from the
left pneumo-gastric nerve join the hepatic plexus at the left side of the vessels.
From this plexus filaments pass to the right suprarenal plexus, as well as other
secondary plexuses which follow the branches of the hepatic artery. Thus there is
a cystic plexus to the gall-bladder; and there are pyloric, gastro-epiploic, and pan-
creatico-duodenal plexuses, which unite with coronary, splenic, and mesenteric
nerves.
The splenic plexus (plexus linealis), continued on the splenic artery and its
branches into the substance of the spleen, is reinforced at its beginning by branches
from the left semilunar ganglion, and by filaments from the right vagus nerve. It
furnishes the left gastro-epiploic and pancreatic plexuses, which course along the
corresponding branches of the splenic artery, and, like the vessels, are distributed to
the stomach and pancreas.
Superior mesenteric plexus. — The plexus accompanying the superior
mesenteric artery, whiter in colour and firmer than any of the preceding offsets, is
mainly given off from the lower part of the solar plexus and the superior mesenteric
ganglion, but it also receives fibres from the right pneumo-gastric nerve at its
junction with the cceliac plexus. Surrounding the trunk of the superior mesenteric
artery, it divides into secondary plexuses which agree in name and distribution with
the branches of that vessel. In their progress to the intestine some of the nerves
quit the arteries which first supported them, and are directed forwards in the
intervals between the vessels. As they proceed they divide, and unite with lateral
branches, like the arteries, but without the same regularity ; they finally pass upon
the intestine along the line of attachment of the mesentery.
Aortic plexus. — The aortic or intermesenteric plexus (plexus aorticus
aldominalis}, placed along, the abdominal aorta, occupies the interval between the
origins of the superior and inferior mesenteric arteries. It consists, for the most
part, of two lateral cords, which are connected above with the semilunar ganglia and
renal plexuses, and extend downwards on the sides of the aorta, meeting in several
communicating branches over the front of that vessel. The cords receive branches
from some of the lumbar ganglia, and at the spots where these join there are often
small ganglionic enlargements, which are more distinct in the infant. Several
filaments pass to the root of the inferior mesenteric artery to form the plexus on
that vessel, and in connection with these is the inferior mesenteric ganglion, placed
below the origin of the artery.
The aortic plexus furnishes the inferior mesenteric plexus and part of the
spermatic, gives some filaments to the lower vena cava, and ends below in the
hypogastric plexus.
Inferior mesenteric plexus. — This plexus is derived principally from the left
lateral part of the aortic plexus, and closely surrounds with a network the inferior
mesenteric artery. It distributes nerves to the left or descending and the sigrnoid
HYPOGASTRIC AND PELVIC PLEXUSES. 377
colon, and assists in supplying the rectum. The nerves of this plexus, like those of
the superior mesenteric plexus, are firm in texture and of a whitish colour.
The highest branches (those on the left colic artery) are connected with the last
branches (middle colic) of the superior mesenteric plexus, while others in the pelvis
unite with offsets derived from the pelvic plexus.
On the branches of the coeliac and mesenteric plexuses Pacinian corpuscles are often
present. They are very variable in number, and are not so numerous or regular in man as in
the cat. Their most frequent seat is in the loose tissue behind the pancreas.
HYPOQASTRIC PLEXUS.
The hypogastric plexus, the assemblage of nerves destined for the supply of the
viscera of the pelvis, lies, invested in a sheath of dense connective tissue, in the
interval between the two common iliac arteries. It is formed by the prolongations
of the aortic plexus on each side, which receive considerable branches from the
lumbar ganglia, and, after crossing the common iliac artery, interlace in the form of
a flat plexiform mass placed in front of the lowest lumbar vertebra. The plexus
contains no distinct ganglia. At the lower end it divides into two parts, which
are directed downwards, one to each side of the pelvic viscera, and form the pelvic
plexuses.
PELVIC PLEXUS.
The pelvic or inferior hypogasfcric plexuses (fig. 234, pl\ one on each side, are
placed in the lower part of the pelvic cavity by the side of the rectum, and of the
vagina in the female. The nerves, continued from the hypogastric plexus, enter
into repeated communications as they descend, and form at the points of connection
small knots, which contain a little ganglionic matter. After descending some way,
they become united with branches of the spinal nerves, as well as with a few offsets
of the sacral ganglia, and the union of all constitutes the pelvic plexus. The spinal
branches which enter into the plexus are furnished from the third and fourth sacral
nerves, sometimes also the second. Small ganglia are formed at the places of union
of the spinal nerves, as well as elsewhere in the plexus.
From the plexus so constituted, numerous nerves are distributed to the pelvic
viscera. They correspond in great measure with the branches of the internal iliac
artery, and vary with the sex ; thus, besides haemorrhoidal and vesical nerves, which
are common to both sexes, there are nerves special to each : — namely, in the male
for the prostate, vesicula seminalis, and vas deferens ; in the female, for the vagina,
uterus, ovary, and Fallopian tube.
The nerves distributed to the urinary bladder and the vagina contain a larger
proportion of spinal fibres than those furnished to the other pelvic viscera.
Haemorrhoidal plexus. — These slender nerves proceed from the upper part of
the pelvic plexus. They join with the nerves (superior haemorrhoidal) which descend
with the inferior mesenteric artery, and penetrate the coats of the rectum.
Vesical plexus.— The nerves of the urinary bladder are very numerous. They
are directed from the lower part of the pelvic plexus to the side and lower part of
the bladder. At first these nerves accompany the vesical blood-vessels, but after-
wards they leave the vessels, and subdivide into minute branches before perforating
the muscular coat of the organ. The lower part of the ureter is also supplied by
these nerves ; and secondary plexuses are given in the male to the vas deferens and
the vesicula seminalis.
The nerves of the vas deferens ramify round that tube, and communicate in the
spermatic cord with the nerves of the spermatic plexus. Those furnished to the
vesicuta seminalis form an interlacement on the vesicula, and some branches
378 THE SYMPATHETIC NERVES.
penetrate its substance. Other filaments from the prostatic nerves reach the same
structure.
Prostatic plexus. — The nerves of this plexus are of considerable size, and pass
between the prostate gland and the levator ani. Some are furnished to the prostate
and to the vesicula seminalis ; and the plexus is then continued forwards to supply
the erectile substance of the penis, where its nerves are named cavernous.
Cavernous nerves of the penis. — These are very slender, and difficult to dissect.
Continuing from the prostatic plexus, they pass onwards beneath the subpubic arch
and through the muscular structure connected with the membranous part of the
urethra, to the dorsum of the penis. At the root of the latter, the cavernous nerves
are joined by some short filaments from the pudic nerve. Having distributed twigs
to the fore part of the prostate and the membranous part of the urethra, these nerves
divide into branches for the erectile substance of the penis, as follows :—
The small cavernous nerves perforate the fibrous covering of the corpus caver-
nosum near the root of the penis, and end in the erectile substance.
The large cavernous nerve extends forwards on the dorsum of the penis, and
dividing, gives filaments which penetrate the corpus cavernosum, and pass with or
near the cavernous artery. As it continues onwards, this nerve joins with the
dorsal branch of the pudic nerve about the middle of the penis, and is distributed to
the corpus cavernosum. Branches from the foregoing nerves reach the corpus
spongiosum urethras. The cavernous nerves are composed mainly of pale fibres.
Vaginal nerves. — The nerves furnished to the vagina leave the lower part of
the pelvic plexus — that part with which the spinal nerves are more particularly
combined. They are distributed to the vagina without previously entering into a
plexiform arrangement ; and they end in the erectile tissue on the lower and
anterior part, and in the mucous membrane.
Nerves of the uterus. — These nerves are derived mainly from the lateral
fasciculus prolonged to the pelvic plexus from the hypogastric plexus, but some
filaments are also added from the third and fourth sacral nerves. They are directed
upwards with the blood- vessels, between the layers of the broad ligament, along the
side of the organ, and some slender filaments accompany the branches of the uterine
artery, but the larger number of the nerves sink directly into the substance of the
uterus, penetrating for the most part its neck and the lower portion of its body.
They form connections in the broad ligament with the ovarian nerves, and the
fundus of the uterus also receives an offset from that plexus. Numerous small
ganglia are contained in the plexus by the side of the neck of the uterus, and a
cluster of these constitutes the ganglion cervicale of Frankenhfiuser. They appear
to be absent in the muscular substance of the organ. One branch continued
directly from the common hypogastric4plexus, reaches the hinder surface of the body
of the uterus above the rest ; and a nerve from the same source ascends to the
Fallopian tube.
The nerves of the gravid uterus have been frequently investigated, with a view to
discover if they become enlarged along with the increase in size of the organ. It is
ascertained that the increase which takes place is confined, for the most part, to the
thickening of the fibrous envelopes of the nerves ; but it is stated also that fibres
furnished with a medullary sheath, which in the un impregnated state of the uterus
lose that sheath as they proceed to their distribution, in the impregnated condition
of the uterus continue to be surrounded with it as they run between the muscular
fibres (Kilian).
LITERATURE. 379
BE CENT LITERATURE OF THE SYMPATHETIC.
Alpig-er, M., A natomische Studie iibcr dasgegenscitige Verhalten der Vagus- und Sympathicusdste
im Gcbicte des Kehlkopfes, Langenheck's Archiv, xl, 1890.
Bayliss, "W. M., and Bradford, J. B,., The Innervation of the Vessels of the Limbs, Journ.
Physio!., xvi, 1894.
Bayliss, W. M., and Starling:, E. H., On the Origin from the Spinal Cord of the Vaso-
constrictor Nerves of the Portal Vein, Journ. Physiol., xvii, 1894.
Bechterew, "W., u. Mislowski, N., Ueber centrale und pcriphere Darminnervation, Arch. f.
Physiol., Supplt. Bd., 1889 ; Zur Frage iiber die Innervation des Magens, Neurolog. Centralbl.,
1890.
Bonuzzi, P., Ueber Vasodilatatorcn in den hinteren Riickenmarkswurzeln, Wiener Jahrbiicher,
18S5.
Bradford, J. B,., The Innervation of the Renal Blood-Vessels, Journ. Physio!., x, 1889.
Bradford, J. R., and Dean, H. P., The Pulmonary Circulation, Journ. Physiol., xvi, 1894.
Braunstein, E. P., Zur Lehre von der Innervation der Pupillenbewegung, Wiesbaden, 1894.
Cavazzani, A., L' inncrvazione vaso-motrice dei polmoni, Rivista veneta d. sc. med., 1891, and
Arch. ital. de biol., xvi, 1891.
Dastre, B., et Morat, J. P., Le systeme grand sympathique, Bull, scient. du depart. duNord,
1880 ; Sur I' experience du grand sympathique cervical, & Sur les nerfs vaso-dilatateurs des parois de
la bouche, Comptes rendus, xci, 1880 ; Sur lafonction vaso-dilatatrice du nerf grand-sympathique,
Arch, de physiol. norm, et pathol., 1882 ; Les nerfs vaso-dilatateurs de Voreille externe, Arch, de
physiol. norm, et pathol., 1882 ; Sur les nerfs vaso-dilatateurs du membre inferieur, Arch, de
physiol. norm, et pathol., 1883 ; Du rdle tonique et inhibitoire des ganglions sympathiques, et de
leur rapport avec les nerfs vaso-moteurs, Comptes rendus, xcvi, 1883 ; Contribution d V etude des
ganglions sympathiques ; leur role tonique et inhibitoire; leur rapport avec les nerfs vaso-moteurs,
C. r. hebd. d. 1. Soc. d. biol., 1883; Recherches experimental sur le systeme nerveuie vaso-moteur,
Paris, 1884.
Doyon, M., Recherches sur les nerfs vasomoteurs de la retine, Arch, de physiol. norm, et pathol.,
1890 and 1891.
Drobnik, T., Topographisch-anatomische Studien uber den ffalssympathicus, Arch. f. Anat.,
1887.
Edg-eworth, F. H., On a large-fibred Sensory Supply of the Thoracic and Abdominal Viscera,
Journ. Physiol., xiii, 1892.
Ehrmann, S., Ueber die Innervation des Diinndarms, Wiener Jahrbiicher, 1885.
Eisenlohr, L., Ueber die N erven- und Ganglienzellen des menschlichen Uerzens, nebst Bemer-
kungen zitr pathologischen Anatomic derselben, Inaug. Diss., Miinchen, 1887.
Fellner, L., Die Bewegunys- und Ilemmungsti erven des Rectums, Wiener Jahrbiicher, 1883 ;
Weitere Mittheilungen ueber die Bewegungs- und ffemmungsnerven des Rectums, Arch. f. d. gesammte
Physiologic, Ivi, 1894.
Prancois-Franck, Recherches sur rinnervation vaso-motrice du penis, Arch, de Physiol. norm,
et pathol., 1895.
Gaskell, "W. H., " On the Structure, Distribution and Function of the Nerves which innervate
the Visceral and Vascular Systems," Journ. Physiol., vii, 1886 ; Do the Nervi Erigentes leave the
Spinal Cord in Anterior or Posterior Roots? Proc. Physiol. Soc., Jan. 15, 1887, Journ. Physiol., viii.
G-aule, J., Versuch eines Schemas der Innervation der J3lase, insbesondere der localen Reftex-
bahnen, Arch. f. Physiol., Supplt. Bd., 1892.
G-ehuchten, A. v., Les elements nerveux moteurs des racines postericures, Anatom. Anzeiger.
viii, 1893.
G-uepin, A., Sur I'innervation vesicale, Journ. de TAnat. et de la Physiol., 1892.
His, "W., Histogenese und Zusammenhang der Ncrvenelemente, Verhandlg. d. x. Internat. Med.
Congresses. Berlin, 1890, and Arch. f. Anat., Supplt. Bd., 1890. (Development of Sympathetic.)
His, W., junr., Die Entwickelung des fferznervensy stems bei Wirbelthieren, Abhandlg. d.
konigl. sachsisch. (resellsch. d. Wissensch., 1891.
Jastreboff, N. W., On the Normal and Pathological Anatomy of the Gang'ion Cervicale Uteri.
Trans. Obstetr. Soc., London, xxiii, 1881.
Jegorow, J., Ueber den Eirtfluss der langen Ciliarnerven auf die Erweiterung der Papille, Arch,
f. Physiol., 1886 ; Zur Lehre von der Inner-cation der Blutgefasse, Arch. f. Physiol., Supplt. Bd.,
1892.
Kasem-Beck, A., Zur Kenntniss der Herznerven, Arch. f. mikrosk. Anat., xxiv, 1884 ; Ueber
das Vorkommen von Ganglien und einzelnen Nervenzellen auf den Hcrzventrikeln der Menschen, der
Sdugethiere und der Vogel, Centralbl. f. d. med. Wissensch., 1887.
Keng1, Lim Boon, On the Nervous Supply of the Dog's Heart, Journ. Physiol., xiv, 1893.
Kolliker, A. v., Der fcinere Bau und die Functionen des sympathischen Nervensy stems,
Wurzburger Sitzungsberichte, 1894 ; Ueber diefeinere Anatomic und die physiologische Bedeutung des
sympathischen Nervensy stems, Verhdlgn. d. Gres. d. deutschen Naturf. u. Aerzte, 1894.
Kiihlwetter, E., Zur Lehre von der Lagerung der Gefdssnerven in den Wurzeln der RucTcen-
marksnerven, Eckhard's Beiti-'age z. Anatom. u. Physiol., xi, 1885.
Lang-endorff, O., Die Beziehungen der Ncrvcnfasern des Halssympathicus zu den Ganglienzellen
des oberen Ilalsknotens, Centralbl. f. Physiologic, v, 1891.
380 THE SYMPATHETIC NERVES.
Lang-ley, J. N., The Innervation of the Pelvic Viscera, Proc. Physiol. Soc., Dec. 13, 1890,
Journ. Physiol., xii ; On the Course and Connections of the Secretory Fibres supplying the Sweat-Glands
of the Feet of the Cat, Journ. Physiol. , xii, 1891 ; On the Origin from the Spinal Cord of the Cervical and
upper Thoracic Sympathetic Fibre*, with some Observations on White and Grey Rami Communicantes,
Phil. Trans., 1892 ; On the Larger Medullated Fibres of the Sympathetic System, Journ. Physiol., xiii,
1892 ; On an "Accessory" Cervical Ganglion in the Cat and Notes on the Rami of the Superior
Cervical Ganglion ; also Notes on the Cervical Sympathetic, and chiefly on its Vaso-motor Fibres,
Proc. Physiol. Soc., Jan. 21, 1893, Journ. Physiol., xiv : The Arrangement of the Sympathetic
Nervous System, based chiefly on Observations upon Pilo-motor Nerves, Journ. Physiol., xv, 1893 ;
Further Observations on the Secretory and Vaso-motor Fibres of the Foot of the Cat, with Notes on other
Sympathetic Nerve Fibres, Journ. Physiol., xvii, 1894.
Lang-ley, J. N., and. Anderson, H. K., On Reflex Action from Sympathetic Ganglia, Journ.
Physiol., xvi, 1894 ; The Constituents of the Hypogastric Nerves (cat), Journ. Physiol., xvii, 1894.
Langley, J. N., and Dickinson, "W., On the Lofal Paralysis of Peripheral Ganglia, and on
the Connexion of different Classes of Nerve Fibres with them, Proc. Roy. Soc., xlvi, 1889.
Lang-ley, J. N., and Sherring-ton, C. S., On Pilo-motor Nerves, Journ. Physiol., xii, 1891.
Lenhossek, M. v., Ueber Nervenfasern in den hinteren Wurzeln, welche aus dem Vorderhorn
entspringen, Anatom. Anzeiger, v, 1890.
Mall, F., Die motor ischen Nerven der Portalvene, Arch. f. Physiol., Suppl. Bd., 1890; Der
Einfluss des Systems der Vence Portce avf die Vertheihing des Blutes, Arch. f. Physiol., 1892.
Morat, J. P., Recherches sur les vaso-moteurs de la tete, Arch, de physiol. norm, et pathol. ,
1889; Les nerfs vaso-dilatateurs et la loi de Magendie, Arch, de physiol. norm, et pathol., 1890;
Recherches sur les nerfs vaso-moteurs de la tete. Trajet intracrdnien des vaso moteurs auriculaires,
Arch, de physiol. norm, et pathol., 1891 ; Origines et centres trophiques des nerfs raso-dilatateurs,
Comptes rendus, cxiv, 1892 ; Les fonctions vaso-motrices des racines posttrieures, Arch, de physiol.
norm, et pathul., 1892 ; Sitr quelques particularity de I'innervation motrice de Vestomac et de
Viittestin, Arch, de physiol. norm, et pathol., 1893.
Morat, J. P., et Doyon, M., Le grand sympathique, nerf de I' accommodation pour la
vision des objets eloignes, Comptes rendus, cxii, and Arch, de physiol. norm, et pathol., 1891.
Nawrocki, P., und Przybylski, Die pupillenerweiternden Nerven der Katze, Arch. f. d.
gesammt. Physiol., 1, 1891.
Nawrocki, P., und Skabitschewsky, B., Ueber die motorischen Nerven der Blase, Arch. f. d.
gesammt. Physiol., xlviii, 1891 ; Ueber die sensiblen Nerven deren Reizung Contraction der Blase
hervorruft, Arch. f. d. gesammt. Physiol., xlix, 1891.
Onodi, A. D., Ueber das Verhdltniss der cerebrospinalen Faserbundel zum sympathischen
Grenzstrange, Med. Centralbl., 1883, and Arch. f. Anat., 1884; Ueber die Entwicklung der Spinal-
ganglien und der Nervenwurzeln, Internat. Monatsschr. f. Anat. u. Histol., 1884 ; Ueber die
Entwicklung des sympathischen N ervensystems, Arch. f. mikroskop. Anat., xxvi, 1885.
Oser, L., Ueber die Innervation des Pylorus, Wiener Jahrbticher, 1884; Experimentelle Beitrdge
zur Innovation des Magens, Zeitschr. f. Klin. Med., xx, 1892.
Pal, J., Ueber die Hemmungsnerven des Darmes, Wiener klin. Wochenschrift, 1893.
Paterson, A. M., The Development of the Sympathetic Nervous System in Mammals, Proc. Roy.
Soc., xlviii, 1890, and Phil. Trans., 1890.
Przybylski, Sur les nerfs dilatateurs de la pupille cJiez le chat, Arch, slaves de Biologic, ii,
1887.
Rein, G., Beitrag zur Lehre von der Innervation des Uterus, Arch. f. d. gesammte Physiol.,
xxiii, 1880 ; Note sur le plexus nerveux fondamental de Vuterus, C. R. Soc. de Biol., 1882.
Remy, Ch., Nerfs ejaculateurs, Journ. de 1'anat. et de la physiol., 1886.
Romberg-, E., Zur Frage der II erzganglicn, Centralbl. f. Physiol., iv, 1891.
Sherringrton, C. S., Journ. Physiol., xiii, 1892 (p. 702, Pupillo-dilator fibres in monkey ;
p. 676, Nerves of bladder) ; ib., xvii, 1894 (p. 217, Efferent fibres in posterior roots of spinal
nerves) ; see also Langley and Sherrington.
Sperino, Gr., Sulla presenza di cellule ganglionari sul decorso delle fiore die compongono i nervi
splanchnicus major ed minor, Grazz. Osp. , 1886.
Steil, A., Ueber den spinalea Ursprung des Halssympathicus, Arch. f. d. gesammt. Physiol., Iviii,
1894.
Stein ach, E.. Die motorische Innervation des Darmtractus durch die hinteren Spinalnerven-
wurzeln, Lotos, xiv, 1893.
Thompson, W. H., Ueber die AbhdngigTceit der Gliedervenen von motorischen Nerven, Arch. f.
Physiol., 1893.
Varoglia, S., e Conti, A., Alcune particolarita macro- e microscopiche dei nervi cardiaci
nelV uomo, Atti della R. Accad. d. Sc. di Torino, xxii, 1887 ; Sur la presence de cellules nerveuses
le long des nerfs cardiaques et dans quelques autres nerfs de I'homme, Arch. ital. de biologic, ix,
1887.
Vas, F., Ueber die Bedeutung der grossen Ganglien im sympathischen Grenzstrange, Allgem.
Wiener med. Zeitung, 1891.
White, W. Hale, On the Histology and Function of the Mammalian Superior Cervical Ganglion,
Journ. Physiol., viii, 1887 ; Further Observations on the Histology and Function of the Mammalian
Sympathetic Ganglia, Journ. Physiol., x, 1889.
Zeglinsky, N., Experimentelle Untersuchung uber die Irisbewcgung, Arch. f. Physiol., 1885.
Zeissl, M. v., Ueber die Innervation der Blase, Arch. f. d. gesammte Physiol., liii, 1893, and Iv,
1894.
MORPHOLOGY OF NERVES.
381
T
MORPHOLOGY OF THE PERIPHEKAL NERVES.
SPINAL NERVES. — Segmentation. — The spinal nerves in their arrangement as they
leave the vertebral column exhibit in a marked degree the character of segmentation. This is
not the case however at their attachment to the spinal cord, where the filaments of both the
anterior and posterior roots form each a nearly continuous series along the whole length of
the cord. In their connection with the grey matter of the spinal cord there is again evidence
of a segmental arrangement, which appears not to correspond exactly to the segmentation
seen in the nerve-trunks, for it seems probable that the fibres composing one posterior root,
for example, may be connected with more than one segment of the spinal cord (cf. p. 350).
Mode of division. — A typical segmental nerve, on leaving the vertebral canal, divides at
once into two parts, which are known as the anterior or central, and the posterior or dorsal
Fig. 238. — PLAN OF THE MODE OF BRANCHING OF A
SEGMENTAL NERVE.
primary f/icixio/i*. In addition to these, the trunk also
gives off a small recurrent or meningeal branch to the
interior of the spinal canal, and the anterior division
furnishes a branch to the sympathetic. The primary
branching of the nerve may thus be looked upon as a
separation into four parts, of which the anterior, posterior,
and recurrent divisions are said to be somatic, while the
offset to the sympathetic is usually called visceral or
splanchnic (rainu* vtieeralis). The latter term, although often convenient, is, however not
strictly accurate, since the sympathetic division contains, in addition to visceral fibres, other
fibres which influence the unstriped muscles of the vessels and skin of the trunk and limbs,
parts which are of somatic origin.
Posterior primary divisions. — These supply the dorso-lateral muscle (see Vol. II, p. 347)
and the overlying integument. As a rule, each is divided into internal and external branches
Fig. 239. — PLAN OF AN UPPER DORSAL NERVE,
SHOWING THE TYPICAL MANNER OF BRANCH-
ING OF THE ANTERIOR AND POSTERIOR
PRIMARY DIVISIONS OF A SEGMENTAL NERVE.
(GKD. T.)
corresponding to the cleavage of the dorso-
lateral muscle, and from one only of these
an offset passes to the skin. The first cer-
vical nerve has no external branch or
cutaneous offset ; while the last two sacral
and the coccygeal nerves give off no muscu-
lar branches, as the dorso-lateral muscle
terminates at the fourth sacral vertebra,
and therefore they do not divide into the
usual two branches. As has been previously
pointed out (p. 341), cutaneous branches are
not usually furnished by those nerves, the
anterior divisions of which occupy a central
position in the limb-plexuses (lower cervical
and lower lumbar nerves).
Anterior primary divisions. — In the
primitive condition the anterior primary
division of a segmental nerve supplies the
ventro-lateral muscle of the segment and a
corresponding zone of skin. The cutaneous
or perforating branches are two in number,
a lateral, which again divides into anterior and posterior branches, and an anterior. This
arrangement is however retained only in the nerves from the second dorsal to the first lumbar
inclusive. Above and below the region thus indicated the primitive condition is much
modified by the union of the nerves in plexuses, in great part for the supply of the limbs.
But the cutaneous distribution of each of these nerves, as has already been shown (p. 345),
is to a definite continuous area of skin, altered in shape and position in consequence of
growth-changes, and in the case of the central limb-nerves shifted so much that all connec-
tion with the trunk is lost.
VOL. III., PT. 2. » B
382 MORPHOLOGY OF NERVES.
Nerves of the limbs. — As to the morphological nature of the limb-nerves, it is held by
Paterson, Eisler, and others that they represent the whole of the anterior primary divisions
of segmental nerves, but it seems probable that the view enunciated by Goodsir, namely, that
the limb-nerves are greatly developed lateral perforating1 branches of segmental nerves, is the
better founded. At the same time it is to be noticed that the increase of the lateral branch
for the supply of the limb is accompanied by a reduction of the other portions of the
segmental nerve, which proceeds so far that the anterior and posterior cutaneous offsets, as
well as the visceral branch, are all wanting- in the case of the central nerves of the limb-
plexuses.
The transition from the typical segmental nerves to the modified form met with in the
limbs takes place gradually, and may be thus traced. The third dorsal nerve has the typical
character ; the second differs but little, its posterior cutaneous branch is drawn out over the
scapula, and its lateral perforating branch becomes enlarged and extends down the arm.
forming a connection with the brachial plexus, while some of the fibres belonging to this
division often begin to take a shorter course to the plexus through the communication with
the first dorsal nerve (p. 307). In the first dorsal nerve the lateral branch, greatly enlarged,
passes directly into the brachial plexus, the anterior and posterior cutaneous offsets are small,
and sometimes wanting, and its contribution to the sympathetic is less than that of the
second. The eighth, seventh and sixth cervical nerves consist almost wholly of large lateral
offsets, the anterior and posterior perforating, and the visceral branches are suppressed, and
the supply from the anterior primary division to trunk-muscles is represented only by the
twigs to the scaleni and longus colli. With the fifth cervical nerve the posterior cutaneous
branch reappears ; and in the fourth, third, and second nerves the lateral offsets are freed from
the limb-plexus (except the fourth to a slight extent in some cases), and furnish the super-
ficial branches of the cervical plexus, the lower of which are however drawn out over the root
of the limb, while anterior perforating branches are wanting.
At the lower part of the trunk, the twelfth dorsal and first lumbar nerves have the charac-
teristic segmental disposition, but their posterior and lateral perforating branches are drawn
down over the root of the limb, as is the case also to a slight extent with a part of the anterior
perforating branch of the first lumbar (ilio-inguinal nerve), while a small part of the fibres of
this nerve often passes into the limb-plexus. The second lumbar nerve is distinctly inter-
mediate in character, since it possesses all the branches of a segmental nerve, although its
larger part passes into the limb-plexus. Its anterior perforating branch is represented by the
genital division of the genito-crural, and its lateral cutaneous offset by the fibres passing to
the crural division of the genito-crural and to the external cutaneous nerve. The third
lumbar nerve has a posterior perforating offset, but it consists mainly of a large lateral
division passing into the plexus ; an anterior perforating branch is wanting, and the contribu-
tion to the sympathetic is very small or absent. The fourth lumbar is purely a limb-nerve,
the posterior and anterior cutaneous and the visceral offsets being suppressed. The fifth
lumbar is like the fourth, except that it may have a small posterior cutaneous offset ; and this
branch is regularly present in the succeeding nerves. With the second sacral nerve the con-
tribution to the limb-plexus diminishes, the visceral branch reappears, the lateral cutaneous
branch begins to be more independent in the small sciatic and perforating cutaneous nerves,
and the continuation of the trunk to form an anterior perforating offset is to be recognized in
the pudic nerve. The third sacral furnishes only a small contribution to the limb-plexus, and
both it and the fourth sacral have the usual constitution of segmental nerves, but their
anterior primary divisions are more or less closely united in the pudic nerve. Of the branches
of the latter, the inferior hasmorrhoidal probably corresponds to a lateral perforating offset,
while the perineal division and the dorsal nerve of the penis represent anterior perforating
offsets.
In the foregoing sketch it has been shown that the lateral divisions of the nerves are
enlarged and carried outwards to supply the integument of the limbs. The cutaneous offsets
of some of the posterior primary divisions are also drawn out to a slight extent over the roots
of the limbs (especially the lower), but they do not enter into the plexuses. The anterior
perforating branches however are not extended to the limbs, except the first lumbar to a slight
degree where the lower limb impinges upon the area of these nerves. The supply of the
muscles of the limbs by lateral divisions of spinal nerves offers no difficulty, since these
muscles are derived from the superficial layer of the great ventro-lateral muscle (see Vol. II,
p. 274), and the obliquus externus, the sole trunk-muscle of this layer (the pectorales, serratus
magnus, latissimus dorsi, <fcc., being limb-muscles, and deriving their nerves from the limb-
plexus), is supplied by the lateral cutaneous branches of intercostal nerves.
The number of nerves entering the limb-plexus is subject to some variation, not only in
different animals, but also in different individuals of the same species. In man, the 'brachial
plexus is formed mainly by the lower four cervical and first dorsal nerves, but contributions
are often furnished by either or both of the fourth cervical and second dorsal : the number
varies therefore from five to seven. The lower limb-plexus comprises the greater part, but
LIMB-NERVES AND PLEXUSES. 383
not the whole, of both the lumbar and sacral plexuses, and the name e rural plc^u* may be
used for the sum of the nerves constituting the proper limb-plexus. Into this enter usually
seven nerves, viz., the lower four lumbar and the upper three sacral, but the first lumbar
nerve in some cases also furnishes a branch, in rare instances even the last dorsal nerve ;
while at the opposite end the offset from the third sacral may be wanting, or in extreme cases
of low form of plexus the fourth sacral may be drawn in (cf. pp. 313 and 325).
In the case of the brachial plexus all the nerves have the same relation to the shoulder-
girdle, passing behind the clavicle. With the crural plexus the arrangement is different : in
association with the greater development of the ventral portion of the limb-girdle the nerves
are separated as they enter the limb, one set, the external cutaneous and anterior crural,
passing in front of the pubic portion of the girdle, a second, the obturator, passing between
the pubic and ischial portions of the girdle, and a third, the largest, the gluteal, sciatic, &c.,
passing behind the ischial portion of the girdle- — the prezonal, diazonal, and m eta-zonal ncrres
of Fiirbringer. Thus there is brought about the separation of the lumbar and sacral plexuses
of descriptive anatomy ; and the nercusfurcalis is only the nerve (entering into loops like the
others) which lies at the boundary between the pre- and diazonal nerves on the one hand and
the metazonal nerves on the other.
As to the significance of the plexuses, it may be remarked in the first place that the term
" plexus " is somewhat misleading. Except in the case of the brachial plexus, the so-called
" plexuses " are not interlacements of the spinal nerves, but result from the multiple origin
of the nerves of distribution, so that most of the offsets of the plexus contain fibres derived
from two or more segmental nerves. This multiple origin is intimately related to the
fusion of the myomeres from which the muscles of the limbs are derived, and in association
with this is the multiple innervation of individual muscles (see p. 354). A similar condition
is seen in the lower intercostal nerves (p. 310) before supplying the broad muscles of the
abdomen, in which the constituent myomeric elements are fused, so that these muscles are
polymeric and pott/neural; whereas such communications are much less frequent between the
upper intercostal nerves, which are distributed to the mono tit eric and moiwneural intercostal
muscles. &c. Similarly also with the cutaneous offsets, the plexuses afford the means by which
the fibres of two or more segmental nerves become mingled in order that they may supply in
common a given area of skin. Gegenbaur and Fiirbringer look upon the plexuses of the limbs
as the result of the shifting of the latter along the vertebral column in the course of phylo-
genetic development, but it is extremely doubtful whether this shifting of the limbs has
taken place to the extent supposed by them, and it is difficult to explain in this way the
presence of the communications between the lower intercostal nerves while they are absent
between the upper nerves, or the formation of the pudendal plexus. It does not appear that
the plexuses have a physiological significance, so far at least as the muscles are concerned,
beyond the provision of the multiple supply, that is, the mingling of the nerves in the plexuses
does not seem to be necessarily related to any functional grouping of the muscles supplied.
The nerves entering the limb-plexuses show a remarkable division, the significance of
which was first pointed out by Paterson, into anterior or ventral and posterior or dorsal port ions,
corresponding to the primary subdivisions of the limb-musculature (Vol. II, pp. 274, 275).
The dorsal and ventral divisions of a nerve entering the limb are regarded by Paterson and
others, who consider that the limb-nerve represents the whole anterior primary division of a
spinal nerve, as corresponding respectively to the lateral offset and the anterior portion of a
segmental nerve. The ventral divisions of the brachial nerves form the inner and outer cords
of the plexus, and the dorsal divisions the posterior cord of the plexus. The ventral divisions
of the crural nerves include the obturator, internal popliteal, and some smaller branches,
while the dorsal divisions furnish the external cutaneous, anterior crural, external popliteal,
gluteal, and some other nerves (p. 325). In their cutaneous distribution, while as a general
rule the skin overlying ventral muscles is supplied by nerves of ventral origin, and that over
dorsal muscles by the dorsal divisions of the nerves, the limits are not strictly kept, and the
territory of the one group is often greatly extended at the expense of the other (cf. figs. 221,
222, and 223). In the following table the nerves of each group are shown, together with the
probable homologies of the nerves of the two limbs, so far as they can be traced : —
CLASSIFIED TABLE OF THE NERVES OF THE LIMBS, WITH THEIR
PROBABLE HOMOLOGIES.
UPPER LIMB. LOWER LIMB.
Dorsal nerres. Dorsal nerves.
N. to rhomboidei.
Posterior thoracic.
Suprascapular Branches of anterior crural to iliacus.
N ( Superior gluteal.
Subscapular (3) P pyrff ormis.
Circumflex : muscular part ... J { Inferior gluteal.
B B 2
384
MORPHOLOGY OF NERVES.
CLASSIFIED TABLE OF THE NERVES OF THE LIMBS, WITH THEIR
PROBABLE HOROLOGIES— continued.
LOWER LIMB.
Dorsal nerves.
Small sciatic : gluteal branches and outer
part of femoral division.
Perforating1 cutaneous.
External cutaneous.
Anterior crural.1
External popliteal.
Musculo-cutaneous.
Anterior tibial.
Ventral nerves.
( Obturator.
< N. to quadratus femoris.
f N. to obturator intern us.
Branches of internal popliteal in thigh.
Cutaneous of obturator.
j Internal popliteal ) ( Internal plantar.
j and posterior tibial \ \ External plantar.
Small sciatic : inner part of femoral division.
UPPER LIMB.
Dorsal nerve*.
Circumflex: cutaneous part ...
Musculo-spiral.
Branches in arm ...
Rest of trunk
Radial
Posterior interosseous
Ventral nerves.
N. to subclavius
Anterior thoracics
N. to coraco-brachialis
Musculo-cutaneous.
Muscular part
Cutaneous part ...
Median ...
Ulnar
Internal cutaneous
N. ofWrisberg
Intercosto-humeral ... ... ... )
Recurrent or mening-eal divisions. — These are presumably afferent nerves, and are said
to be furnished by all the spinal nerves (p. 278).
Visceral or sympathetic divisions. — These are the white rami communicantes of the
sympathetic system, in connection with which their arrangement has been described (p. 358).
They are absent in the cervical region, as well as from the lower two or three lumbar, first
sacral, last sacral, and coccygeal nerves. The grey rami communicantes. as has already been
explained, are not branches of the spinal nerves, but are given off by the sympathetic to the latter.
* Ganglia. — The ganglia found in connection with the peripheral nerves fall into two
groups, which differ in their structure and position. To the first group belong the spinal
ganglia on the posterior roots of the spinal nerves, which contain unipolar nerve-cells. The
other group includes the various * i/ntpa tlietic ganglia, the cells of which are multipolar. Both
groups have a common origin, their nerve-cells being derived from the neural crest of the
embryo (see Embryology, pp. 73 and 81). The spinal ganglia undergo but little change in
position in the course of development, and are always placed on the posterior roots of the
nerves at or near their aperture of exit from the spinal canal, whence they have been named
stationary ganglia by G-askell. The neuroblasts which form the nerve-cells of the sympathetic
ganglia, however, make their way from the primitive ganglion-rudiments along the spinal
nerves and their visceral offsets into the ventral portion of the body, and there become
collected into groups which give rise to the various sympathetic ganglia — the splanchnic or
vagrant ganglia of Graskell. It is probable that all the ganglia of the sympathetic arise in
this way, but they have as yet been fully traced only in the case of the heart. The mode of
development especially of the ganglia in the my enteric plexuses of the alimentary canal has
not been observed.
Constitution of a seg-mental nerve.— A typical segmental nerve comprises — (1) somatic
efferent fibres distributed to skeletal muscles ; (2) splanchnic efferent or sympathetic fibres
passing through the sympathetic system, where many if not all are interrupted by the nerve-
cells of the ganglia, to the visceral muscles and other unstriped muscles of the body, as well
as to the glandular organs ; (3) somatic afferent fibres supplying the skin and other parts of the
body- wall with sensory nerves ; and (4) splanchnic afferent fibres furnished to the viscera.
The somatic efferent fibres and the greater part, if not the whole, of the splanchnic efferent
fibres constitute the anterior root of the nerve, while the somatic afferent fibres run in the
posterior root, being connected with the cells of its ganglion, and the same is probably the
case with the splanchnic afferent fibres. In the cervical region, in addition to the two roots of
1 According to Eisler the anterior crural nerve is not exclusively dorsal, but contains both ventral
and dorsal elements. The ventral part comprises the internal cutaneous nerve, the branch to the
pectineus, and the internal saphenous nerve. Instead of occupying a ventral position at their origin,
however, these branches are placed on the mesial side of the trunk, in consequence of a torsion,
amounting to about 90°, which is to be recognized in the bundles of the nerve between the lumbar
plexus and Poupart's ligament, and which is probably associated with the inward rotation of the limb
during development.
CRANIAL NERVES.
8S5
the cervical segmental nerves, there is also, arising separately from the cord, the spinal
accessory nerve, which, although reckoned with the cranial nerves, is in greatest part of spinal
origin. This belongs to a group, more developed amongst the cranial nerves, which is
designated by Gaskell splanchnic non-ganalionated efferent, but as it is distributed to skeletal
muscles, it is better termed lateral somatic efferent. The somatic efferent fibres in this region
are therefore again divided into a menial set, which arise from the cells of the fore part and
inner side of the anterior horn of the grey matter of the cord, and a lateral xrt derived from
cells placed at the outer part of the anterior horn. It is uncertain whether the latter fibres
are represented in the lower parts of the cord, but Gaskell places the phrenic nerve and the
branches supplying the transversalis abdominis muscle in this group ; if present, they also run
in the anterior roots of the spinal nerves.
CRANIAL NERVES. — The attempt to determine the morphological position of the cranial
nerves is beset with difficulties, and any classification that is based on the facts at present
known with regard to their development, connections, and functions can only be regarded as
tentative. Assuming that they include the representatives of a series of segmental nerves, the
arrangement is profoundly modified, on the one hand by the separation of the constituent
portions of some of these nerves so as to form independent trunks, and on the other by the
coalescence of elements belonging to different segments in a single stem. In many cases also
parts of the typical segmental nerves are suppressed, either not being formed in the embryo,
or disappearing more or less complete!}' in the course of development. So great indeed is the
STATIONARY GANGUON
SOMATIC AFFERENT
TERAL SOM. EFFT.
MESIAL SOM. CFFT.
ANCHNIC AFFERENr
Fig. 240. — SCHEME OP THE HYPOTHETICAL CONSTRUCTION OP A SEGMKNTAL NERVE, BASKD MAINLY ON
GASKELL'S CLASSIFICATION OF THE CONSTITUENT FIBKES. (G. D. T.)
change that it may be affirmed that no cranial nerve, according to the usual enumeration,
corresponds exactly to a single complete segmental nerve, such as is met with in the dorsal
region for example.
In considering the cranial nerves from this point of view the first two pairs are generally
set aside as occupying an exceptional position, but evidence is not wanting that these have in
some respects a similar origin to other sensory nerves. According to van Wijhe and Hoffmann
the olfactory nerves are developed at the anterior margin of the neuropore, at a spot where
the floor of the neural groove or canal passes into the epidermis. This would correspond to
the foremost part of the ganglion-groove of His, the forerunner of the neural or ganglion
crest, at the place where it passes from one side to the other, following the margin of the
medullary plate, and is not irreconcileable with the statement of Milnes Marshall that the
olfactory nerves are derived from the foremost part of the neural crest. The optic nerve,
including the retina, is developed as a hollow outgrowth of the neural tube, and Hoffmann
states that in the elasmobranch the dorsal portions of the other cranial nerves are formed in
the same way, their ganglion-rudiments at first enclosing a cavity which is continuous with
the medullary canal, so that the retina would correspond to a specially developed root-ganglion,
and the optic nerve to a dorsal root. The relations of these nerves to the head segments,
however, have not been ascertained, and at all events for the present they cannot be grouped
amongst the segmental nerves. In the following observations therefore only the ten nerves
from the third to ohe twelfth inclusive are dealt with.
Constitution of the cranial nerves. — Four of these nerves, namely, the twelfth, the
sixth, the fourth, and the third, arise from large-celled nuclei forming a group which appears
386
MORPHOLOGY OF NEKVHS.
to be in series with the anterior and internal cell-columns of the anterior cornu of the spinal
cord. These nerves also, with the exception of the fourth, emerge from the axis in a line
which forms a continuation of that of the anterior roots of the spinal nerves, and like those
they consist mainly of large fibres (not so large in the hypoglossal however as in the others),
which are distributed to voluntary muscles. In this group therefore are comprised the menial-
.•to 111 (i tic efferent fibres of the cranial nerves.1
It has already been seen that in the upper cervical region the lateral somatie ejjereni jihrex
are separated from the anterior roots, and form the spinal accessory nerve, which arises from
the outer group of cells of the anterior horn. Proceeding upwards in the brain-stum, the
following nuclei form a lateral series from which the fibres of this group arise — the bulbar
portion of the accessory nucleus in part, the accessory vago-glosso-pharyngeal nucleus (nucleus
ainbiguus), the facial nucleus, and the nuclei of the motor root of the fifth nerve, ventricular
and mesencephalic. The cells of the facial and accessory vago-glosso-pharyngeal nuclei are of
moderate size, but they are larger in the motor nuclei of the fifth nerve and in the nucleus of
the spinal accessory nerve. The fibres of the nerves arising from these nuclei are mostly of
medium size, but the spinal part of the spinal accessory consists of large fibres.
Sfilanehn'u' eft'ere/// ///;/r.v, characterized by their small size, are present in the bulbar
portion of the spinal accessory nerve, in the vagus nerve of which they form a large part, in
SPLANCHNIC AFFERENT
SPLANCHNIC EFFERENT
LATERAL SOW. EFFT.
MESIAL SOMATIC EFFERENT
Fig. 241. — PLAN OP THE ARRANGEMENT OP THE CONSTTTUENT PIBRES OK TIII; CKANIAI, NKKVK.S IN TIIK
BULB. (Based on Gaskell, with modifications.) (GK D. T.)
the glosso-pharyngeal nerve (small superficial petrosal branch), in the facial nerve (J:irgi>
superficial petrosal branch and the efferent part of the chorda tympani), and in the third
nerve (ciliary portion). The origin of the splanchnic efferent fibres in the spinal cord has not,
been determined, but in the brain-stem there are special nuclei from which the fibres of this
group arise. These are the bulbar portion of the accessory nucleus (in part), the small-celled
vago-glosso-pharyngeal nucleus, from which not only the splanchnic efferent fibrefc of t he
vagus and glosso-pharyngeal proceed, but according to Duval also those of the facial through
the portio intermedia, and the groups of smaller cells at the upper end of the oculomotor
nucleus (see Part 1 of this Volume, p. 99).
Somatic afferent film's constitute the greater part of the large root of the fifth nerve and
the auditory nerve ; and a small group of these fibres occurs also in the vagus, composing its
auricular branch. S/)laneli »i<- afferent Jibnx are contained in the facial (afferent part of the
chorda tympani), glosso-pharyngeal and vagus nerves, probably also in the sensory purl, of tin-
fifth nerve. With regard to the central connections of these fibres it is to be remarked that
many of them descend in the bulb and upper part of the spinal cord, forming the so-called
" ascending roots " — the funiculus solitarius for the vagus and glosso-pharyngeal, perhaps also
for the portio intermedia, and the bulbar root of the fifth nerve. A great number of the fibres
enter the auditory nuclei, the sensory nucleus of the fifth nerve and the siibstant ia grlatinosa,
which may be looked upon as derivatives of the posterior horn of the grey substance of the
cord, just as the nerves at their attachment to the brain-stem form a series continuing the
1 According to Hatschek there are also ventral roots to the glosso-pharyngeal and vagus nerves in
Ammoctt'tes, anil the same have been described in the embryo of man and the rabbit by Zimmermann.
CONSTITUTION OK CRANIAL NKKYIX
387
lino of I !'<• |H, I -ri-ir ruol.s. Tin- ;iM'«-rcnt, fibres, l>oMi . nm.'il i<- :in<l hplaiirlim. :n« oil '. , I - of Um
of st,af,ion:i.r\ y.-.n -lia (see below ) and tf''"w t,henoe into i hr rcrrhro-Hpinal axin. The
vcral cranial IKTVCN an; Hliown in Ui«- following lal.lr :
TAKLK SIloWI.N'i; TIIK CoXSTITI'TloN OK TIIK CRANIAL NKRVKS FROM
Till'] TlllltD TO TIIM TWKU'TII.
MAI,
I !
MI- i.il ;nlii:il n-
cll'ri i-nl,
l,.(l«-i.il HOlllflUr
HI,-,. ,,l
,S|.lunc,iiiii(! efferent.
.Spliiliclinic ;i||i-|i -lit
HomnMr
THIRD
To orliil,:i.l
Ciliary.
_
inn r;lc
PotTBffl
To obliquuH
._.
superior.
I'M 1,1
-
Motor root.
?
Sensory
loot.
S I \ T 1 1
To reel us
external.
—
—
—
—
' 1 '. 1 '. 1 II
_
Facial, main
Large superficial petro-
Chorda tympani,
part.
sal nerve ; chorda
taste-fibres.
tympani, librcHtoHiili-
rn axillary ganglion.
BUSH
—
—
—
—
\.i.litory.
NINTH
—
To stylo-
pharyngeus.
Small :<up»:rli«-i:,| |.<-tro-
sal, to otic ganglion.
Lingual, including
laHt«;-fil,r.'.H.
Turn
—
To laryngeal
FlIHW.kM '
To unstriped muscle of
alim- hi .1 .1, iL .HI
From alimentary
canal, air-passage,
Auricular.
passages, &c.
&c. ; cardiac de-
pressor fibres.
Kl.KVKNTH
—
To st<:nio-
Toi)alatineari(l[)haryn
—
.,,.'• ! HI !
K<:al »IIIW:|«JH; c;inliac
trapezius ;
iiiliibitory fibre*.
to lary Fiscal
muscles •'
TWELFTH
To tongue-
.-._
—
—
—
mugcles.
Gangrlia.— The ganglia in connection with cranial nerves also fall into the two groups,
stationary and vagrant, which have been characterized in dealing with the upinal norve*
• I).
StiiiiiHHi,-,/ ijuntji'in, necessarily occur only on those nerves which contain afferent fibres.
They are th ,\\ on the large root of the fifth' nerve, the geniculate ganglion
on the portio intermedia, the acoustic ganglion on the auditory nerve (see p. 256), the jugular
and petrowal ganglia of the glosso-pharyngeal nerve, and the upper ganglion (possibly also the
lower) of the pneumo-gastric nerve. The nerve-cells are unipolar, like thone of the spinal
ganglia, in all of thene except the acoustic ganglion, in which the cells retain their primitive
bipolar form. There are also found upon the roots of the third, fourth, motor part of the
fifth, and seventh nerves traces of ganglionic structure which are regarded by Gaskell as
indications of the former existence of stationary ganglia and afferent fibres belonging to those
nerves. In some animalu, and in rare cases in man, there is moreover a gangliated posterior
root to the hypoglos»al nerve.
The vagrant ganylia in connection with the cranial nerves include four ganglia usually
associated with the fifth nerve, namely, the ciliary, spheno*palatine, submaxillary, and otic,
all of which are of sympathetic type, containing multipolar nerve-cells, and according to
Gaskell also the lower ganglion of the vagus, the cells of which are, however, of the spinal
type. The ciliary, spheno-palatine and otic ganglia are known to be developed as offsets of
the Gawerian ganglion, and the same is probably the case with the submaxillary ganglion,
but they receive splanchnic efferent fibres, with which they form physiological connections,
from other sources — the ciliary ganglion from the third nerve, the spheno-palatine ganglion
from the facial nerve (portio intermedia ?), the submaxillary ganglion from the portio
intermedia through the chorda tympani, and the otic ganglion from the glosso-pharyngeal.
The condition in the last three cases resembles that in the sympathetic, where a given ganglion
of the cord, presumably derived from the spinal ganglion of the wuw Moment, receives
efferent fibres from spinal nerves at different levels.
388 MORPHOLOGY OF NERVES.
Segmentation. — It has been shown in some of the lower vertebrates, especially elasmo-
branchs, that at least nine segments are included in the constitution of the head (see
Embryology, p. 161), and it is probable that the number is not less in the higher vertebrates,
although it may be that the segments have not the same morphological value in all cases,
since there is reason for believing that only six of these belonged primitively to the head,
while three or more, originally spinal, have also become incorporated in the head in later
stages of phylogenetic development. Assuming provisionally, however, that the nerves of nine
segments are represented more or less completely in the ten cranial nerves, there is still much
uncertainty as to the manner in which some of these nerves are to be allotted to the several
segments. It is also to be observed that, as in the case of the spinal nerves, the segmentation
which is to be recognized in the central grey matter does not always correspond to the
segmentation represented in the nerve-trunks, since fibres which arise from what appears to
be a single segmental nucleus may pass out in nerves at different levels, and conversely, a
single nerve may contain fibres derived from the nuclei of more than one segment.
The third nerve belongs to the first head-segment. It includes a large-fibred mesial
somatic efferent part, distributed to the orbital muscles developed from the first somite, and a
small-fibred splanchnic efferent part passing to the ciliary ganglion. The lateral somatic
efferent fibres of this segment are perhaps represented, as suggested by Gaskell. by the ocular
facial, which arises from the oculomotor nucleus (p. 251). The ophthalmic division of the
fifth appears to be the afferent nerve of this segment. In the elasmobranch Hoffmann finds
that the " ramus ophthalmicus profundus," which corresponds to the nasal nerve of man
(Ewart), is developed independently of the rest of the fifth nerve, and in close relation to the
first somite. Gaskell considers, however, that the afferent fibres of the first segmental nerve.
with their stationary ganglion, have undergone degeneration, and are now represented only by
the vestigial structure in the roots of the third nerve ; and his view receives support from the
observation of Martin that in the early embryo of the cat the third nerve is provided with a
dorsal root, which subsequently disappears.1
The fourth nerve, supplying the superior oblique muscle formed from the second somite,
is the mesial somatic part of the second segmental nerve. The fifth nerve, excluding the
ophthalmic division, also belongs to this segment (Hoffmann), of which the small root of the
fifth will therefore form the lateral somatic efferent nerve, while the superior and inferior
maxillary portions of the large root will be the afferent nerve. The existence of splanchnic
efferent fibres is uncertain, since it is not known whether any efferent fibres are furnished by
the fifth nerve to the spheno-palatine, submaxillary, and otic ganglia, all of which must be
referred to this segment if, as is most probable, they are derived from the Gasserian ganglion,
although they receive efferent fibres from other segmental nerves (of. siqira).
The third segmental nerve includes the sixth, seventh, and eighth cranial nerves. The
sixth is the mesial, and the facial proper the lateral somatic efferent portion together with, in
the large superficial petrosal branch, a part of the splanchnic efferent. In the portio inter-
media are comprised also splanchnic efferent fibres to the submaxillary ganglion and splanchnic
afferent fibres which are connected with the geniculate ganglion. The somatic afferent part
is the auditory, with the acoustic ganglion, the resemblance of which to the posterior root of
a spinal nerve has already been pointed out (p. 256).
The fourth segmental nerve, according to Hoffmann, is suppressed. A rudiment is present
in the early embryo of the elasmobranch, but it afterwards aborts. It would seem possible
that the portio intermedia, in view of its central connection and partially independent course,
might belong to this segment.
The nerve of the fifth segment is the glosso-pharyngeal. In this, mesial efferent, and
afferent somatic fibres are altogether wanting. Lateral somatic efferent fibres are present in
the branch to the stylo-pharyngeus, and probably arise from the accessory vago-glosso-
pharyngeal nucleus. Splanchnic efferent fibres run in the small superficial petrosal nerve to
the otic ganglion. The chief part of the nerve however is composed of splanchnic afferent
fibres, which enter the funiculus solitarius.
The sixth and seventh segmental nerves are united in the vagus (Hoffmann), which con-
tains fibres of all groups except mesial somatic efferent (see p. 386). The latter fibres of the
seventh segment may be included in the hypoglossal nerve, which is composed of the mesial
somatic efferent parts of the last three or more cephalic (originally first spinal) segmental
nerves. Otherwise, these segmental nerves are only represented (doubtfully) by the oral
fibres of the facial which are said to arise from the hypoglossal nucleus (lateral somatic
efferent), and by the bulbar part of the spinal accessory (lateral somatic efferent and
splanchnic efferent), except in those cases in which the hypoglossal nerve is provided with a
gangliated dorsal root.
The arrangement sketched out above is summed up in the annexed table.
1 What appears to be a gangliated dorsal root to the oculomotor nerve has also been described by
Kupffer in Ammocostes, and by Froriep in Torpedo.
8EGMENTAL NERVES OF HEAD,
389
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390 MORPHOLOGY OF NERVES.
Course and distribution. — While it is obvious that in the distribution of the cranial
nerves the segmental arrangement, if it ever existed, has been in many cases greatly modified,
there are certain striking1 relations between the course and distribution of some of these
nerves and the developmental subdivisions of the head.
The distribution of the third, fourth, and sixuh nerves to the muscles of the first three
somites has already been pointed out. The nasal branch of the ophthalmic division of the
fifth is the nerve of the fronto-nasal process. The inferior maxillary is the nerve of the
mandibular arch, its motor root supplying- the muscles of that arch (Vol. II, p. 349), and its
sensory part extending by its splanchnic lingual branch into the part of the tongue which is
formed from the tuberculum impar in the concavity of the arch. The superior maxillary
nerve is the offset furnished by the more primitive mandibular nerve to the maxillary process.
The three divisions of the fifth supply the skin externally, and the mucous membrane inter-
nally, of their respective portions of the face ; and they send dorsal branches — supraorbital
and supratrochlear, temporo-malar, and auriculo-temporal — to ramify over the neural cavity
in the same way as the posterior divisions of the spinal nerves, the cutaneous area of which
they continue anteriorly.
The facial is the nerve of the hyoid arch, supplying the muscles of that arch — stapedius,
posterior belly of digastric, and stylo-hyoid — and the system of cutaneous muscles which
according to Rabl take their origin in that arch (Vol. II, p. 349).
The glosso-pharyngeal is the nerve of the third cephalic visceral (first branchial) arch, in
which it runs to the root of the tongue, but its lingual distribution extends considerably
beyond the part which is formed from that arch. It also supplies the muscle of the third
arch — the stylo-pharyngeus.
The vagus is a complex nerve. Its auricular branch, somatic in nature, is the diminished
representative of a largely developed somatic portion in fishes, known as the " lateral branch."
The superior laryngeal is the nerve of the fourth visceral (second branchial) arch, and the
inferior laryngeal of the fifth (third branchial) arch, the latter being drawn down so as to
acquire its recurrent character by the shifting of the arteries during development. The
remaining portion of the vagus extends far beyond the limits of the head, and supplies nearly
the whole of the alimentary canal with its derivatives, and other abdominal organs, the
greater part of which, it is to be noted, are developed from the f oregut or cephalic segment of
the enteric cavity. The accessory part of the spinal accessory in its distribution cannot be
separated from the vagus ; and the spinal portion of the same nerve is not morphologically
cranial, but entirely spinal both in origin and distribution.
Lastly, the hypoglossal nerve, also spinal originally, is distributed to tongue-muscles,
which are also foreign to the head, being probably derived from the longitudinal system of
the ventral muscles of the trunk (Vol. II, p. 348). It is thus in series with the upper
cervical nerves supplying the muscles of the front of the neck, and the connection that
is formed between the hypoglossal and these nerves, giving rise to the ansa cervicalis, &c.,
may be regarded as representing a prolongation of the cervical plexus.
LITERATUBE OF THE MORPHOLOGY OF THE PERIPHERAL NERVES.
Adolphi, H., Ueber Variationen der Spinalnerven und der Wirbelsdule anurer Amphibicn,
Morphol. Jahrh., xix, 1892.
Beard, J., The Ciliary or Motoroculi Ganglion and the Ganglion of the ophthalmicus profundus
in Sharks, Anatom. Anzeiger, ii, 1887.
Bolk, "L., Beziehungen zwischen SMet, Musculatur und N erven der- Extremitdten, dargelegt am
Betkengurtel, an dessen Musculatur •, sowie am Plexus lumbo-sacralis, Morphol. Jahrb., xxi, 1894.
Davidoff, M., Ueber die Varietdlen des Plexus lumbo-sacralis von Salamandr a maculosa, Morphol.
Jahrb., ix, 1884.
Eisler, P., Der Plexus lumbo-sacralis des Menschen, Abhandlg. d. Naturforsch. Gesellsch. zu Halle,
1892.
Ewart, J. C., On the Cranial Nerves of Elasmobranch Fishes, Proc. Roy. Soc , xlv, 1889 ; On the
Development of the Ciliary or Motor Oculi Ganglion, and The Cranial Nerves of the Torpedo, Proc.
Roy. Soc., xlvii, 1890.
Froriep, A,, Ueber ein Ganglion des ffypoglossus und Wirbelanlagen in der Occipitalregion,
Arch. f. Anat., 1882 ; Ueber Anlagen von Sinnesorganen am Facialis, Glosso-pharynyeus und Vagus,
iiber die genetische Stettung des Vagus zum Hypoglossus, und iiber die Herlcunft der Zungenmusculatur,
Arch. f. Anat., 1885 ; Ueber das JJomologon der Chorda tympani bei niederen Wirbeltieren, Anatom.
Anzeiger, ii, 1887 ; Zur Frage der sogenannten Ncuromerie, Verhandlg. d. anatom. Gesellsch., 1892.
Furbringer, M., Zur Lchre von den Umbildungen der Nervenplexus, Morphol. Jahrb., v, 1879.
G-askell, W. H., On the Structure, Distribution, and Function of the Nerves which innervate the
Visceral and Vascular Systems, Journ. Physiol., vii, 1886 ; On the Relation between the Structure,
Function and Distribution of the Cranial Nerves, Preliminary Communication, Proc. Roy. Soc., xliii,
1888 ; On the Relation between the Structure, Function, Distribution and Origin of the Cranial
Nerves; together with a Theory of the Origin of the Nervous System of Vertebrata, Journ. Physiol., x,
1889.
LITERATURE. 391
Geg-enbaur, C., Die Metumcrie des Kopfes und die Wirbeltheorie des Kopfskelctes, Morphol.
Jahrb., xiii, 1887.
Hatschek, B., Die Metamerie dcs Amphioxus und des Ammocceten, Verhandlg. d. Anatom.
Gesellsch., 1892.
Hill, A., The Plan of the Central Nervous System, Cambridge, 1S85; The Grouping of the
Cranial Nerves, Brain, 1888.
His, "W., Ucber die Anf tinge des pcripherixchcn N erven systems, Arch. f. Anat. , 1879 ; Ucber das
A ujtreten der weissen Substanz und der Wurzelfasern am Riickenmark menschlicher Embryonen, Arch,
f. Anat., 1883 ; Zur Geschichte des menschlicher* Ruckenmarkes und der Nervenwurzeln, Abhandlg. d.
Kgl. Sachs. Gesellsch., 1886 ; Zur Geschichte des Gehirns, sowie der centralen und peripherischen
Nervenbahnen beim menschlichen Embryo, Abhandlg. d. Kgl. Sachs. Gesellsch., 1888 ; Die Entivick-
lung der crsten Nervenbahnen bcim menschlichen Embryo, Ucbersichtliche DarsteUung, Arch. f. Anat.,
1887 ; Die morphologische Betrachtung der Kopfnerven, Arch. f. Anat., 1887 ; Histogenese und
Zusammenhang der Nerrenelemente, Verhandlg. d. x internat. med. Congresses, Berlin, 1890, and
Arch. f. Anat., Supplt. Bd., 1890.
His, W., jun., Zur Entwickelungsgcschichte des A custico-facialis Gebietes beim Mcnschcn, Arch,
f. Anat., Supplt. Bd., 1889 ; Die Entivickdung des Hcrznervensy stems bei Wirbelthieren, Abhandlg.
d. Kgl. Sachs. Gesellsch., 1891.
Hoffmann. C. K., Zur Eatwickclungsgeschichte des Sclachierkopfes, Anatom. Anzeiger, ix, 1894.
Holl, M., Uebcr die Lendennerven, Wiener Jahrbiicher, 1880.
Jhering, H. v., Das peripherische Ncrvensystem der Wirbelthiere ah Grundlage fur die
Kcnntniss der Rcyionenbildung der Wirbelsaule, Leipzig, 1878.
Kupffer, C. v., Die Entivickelung der Aopfnerven der Vertebraten, Verhandlg. d. anatom.
Gesellsch., 1891.
Marshall, A. Milnes, The Segmental Value of the Cranial Nerves, Journ. Anat., xvi, 1882.
Martin, P., Die Entwickdung des neunten bis zwolften Kopfnerven bei der Katze, Anatom.
Anzeiger, vi, 1891.
Paterson, A. M., The Morphology of the Sacral Plexus in Man, Journ. Anat., xxi, 1887 ; The
Liinh- Plexuses of Mammals, Journ. Anat., xxi, 1887 ; On the Fate of the Muscle-Plate, and the
Development of the Spinal Nerves and Limb-Plexuses in Birds and Mammals, Quarterly Journ.
Microscop. Sci. , xxviii, 1887 ; The Position of the Mammalian Limb, regarded in the light of its
Innervation and Development, Journ. Anat., xxiii, 1889 ; The Origin and Distribution of the Nerves
to the Loiver Limb, Journ. Anat., xxviii, 1894.
Rabl, K., Zur Bildungsgeschichte des Halses, Prager med. Wochenschr. , 1886 ; Ueber das Gebiet
des N. facialis, Anatom. Anzeiger, ii, 1887 ; Ueber die Metamerie des Wirbeltierkopfes, Verhandlg.
d. anatom. Gesellsch., 1892.
Rug-e, G., Der Verkurzungsprocess am Rumpfe von Halbaffen, Morphol. Jahrb., xviii, 1892;
Zvugnisse fur die metamere Verkurzung des Rumpfes bei Saugethieren. Der Musculus rectus thoraco-
abdominalis bei Primaten, Morphol. Jahrb., xix, 1892 ; Verschiebungen in den Endgebieten derNerven
des Plexus lumbalis der Primaten, Zeugnissefur die metamere Verkurzung des Rumpfes bei Saugethieren,
Morphol. Jahrb., xx, 1893.
Schwaltoe, G-., Das Ganglion oculomotorii, Jenaische Zeitschr. f. Naturwiss., xiii, 1879.
Sherr ing-ton, C. S., Notes on the Arrangement of some Motor Fibres in the Lumbo- sacral Plexus,
Journ. Physiol., xiii, 1892 (p. 708, Significance of limb-plexus).
Shore, T. W., The Morpholojy of the Vagus Nerve, Journ. Anat, xxii, 1888 ; On the Minute
Anatomy of the Vagus Nerve in Selachians, with remarks on the Segmental Value of the Cranial
Nerves, Journ. Anat., xxiii, 1889.
Utschneider, A., Die Lendennerven der Affen und des Menschen, Miiuchener medicinische
Abhandlungen, 1892.
v. Wijhe, J. "W., Ueber die Mesodermsegmenteund die Entwickelung derNerven des Selachierkopfes,
Natuurk. Verb, der Koninkl. Akad., Amsterdam, 1882 ; Ueber S >mit"n und N erven im Kopfe von
Vogel und Reptilienembryonen, Zoolog. Anzeiger, 1886.
Zimmermann, W., Ueber die Metamerie dcs Wirbeltierkopfes, Verhandlg. d. anatom Gesellsch.,
1891.
INDEX AND GLOSSAEY TO VOL. III., PT. II.
ABDOMEN, nerves to muscles of, 352
Abdominal branch of ilio-hypogastric, 315
intercostal nerves. 310
splanchnics, 367
viscera, afferent nerves of, 370
Abducent nerve. See NERVE.
Accelerator fibres of heart, 367, 369
Accessory nerve. See NERVE.
Acoustic ganglion, 256, 387, 388
Acromio-clavicular joint, nerves of, 293, 294
Afferent nerves. See NERVES.
Alveolar nerves, 239, 240, 247
Ampullary nerves, 257, 258
Ankle-joint, nerves of, 332, 333, 335, 337, 338
Ansa (loop) cervicalis, 273, 287, 288, 390
subclavia, 365, 366
Anterior crural nerve. See NERVE.
cutaneous nerves of abdomen, 310, 311, 381
thorax, 307, 308, 310, 381
interosseous artery, nerves of, 301
roots of spinal nerves, 276, 358, 359, 381,
384
thoracic nerves. See NERVES.
tibial nerve, 335, 336, 337, 384
Antrum, maxillary, nerves of, 338
Anus, nerves to muscles of, 352
Aortic plexus, 370, 375, 376, 377
Aortico -renal ganglion, 369, 375
Arm, cutaneous nerves of, 343
nerves to muscles of, 353
Arnold, ganglion of. See GANGLION, OTIC.
nerve of, 265
Arterk-s, nerves of, anterior interosseous, 301
brachial, 297
carotid, external, 364
internal, 362
central of retina, 362
cerebral, 362
femoral, 319
internal mammary, 366
ophthalmic, 362
palmar, 300
peroneal, 333
subclavian, 366
tibial, anterior, 332
posterior, 332
ulnar, 299
vertebral, 366
Articular nerves. See the several joints.
Ascending branch of upper cervical ganglion,
361, 362, 366
branches of cervical plexus, 286
root of fifth nerve, 233
Astragalo-calcaneal joint, nerve of, 332
Astragalo-navicular joint, nerve of, 333
Atrial plexus, 373
Auditory meatus, external, nerves of, 246
nerve. See NERVE.
Auricular nerves. See NERVES.
Auriculo-temporal nerve. See NERVE.
BACK, cutaneous nerves of, 341
motor nerves of, 352
Bladder, inhibitory nerves of, 370
motor nerves of, 370, 372
sensory nerves of, 350
Brachial artery, nerves of, 297
plexus, 283, 289, 307, 382, 383
Buccal nerves. See NERVES.
Bulbar plexus of heart, 373
portion of spinal accessory nerve, 269, 270,
386, 388
root of fifth nerve, 233
Buttock, cutaneous nerves of, 344
CALCANEAL branches, 332, 333
Calcaneo-cuboid joint, nerve of, 334
Calcaneo-plantar nerve, 333
Cardiac nerves. See NERVES.
plexus. See PLEXUS.
Carotico-tyrnpanic nerve, 260, 262
Carotid artery, external, nerves of, 364
internal, nerves of, 362
branch of ninth nerve, 260
upper cervical ganglion, 362
plexus, 234, 243,250, 260, 362
Carpo-metacarpal joints, nerves of, 305
Cauda equina (horse's tail), 277
Cavernous nerves of penis, 378
plexus, 230, 233, 235, 238, 362
sinus, nerves in relation to, 231
Cavities cf head, nerves of, 338
Cavum (a hollow) Meckelii, 234
Central artery of retina, nerves of, 362
Cerebral arteries, nerves of, 362
Cerebro-spinal nerves, 221
muscular distribution of, 351
sensory distribution of, 338
Cervical branch of facial nerve, 256, 287
gangliated cord, 361
ganglion. See GANGLION.
nerves. See NERVES.
plexus, 283, 285
cutaneous area of, 341
posterior, 280
splanchnic nerves, 361 •
sympathetic, 361
constitution of, 366
394
INDEX AND GLOSSARY TO VOLUME III., PAKT II.
Cervico-cranial rami viscerales, 359
Cervico-facial division of facial nerve, 252, 255
Chest-wall, nerves to muscles of, 352
Chiasma. See COMMISSURE.
Chorda tympani, 226, 247, 248, 249, 253, 256,
386, 387
SBi
Ciliary ganglion. See GANGLION.
nerves. See NERVES.
Circulus tonsillaris, 261
Circumflex nerve, 291, 294, 383, 384
Clitoris, dorsal nerve of, 328, 330
Coccygeal ganglion, 371
nerves. See NERVES.
plexus, 323
Cochlea, spiral ganglion of, 256
Cochlear nerve, 257, 258
Cceliac plexus, 376
Collateral digital nerves, 300, 302, 305, 333
ganglia, 357, 361
nerve, ulnar, 303, 304
Commissure, optic, 227, 228
Communicating nerve, fibular, 336
peroneal, 332, 336
tibial, 332
Cord, dorso-lumbar, 312, 315
gangliated. See SYMPATHETIC.
lumbo-sacral, 313, 322, 323
Cords of brachial plexus, 289, 291, 383
Coronary nerves, 372, 373
plexus of heart, 372
of stomach, 376
Cranial cavity, sensory nerves of, 341
nerves. See NERVES.
plexuses of sympathetic, 362
Crural nerve, anterior, 313, 317, 3 1 9, 383, 384
plexus, 383
Cutaneous area of cervical plexus, 341
of dorsal and first lumbar nerves, 341
distribution of nerves to trunk and limbs, 344
innervation of limb, rules of, 345
nerves. See NERVES.
or perforating branches of segmental nerves,
381,382
Cystic plexus, 376
DENTAL nerves. See NERVES.
plexus, inferior, 247
superior, 241
Depressor nerve, 268
Descending cervical nerve, 271, 273, 274, 283,
287, 288
root of fifth nerve, 233
Diaphragmatic ganglion, 375
nerve, 288
plexus, 375
Diazonal (5fa, through ; ((avi}, girdle) nerves, 383
Digastric branch of facial nerve, 254, 390
Digital nerves. See NERVES.
Distribution of cranial nerves, 225, 338, 351
cutaneous, of nerves to trunk and limbs,
344
muscular, of cerebro-spmal nerves, 351
of spinal nerves, 354
sensory, of oerebro-spinal nerves, 338
visceral, of sensory spinal nerves, 350
Divisions, of nerves of limb-plexuses, 383
primary, of spinal nerves, anterior, or ven-
tral, 283, 341, 381, 382
posterior, or dorsal, 278, 341,
38i
Dorsal nerve of clitoris, 328, 330
Dorsal nerve of penis, 328, 329, 382
nerves. See NERVES.
Dorso-lumbar cord or nerve, 312, 315
Dura mater, nerves of, 341
EFFERENT nerves. See NERVES.
Eighth pair of cranial nerves. See NERVES.
Elbow-joint, nerves of, 297, 299, 301, 303, 304,
307
Eleventh pair of cranial nerves. See NERVES.
Eyelid, nerves of involuntary muscle of, 367
sensory nerves of, 338
Epididymis, sensory nerves of, 351
Epigastric or solar plexus, 373
Ethmoidal cells, nerves of, 338
nerve, posterior, 237
Eustachian tube, nerves of, 341
Exit of nerves from cranium, 223
FACE, motor nerves of, 351
pilo-motor nerves of, 367
sensory nerves of, 338
Facial nerve. See NERVE.
Femoral artery, nerve of, 319
cutaneous branches of small sciatic, 328
nerve, 319
Femur, nerves of, 319, 321, 322
Fibres, sympathetic, 357, 358
Fibular branch of posterior tibial, 333
Fibular communicating nerve, 336
Fifth pair of cranial nerves. See NERVES.
Fila radicularia, 275
Fingers, cutaneous nerves of, 343
First pair of cranial nerves. See NERVES.
Foot, motor nerves of, 353
sensory nerves of, 344
Forearm, motor nerves of, 353
sensory nerves of, 343
Fossa, nasal, nerves of, 338
Fourth pair of cranial nerves. Sec NERVES.
Frontal nerve, 231, 233, 235, 236
sinus, nerves of, 338
Funiculus solitarius, 258, 261, 386
Furcal (furca, fork) nerves, 313, 325, 383
GANGIJATED cord. See SYMPATHETIC.
GANGLION or GANGLIA, aberrantia, 277
acoustic, 256, 387, 388
aortico-renal, 369, 375
of Arnold. See GANGLION, OTIC.
cardiac, 373
cervical sympathetic, lower, 268, 283,
288, 365
middle, 283, 288, 365, 366
upper, 259, 264, 265, 272, 273,
283, 284, 361, 366, 367
cervicale uteri, 378
ciliary, 221, 228, 230, 236, 237, 241,
357, 359, 363, 387
coccygeal, 371
cceliac, 375
collateral, 357, 361
connected with cranial nerves, 387
diaphragmatic, 375
Gasserian, 225, 234, 246, 247, 362, 387
geniculate, 243, 252, 253, 258, 260,
365, 387» 388
geniculi, 252
of hypoglossal nerve, 274
INDEX AND GLOSSARY TO VOLUME III., PART II.
395
Ganglion or ganglia — continued.
impar, 371
intervertebral, 275, 276, 277
jugular, 258, 259, 387
jugulare, 262
lateral, 357
of lateral root of auditory nerve, 256,
257
lenticular. See GANGLION, CILIARY.
lingual. #«GANGLION, SUBM AXILLARY.
of lingual branches of ninth nerve, 261
of lingual nerve, 248
of Meekel. See GANGLION, SPHENO-
PALATINE.
mesenteric, inferior, 370, 371, 376
superior, 375, 376
lumbar sympathetic, 370
nasal. See GANGLION, SPHENO-PALA-
TINE.
of nasal nerve, 237
nodosum, 262
ophthalmic. Sec GANGLION, CILIARY.
otic, 221, 237, 244, 246, 248, 260, 357,
387, 388
petrosal, 258, 259, 387
of pharyngeal plexus, 265
phrenic, 288, 375
of posterior pulmonary plexus, 269
prevertebral, 357
radicis cochlearis, 256
renal, 375
of root of tenth nerve, 262, 264, 270,
36i, 387
sacral, sympathetic, 371, 377
semilunar, 367, 369, 375
semilunare, 234
spermatic, 375
spheno-palatine, 221, 237, 238, 239,
241, 357, 387, 388
spinal, 275, 276, 277, 384
of spinal-accessory nerve, 270
spiral of cochlea, 256, 258
splanchnic, 369
splanchnic or vagrant, 384, 387
stationary, 384, 387
stellate, 366, 369
sublingual, 248
submaxillary, 221, 237, 248, 357, 387,
388
superius of ninth rierve, 259
of suprarenal nerves, 375
sympathetic, 259, 264, 265, 268, 384,
387
temporal, 365
of tenth nerve, lower, 262, 264, 265,
272, 284, 361, 387
upper, 262, 264, 265, 270, 387
terminal, 357
of terminal branches of phrenic nerve,
288
thoracic, sympathetic, .365, 367
thyroid, 365
trunci sympathici, 358
of trunk of tenth nerve, 262, 264, 265,
272, 284, 361, 387
vertebra], 357
vestibular, 256, 257
vestigial, of facial nerve, 252, 387
of fifth nerve, 233, 387
of fourth nerve, 233, 387
of third nerve, 231, 387, 388
of Wilsberg, 372
Gasserian ganglion, 225, 234, 246, 247, 362, 387
Gastric nerves, 226, 263, 264, 269
plexus, 269
Gastro-epiploic plexus, 376
Geniculate ganglion. See GANGLION.
Geniculum nervi facialis, 252
Genito-crural nerve, 313, 315, 370, 382
Genu (knee) inner, of facial nerve, 251
outer, of facial nerve, 252
Gland, tympanic, 260
Glosso-pharyngeal nerve. See NERVE.
Gluteal nerves. See NERVES.
Grey rami communicantes, 358, 359, 361, 365,
367, 384
Gudden, inferior commissure of, 228
H^MORRHOIDAL nerves. See NERVES.
plexus, 377
Hand, cutaneous nerves of, 343
muscular nerves of, 353
joints of, nerves of, 301
Head, nerves to muscles of, 351
sensory nerves of, 338
vaso-motor nerves of, 367, 369
Heart, accelerator nerves of, 367, 369
inhibitory nerves of, 269, 270
sensory nerves of, 350
Hepatic plexus, 269, 288, 375, 376
Hip, nerves of muscles of, 353
Hip-joint, nerves of, 318, 319, 321, 322, 325
Homologies of limb nerves, 383
Humei us, nerves of, 297, 304
Hypogastric plexus, 361, 370, 372, 376, 377, 378
inferior, 377
Hypoglossal nerve. See NERVE.
ILIO-HYPOGASTRIC nerve, 311, 312, 313, 314, 315
Ilio-inguinal nerve, 312, 313, 314, 315, 382
Incisor branches, 241, 247
Inferior maxillary nerve, 223, 234, 243, 248,
249
Infraclavicular branches of brachial plexus, 290,
291, 294
Infrahyoid muscles, nerves of, 351
Inframaxillary nerve, 256
Infraorbital branches of facial nerve, 255
nerve, 238, 240
plexus, 241
Infratrochlear nerve, 233, 236, 237, 255
Inguinal branch of ilio-hypogastric, 315
Inhibitory nerves of bladder, 370
of rectum, 370
Inneivation, cutaneous, of limbs, rules of, 345
Intercostal nerves, 288, 307, 308, 310, 345, 382,
383
Intercosto-humeral nerve, 296, 297, 308, 310,
384-
Intermediate plexus, 373
Intermesenteric plexus, 376
Internal cutaneous nerve of arm, 291, 295, 299,
301, 384
small, 291, 295, 296
of thigh, 318, 319, 321, 322, 384
mammary artery, nerves of, 366
saphenous nerve, 318, 319, 320, 321, 384
Interosseous nerve, anterior, 301, 303, 307
posterior, 300, 303, 306, 384
Interphalangeal joints, nerves of, 302, 303, 305,
307, 334
Intervertebral ganglia, 275, 276, 277
396
INDEX AND GLOSSARY TO VOLUME 111., PART II.
Intestines, sensory nerves of, 350
viscero-inhibitory nerves of, 369
Intumescentia ganglioformis Scarpse, 257
Iter chordae anterius, 254
posterius, 254
JACOBSON, nerve of, 260
Jugular ganglion, 258, 259, 387
KIDNEY, sensory nerves of, 350
vaso-niotor nerves of, 370
Knee-joint, nerves of, 318, 319, 321, 322, 331,
335. 336, 338
LABIAL nerves, 241, 247
Lachrymal nerve, 231, 235, 238, 240,254, 255
Laryngeal nerves. See NERVES.
Larynx, motor nerves of, 352
sensory nerves of, 341
Last dorsal nerve. See TWELFTH DORSAL
NERVE.
Lateral cutaneous nerves. See NERVES.
Lateral ganglia, 357
Leg, cutaneous nerves of, 344
muscular nerves of, 353
Lenticular ganglion. See GANGLION, CILIARY.
Ligament, round of uterus, motor nerves of,
370
Limb, cutaneous innervation of, rules of, 345
lower, cutaneous nerves of, 344, 349, 382
muscular nerves of, 353, 354, 382
upper, cutaneous nerves of, 343, 344, 348,
382
muscular nerves of, 352, 354, 382
Limb-nerves, morphology of, 382
homologies of, 383
Limb-plexuses, divisions of nerves of, 383
Lingual branches of ninth nerve, 261
branch of vagus, 265, 272
ganglion. See GANGLION, SUBMAXILLARY.
nerve, 243, 247, 261, 271, 272, 390
Lips, nerves of, 238, 241, 247, 338
Liver, sensory nerves of, 350
Long scrotal nerves, 329
Lower limb, cutaneous nerves of, 344, 349
muscular nerves of, 353, 354
Lumbar gangliated cord, 370
Lumbar nerves, 274, 281, 311, 355, 382
fifth, 322
plexus, 283, 311, 312, 383
sympathetic, constitution of, 370
ganglia, 370, 375, 377
Lumbo-sacral cord, 313, 322, 323
Lungs, sensory nerves of, 350
MALAR branches of facial nerve, 254
nerve, 239, 240, 255
Mandibular branch of facial nerve, 256
nerve, 247, 390
Masseteric nerve, 243, 244, 245
Mastoid branch of great auricular, 286
cells, nerves of, 341
Maxillary antrum, nerves of, 341
nerves. Sec NERVES.
Meatus, external auditory, nerves of, 246
Meckel's ganglion. See GANGLION, SPHENO-
PALATINE.
Median nerve, 291, 299, 300, 301, 384
Meningeal branch of vagus, 265
or recurrent branches of spinal nerves, 278,
360, 381, 384
Mesenteric ganglia. See GANGLIA.
plexus. See PLEXUS.
Metacarpo-phalangeal joints, nerves of, 300, 302,
303, 305> 307
Metatarsal bones, nerves of, 338
Metatarso-phalangeal joints, nerves of, 335, 338
Metazonal (juerct, behind ; C*"*?* girdle) nerves,
383
Middle cutaneous nerve of thigh, 317, 319, 320,
322
Mononeural (^6vos, single ; vtvpov) muscles, 383
Morphology of cranial nerves, 385
of limb- nerves, 382
of peripheral nerves, 381
Motor nerves of bladder, 370, 372
of rectum, 370, 371
of round ligament of uterus, 370
of uterus, 370, 372
of vas deferens, 370
nuclei, 222, 386
root of ganglia, 237, 386
Mouth, sensory nerves of, 338
Muscular distribution of cerebro- spinal nerves,
35?
of spinal nerves, 354
Musculo-cutaneous nerve of lower limb, 332.
335, 336, 384
of upper limb, 291, 297, 306
Musculo -spiral nerve, 291, 300, 303, 384
Mylo-hyoid nerve, 244, 247, 261
NASAL branch of superior maxillary nerve, 241
of spheuo-palatine ganglion, 242
of vidian nerve, 243
fossa, nerves of, 338
ganglion. See GANGLION, SPHENO-P ALA-
TINE.
nerve, 231, 233, 235, 236, 238, 255, 388,
390
Naso-ciliary nerve, 236
Naso- palatine nerve, 242
Naviculo-cuneiform joint, nerve of, 333
Neck, muscular nerves of, 351, 352
NERVE or NERVES (vevpov, originally sinew,
tendon), 221
abdominal vaso-motor, 369, 370
abducent, 222, 223, 225, 231, 235, 238.
241, 250, 386, 388, 390
accelerator, of heart, 367, 369
afferent, of abdominal viscera, 370
alveolar, superior, 239, 240
inferior, 247
ampullary, 257, 258
of anconeus, 304, 307
anterior crural, 313, 317, 319, 383, 384
thoracic, external, 291, 293, 294, 384
internal, 291, 294, 384
of antrum, maxillary, 338
of Arnold, 265
articular. See the several joints,
auditory, 222, 223, 224, 225, 252, 256, 286,
3.88
auricular, anterior, 246
great, 254, 256, 286
of great occipital, 280
posterior, 254, 265, 286
of small occipital. 286
INDEX AND GLOSSARY TO VOLUME III., PART II.
397
Nerve or nerves— continued.
auricular, of vagus, 265, 386, 390
auriculo-temporal, 240, 243, 244, 246,
390
of bladder, inhibitory, 370
motor, 370, 372
sensory, 350
of brachial artery, 297
buccal, 240, 243, 246, 249, 256
of facial, 256
bucco-labial, inferior, 256
superior, 255
cardiac, deep, 365
of descending cervical nerve, 274
of external laryngeal, 265
great, 365
lower, 363, 365, 372
middle, 363, 365, 366, 372
of recurrent laryngeal, 268
upper or superficial, 268, 361, 363,
365, 372, 373
of vagus, 262, 265, 268, 372
calcaneo-plantar, 333
carotico-tympanic, 260, 362
cavernous, 378
cerebro-spinal, 221
muscular distribution of, 351
sensory distribution of, 338
cervical, 274, 276, 277, 280, 283, 354,
382
descending, 271, 273
first, 222,^278, 283
superficial, 256, 286
splanchnic, 361
chorda tympani, 226, 247, 248, 249, 253,
256, 386
ciliary, long, 236, 238, 366
short, 237, 238, 359
circumflex, 291, 294, 383, 384
coccygeal, 278, 283, 322, 371, 381
cochlear, 257, 258
of coraco-brachialis muscle, 297, 384
coronary, 372, 373
cranial, 221
constitution of, 385
distribution of, 225, 390
eighth pair. See Auditory.
eleventh pair. See Spinal Acces-
sory.
exit of, from cranium, 223
fifth pair. See Trifacial.
first pair. See Olfactory.
fourth pair. See Trochlear.
morphology of, 385
ninth pair. See Glosso - pharyn-
geal.
nuclei of, 222
number of, 221
origin of, deep, 222
superficial, 222.
second pair. See Optic.
seventh pair. See Facial.
sixth pair. See Abducent.
segmentation of, 388
Scemmering's enumeration, 221
tenth pair. See Pneumo-gastric.
twelfth pair. See Hypoglossal.
third pair. See Oculomotor.
Willis's enumeration, 221
cutaneous, anterior, of abdomen, 310, 311
of thorax, 307, 308, 310
external, of upper limb, 297, 304
VOL. III., PT. 2.
Nerve or nerves— continued.
cutaneous, external, of lower limb, 313,
317, 382, 383, 384
of head, 338
internal, of anterior crural, 318, 319,
384
of musculo-spiral, 304, 310
small, 291, 295, 296, 384
of brachial plexus, 291, 295, 384
lateral, of abdomen, 310, 314, 381
of leg, 336
of thorax, 307, 308, 344, 381,
382
of lower limb, 344, 349, 382
middle, 317, 319
occasional, of obturator, 318, 320
perforating, 324, 325, 328, 382, 384
plantar, of posterior tibial, 333
of perineum, 343
of trunk, 341', 344, 350
of upper limb, 343, 344, 348, 382
cutaneous or perforating, of segmental
nerves, 381, 382
dental, inferior, 243, 246, 247
lesser, 247
superior, 239, 240
depressor, 268
diaphragmatic, 288
diazonal, 383
digital of foot, 322, 332, 333, 334, 336,
of hand, 300, 302, 303, 304, 305
dorsal, 274, 276, 277, 280, 283, 307, 344,
355. 36i, 366
of clitoris, 328, 330
first, 307
of penis, 328, 329
twelfth, 307, 311, 314, 315, 317, 322,
344, 382
of dorso-lateral muscle, 381
dorso- lumbar, 312
of epididymis, sensory, 351
of ethmoidal cells, 338
ethmoidal, posterior, 237
of external auditory meatus, 246
facial, 222, 224, 226, 236, 251, 262, 359,
386, 387, 388, 390
genu of, inner, 251
outer, 252
femoral, 319
fibular communicating, 336
frontal, 231, 233, 235, 236
of frontal sinus, 338
furcal, 313, 325, 383
gastric, 269
genito-crural, 313, 315, 370, 382
gluteal, inferior, 324, 325, 326, 331, 383,
384
superior^ 322, 324, 325, 383, 384
glosso-pharyngeal, 222, 223, 224, 225, 226,
254, 258, 359, 386, 387, 388, 390
haemorrhoidal, interior, 328, 329, 330, 382
superior, 377
of heart, 268, 269, 270, 350, 363, 365, 367,
369, 372
hypoglossal, 222, 223, 224, 225, 226, 248,
26$, 271, 385, 387, 388, 390
iho-hypogastric, 311, 312, 313, 314, 315
ilio-inguinal, 312, 313, 314, 315, 317, 382
inframaxillary, 256
infraorbital, 238, 240
infratrochlear, 233, 236, 237, 255, 390
c c •
398
INDEX AND GLOSSARY TO VOLUME III., PART II.
Nerve or nerves — continued.
inhibitory of heart, 269, 270
intercostal, 288, 307, 308, 382, 383
first, 307
lower or abdominal, 310
upper or pectoral, 308
intercosto-humeral, 296, 297, 308, 310, 384
interosseous, anterior, 301, 303, 307
posterior, 300, 303, 306, 384
of intestines, inhibitory, 369
motor, 269
sensory, 350
of Jacobson, 260
of joints. See the several joints.
of kidney, sensory, 350
vaso-motor, 370
labial, 241, 247, 338
lachrymal, 231, 235, 238
laryngeal, external, 265, 268, 361, 363, 364,
365
inferior or recurrent, 264, 266, 268,
363, 365, 366, 390
internal, 265
middle, 266
superior, 262, 265, 268, 270, 363, 390
of levator ani, 323, 329
of limbs, homologies of, 383
morphology of, 382
of limb-plexuses, divisions of, 383
lingual, of fifth nerve, 243, 247, 261, 271,
272, 390
of glosso-pharyngeal, 261
of vagus, 265
of lips, 241, 247, 338
of liver, sensory, 350
long scrotal, 329
lumbar, 274, 281, 311, 344, 355, 382
fifth, 322
of lungs, sensory, 350
malar, 239, 240, 255
mandibular, 247, 390
masseteric, 243, 244, 245
maxillary, inferior, 223, 234, 243, 388,
39p
superior, 223, 234, 238, 388, 390
median, 291, 299, 300, 301, 384
mental, 247, 256
met-azonal, 383
morphology of, 381
of muscles of head, 351, 390
of lower limb, 353, 354, 382
of neck, 351, 352, 390
of trunk, 352, 354
of upper limb, 352, 354, 382
musculo-cutaneousof arm, 291, 297,302, 384
of leg, 322, 332, 335, 336, 338, 384
musculo-spiral, 291, 300, 303
mylo-hyoid, 244, 247, 261
nasal, 231, 233, 235, 236, 238, 255, 388
of nasal fossa, 338
naso-ciliary, 236
naso-palatiue, 242
obturator, 313, 317, 320, 321, 383, 384
accessory, 317, 319, 322
of obturator interims, 324, 325, 384
occipital, great, 280, 286
small, 254, 280, 286
third, 280
oculomotor, 222, 223, 225, 228, 238. 359,
386, 387, 390
external. See Abducent,
oculo-nasal, 236
Nerve or nerves — continued.
olfactory, 222, 223, 225, 227, 385
ophthalmic, 223, 230, 231, 233, 234, 235,
250, 388
optic, 222, 223, 225, 227, 24T, 385
orbital, 239
of ovary, 351, 375, 378
palatine, external, 242
large or anterior, 242, 243
small or posterior, 242
parotid, 246, 249, 256, 261, 286
pathetic. See Trochlear.
of pectineus muscle, 320, 384
pelvic splanchnic, 359, 371
of penis, 341, 343
vaso-constrictor, 370
vaso-dilator, 370, 372
perineal, 328 ^
deep, 329
superficial, 328, 329, 330
peroneal. See Popliteal, external.
communicating, 332, 336
petrosal, external superficial, 253
large deep, 243, 253, 262
superficial, 243, 252, 256, 260,
362, 386
small deep, 260, 362
small superficial, 249, 253, 260, 261,
386, 388
pharyngeal, of glosso-pharyngeal, 260
of sympathetic, 363
of vagus, 265
phrenic, 274, 288, 385
accessory, 288
pilo-inotor, 359, 367, 369, 370, 371
plantar, external, 332, 334, 337, 384
internal, 332, 333, 33 j, 384
pneumo-gastric, 222, 223, 224, 226, 254,
259, 261, 270, 274, 359, 364, 386, 388,
390
popliteal, external, 324, 325, 328, 330,
332, 335' 383, 384
internal, 322. 324, 325, 328, 330, 331,
383, 384
postaxial of limb-borders, 349
posterior thoracic, 291, 293, 383
preaxial of limb-borders, 348, 349
pretracheal, 364
prezonal, 383
of prostate, secretory, 372
sensory, 351
pterygoid, external, 243, 246
internal, 244, 246, 248, 249
pudendal, interior, 326, 328, 329, 330
pudic, 324, 325, 328, 370, 378, 382
pulmonary, anterior, 268
pupillo-dilator, 366, 369
of pyriforrnis, 324, 325, 326, 383
of quadratus femoris, 324, 325, 384
radial, 297, 298, 300, 302, 303, 304, 384
of rectum, inhibitory, 370
motor, 370, 371
sensory, 350
recurrent articular, 336
of hypoglossal, 271
laryngeal. See Laryngeal, inferior.
of maxillary, inferior, 244
superior, 239
of ophthalmic, 235
of spinal nerves, 278, 360, 381, 384
of vagus, 265
of rhomboid muscles. 292, 383
INDEX AND GLOSSARY TO VOLUME III., PART II.
399
Nerve or nerves — continued.
of round ligament of uterus, motor, 370
saccular, 257, 258
sacral, 274, 276, 277, 278, 281, 322, 356,
38i
fifth, 323, 381
fourth, 323, 381
sixth, 323
saphenous, external or short, 327, 331, 332,
336, 338
internal or long, 318, 319, 320, 321,
322, 336, 338, 384
sciatic, great, 324, 328, 330, 383
small, 324, 325, 326, 331, 336, 382,
383, 384
of scrotum, 341, 343
segmental, 344, 350, 354, 381, 382, 384,
385, 388
sensory, of cavities of head, 338
distribution of, 338
of head, 338
of viscera, 350
somatic afferent, 384, 388
efferent, mesial, 384, 385, 386, 388
lateral, 385, 386, 388
spheno-ethmoidal, 237
sphenoidal, 243, 249
of sphenoidal sinus, 338
spheno-palatine, 239, 241, 242, 243
spinal, 221, 274
connection of, with sympathetic cords,
283, 357, 358, 359,' 361
cutaneous distribution of, to trunk
and limbs, 344
muscular distribution of, 354
roots of, 256
segmentation of, 381
sensory distribution of, to viscera, 350
spinal accessory, 222, 223, 224, 226, 262,
265, 269, 359, 385, 386, 388, 390
splanchnic afferent, 384, 388
efferent, 384, 386, 388
non-gangliated, 385
great, 367, 369, 375
small, 367, 369, 375
smallest, 367, 369, 375
of stomach and intestines, motor, 269
sensory, 350
viscero-mhibitory, 369
subcostal, 307
of submaxillary gland, secretory, 367, 369
suboccipital, 221, 222, 274, 277, 278, 283
subscapular, 291, 294, 383
long, 294
supraclavicular, 287, 310
supramaxillary, 256
supraorbital, 236, 254, 255, 390
suprascapular, 291, 293, 383
supratrochlear, 233, 236, 237
of sweat-glands, secretory, 369, 370
sympathetic, 221, 357, 372, 384
temporal, 235, 239, 254
deep, 243, 245, 246
superficial, 246
temporo-malar, 239, 390
thoracic. See also Dorsal.
anterior internal, 291, 294, 384
external, 291, 293, 294, 384
of testis, sensory, 351
tibia), anterior, 335, 336, 337, 384
communicating, 332
posterior. 331, 332, 384
Xerve or nerves — continued.
of tongue, sensory, 248, 256, 261, 338
muscular, 351, 390
trifacial, or trigeminal, 222, 223, 225, 233,
386, 387, 388
trochlear, 222, 223, 225, 231, 235, 238, 386,
387, 388, 390
of trunk and limbs, cutaneous distribution
of, 344
tympanic, 259, 260, 362
ulnar, 291, 295, 296, 299, 302, 303, 306,
384
collateral, 303, 304
of ureter, sensory, 350
of uterus, 351, 370, 372, 375, 378
motor, 370, 372
and appendages, sensory, 351
utricular, 257, 258
vaginal, 378
of vas deferens, 370, 377
vaso-constrictor, 359
of limbs, 369, 370, 371
pulmonary, 369
vaso-dilator, 359
vaso- motor, 359, 367, 369
of ventro-lateral muscle, 381
of vesicula seminalis, 377
vestibular, 257, 258
vidian, 243, 249, "253, 362
viscero-coristrictor, 359
viscero-inhibitory, 359
of Wrisberg, 291, 296, 384
Nerve-plexuses. !See PLEXUS.
Nerve-roots. See ROOTS.
NERVUS vel NERVI, acusticus, 256
alveolaris, inferior, 247
ano-coccygei, 323
axillaris, 294
carotici externi, 364
caroticus internus, 362
cerebrales, 221
clunium inferiores, 327
medii, 281
superiores, 281
cutaneus antibrachii dorsalis, 304
medialis, 295
brachii medialis, 296
lateralis, 295
posterior, 304
femoris lateralis, 317
posterior, 326
sura? lateralis, 336
medialis, 332
dorsalis scapulas, 292
erigentes, 372
furcalis, 313, 325, 383
genito-femoralis, 315
hsemorrhoidales medii, 323
intercosto-brachialis, 310
intermedius, 251
ischiadicus, 330
jugularis, 361
labiales posteriores, 329
lumbo-inguinalis, 316
mandibularis, 243
masticatorius, 243
maxillaris, 238
meningeus medius, 239
perforans coccygeus major, 328
peronaeus communis, 335
profundus, 337
superficialis, 336
400
INDEX AND GLOSSARY TO VOLUME III., PART II.
Nervus vel nervi — continued.
pudenclus, 328
radialis, 303
renalis posterior, 369
scrotales posteriores, 329
spermaticus extermis, 316
spinosus, 244
splanchnicus supremus, 369
subcutaneus colli, 286
suralis, 332
tentorii, 235
thoracalis longus, 293
thoraco-dorsalis, 294
tibialis, 331
vaginales, 323
vagus, 261
vesicales inferiores, 323
vestibuli, 257
zygomaticus, 239
Ninth pair of cranial nerves. See NERVES.
Nuclei of nerves, motor, 222, 386
sensory, 222, 386
OBTURATOR nerve, 313, 317, 320, 322, 383, 384
accessory, 317, 319, 322
Occasional cutaneous branch of obturator,3 18.320
Occipital nerve, great, 280, 286
of posterior auricular, 254
small, 254, 280, 286
third, 280
Occipito-atlantal joint, nerve of, 284
Oculomotor nerve. See NERVE.
Oculo-nasal nerve, 236
(Esophageal branches, 268, 269
plexus, 262, 264, 269
(Esophagus, motor nerves of, 269
sensory nerves of, 341
Olfactory nerves, 222, 223, 225, 227, 385
Ophthalmic artery, nerves of, 362
Ophthalmic ganglion. See GANGLION, CILIARY.
Ophthalmic nerve, 223, 230, 231, 233, 234, 235,
250, 388
Optic commissure, 227, 228
nerves, 222, 223, 225, 227, 241, 385
tracts, 227
Orbit, nerves to muscles of, 351
Orbital nerve, 239
Origin, deep, of cranial nerves, 222
superficial, of cranial nerves. 222
Os uteri, sensory nerves of, 351
Otic ganglion. See GANGLION.
Ovary, nerves of, 351, 375, 378
PACINIAN bodies, 301, 302, 332, 333, 334, 377
Palate, soft, motor nerves of, 352
sensory nerves of, 339 '
Palatine nerves. See NERVES.
Palm, cutaneous nerves of, 343
Palmar arteries, nerves of, 300
branch of uinar nerve, deep, 300
superficial, 300
cutaneous branch of median nerve, 302
ulnar nerve, 299, 302
Palpebral nerves, 235, 236, 237, 241, 255
Pancreatic plexus, 376
Pancreatico-duodenal plexus, 376
Par (pair) vagum (wandering), 261
Parotid nerves, 246, 249, 256, 261, 286
Pars intermedia of Wrisberg, 251, 252, 254, 258,
Patellar branch of internal saphenous, 322
plexus, 317, 322
Pathetic nerve. See NERVE, TROCHLEAR.
Pectoral intercostal nerves, 308
Pelvic plexus, 370, 371, 372, 377
splanchnic nerves, 359, 371
Penis, nerves of, 341, 343
cavernous, 378
dorsal, 328, 329
motor, 352
vaso-dilator, 370 372
vaso-constrictor, 370
Perforating branches of external plantar nerve,
cutaneous nerve, 324, 325, 328, 382, 384
or cutaneous branches of segmental nerves,
381, 382
Pericardial branches of vagus, 269
I Perineal branch of fourth sacral, 323, 382
nerve, 328
deep, 329
superficial, 328, 329, 330
Perineum, cutaneous nerves of, 343
Peripheral nerves, morphology of, 381
Peroneal artery, nerves of, 333
nerve, 324, 325
communicating, 332, 336
Pes anserinus (goose's foot), 252
Petrosal ganglion, 258, 259, 260, 262, 265, 361,
387
nerves. See NERVES.
Pharyngeal branches of upper cervical ganglion,
36i, 363
of vagus, 261, 265, 270
division of ninth nerve, 260
nerves, 243, 260, 261, 262, 266, 268
plexus, 261, 265, 266, 363
Pharynx, motor nerves of, 352
sensory nerves of, 339
Phrenic ganglion, 288, 375
nerve, 274, 288, 291, 293, 366, 375, 385
accessory, 288
plexus, 375
Pilo-motor nerves, 359, 367, 369, 370, 371
Pituitary body, nerves of, 363
Plantar nerves. See NERVES.
PLEXUS (plaiting, twining) or PLEXUSES, nervous
221, 383
aortic, 370, 375, 376, 377
aorticus abdominalis, 376
thoracalis, 367
atrial, 373
beneath sartorius muscle, 318, 322
brachial, 283, 289, 307, 382, 383
bulbar, 373
cardiac, deep, 268, 363, 365, 366, 372, 373
superficial, 268, 363, 372, 373
caroticus externus, 364
internus, 362
carotid, 234, 243, 250, 260, 362
cavernous, 230, 233, 235, 238, 362
cervical, 283, 285
cutaneous area of, 341
posterior, 280
coccygeal, 323
co?liac, 376
co3liacus, 373
coronary of heart, 372
of stomach, 376
cranial, 362
cystic, 376
dental, inferior, 247
INDEX AND GLOSSARY TO VOLUME III., PART II.
401
Plexus or plexuses — continued.
dental, superior, 241
diaphragmatic, 375
epigastric, 373
facial, 248
gastric, 269
gastro-epiploic, 376
great, of sympathetic, 372
hepatic, 269, 288, 375, 376
heemorrhoidal, 377
hypogastric, 361, 370, 372, 376, 377, 378
inferior, 377
infraorbital, 241
of intercostal nerves, 310, 383
intermediate, 373
intermesenteric, 376
ischiadicus, 324
linealis, 376
lumbar, 283, 311, 312, 317, 318, 383
mesenteric, inferior, 376
superior, 376. 377
middle meningeal, 249, 253
O3sophageal, 262, 264. 269
pancreatic, 376
pancreatico-duodenal, 376
parotideus, 252
patellar, 317, 322
pelvic, 370, 371, 372, 377
pharyngeal, 261, 265. 266, 363
phrenic, 375
prevertebral, 357, 359, 360, 361
prostatic, 378
pudendus, 324
pudic, 324
pulmonary, anterior, 268, 269, 364, 372
posterior, 262, 264, 268, 269, 367
pyloric, 376
renal, 269, ,367, 369, 370, 375
sacral, 283, 3", 3 12, 31 3, 322,323, 33O> 383
sciatic, 324
solar, 263, 269, 288, 361, 369, 372, 373
spermatic, 375, 376, 377
splenic, 269, 376
subclavius, 366
suprarenal, 375
tympanic, 260, 362
vertebralis, 366
vesical, 377
Pneumo-gastric nerve. See NERVE.
Polyneural (TTO\US, many ; vtvpov] muscles, 383
Popliteal nerves. See NERVES.
Portio dura (hard, tough), 222
intermedia, of Wrisberg, 251, 252, 254,
258, 386, 388
mollis (soft), 222
Postaxial limb- borders, nervos of, 349
Posterior auricular nerve, 254, 265, 286
interosseous nerve, 300, 306, 384
roots of auditory nerve, 256
of spinal nerves, 275, 276, 358, 359,
381, 384
thoracic nerve, 291, 293, 383
tibial nerve, 331, 332, 384
Postfixed type of lumbar plexus, 313
Preaxial limb-borders, nerves of, 348, 349
Prefixed type of lumbar plexus, 313
Pretracheal nerve, 364
Prevertebral ganglia, 357
plexuses, 357, 359, 360, 361
Prezonal nerves, 383
Primary divisions of spinal nerves, posterior or
dorsal, 275, 278, 341, 381
Primary divisions of spinal nerves, anterior or
ventral, 275, 278, 283, 341, 381, 382
Prostate, secretory nerves of, 372
sensory nerves of, 351
Prostatic plexus, 378
Pterygoid nerve. See NERVK.
Pterygo-sphenoidal ligament, 244
accessory, 247
Pudendal nerve, inferior, 326, 328, 329, 330
Pudic nerve, 324, 325, 328, 370, 378, 382
Pulmonary nerves, anterior, 268
plexus. See PLEXUS.
Pupillo-dilator fibres, 366, 369
Pyloric plexus, 376
QUABRATUS femoris muscle, nerve of, 324, 325,
384
RADIAL nerve, 297, 298, 300, 302, 303, 304, 384
Radius, nerve of, 301
Radix cochlearis, 256
vestibularis, 256
Ramus vel Rami, communicantes, grey, 358,
359,361,365,367,384
white,357,358, 367,371, 384
cutaneus anterior, 315
lateralis, 315
descendens hypoglossi, 273
efferentes, 357, 358, 360
ophthalmicus profundus, 388
perineales, 328
profundus nervi radialis, 306
superficialis nervi radialis, 304
viscerales, cervico-cranial, 359
visceralis, 381
zygomaticofacialis, 240
zygomaticotemporalis, 239
Rectum, inhibitory nerves of, 370
motor nerves of, 370, 371
sensory nerves of, 350
Recurrent nerves. See NERVES.
Renal ganglia, 375
plexus, 269, 367, 369, 370, 375
Rhomboid muscles, nerve of, 292, 383
Ribs, nerves of, 308
ROOT or ROOTS, ascending or bulbar of fifth
nerve, 233
of auditory nerve, 256, 257
of ciliary ganglion, 230, 236, 237, 238, 359,
363
descending or mesencephalic, of fifth nerve,
233
of ganglia, 237
of hypoglossal nerve, 271, 274
motor of fifth nerve, 225, 233, 243, 247
of otic ganglion, 249
sensory, of fifth nerve, 225
of spinal nerves, anterior, 275, 276, 354,
358, 359, 384
posterior, 256, 275, 358, 359, 381, 384
of spheno-palatine ganglion, 243
of submaxillary ganglion, 248, 365
of tenth nerve, 261
Round ligament of uterus, motor nerves of, 370
Rules of cutaneous nerve-supply of limbs, 345
SACCULAR nerve, 257, 258
Sacral nerves, 274,276,277,278,281,322,356,381
fifth, 323, 381
402
INDEX AND GLOSSARY TO VOLUME III., PART II.
Sacral nerves — continued.
fourth, 323, 381
sixth, 323
gangliated cord, 370
plexus, 283, 311, 312, 313, 322, 323, 330,
383
sympathetic, constitution of, 371
Sacro-iliac joint, nerves of, 281
Saphenous nerves. See NEKVES.
Scapula, nerves of, 293
Sciatic nerves. See NERVES.
plexus, 324
Scrotal nerves, long, 329
Scrotum, nerves of, 341, 343
Second pair of cranial nerves. See NEUYES.
Secretory nerves of prostate, 372
of submaxillary gland, 367, 369
of sweat-glands, 369, 370
Segmental nerves, 344, 350, 354. 381, 382, 384,
385
Segmentation of cranial nerves, 388
of spinal nerves, 381
Semilunar ganglion, 367, 369, 375
Sensory distribution of cerebro-spinal nerves,
344
of spinal nerves to viscera, 350
fibres, spinal, to sympathetic system, 359
nerves. See NERVES.
nuclei, 222
root of ciliary ganglion, 236, 237, 238
of fifth nerve, 225, 233
of ganglia, 237
of otic ganglion, 249
of spheno-maxillary ganglion, 243
of submaxillary ganglion, 248
zones of trunk and limbs, 344
Septal branch of nasal nerve, 237
Seventh pair of cranial nerves. See NERVES.
Shoulder, cutaneous nerves of, 343
motor nerves of, 352
Shoulder-joint, nerves of, 293, 294, 295
Sinus, frontal, nerves of, 338
sphenoidal, nerves of, 338
Sixth pair of cranial nerves. See X Kit YE.
Sixth sacral nerve, 323, 381
Soemmering's classification of nerves, 221
Soft palate, motor nerves of, 352
sensory nerves of, 339
Solar plexus, 263, 269, 288, 361, 369, 372, 373
Sole, cutaneous nerves of, 344
Somatic (o-oj/ia, body) afferent nerves, 384, 388
division of spinal nerves, 381
efferent, mesial, 384, 385, 386, 388
lateral, 385, 386, 388
Spermatic ganglion, 375
plexus, 375, 376, 377
Spheno-ethmoidal nerve, 237
Sphenoidal nerve, 243, 249
Sphenoidal sinus, nerves of, 338
Spheno-palatine ganglion, 221, 237, 238, 239,
241, 253, 256, 357, 387, 388
nerve, 239, 241, 242, 243
Spinal accessory nerve. See NERVE.
cord, 223/274, 275
ganglia, 275, 276, 277, 384
nerves, 221, 274
connection with sympathetic cords,
357,358, 359, 361, 365, 367, 370, 37i
cutaneous distribution of to trunk and
limbs, 344
morphology of, 381
muscular distribution of, 354
Spinal nerves, primary division of, anterior, 275.
278, 283, 341, 381, 382
primary division of, posterior, 275,
278, 341, 381
roots of, 256, 275, 351, 359, 381
segmentation of, 381
sensory distribution, to viscera, 350
portion of spinal accessory nerve, 269, 270,
271, 385, 386, 390
Spiral ganglion of cochlea, 256, 258
Splanchnic ganglion, 369
nerves. See NERVES.
Splanchnic ((nr\dyxva, viscera), or vagrant
ganglia, 384
or visceral divisions of spinal nerves, 381
Splanchnics, abdominal, 367
cervical, 361
pelvic, 359, 371
Splenic plexus, 269, 376
Stapedius branch of facial, 253, 390
Stationary ganglia, 384, 387
Stellate ganglion, 366, 369
Sternal branches of intercostal nerves, 308
Sterno-clavicular joint, nerves of, 287
Sternum, nerves of, 308
Stomach, motor nerves of, 269
sensory nerves of, 350
viscero-inhibitory nerves of, 369
Striae medullares, 256, 257
1 Stylo-hyoid branch of facial, 254, 365, 390
Stylo-pharyngeus, nerve to, 261, 390
Subclavian artery, nerves of, 366
Subclavius muscle, nerve of, 288, 291, 293, 384
Subcostal nerve, 307
branches of intercostal nerves, 308
Sublingual ganglion, 248
Submaxillary ganglion, 221, 237, 248, 254, 256,
357, 365, 387, 388
gland, secretory nerves of, 367, 369
| Suboccipital nerve, 221, 222, 274, 277, 278, 283
Subscapular nerves, 291, 294, 383
Superficial cardiac nerve, 268, 361, 363, 365,
372, 373
cervical nerve, 256, 286
Superior maxillary nerve, 223,234,238,388,390
Supra-acromial branch of cervical plexus, 287
Supraclavicular nerves, 287, 310
Suprahyoid muscles, nerves of, 351
Supramaxillary nerve, 256
Supraorbital nerve, 236, 254, 255
Suprarenal plexus, 375
Suprascapular nerve, 291, 293, 383
Snprasternal branches of cervical plexus, 287
Supratrochlear nerve, 233, 236, 237
Sweat-glands, secretory nerves of, 369, 370
Sympathetic branch of spinal nerves, 381, 384
Sympathetic, cervical, constitution of, 366
fibres, 358
ganglia. See GANGLIA.
lumbar, constitution of, 370
nerves, 221, 357, 372, 384
plexuses, great, 372
roots of ganglia, 237. 238, 243, 248, 249,
363, 365
sacral, constitution of, 371
thoracic, constitution of, 369
Synopsis of muscular distribution of nerves, 351
of sensory distribution of nerves, 338
TABLE of homologies of limb-nerves, 383
of muscular distribution of spinal nerves.
354
INDEX AND GLOSSARY TO VOLUME III., PART II.
403
Table of origins of brandies of brachial plexus,
291
of segmental nerves of head, 389
Tarsal joints, nerves of, 337
Tarso-metatarsal joints, nerves of, 335, 338
Temporal branches of facial, 254
ganglion, 365
nerve, 235, 239, 254
deep, 243, 245, 246
superficial, 246
Temporo-facial division of facial, 252, 254, 256
Temporo-malar nerve, 239
Temporo- maxillary joint, nerves of, 246
Tenth pair of cranial nerves. Sec NKRVKS.
Terminal ganglia, 357
Testis, sensory nerves of, 351
Thenar eminence, cutaneous nerves of, 344
Thigh, nerves of, cutaneous, 344
muscular, 353
Third occipital nerve, 280
Third pair of cranial nerves. See NERVE.
Thoracic ganglia, sympathetic, 365, 367
gangliated cord, 367
nerves. See NERVES.
spinal, 274, 307
sympathetic, constitution of, 369
Thumb-muscles, nerves of, 302
Thyroid branches of middle cervical ganglion,
365
ganglion, 365
Tibia, nerves of, 331, 332, 336
Tibial artery, anterior, nerves of, 332
posterior, nerves of, 33.^
Tibial nerve. See NERVE.
Tibial communicating nerve, 322
Tibio-fibular joints, nerves of, 331, 332, 336
Toes, articular nerves of, 334
cutaneous nerves of, 344
Tongue, muscular nerves of, 351, 390
sensory nerves of, 248, 256, 261, 338
Tonsillitic branches of ninth nerve, 261
Trachea, sensory nerves of, 341
Tracts, optic, 227
Trifacial or Trigeminal nerve. See NERVE.
Trochlear nerve. See NERVE.
Trunct sympathici, 358
Trunk, cutaneous nerves of, 341, 344, 350
muscular nerves of, 352, 354
Trunk-ganglion of vagus, 262, 264, 265, 272,
284, 361
Trunks of brachial plexus, 289
Tube, Eustachian, nerves of, 341
Twelfth dorsal nerve, 307, 311, 314, 315, 317,
322, 344, 382
Twelfth pair of cranial nerves. See NERVES.
Tympanic branches, 246, 260
cavity, sensory nerves of, 341
gland, 260
membrane, nerves of, 341
nerve, 259, 260, 362
plexus, 260, 362
Types of lumbar plexus, 313
ULNA, nerve of, 301
Dinar artery, nerves of, 299
nerve, 291, 295, 296, 299, 302, 303, 306,
384
collateral, 303, 304
Ureter, sensory nerves of, 350
Urethra, muscular nerves of, 352
Uterine appendages, sensory nerves of, 351
Uterus, nerves of, 351, 370, 372, 375, 378
Utricular nerve, 257, 258
VAGAL portion of spinal accessory nerve, 270
Vaginal nerves, 378
Vagrant ganglia, 384, 387
Vagus nerve. See NERVE, PNEUMO- GASTRIC.
Vas deferens, nerves of, 370, 377
Vascular branches of hypoglossal nerve, 272
of musculo-cutaneous nerve, 297
Vaso-constrictor nerves, cerebro-spinal, to sym-
pathetic system, 359
of limbs, 369, 370, 371
of penis, 370
pulmonary, 369
Vaso-dilator nerves, cerebro-spinal, to sympathe-
tic system, 359
of penis, 370, 372
Vaso-motor nerves, 359
abdominal, 369, 370
of head, 367, 369
of kidney, 370
Ventral or anterior primary divisions of spinal
nerves, 283, 341, 381, 384
Vertebral artery, nerve of, 366
Vertebral ganglia, 357
Vesical plexus, 377
Vesicula -seminalis, nerves of, 377
"Vestibular ganglion, 256, 257
nerve, 257, 258
Vestigial ganglia of cranial nerves, 231, 235,252,
387, 388
\ridian nerve, 243, 249, 253, 362
Viscera, abdominal, afferent nerves of, 370
sensory distribution of spinal nerves to, 350
Visceral branches of fourth sacral nerve, 323
of sacral nerves, 371
or splanchnic division of spinal nerves,
3»i, 384
Viscero-constrictor nerves, cerebro-spinal, to
sympathetic system, 359
Viscero-inhibitory nerves, cerebro-spinal, to
sympathetic system, 359
of stomach and intestine, 369
WHITE rarni communicantes, 357, 358, 367, 371.
384
Willis's classification of cranial nerves, 221
Wrisberg, ganglion of, 372
nerve of, 291, 296, 384
pars intermedia of, 251, 252, 254, 258
Wrist-joint, nerves of, 300, 301, 303, 307
ZONES, sensory, of trunk and limb.-, 344
END OF PART II.
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