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995

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maoam •bouition tbi chut

(«NSI oM ISO TIST CHMI No. 2)

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III '•'4 ■■■6

/APPLIED IIVMGE In.

PRACTICAL ANATOMY
OF THE RABBIT

AN ELEMENTARY

LABORATORY TEXTBOOK IN

MAMMALIAN ANATOMY

By
B. A. BENSLEY, Ph.D.

Axtociate Pro/tmir of ZoUogn in it
Uniwrgity of Toronto

TOnONTO:
THE UNIVKBSITY PRESS

PHILADKLFHIA:

P. BLAKISTUN'S SON & CO.

UIO

CoPYRiOHT, Canada, 1910, av
The Univbrsity Press

PREFACE.

m»m!lf r ''^".' °' ''■'•P''"'",' '^'' '» '° *« f""" "■' '^•■iet facts of
mamma ban structure in an elementary, practical form: further, to um
'*!,™'°"'.y.<'f "typical mammal as a means of applying the mn"

rinil^ .v~""'°"?.°','"'r"u»"^"""y »"''• » f" " the limitation, of T
«ng e type permit, also he broader conceptions of morphological zooloiry.
On the practical side its chief aim is to place before the student the
matenals necessary for a practical study of the type, rather than a
fnTh^'^r ^"T"/.u' Its organ zation, though in i,me cases, notably
t?yl m^Zn™".?' l''5 skeleton it has been possible to follow i descrip'^
tiye method without departing from the original plan.

str„TH?r!"M?^°" °kk'."^,V°P ^^r'"" '" •="'»'" K*^""*' »SP<!<^tS of the

™7, w^. r* ?''.'"i """•■ L' " ^°P^' encourage the student to prose
«M I P™"<^«' I'.'x'y «'th a more liberal point of yiew. As to the
dJfficultTVny S 'km '"''°"' '" *''"'"" "^^ been a matter of no little
umS On. Lfr^'f^'i'" "*"'' "L"P*<^'' " «■«'■' have been improved
E 1^., „r„ ' ■ '■""'^''r' '^*' "■* «"' I""""" '^ "ot one of
MtP„; ^n .1, 1^?!™' Pnnciple. Progress depends to a considerable
extent on the abdity to attack small problems with a large spirit At

ote™,"„Vl'"" * "*'' ^r*?".' •"' ^"o" " *>""« <l'=^'"»d to the planning
thin^yer Se™r,v'' f ^^ "' "" '°"»^'°8 specUlization it becomes morf
than ever the duty of the mstructor to see that the student does not

wrth%™J«^"""'';P™^""'* T"- * "»» "f detailed informa«rn! Zt
with general conceptions as crude as when he entered it

thm^,th '*'"™t<'ry type the rabbit has been made familiar to students
■•/^^,!L™^l°p r^'Tu*' textbooks and especially through the

S\o w»r™n, T?"" "^extensive as its general conyenience would
HnT.^ .r f K ' "^y' herefore, be of some yalue to direct atten-
tion to this form by providing more facUiiies for its study. It is un-
ortunate, m many respects, that no recent and adequate account of

us^d fo TL°ri ^' '*■?":,' " t::*"^*"^'. ^ « "-^ ™^ "«h „ther mammal
used for laboratory study, the classic " Analomie des Kaninchens" of
Krause, published in 1884, being still the common source of inC^tion

studen^^^^r^lv'Ti-""," V'°^^iy of most yalue to two classes of
H„.h1 '. \ '^^ ""^"'*' °^ Premedical students using it as an intro-
duction to human anatomy, histology, or physiology and zoolorical
students using it as an introduction, or as part of the aboratoTpMC
lubi^f vertebrate zoology^ For the latte? class two aspects '^f'^ he
H-?'^ii ? '^"P*"^"y ™rthy of consideration. One is the more or less
detailed study deyoted to a single type; the other, the study of a
specialized type, the latter point being of more impo tance if the sub

2.79 15

PlEFAOi.

iv

ject is being used as an introductory one. In manv rr<niH-i. tk. ^.,

ZZ^in^'li^''^'" """""' » " «°«1 co"«L'rS^'he'roug"h
Lv SL j° .''T'^'"'V '"M"'"! by the loological textbooks and
may be made o share the well-known merit of human anatXv as a

~™ 5 "L''"^'P'i"'- ^«*'»' '<"■ ""^ »«"<>''"' v'ho afterwards i^ "n
TsTl^lr''''''".'?^ '™''"^°"' "■« ""Oy "' « 'Pecialized rvp^ s"ch
Sn wKrrban?,!'^' "'r"' ""/"'■ '""""hing dTfinite and J^iicrete
«P». vai, ' conceptions o sequence. Primitive structure is of

fore ii »h .k * "'™"' °I "P'"""""". but the question, now as hereto-
fore, IS whether or not the study of primitive animals as a preliminary

Them„?rr".*H" .^T!'' P*^'^"" '"■" » laboratory «an"™nt^
he wUI te comW^' 1^""' '""■'■"'^'' '" "■"'"« "l-"^"". 'be more

■.^J';^/™"'"''^' <•"'«"" j"! "bich the p,esent book is based have been
UKd lor several years and in different forms in the laboratories of the

ments'to Z JT'"- " T""'.'* '"*™" '" ">"'« "ue ackTow e^g
?^?.\^- °.^ "'"kagu.es and students who at one time or another have
assisted in Its preparation. Indeed, our chief obligation is to Professor

ha's'^Si^T'^,".""' '" "'"Wishing Ikboratorv ™ur«s of this kLT
has laid the foundation on which we have tried to build.

University of Toronto,

January 3rd, 1910.

B. A. BENSLEY.

CONTENTS

INTHOOUCTION.

Part I. A GENERAL CONSIDERATION OF THE
STRUCTURE OF THE RABBIT.

Divisions and Methods

Interpretation of Structure

ZooLOGic-iL Position

General /anatomy

Epithelial Tissues

Connective Tissues

Muscular Tissues

Nervous Tissues

Terminology

The General Features and Ground Plan of the Organ Systems 25
The Skeletal Svstem _.

The Nervous System.
The Digestive System .

The Respiratory System .3

The Vascular System
The Urinogenital System

The Serous Cavities

Regional Sections

43
4S
49
52

Part II. OSTEOLOGY OF THE RABBIT.

General Divisions of the skeleton m

The Vertebral Column ....

The Rips „

The St. num

The Skeleton of the Head

The Skull as a Whole

The Bones of the Skull

The Hyoid Apparatus

The Skeleton of the Anterior Limb

The Skeleton of the Posterior Limb

73
74
75
. 75
. 86
. 97
. 98
.103

i:

»f CONTKNTI.

Part III. DISSECTION OF THE RABBIT.

1. External Features jjO

2. The Abduhinal Wall 113

3. The Stomach and Spleen HD

4. The Liver I2q

8. The Intestines 122

6. The Urincicenital System 127

7. The Abdominal Aorta, Inferior Vena Cava, and Sympathetic
Teunks ,33

8. The Anterior Limb I35

9. The Posterior Limb I44

10. The Head and Neck 1 j7

11. The Thorax 172

12. The Vertebral and Occipital MusruLATURE 180

13. The Central Nervous System ' ig4

Appendix. Directions for the Preservation or Material 194

IXTRODUCTIO.V.

AS llaboratory cxcrci«., ,l„. analomicul ,t,„lv of an animal i, largclv a
matter of applymg a n-rtain practical method of exposition the
student , attention Uing concentrated on ,ho«. fact, whilT mav
be made „„, by direct observation. For this reason, and airtcau'
contmutty ,s a prime consideration, various important iTpc^.sol
.ructure are of necessi. left in ,he back.round'^ It is ""^ con
..dered^ namely, that i tudying the structure of any crjnis™ the
fina object ,s not s,n.,.y to determine in what its structtfre ™";i t,
he la ; "'.''":';°'">; ■" " ^"'"^'-'' *",<■, but also to understand whl;
the latter s^niHes when considered either as functional mechanism or in
.eneral, as u product of the various factor .derlvinirii i.v r ' '"

reflects in its structure the operation . ta.^:;'' , mfl" n^ Tnd
con^quently ore cannot form an adeqt ... c-onception of In mal or
gan.zat.on w.thout considering it from various ^in,, of view T„
many respects, as indicated below, the interpretaUon of t^cTure i^
not nnply a matter of what is to be found in a given form but 1"» of
wha the latter repre^nts in comparison with others Assuming a
.n the present case, that the student is principallv occupie,! w th ,he
™utn,e of a type dissection, the question of how far he ml; ^"aHeW
m the cons,derat,on of accessory facts is one which must be detfrr^ined
by h,s own mchnafons. His first need, one which the pres.!^Mx"ok
ndeavours to mi, is to understand the sources of inforn 'il Trt
I therefore, the subject matter of which has been selected espcc X
w.th reference to the student who has had no previous expc^Tnce n

" tr^:^r:^:,^t- ri^;r - "' "";.-'^'^'"

PART I.

A GENERAL CONSIDERATION OF THE STRUCTURE
OF THE RABBIT.

DIVISIONS AND METHODS.

structure; Physioloey. the studv nf f,^^ ~»«<»ny. 'he study of organized
of development A^loX „/comJ.rrt.'rWom"*/?°^^^^^ '"" ^'""^^
to the comparative stud- of oT^fsms ^hf^'k''* ',*"" «'"""«
considered as divisions, or as prfcticaT ;n.,h m "^'S'^^y ""^^ ^'»
general science of the evolution oHorm °'*'' °' ""P^ology, the

study" VTe htirb^odv^UlfsfilrcZ'!?' iT ""^ ?'-^"'"' -
especially to the latter. Even in the eiriv™,' 'f '■"'^, ?^ '^^'^""g m»re
however, the use of the term was extenni ,^" °? biological science,
afterwards, chiefly as a resuTt of ?he n?rl!f ?■ "'San.sms generally,- and
new method of L^mtniug structure ,T1,»-""J''-'''^ '"'"''*^''P'''s a
hensivencssasatcrmLpXingtothe'studv^}"f '? P"'^*"' <^P'^-
^. It has been found ^^rivenientesSv in h""" «''""^">'-
distmguish as Gross Aruitomy the s'tudTnf .h f t ■ ^ T" ^nat-n-y. to
is displayed by dissection ?Hs revealed bt nak^n"'' °' """^'"<= "^ich
as Microscopic Anatomy, the studv offinL,?''' appearances, and
plicationof themicroSpe or again todLi„'''"-'{f' 'c™"«'' ">« ap-
cripave Anatomy, the stud^ of the oardc n/r f .^'"' f^SP":'"' or Dm-
body, and as 6;nen.l ^tomy ^th^^f'^J T-!"^ °^ ^^^ r^^"' "' '^^
composition. General ^toTy "is practSv L T"' ^-^iamental
the latter considering the body Lm tife nr.T„r ^'"".^alent to Histology,

and arrangement of its cells ar^dtl^ues ^ "'" "^ ""= ''™'^'"^=

These distinctions are of inter^sf in ,u
defining more exactly the pract^cl! method and fu"V'/T '^'"^y »»
be considered. Thus, disiection s to be rJ^,,^ J" °^ ^"-""^ture to
displaying structure of rgross and ° '^fj^^T^"'''''', ^^ » method of
orderly exposure and displac'emen'ofor^^s with fhe obi Tt't '" ""^
their features and relations to surrounS panf Th°^r - "''"^'y'nS
one of analysis, since conceptions of strn?M,f I 2'*" "' "essentially
tion of differences, the SbeTng estimated T ^^"^^ °? "■' "^°^'''-
as form, color, texture, or ms.W On .h» ^J "?""';" '"^i'^'^^. such
class of structure with whiih it deals ^ll..' " H""''' ^^'''^ of the
as a preliminary method Tn^mparisonwith"" "-''''° \^ --eeognized
the use of the microscope """P^™"" ""'h ™"ous others involving

Anatomy of the Rabbit.

THE INTERPRETATION OF STRUCTURE.

Gross structure is, in a sense, only the outward expression of the
finer microscopic structure underlying it, the latter being the true basis
of the body. This refers not so much to the individual features of
organs as to the relation existing between their appearance as gross
objects and their tissue composition. Since this relation is more fully
discussed below under the head of general anatomy, it need only be
tnentioned here as an element in the interpretation of structure as
viewed from the gross standpoint. All structure, however, may be con-
sidered from two points of view — physiological, and morpbological. The
former is more easily understood. All parts of the body are constructed on
a basis of use or function ; and although the various processes and activi-
ties of the body are more properly considered under the head of physio-
logy, a thorough conception of the anatO|my of an organ is usually to be
gained only by a consideration of its particular role in the general
economy.

The morphological aspect of structure concerns various features of
form and arrangement which, although they have been developed on a
basis of utility, cannot be explained directly on that basis, because the
factors controlling them lie outside of the body of the individual, and are
such as have operated only through a long series of gradually changing
conditions in the evolution of its type. As applied to a particular
animal, the morphological method consists in explaining its adult
structure by reference either to its embryonic development, or to the
equivalent conditions in lower existing, or perhaps fossil, forms. The
recognized principle of embryology is that known as the Law of Re-
capitulation. It is based on the general observation that the definitive
structure of an organism is attained through a series of embryonic stages,
in which it not only develops from a simple or ground type to a more
complex condition, but also reflects in passing the features of lower, and
presumably its own ancestral, forms. That of comparative anatomy
depends on the comparison of higher, specialized animals with lower, or
generalized ones, the latter being assumed, in one feature or another, to
have remained in a backward or primitive state of specialization, and
therefore to reflect in such features a low grade of structure of a kind
possessed by the ancestors of existing higher forms. These relations
forin a basis for the comparison of the embryonic development of or-
ganisms with the evolution or history of the groups which they represent,
the former being distinguished as ontogeny, the latter as phylogeny.
The interpretation of the adidt structure of an organism is a matter of
distinguishing its more general features from its more special ones, the
former being in all cases those to which the ontogenetic and phylogenetic
principles are especially applicable.

All characters of animals have an evolutionary basis, the general

Inteupketation of Structure. 5

Anatomy of the Rabbit.

ZOOLOGICAL POSITION.

It will be evident froifl the foregoing statement that every specialized
7lTl PS^*^^'" '" organization a vast assemblage of featurVs which,
if referred to their proper categories, are found to represent many graded
of morphological value. In so far as the adult structure of a parUcular
form IS conrerned, it is possible to consider them anatomicalirwithout
discrimmation ; but on the other hand, if they are to be explaLrd iHs
necessary to proceed on a basis of function, embryonic development or
evolution. The study of an animal as a type or representative o? a group

v»rio,Tr;,^^"i?""' °"'^'A" * «?"^"'' ^y "" '^»">^" common to its
various members, since the majority of features present in any animal
^re of minor importance, and as such are significant ehiefly as indicating
the developments which may take place inside it. The question of what
an animal is actually representative is a matter of comparison with other
forms, in other words, of its zoological position. This is expressed
through the medium of ctassiflcation, the latter being arranged to indicate
so far as is possible the relationships of organisms to onl another In
™ifhft°™"fv n ">' fol'^ins statement of the zoological position of the
fhrn, Ir^J found useful; and it may also be considered Vs illustrating,
through the comparison of this animal with allied forms, some of the
more general characters of animals as outlined above

The domestic rabbit is represented bv several races, of which the
«>inmon var.oudy-colored forms, long-haired Angoras. Lop-Ear
Rabbits and Belgian " Hares" are more famUiar. Thiy are all descen-

Eulooe Ih',","* "H''" ^""/y^!"'^' «"-■"-. LepurcuniculS of
Europe. The latter is thought to have belonged originally to the countries
bordermg the western portion of the Mediterranean, but its distribution
human^gfi^cy ''^ '"^ "°"''"'''' ""'' '" ""^er continents through

■^^"""/^■""T ^'^^f. "Contains a large number of closely related
species formeriy included in the single genus Lepus. They are Variously
amTvV.'.^"'" and rabbits but the latter desfgnation is »nsidered o
apply more exactly to the European rabbit and its domesticated races
the others with one cr two exceptions, being more properiv described as

T»ir % T f """■« T'''^'' 'P"" '"^'"'■'^ "'<' f^'""' American Cotton-
i3il(Syh,lagusflarulanus. Lepus sylvaticus). and the Prairie Hare r
Jack-Rabbit (Lepus campeslris): the European Common Rabbit
(OrycMagus cumculus) and Hare (Lepus euwpa-us). The two European
species differ in several well marked feat-es. which form the basis of the
accepted distinctions between hares and rabbits. The rabbit is dis-
tinguished by Its shorter ears and less elongated hind limbs; also bv its
burrowmg habits, and by the circumstance that the young are born in
a blind and naked condition. The hare is more neariv a running or
cursorial type and is distinguished by its longer ears-which, moreover,
are tipped with black-longer hind limbs and prominent eyes. Unlike
the rabbit it does not burrow, but inhabits cnlv an open " form," and the
young when born are clothed with hair and able to see.

ZooLoGicAi, Position. 7

tail, from the Picas or SesfHlr.n! j*"^i'"«'' ^^^^''^ educed
ous districts of Cemrri A\^a aTd of nL hl"''''""^'"^"',"'' mountain-

'^'^^'^ol^f^^^^Z^'^^^^'^;;^ of rodents
tlieire„amenaverTsMiHThi.flff ! ^""^ "«""'• "''^ '«'h having

^:ss-rt:d"£?~S££^?r?-^^^^^^
^nr^h-.-CSS^r^^"f^^.'::?"irsd

ward and backwarrothnawmu^,fl"Z^i' tk"" ^"'f"™", both for-

however, as in the rnrtsnt V.i,!.T . "i tne brain. In other respects,
elaboration of t .e%™tesriL esSSv 'th" "'"'""''"t'' ="«* '" ""^
characters of highly spectuzedhSoVes' "''"'"' '"^^ ^'"■">'' ""^
Like all higher or placental mammalia (PhicenbiHiii it,„ ,

nectbn, the placenta i ' ,1,,^,.".'?'^^ 3"''™«d by a vascular con-

forms'. The^' hr^Lb'Salr • P' ""^ T^''"'^ "^ "'^ lower reptman
common fea'ues of the class1^Z^'""Tr'''''' """'''"■ ^^ ""^

^S^I^eKi'^-l^S^t^-'^--"

^oi-^,tm-i»r--^-==mS^

8

Akatohv or Tm. JUimn.

M

or Sih-typc of nqiintion and the new dJaxMitioii of the teZ^^
jtmctHm; the de^rdoi»>e>t of . tri-«,pn.SST^of luSb irittT^
compleiiMnt of muide*. wid niglaitOy a pcntadntvl iifa^Un.^ cJT

rf the vertebnl odanm, eapMaOr the mobfflty rfttToeAd^W

^^Se^'-.nsssr^rr^&s^^S

Sriit^^fi:!'."" »»*?'*5n>. «>• tatter beinf an embryonic Mintbuc
«Kept m the Joweat chordate* In a morenStricted lei^M S2SS!
^J1!^J^ ot,«U«d head region with diderenUatedbrS
«P«ial aenw organs, and endonng primary skiUl. Thev ooaHss n »^

S^,^'."i5 S^'L' " P"» o* the unSiyingpIaa in the mbry^
condition; and they add to their genenU featiiet fctte ammg^te*
the organ-syytem. the further feature of tmnmSie^SS^tiiM
(metameram) of a coniidendiie portion ol the body »«P»«'«?««

GENERAL ANATOMY.

«,«^2° w "■ T^ "^ ' continuou, .tractuie, the body fa di«er-
entiatei" into a large number of parts, or «0mt. the totter bda>
more or K_, individuid in form, oompo-tioTTfuncti™^ o^
^th'IZ^J'" *^ TJ^ ^ ^»«-Sr«ch of which fa CO.SS
ly^n^bST" " f»«l.«en..l function, to which aeverl oigan.

rf »;i»»°'l£^ ""y tb« body may be conridered aa an ««mbl«ge
SLST^i ^..'*"" ■" '»y*" " «iJ«g«tion8 of omitarly diffiw^.
t»ted cdl., They are of Kveial (^KreSt kinds, ^iu« i^uiSSr

S!Sfal.^ti^/r~'"°°^««^ Being stAcC" in^!
oTi"^r'.^ ^^ be«n«dered dther a. org«. component.

As a body-unit a caD oonsfau of a small mass of livinff iratoiriMn
j^,«S:»*|«i«?«™' W»dy. the n»d«», and SISJ^LiSd^ S3SriS

lSrf^h.^S?*"'r*"yT?*~»- Thenucteusfa.hiSly^pSirf
body, havulg an important function in the nprodactionS Ae^uS

^B

■^'"^■"

Emni^i SniicTuiM. a

a«» •« ffli^by . S"ES^ otg.B«M, in which .a func-

iS«"? -' '^.«»«. to o^y o,
•Mother to >tiniuli arising outnde oi
tte body. Moreover, the proloioui

^^^^'^ "' "' •«'»«•«* into
th^I^ »Wch proce. originates in
the nndeo^ and u awdated at tome
^Si^S^y'^ I«»t. with union or
••W«l0B of puent cella.

«Mar oigamni ate pradocti oJ a

tete fa a modnct of fnSn <rf tin.
P«i«My elementi, the mnMtonaa

•lone, «e -upende^^fe";^ "•"« «»« «« "Wte eIem«S
1- Bpitrbual Tiasuns.

i

lip

ii
1^

*" Anatomv or iH« Rabbit.

tary tract the epithelial lavcr is asso-
ciated with a thin laverof smooth
muscle to form a mucoua tunic
ef (F'H- IS, t.ms.).

The cokting of hairs on the surface

,f of the body, the presence of which is

a notable mammalian feature is a

protective investment arising from

the epidermis. A hair is produced bv

.,^_ ^omRK '* '• '"^'''•''^''on of the central por-

"^ HBImLdSIHK «. 'I™ of an ingrowth of the epidermis

• "-P termed the hair follicle (Fig. 2, f.)

.5 The latter contains at its base a

small elevation of the underlyini?

vascular connective tissue, the hair

papilla, through which the structure

_,,,_ f « nourished. On the general surface

JiM °' '"* body 'he hair follicles are

V/iAiU arranged m groups (Fig. 4), and on

the lips certain large follicles are set
apart for the production of the
greatly enlarged sensory hairs or
vibrinae. Connected with the hair
follicles are thin strands of smooth

!r&ai'?.''Snh/,'rf traCrS'' f ^''i 7*''y"^ placed in the broad
ip'"*;riiLr°"""V"u«"" «' 'i^' ~ri"Sl: »■?«'« formed by the inclined follicles
lS^v.Tt.'»&..^i^£i<'''""'- '■■ '»'' «''"' the «>""■", and their contrac-
tion throws the hair into a more
ir„j,i,.,i., . . nearly erect position.

becfri et^tK^^'/fiT^""''"' ?' "■' «*»"^ '^y^' ">= «1I^ of which
7r!h^J^> modified as secreting structures. The lumen or cavitv

?L„Zr ■,,'". '"°'' J^*""" «''^"y ■^""■plicated through™* dividon 0^
Ihi/h .h ™''^'»"«' '^ connected with the general surface by a due
rinL f "^7"!. "'■'t"y ^^^y "^ «creticn In some cases'^^he ran
nection of a gland with the epithelial surface is embryonic and in™he

Epithkuai Stuuctuiim. n

nature. '"* intestinal wall are structures of this

nanilt'ThftibLtgra^.f'llJ'thlcff •""!"■" "' "« <" '™ 'yP«».
calibre, and the ri^ or .Ty,^tar riiln •" 1."*^^°;'^ """°™

are sacculated (FiiT 3 A) Bo^h .? ' " *''•"''' ""^ «"'^'ing portions
and greatly branched ^^nditirns "^' """^ '" '""P'*' '""" ^"""^'^

.sso^c?is^rwitWe%°Lrni^ii%L^r;;:'^ ""*"• '"r--" -

are glands of the tubullr tvT Jid"^^'^"" " sweat-glands, which

^ 'ln"'','h ""l^^ "^, "'^he-cino':,

type, in the rabbit, glands are absent <

from the general surface but are foundr"n *

special situations, as, for example, in coi

nection w,th the hair follicles of he iZ

the mternal surface of the ear, and the

external genital organs. The '^J^

portions. The mamjnarjr glands of the

ria"ntofln^'^"^ ""'^•«*'' ™'--"
glands ol an acinous type.

Apart from the mucus-secreting cells of
L^mfmarv '""I'"'""' ?"' s'-dsoflhe
h^ M.^ 7k™"*'."'™P"« 'h' important
but less elaborated glands of the wal^ such

stomach, and the greatly elaborated, out
standmg glands which lie beyond th4 »^ I

c^.=^^"!'u""^'"'' ""h "-e interior of the
canal only through their ducts. The latter

SS^ "Th""^ ^"r?'- i"^ "^"- '"'d "he

fhf ?T' J.^' "'"' K'^nds include chiefly

the snbm«iU,,y, paroUd, sublingual" and

mfr,^,t., gtands-conspicuoullZ'tures

n the direction of the surrounding nor

tions of the head and neck. Theh^^dE^ts

communicate with the cavity of the mouth

body and Th^ nt^us Usrues™arilTr "'^^Pi'.helia of the surface of the

derivatives of a rarmTemh/S i™"" "^e circumstance that they are

we may distin^iTa^inso^^Sl .*•'"' • '',' ^'°^"'"- I» «he adult

^^.Je^^:«P^-^=^^-^ci!^

Of the nasal cavitr»SThe cIirofTh^.;e^°X°;?etrtr

Fio. 3 A. CiaKram of a nmlti-
celluUr gland: al, alveolar type; d
ditct; ep., aencral epithelium- t
tubular type. B, The pancreatic duct
and assoculed portion of the duo-
denum m the rabbit.

Anatomv „r TiiK Rab.it.

IR

12

mesoderni or intermediate laver of .h^Vll. "'J?" '" 'P»«» •>' the

ia>erj of the smooth, moist ^oui iMmk;.- "««"helia are the chief
pleural, and pericardial caviti^ "WmbimiM. which line the peritonei"

- Connective Tissues.
A, 0rtU^*,S!!rA«*J:",^,J::7H,V^y^';.P^ *'™'"" "f 'he body.

susDenrifH Ti. "^ .. '"e bodv are
prewnce „f T^^y ^'^distinguished bv the

-tV^ .be ce„ hasis with ^^£ ^^^f ^^ ^^^

bu are joined in a parallel fa^h^S t;u°' """^ independently,
m this way fibre bundles of !ar«r or sm»lw- '"'?,»'«'"'". forming
of greater diameter. They branch »nrf ""' ^""e yellow fibres are

ciated to form bundles. ^heya?^5?,rrf'°"'°'!'. """ "^ °°t «»»"
highly elastic. The tissue produ^d?,^'™" "•''"" «'''" ™ being
connectiT. Umu.. It occurs ta^ve^raifoim^'L.'^''"''™ " «""»»
m several forms according to the relative

fi.cm.

Ordinary Connective Tissues.

CoNNgCTIVK TlMU« STIUCTUBg,.

•"im an emhafmrd aurciiran ,. ^
connect ve liwue i^ii » f i».-^i I
.1.11. (ibr..: y.f.".,i.:i,J','j?'Sj^'

13

«.««mr..ion of .he .„„ kind, of fibre, or .h. .d„i„ur. „, o.hcr
The co™™„„, ,i„a or aro^i^„, , , ^, .,^, ^^^^^^

the ,Un.X .^'y/^uT'' ^,r,S
occur, al» in variou. po,itio„, wl,e ™I
ha, a similar function of>i„ing .(rucure^

iiMue 1, a white material, the peculiar

due to he fact that the two kind, of
fibrou, element, are arranged in a 1™«

r . r' "!■'""'' .<"'« *' When ,tretc"ed
It 1, found to yield up to a certain noint

'::'i™ i/rfmov"",.""''''"" "»■- «"- "-e
Fibrou, connective liMue raav be
Krealy modified through the concentration
of either one of the fibrou, elements Con

Thi, CM.dition i, illustrated ir?heVhll-tln """t'"''^' " ■"°'' -^"'"«'>'-
the true skin or corinm (Fig 4 bit ?.\^ *""''■ '"'"^ '»>" '°™i"«
mg white tnidoiu (Fig 6) hv wM^i 7 conspicuou, in the gli,ten-

attached to bone surflces h,^fhv^ """^'" "^
bone, with one ano her and'^^'*r'f?*""!l'''"'f
■poneurom whir.h ... V '" ""^ 'hm, broad

iC^^re, k„„wn an^,"' ""''.V'" ""^-^hment,

necti::°[i,?*''r i^s '^h: "?, ""^ -' ""■

fn Particullr^a^ utbn :,"iJ'h"'f'" situations and

n«kin.heVab^!r{L"J'her.;isrcf'plrr^I?U'''^

other mammals ""^'""""S glands of certain

of the^Tdtes^p^ctef^'T I' ■^"'5'" P°"'°"^ o,^,«„/- ,■-"'-
of the relink crarvtodv Inrf "" f*"."" *""'"• ""^ E^ V^P ™°''-°™-<°'
partly to the prSn^^r^^'r-^^^^e, is due p^ra^^

14

Anatomy or thi Ra,,„.

■ 3''

"". I-. tocun,: m,. m.i,"

I

nlltLgt

Th t , , "• Skklbtal Tissues

the cell, are imbeMlr T e ^Sj
are distributed singly ur iS"

or in connection with the 1, °"'' *' " ""^ 'VniphjS; of th, n^i '
mar^ns of the joint"" "■' '"'"""^lar meni^i and'"a,1h '^rsuu';
In the adult skeleton car.il-, ■ •H'uwr

Ss th """^•"ar surface, of

S'car'tUar.Tlh '";"""' -
portion of th^"„aU '^5"'''' ^"-^ »

also found uniting^'heCTL^' ''
of.he,kull, InfheenI?ryo,tT

course of develonmooT '"^

the situations tdS 'he'?' r

lager's replaced by bone •--■•mim: w. toe™™"" ■'• '"'^

"^-^T

-he.

•ll.

M,
-toe.

SKItlCTAl STtlXTl'ul.

15

parallel fashicn bet««n tht HavTrl^ ' f ouposed in a somewhat
clrcuin/er.ntl«l Uuntlh* LrJ Hif^ ?" ».v»ten«; while a third Mrie. ih

t r.*K SrS "«.'— "■'"»-!:

except on its articular »Iirf»r!.. k ? " '""^'owd
nect/ve tissue the bS^™ h " '»>" °' """
of growth thfs mem'^^^-, ""r* ""e period

of .'»ne-formi„r"r, the «?«bb.i"f.' "•""""'
activity of which the deposition nf^h /„"'";''«'' "•«^
i» acctjraplished. "''•"""on of the bone lamellae

It is only in a few cases ihot ii,. k
skeleton raav be lookert n~, '"e bones of the

as a rule thev con^st of =T- ?' "? ''' structures-
or comp.ct bone su'i^' L? J" """ ""^" "' hard
spongy Tr c«,c.Sou, ton" '"^.^ "•"'"' ™« of
oneo/'g.eat mechanic^ strength ^"^' ''T"'. "
•ghtness, and at the same tim! ' ""."^ 'ed with
'n the interior of the tone Tr'^^i^'T" " '"*''''
marrow spaces. Thus I'^a Inn .^"'"'"ssels and
central ponion or ii;,<^"„^J°"«>;''.<F« ») the
pact tone surrou^nHn ex^I^.''''""'"°'«""-
each of a thii shell of «m'^°'*'" ""«"
that of the shaft and sum.ni!? """' ^minuing
cellous tissue. In the sh^t fit"* *• ""» "' can*
of the slieleton no contlous '' " '"*^'" •""es
formed. loniinuous marrow cavity is

"placing bones. butTthil?' *"''■ "^U*!!* or
by tht* tend"n or\iS^„S'°'JP '^ repre«„ted

r^^""^.^: lir ^i^^^T^^shT^th-

of the rabbit: c.t., an^
"I.IOU. tiuue; ,,. V.ui
Km';- " ■ 'W*V>U1
• rtaft ™"'o»'-c«vilj.;

16

Anatomy of thk Rabbit.

IWi:

.he'^lr„.'""T;'e;"aJe'\l':;\\neor '>"^-'-stic element, of
formed on a cartilage basis Tl,Tl,»..P-'!;? *""" •>«»"« "-ey are
the primary car.i.ag^%Koi':f'? \^;I^;:''-'^:f?,«'»ve, repre^^^
ment, except in certain regions wher!^h7 .1 ^ '^°'"'" "' develop-

it' '?' ^""!f«^ ■"'''"'''l « "eptaceTbv b^^^^^ throughout

and also mvade it. Fi<".eu py oone, which tends to surround

ex^^ S;Vcu«ar!;^ero?7h^artT.et ,"""T ''='- -"« '°
condition the cartilage rudiments are acs^ciaSdlllf '" '"" ^^^ryonic
prirai ive skeleton. In many cais th^r!^I . '7"? * ""P'ete but

bone is not direct, certa™read?Sm^n.?^K "'"^"' "' ""^^ elements by
poses of growth and on account oT the ^""h "'"^^^y' ^oth for pur^
requirements of the adult skdeton ""'^ "P*""' f"netional

conn^cltTs'su^l^eZ'eXtirrt'i'Te™''"-?'^ "^ —0 "X a
described as the perichondrii™ Vi. . Pt™'"^-"" "' » bone, but
concerned with the^formrnTf Z'^t Z^^^l^, ^^^^J^

^[^^7rhSLsrir,.°Vh^-f-r

tion of endochondral bone is preceded
by certain changes which take pLce in
the interior of the cartilage. In th"
latter, in certain areas, known as the
centra of ossiflcation, the matrix
becomes t«irtly dissolved, the cells en
^rged and ultimately broken down
These changes are associated with a
«w«'"?" °l calcareous material, or
calciflcation, by which the portion of the
cartilage undergoing transformation is
temporarily strengthened. Into this

association with the rLS/Dortion. nfT ™.°' •'""c ."laterial in

four-dav-old ribbit ^ ' °' ^ ™"'™' ^'^"°" °< '"c elbow- joint of a
tion "akc^ pfa'ce i"7he''shafnnd°"th^'''' "7 "' T^ "»•"» "' "-"ca-

later the periosteum a ornc'« iV?* r"^^^ I" ""^ Pe"chondrium, or
.oes on du^ng tLraS^fg^^^^S^l-dthSt^ot^^^^^^^^^^^

third (tr.t.) trochantera.

Skelktai Stkuctukes.

17

agei" Srh1"a[etmeSir';''''"f' ""'^"""^ '"e masses of car.U-
bone (cf. Fi« I2 :3) Thl" '1 "P^' T'^^"^ "^ f"™ '^e body of the
epiphkl c/„tre's'en^s Jfag £ f„T Lt'STh" '"^ forma.io,/of ,he
the carti age extremities of iLtj. ■J'^ '™'" «n'«s, and thus

tion of thf shaftTs unde, way 7^ TZ ""'l"' 'T" =>"" '"e forma-
formation is endochondral Tho ho„ ^P"Ph>sial centres the bone

guished as epiphy„8 Durinl^h ^^"7 "^"'^ ""^ f°™ "-^ distin-
with the bodvof t" bone b nli, P?™.'' of growth they are connected
surrounding ^Aricho^rfum P'^';^„%°f^P'Phv^'al cartilage, into which the
region bone formation takes ,^1° ' as an ossification ridge. In this
structure is great" irreiidin'^lfngth"''''' "^ '""" "■"' ""^ '^"ole

bones 'Ltirhyse'stZ:efirmrv'"''"?"H°' ^t'^'' "'""' '" "iilerent
although th^lin^es or,Tc'ioror."JnhSr,"-'''''''^*'''''>°f ""= ''<"--.
Thus in the distal extreSes of theSs ^" "^^ '"" ^' ^■■^"'''^•
?he fihn?^ '" '!'' P™''™al extremities of so

vertebrae 'th' '" "l*^ ^^'^-^ "' "-e lumbar
,^ Iw ■• ^, "^P'Pbys'al lines appear even
9^ f^^r^'j-- .'" 'he foregoi^ figure
ieen th» ?h '^'"^•'^ f™"' ■' '^i" be
w. • • ^-^ position of the epiphysial

tissue" F^'T"^ ''J' '"'"•'^ °f ^-npac
tissue. Finally, in thoroughly macerated
bones of young animals, the epiphyS^are
the"lIiLr"'' '° "' '"^"'"'•^ «^rabl?L"'

with" ".."""P^ri"" of the adult skeleton
with the more primitive embryonic

mfnTo^rf ''"'"^""^ '" "-earrang -
ment of the elements are eyident. Thus
many bones, notwithstanding their wis

^ne'co^n^diS^" T:,^1^^^'^ I^Z'^ '"e cartilage or in the
separate bone elements are S.^tn " ^^^ .P""'"" "' ""e skull,

continuous. These either rematnHw" A."""'."' '^"'*1»«"= primarily
occipital region, (Fig 11) ^«me 1 .Hh",' "";r«''™' '"e, or, as in the
composite bones In stil othe?^Sl! • T"'" '" '°™ compound or
single elements of the adnU conSn 'are th'^'^'r' "■" "PP^'-t'-V
originally distinct bones bualTonri ■• P^^ucts not only of

The bones of the skeleton a^ nni?T*''''L*f '•^" ™'"'»«^ "asses,
by connectiye tissue in the fo?™ nf r °' "^«"J»t«l with one another
cases by both together L by Vh'^*"^^"• '''' '"''^''«'^' °' '" «>»«
distinguished as syndw^oris is he mo^'"'"^"-, ligamentous union,
jr ucsmosis, IS the most general type of articulation.

■n of the ■

.\.^i'S'- "■ T^^'^^iP'ta' portion.
f»^ul in a three-day-old rabbit ■ do

cartilw. of chondrocranit^mr c^'

maBnum; ex.o., exoccptal' so
fiupraoceipiUl. ■'

Anatomy of the Rabbit.

1'

18

bar.'^Von'Tf°;hr?k'ur'rnioTb^ '"fib"""';', ^""''"°=''' - '" '"«
charac.eHs.c„reHeani«„l;n^^^^^^^

surfeces is'a space necav™'of the S '"'"\"" ■ ''^'"^™ ""■^' '™
the synovU, vSlich ^rveTfnV Inhr,^ / ' ^™'»'"">8 » viscid material,
connective issue c.~ur. The strenlrnf Ju^'^'l '' ^"^'"^'^ ''^ ^
the enclosing capsule but it is usualh ^riln ■ ' J"'"' depends largely on

ralihii '~n "^'J"", °f 'h<;rlbow- joint of a four-day-old

oi.. o]»™„o,„ r,. f.df,"Tc°Ul;'„^irc;v!;y;''uTuK:

lour-d.y-old rabbit: c. capmie; t.. di.tJ

(insertion of quadriceps feraoris* n v
popliteal V .-isels and nerves; t pfoxima
ewplivBi, J tibia; +„lii!amelit of tlie
ifJ™ I" ^'""''- '^ ' posterior cruciate
ligament ax . anterior cruciate ligament.

(Fig. 13), interartictilar cartilages (men-
isci) are enclosed between the bone
surfaces, and the latter are connected
directly by short ligamentous cords. The

upr: cfrtr';?n't^ '"'"' '"™'' '"^ ■"°"^-°f ">^ "--■ »".« omy

Several differences are observable in joints according to the form of

the apposed surface and the kind of motion provided for ThusTn the

and h^';' a'ton ^"" w/tr^'*^"' ^^^"P''.^'" ">' ""'^ "^ the shoulde
«t.,.K™ . wi , """"^'^ '" various directions about its base of

^esfrict^dtoai^r'" "''""."'■■ V° '^' '™''^' "-'^ motion fs almost
restricted to an anteroposterior direction. In the ginglymus or hinee-
jomt, as exemplified by the distal articulations of f^liS^mot^n^ts

MuscixAK Tissues and Muscles. {9

over the otherf uL ermnHfied in th'"'''''''^ '''' °"' ^"^^^ ^'iPPi"8
vertebral arches! <^«">P'-fied in the accessory articulations of the

3. Muscular Tissues.

of ^^^\o^fo!VL'^:^T:r:r' ',"' '-'''"''- "■--'-

feature consists in the eloneation^f th n"^' "/«*"" ^heir chief
fibres may be considered toX'^",°Lcn„^rl',° '°™ *?"■"• ^hese
plasm, but with the contract!™ ifmit,,! „!""'• P™!*'"" "' P™'"-
cases the fibres are arrangeTinToarlnri"^ Except in a few

contraction of the muscle Irmusdek«r1,?h°"' '" ""?' "" ""<^ "'
Its fibres. The result of ronZTtion in both if ,h ' "l "'^' "' '"'''^ "'
longitudinal axis and the increai'^onhr.ransverse axi:'""'"'"^ "' "■'

u=s?^Lt.dX'^;•:Ll^e1h\t^^sI^/^^^ -<»"' -^

Smooth fibres (Fig 14 B) are eCrr*"'^,'";^''*' "' "-e skeletonT
of which is bnltudinairitSdh*'; '"''''"""'■''■'= ^"'''*'''"«
markings. The single nucleus of ,h-' n P°"?^^*^ "o transverse
The muscles which they form are dis "'""P"" " '™'''" P»^'"°"-

tinguished as involuntary because
their operation is not under the con-

wL I^..*'"' "'"^ -connections
being with the sympathetic nervous
system. The striated fibres (Fig 14 A)
are very much larger, cvlindrica
structures, the substance if which
possesses characteristic transverse
striations. Each fibre is enclosed bv
a loosely attached membrane the
sarcolemraa. on the inner surface of
which many nuclei occur* The

fhTPl,"^?' ^^'"^ °"'^'^' indicates
that the fibre is not a single cell but
a syncytium, i.e.. an association of
cells unseparated by cell boundaries - • ■-

S5,r":SiX^£V-. ».. •;■';',''-■""'"'"''»• -«•

r.lj!,'; "b*- lS° 1 <*''"«» "•«"!' of th.

Il.'l

20

Anatomy of thk Rabdit.

^Sis^rrri'tetr err "^'r' ^k""= ^'-'«' °'"->^. ^

»u«lejt is under the rontro?nf.T '""'""K^. but, like involunt^y

tion of the flbm. and wh ch i^ nf T"^';''' '^'^''^'l '" ^^ 'he direc-
striation is d^Vrfhe 'drc„mstL'cr.U'''VL'''«if^""«^='"°"- The
m parallel groups or muscle buTdlereach of wh.i'" "^ ^™"«"*
separated from the adjacent bundle,' hv . . ? '^ ?urrounded and
the perimynnm. oundles b> a connective tissue enclosure

portt^rrmerihrb^yTtirl^t '"T''^' "' ^ middle fleshy
provide for attachmem Thl=»^' *""*'" 'ap<=ring e- which
band of fibrous «"^ectivetrssue^?t"'^' '? f ''[."^'^ ''y •' »'™"g
comraction it is usually 4n thai one "nd fh, "l^''" <"'« «'• I"
ongu. of the muscle, rem^ains stati^ryr^hl tt^otferSl ^s 't£:
insertion, assumes a position nearer
the ongin, carrying with it eithei the
structure which is to be moved, or
another portion determined by the
point of leverage or the position of
the joint. The action of the muscle
IS estimated in a direct line between
X^l" f".u '"^'rtion. although the
effect of the contraction, on account
of the position of the joint, may be
otherwise. From these more typical
conditions, however, many modifica-
tions occur.

Some muscles, such as those of the
abdominal wall, are disposed in the
form of flattened sheets, the ends ot
which are attached by broad, thin
sheets of connective tissue, the apon-

fibresare attached obliquely to thrSl^of Jh.T''^""*" ■'""'^'" ">«
muscles tj both sides, like the vane nf'f".!."" '?"''?"• °'^ "> Wpennate
triceps and quadriceps muscles ofThe l^h ^^ • '° ^'"^ «>-called biceps,
three or four porta" F?rthermor^^thi''""«'" '? '''^'<'<^<i in'o '«"
insertion depends on usual but Z;-"' w™^,""" °' °"Sin and
effec; of muscle contraction al^ de»„Hr»'' r'"""?'- ^^-^ ^'«'<^t
action of other muscles. A mu^elfke'th/^L'. "T''""''"?''""™^
possess an insertion after the fas^^on^f',^ ^ diaphragm does not
cases, as in the intrinsic mu^ie of the -ojf,"'' 7"'"'"^ *"'' '" »««=

and by its sm.ith ^o^=^Z:'^tVS^^^^^^^^

lE^'^'J:^- ^'^ * section of the ny-. ric enH
raobit. m.n,.. imiscul.™ iiiuc„„e ,' ™

Nervous Tissues. -i

mS' LT„"di:izr'tL^thr™zr " ""i "-= "^--d » '»„,

particular parts It form^ .h« ™luntery muscles in its relations to

of t^ "uci^stunic l/r:iitnTa"t^i" r/n'r, ^°"~"^ ""'^•)
^c lying in the outer porbrof Us wan' fp^l^^,^^ ''*•»'•»'« '°'»«<«1"
tunic the fibres are arranred n hnthli, * ?; .'*'■ '" "'^ muscular
Involuntary muscle al" forms a smaH contff "'' "T'^dinal directions'
as certain glands, in which c^ntStVn''"^"^'',^"': "S*"^' '""^h
a larjte constituent of the ^^■M nftu^ ■ ? '^'"'' function. It forms

bladder and the uteru ■" In asso<!iaUo"wTh""l'";'"'"' P»"'™'arly the
■s an important constituent of th"wairs rf'.'i "^m''^^ "'"""'^"™ "«"' it

Although there is an utiHprlliL .^ bloodvessels,

of the blo^dves's^ls th"eZ'"-h:f uZ77lL"\'''"'"'"' '" '"^ "=""
present conspicuous differences toth in^unl vessels arteries and veins,
appearance in the dead anrmal The d^S^t» "' ''""'r'"'"'' ^"^ in thei^
f f5"J"«^ '■> the relatk^^mounts '''""™'^" "^ '^■'Kely the result
tU ,rf^™"""^""'"«^<' '^°"'"t"cnts.
The arteries are thick-walled, elastic

fJ^rVr^'K''' '""^" ""^ fo™ "' blood
exr„ri.H'"'"i' 1'^' become greatlv
tr^ :u ""'' "'^" Kraduallv con-

the smaller capillarv vessels. The
walleV'l '"''?•''";'''''"'' '''^•hinnVr
walled, less elastic vessels, through
which the Hood is forced largely
hrough the pressure from behfnd'^
in the dead animal the arteries

:Zt: "t^' "■'' " collapsed, a" d
cmpt>. The veins on the other hand

rfel^'d'i 'r^' ='"" .''"''■ ™ -«°"nt" f
ineir distension with blood.

4. Nervous Tissues.

o!t^ZXi^n^J:iy^„^r Th""= ""'^'" ""™- »-'™ and
-nerve cells and neAreflbref In thT^'^n";"?' '''° '''"ds of elements

^'^rr^;'';eiira''r:'"'h'' '" f "^^ of"„fu'.r:rSe,"tr„r4r '"^^

the s;rn:.tnd 's^tThe'^rgl" hi '"^t""'-' ""™us ^v^^" ,„„ „,
typically each consists of ' erflfc^" ^^ d<ffer greatly in form, br.c
processe's-a fibre rocess theneuS^^'f' ."^ ''?""S '-^^ '''"ds o
protoplasmic p.-ocess^rSVdS« Th?^*.' ^^'' ■ ^"" °' •'^^"'^hed
the presence in its in er or of ™;,1 J t ^^""^i!: " d'stinguished bv
tigroid bodies. The latter ex enrt^nthr':, ''^ <=hromatophile or
neuraxis. The dendrites mavTegreXelabor!.';''d"'"'.''"' "°' ■"'" 'he
to a considerable number kefeuraxisisp.T-rl'fiK'' '"'■"^ '"' P^*^*"'

Anatomy or ras Rabbit.

kinds of fibres arrdfstfnSeT^.'S'X.'^' «T""" "^bS- Tw'o
fibres. The former are charlrt-?^ r^u'"'"'' ""^ non-mwlultate*
"-ese (Fig. ,7) the axS »rdTs sur^oun"/ d''hv'*"P''"''' »'"e^^
membrane „r"S^^^?' ^?,U ~r'™"yt "■''^''
myelin Oumth. The tatter is con.,? """"^ °'
at certain points, the n^i M S^Zr°"% ""f
axial cord appears frerScentT ' "'""■' ""^
investtnem o/'?^e whofe^br: •^L'.^^u^".^""'''

nective t ssue which ,= „ ■ . ? *"y "^o"'

n~fib^:^ ■"? Of whrz's'tio:"'' "•'

or.ns of eondne.io„f^^£^i«r- ^^S^^'"?C^

parts of the body to tC centralnerourL',;'''" '""? ""^ '*"P''"aI

direction. Sensory nerves are ""™' "f "n the opposite

afferent, while motor .;»rves

are efferent. Nerve., however """

usually contain both afferent

and efferent fibres and are

hence described as mixed In

IZ d'^tribution of afferent

and efferent fibres there is a

tnarked difference between

the external or somatic por-
tions of the bodv and the
internal or visceral portions.
Consequently, both somatic
and VKceral kinds of afferent
and efferent fibres are c^n
venienlly distinguished.

On account of certain diff-
erences in coloration, the
cellular and white fibrous

constituents of the central "»'•■>». wWle iub.unic "■—" P<»«nor nerve

nervous system produce characteristic patterns where either one is

Pio. 17. Portio
ptaullaud

w??i ihf '=ciatic of Ill-
rabbit; a.c. *^(nl cord,
•ns.. myelin shcaih.
•Uined black with osmic
•cid; n., ncurikinnia ;
n-r., node o( Ranvkr.

c^cS.aef„a'rf„°'.*.'„.S:r'lnfr S' "" "«'
l™t«Mor medl,;, ™fa,; ","'° ,T^i»" ".'•""i ■ "H-p..
I«er.l, and po-.terior funfcnl" of the J^-d '''; ""«™',
t^KO.. anterior and portrtinr Brri- V,^ ' "^ ? * ""^
Brey matter); r a and r n a„.?^^ eolnmn. r Horns n.'
root.; ,,,., while iubLunJc """"■* ■"'"'°'"

Tenumoiocy. 23

duces when concemra^d a" oS^u; ^h "''"" fi''■•™^™'«■"'>l pro-

in the cerebral hemisohere, anrt in .i, ''ut the characteristic pattern
grey substance f„™7aX^'[aT iLtr^^'^^^^^^^

TERMINOLOGY.

In special or descriptive anatomv it is necessarv to . i

extensive system of terminology in order tha^ th„ 2,- P'"''' ""

f:?t^iru^i--?|>.-^H=-^^

classified into fouV^roups as follows (na.n.„i. P"T°* """>' ^

ra.^:ier„-rvt4,i-^^^^^^^^^^

(topographic); and (^) te'rj of Xntation """^ "^'^"'"^ ""=*'

the^t ^SS ■..zfs.ir^ss^i^^^rzr^i:'^^^^^ -

to the exclusion of o.hersof%^X%'^ScU^g';TInSu,r'tr„^^

?^^:ti:r--^s,';!£SS£TH?'-^^'^^^

sagittal), the median verdcal plane ' ^ ^''" '""'"'''"S ^^^ '"id-

half'' SF z" bo"drr;T.:„f d-efii'ed'ti-ii'g^"^ t ^;^ -y^^'-y- -"

counterpart of the other. Structu^r^ituated'™ part'in .h' '"7""
plane are unpaired, and are described as m.Hl.„ u;^. ""^ median

wholly outside of the pTanfrre paired rirt?'a^dw"'""i" '''"'''^''

-Im ...rer ,h. .id,, .r ,t, M,, I»r,™™'^l;Si,» "pS

24

Anatomy of ih* Rabbit.

iS'^s'„°o?jS;?X'«'"'«" --"^ -" 'a«enU, but thi, rc.ric.ion

as is seen, for exam^e, in i™cli of ,he aMl""" '.° * '"•'"^' P°''''°"'
memary canal; or, agiin, bv the reduc inn „^ h° ""' P""'"" "' ""^ »«'
belonging to one side o the body as fL '^^'i*"':''"" "' >"™<^"'««
mammalian aortic arch. '^' ' " "a^Ple. m the case of the

Referring to centre and circumference eith.r ™ .1. k j
or m particular parts, the terms dwo a„H .f™^ . * ^"^^^^ ' "''"'''•
.«!, or intmuil and'e.TtMn.rmaT be iX^^;'•°'"i''"'l>«''I'''-
however, that the terms internal and ex.^S ' ""?'' ^ observed,

nlmlso'f -art' ^^ "'-^'' -'^ Stlv;Ta™rgra7d<'iir tt

anu's^trtZ^dSJilr^tdiS-^arbtu's^d-to^'f ^-^ '""' T''- '""^-^'-
a structure lying between two "hers thMattr'h"^"'"'.'.''" P°""°" "'
nated, for example, as anterior and n^'J.L ^'"^ otherwise desig-

The limbs being more orTess ind^^^T^'."?"^ '" ""^ '"'^'"=" P'ane.
apply to them certlin terms otherwfi'^ppiv'ble' to r^' "■" <"°^' ">
the body. The chief terms not pro^rlyTppue" elt w' """ P""'?" °'
nleanmg nearer the centre or baC- of ot.„ t "''^ proxinul,

extremity. I" the middle „fo? the fore Hmhth"'' ''''''*■ '"^■"'^ ">«
of the bones (radius and ulnarare ndi^afed^^ '^V?'P^5''7 P"^'"""'
terms tibial and fibular are also atmli^w? ui, ^ *"'' '^" The
the corresponding segment orth^'^rnd,imb'''°-?f' T"' '^ •■'''^"' '"
surfaces of the fore foot are described re^~^n. > I ^"'- "■"'™'
those of Ibe hind foot as dor»Tfnd pLlter '^^'^ ^' """' »■"• »<"".

consi"de''r:t™Sft';^ -v"7fitt''a™rf^ '".^n^f ''^' — ■
terms, such as those iust defin-H L f '"""the fact that descriptive
?f parts, the latterbeing ^f The Ime Zr^'""'"''^'? '" "-' °^"'^'
instance to the human bo^dv, in whS, thi «^L"'"'/Pp"?'" '" "^e first
what different. In comparison wth ,r"'?8'"«d delations are some-
the human body occm,"s aTerii™! „ °. ' quadrupedal vertebrate
sidered as having bTn rota eduDw°rH?h' ^f'°"' ""^ '^ '" ^ «>"-
posterior limbs. The latter accorS "'™»8'' "mety degrees on the
original position, andlhe human "f^ TnT^J \°' '^ '"°^' P"' 'heir
position when allowed to hangTreelv ™the sld^ f\i'\ "J^'^"-"'^ '^is
cases, the face retains its forward direction Thufh*"?^' ^' '" ""
and posterior as used in human aiatn^v J J^^ .'"""^ anterior
provided theyrefer to parts™ he bodvT^hT^J ''°™' =""> ^^'ral.
which have been affected bv rotation Th»t '^""^'^ '™"'^ "=sion,
as applied ,0 man are simiLriy Interior andT', "^P*"" ='"" '°'*'^»'

"sed for a quadrupedal -n-LTr^L^^o-Kat'^^^^^^^^^^^^^^

GenssAi Plan oh Orcanization.

25

•"d posterior applv wi.h greater force to TZ'^^" l*" '""» «"'"»'
*<>-le the terms ^uperior'^and InferSr l?e ^X!;;"';''"'' """" '" "«".
|r."""»«the rule here followed™ to usT^h , '"'""' '" "'* '«""•
tenor for descriptive nurDo«.« »^i, . f ""* ^""'^ anterior and i»»

and backward. It mav be pointed out Z ' ''?«'"»"'*-<l. forward,
the practice with some (o en,plov"n nlaT^ff' "• """ " ^as become
terms as cepluiUc and c.ud2f herebv eH-?" ^nlenorand posterior, such
or similarly to use the Snaton-id" ""'"'' °"^ °' ""^ difficulties;
n.fy.nR position, for the pur^se of inrii... ""r*^"™ "''"' »°«'s sig-
cephala<riaterad,fordors^rwS??eVc; * "'"'°" ^'■^- ""■'^d,

.ructtr;S?ir„ttinTnVer:relrd'r' '- "■<= --

be represented bv independent iafts 1?.^ ."PP'"'''' '°' -^"ample may
n form or function mav be L'^Je .enf Fln^n'"?.""''^'' "■'e similar
Oal to endeavor to apnlv all ,prm. Fmally, although it is essen-

remembered that a teffino ogv p" marih':Tr''''^'-.f'', P"^^'^'^' " «^" b-
be exactly applied to another l^tC''^Lrdr5::^^;.-|ifi"c:t'ioT ^""""^

THE GENERAL FEATURES AND GROUND PLAN
OF THE ORGAN SYSTEMS

or o~ ".r ^efa^i^n-^ToratrhrZ^^^ '"^ -^■•^' '-'-
ound useful in many cases to consider them i"*^?"'?™''"' " "''" ^
tion from a general or gtound form ATrie? ?^ ^^'" °' """' ''"iva-
be accomplished in this wav and o7'the me hnn""?' "' """" "-^X
been given above (p. 4) j„ "rscussint ?hi '"5° ™'' ''^^ ^''^ady

structure and the zoological posi^lb^o .h . ^^""*' interpretation of
pages only the actual fLls S^o gam/a tion w^' ^ """"" ""^ f°»°>-ing
^™"'-<-';™ " will be remembered^thlt he snhL f •™"'"'ered. In thif
and in the present case it will „o be possible 7' h "" """^ ^"""^ ""«.
m the various organ svstems the m„i^ ■ ° '^° """■e than select

sideration of which wiilbeoT direct . ""PO'-tant fcat^re,^ the c^-

the t^ype. Before takLg up thT ndivWr,"?' '" ""^ P^^"'^"' "'"d^of
■t will be advisable to refer i^ the fiJst „V» ".'?''", '-"'™^' however

and s-condly to explain th" more ?un^da^eL°, '.''r P'"*" "' ^''''''fication
organization as something unTrlvir .hr^-*' ''"""■" "' vertebrate
themselves. It will also be convenien, to ''''P"^"'"" °f the svstems
of the embryonic organ svst^s sin" 1. iT"""'" '"" ''^'^' ^
condmons that the general features^oTthe' l^ "^ZS r'^adT^r^^t

26

Anatuiiv of ti;k Rabbit.

ii'l

' CUMlllcation of th« Oifu Sy«t«ni.— The term organ ivitem ii
employed in descriptive anatomy to designate a group o( organs which
cooperate in a general function. In manv respects the systems repre-
sent primitive functions, and it is therefore largely on account of the
iiidependent elaboration of these that the svstems may be recognized
also on a structural basis as groups of organs allied in origin and de-
velopment. The exact number of svstems recognized depends on certain
arbitrary distinctions, the following being those usually distinguished:

(1) The intigummtary syttom, comprising the skin, and its ap-
pendages, namely, the hain and the (annal cutantoui, numnurr. and
infuinal glands.

(2) The tktletal ijrttam, comprising the cartilage and bone elements
of the skeleton, with their connections.

(3) The muscular system, comprising all contractile structures of the
body. Since, however, the involuntarv muscles are arranged as muscle
layers in connection with visceral organs, the muscular system is
usually considered as including onlv the! individual or voluntary muscles
of the skeleton and skin.

(4) The nervous system, comprising the central nervous system (the
bnin and spinal cord) and the peripheral nervous system, the latter
consisting of the paired cranial and spinal nerves with their associated
ganglia. A special portion of the peripheral nervous svstcm is set apart
as the sympathetic nervous system. The latter consists of a pair of
ganglionated sympathetic trunks lying along the ventral surface of the
vertebral column, and of two series of ganglia, prevertebral and peripheral,
connecting the trunks with the visceral organs.

(5) The digestive system, compridng the digestive tube and its out-
standing glandular appendages-the oral glands, the liver, and the
pancreas.

(6) The respiratory system, comprising the lungs, and respiratory
passages, namely, the bronchi, the tracbea and the larynx. With this
system may also be included the accessory respiratory passages formed
by the nasal fossae.

(7) The vascular system, comprising the organs of circulation,
namely, the heart, arteries, capillary vessels, and veins. The Ivmph-
conductmg canals are also portions of the circulatory svstem, but since
they are largely independent of the bloodvessels, thev are usually con-
sidered as forming with their associated lymph glands a separate
lymphatic system.

(8) The urinogenital system, comprising the reproductive and
.xcretory organs, together with their common ducts— the urethra of the
male and the vestibulum of the female— and the associated bulbourethral
gland. The reproductive organs comprise, in the male, the central organs
or testes, and the deferent ducts, both of which are paired, the unpaired
seminal vesicle, and the paired prostatic and paraprostatic glands. In
the female, the reproductive organs comprise the paired ovaries, uterine
tubes and uteri, together with the unpaired vagina. The excretory

GUXKiAl, 1'I.AN OF ObcANIZATION. y

rn T*h!.'^h.™'''"'j°.'ui!lLi^/ Y* "°' '•"^'"•"'•d in «h» classification:
i„ .^ thymuf and tbynoid (Undi are ronnected with the digestive lube
-i.h .h™ J-^T "'"''""'"• »"•' 'Of "•« reason are wmetimes included
With the digestive system, although in the adult thcv occur as in-
dependent «lruclure,. (J) The ,upr.r.n.l bod; i, situated close to the
kidney of either side, but is independent of the latter, both in the adult
condition and in point of development. (3) The qMclal (olfactory, optic
and auditory) Miue-organi of the head are highly elaborated slrictu.es.
the ulalions of which are partly with the central nervous svstem
„n?T'f O'K""*"™ : '1 ">e rabbit, as in all vertebrates, the
genera plan of organization involves three chief features, as follows
ili ^ orientjUon-the arrangement of the chief organ systems
longitudinally about a more or less central, axial support: (a)inete-
merinn—the arrangement of a con-
siderable portion of the body on a
segmented or metameric plan
according to which structures are
repeated in a serial fashion along
the axis; (3) branchiomerism — the
arrangement of a small anterior
portion of the body on a seriai but
branchial plan, the latter depending
not on the succession of true
metamercs but of visceral arches.

The extent to which the general
disposition of the organ-svstems is
dependent on a fundamental plan will
be evident from a comparison of the
accompanying figure (20) of a trans-
verse section of the rabbit-embryo, or
of thj schematic section of a general-
ized vertebrate (Fig. 21), with the
actual sections of the rabbit-foetus

renera/fe:t'ures''„rtS"o:rat,s""'" '"">■ '^'"-^ '° ™""-'»" -"■ '"e
Metamerism (Fig. 19, me.) is characteristic of a dorsolateral oortion
of the body. Identifiable in the embryo as that includ°nTthe cforS and
intermedia e portions of the middle layer or mesoderm Kg T d m
and n.). In the ariult it determines a number of features of ser^
arrangement including the succession of the ver.ebrae and rib, he
divisions of the related dorsal musculature and its extensions to the r bs
a^dlh fT'"'''^"^"'r^?'' i"''.''-''^'!.^- 'he succession of th" spinal nerves
roots of thetnf"' "' ""i P'"™'"' ''""'^''" °f 'he aorta, and the parictll
roou of the mferior caval vein, as well as of the tributaries of the az,^os

R«l>t)it tmbryo o( lOJ days (4 H
■ .. hyoid;! and a. first

.. manditiuia;

—■"•-' "•iiuiiiumr; n,, iiyou

■iHl aeoond branrhiat arches;

Keibels Normtntfl/cln. V.. Pig 12 )

Akatomv or TH« Rabiit.
.. fi"r,! w"hr'ri'pL",:.'''j! 'T" -' '-" 'qu-ic v.r.ebr.,M. .uch
In higher terre.irurEaf" ,.„""' '"""'•'"»' "'P'^'T-V organi

a. a mark of aquat^anw,?" A. fnl^^ <)'t"niinant of adult form and
only itnicturaof brancmal ,Lifi™n~ ?K ''"'f b™'". it underlies not

th. fir,, or niandibuar a ch (m ) a?d ?he:!;^'„^"'' ''"'"•""including
.re«M. .He modification of .Hl:;i;r.:trpSXar.*rbJyo„^

'1

port on o( . myotome Tniphw™. „(.»&"■■. C'^ ■ """»'

SK K^s,nssro, SSi^ !^--! -

relations of certTi.Xetarstror.„rr"'",' ^/'"■"'"« 'he position and
the hyoid,and inpart thellrvnTearclriLr'"^'"'^''''/"''''"'--'' ''^^i'^"«,
classification of the parts o the h^^rt It^fr* ^T' f *""^ ™'«^ 'n the
succession of certain ^ft stn^ctur,^ i„^ S-™' J'.*.'^ determines the
and tenth cranial ner^el aU^ the cWe?*^ '^^ "'""i *"""■■ "*""■
whicharemorefullyrefe red to below "'""^ ^"^" "' ""« ''«"'.

G<N«tAl. I-IAN or OlOANIIATION. 29

•fcvelopnienl, may be outlined a. foUow,: """W'") <>•> embryonic

"»"u-d c.rH.a«i„oui%/;:rardJurv''cr;^b.:r„^:''""'>- •" ■» «/
.. a- llu°,Tz ta'r„' ''a:dT.'^L^"r!?''!H:''",'i'"'r'«'™-"'""""'

(neurocranium or cerebral craniumT and fhl » '?^"'l *"* "'«»■»
v.«eral arche. (.pIanchnocran■um"^v'itl?cra„k;™; "' '"''''«''""»

.4 .^heVS"""'"" °' "" ""'' '"'""•■ ""■«'' '" " dorsolaeera. p„,i,io„

maUer^tirirTut'; "/vL^* ^nlu^ T'Tr'''" " » '"bo of nervou,

differentiated inroa'gSr"p^',;r1o;t,rUo„°',h''^ """',' '"P"""' '"'"
anterior expanded portion, the braTn ^ ' ■" 'P'""' ""<■ '"d »"

dir«tlytirh'tt\1i:5':j'rrfa%d''? " "■ T'-'f "" "™^'"«. 'vm.
arising from the epitheHlfm oT.^ waH '**'"" «'""''"'" "PP-nJ-Kes

»alfof^tX--t",u'be''':fJe"rZrSs P«'«^''':'<^?>wth, of the ventral
body hv accef..ry reJpttot":"',' .^"r^i'g'.rt'ad^ °"""''= "' ""^

pJ; ™str,l;:,^°h'e'ft™'r!^Xf>rT """■"">' °" - ^o-'-

to the digestive tube and [mme5?awXhrnd t'he '."nf 'Tu?' P°''"°"
aorta, passmg forward to the gills and HivJill- P"'' 'b' * ^<^"'"'
branchial aortic arches c) f ri^rt^f '''^'''"'« ""° " Paired series of
arches, and passing backward al™, ^r*' ""''■ning the aortic
axialsupport; and(d)airfesof™?H ^' ™"'"' ""'^<^ "' the
various^,, 'of the body to the hSJt" '""' """"'"« ">« "ood from

withth'^'dJS' HZg°:/''rhrSom"^" "T"' "I ^-■'^ '" "-"="»„
the outside of the boly by'';Std'kirev"d:c"^ '""' "•""''"™ "'"■

s.ru^uris^:i"':itt:r'j;^dia'ifs^;''tti:: r ^'"""^ - p^™--'

the dorsal musculature and the linTnTof .hL!^i ' '"^^ '" ^""""^ between
of embryonic kidney in F^g. 20, n ) ««'°n"<^ cavity (cf. position

spa.ce, I': »rmt"civilJ%7t:lo^''Z°' "■^h'»S a ' ' "" «'--'
pericardial, pleural and perLnear^rHons ""' '''«""'"»«'<i into

30

Anatomy of the Rabbit.
THE SKELETAL SYSTEM*.

base of the skull. TZl drawn ThouSf fh„ '" ^ ""^'I ^"''°" "' '^e
bodies indica.es .he posUi„„t?rHnrir.?a'x^fa,T;-^.^^^^^^^^^^^^^^

Nervous system— m s stinal rnrrf^^!^,£Vi. '"■ ^'"""1 m«sce.
P0.1e..or root: r.c. ramus co"m,?„i™™?o°*'""":i- /'"•''• "■"""m o the

Omtstivc ,y,tem-i,. intistine "' " 'P'"»"i«"e . t.s. sympathetic trunk.
Vascular svstem— ao aorta

.^«P%^To7.i;ltefat7d"lTu,^Jf^„'fe1 T"" ""^ ^^^^^ f"-'"- °f
lower vertebrates the l^e7nr™.H K .i. "'"'"^^ "' ""^ '?'■>«' ""-d. In

of the skull is f?r the m^sfparf XhV^l'n ;m?''"'"?r'' '"' "*-
"^ "^"'S"'- "1 <• mammal the vertebral

references are not indicated excep? in sfiS^a" cLe, "' '""^ f"-- 'W^ reasoS the

The Skeietai, System.

of '"■".S^^p:";^ SS'yx^''/Ti;^=^ «--"■ The a>l!

iw, ..:-! ■^.^Tbyaco„sideraMeTnl?i'f ■'A''^"".''' *"<" Presphenoid

bon.

vertebrae; Furth;;, the' b;;ic"ra;;iai'1in^'T '"^'•'" '"^ '■'='''«^'' «"•'«'
rabbit, would pass thrZfh the rfnrti ■>,'', ™!'"""^'' f"™"^'' '" the
front of the or^bits i^Sa e ifTFi? 33 of ^h^"" '7.^?'^'^'^ '"

exte^„t^t"JL.?h"ifrj;;r;"^dera''bi/t^rh°' - -««^^^•™"'^•'. «>.«

occipital, anterior and nnit.ri^, u ?j ','"' '"''^a occupied by the
(cf. Plates Ill-n AsaCia;efct'^''H''"'' ^'.^'"™''»' P"''""^
cranium, and after its conversion fnto hi *"' gnati^d as the chondro-
more than an enclosure fo 'he bra^t^^xcem'that' fl;"'"™'""- " i^ "o
the cartilage capsules of the nasal "suala'^V^^H ^"^ assccated with it
case of the first and last of theTe the can^nf ^'"'""■■>-°rKans, and, in the
skull proper. Thus, the primaV sk,T /'■ '"""'P"^''''''' ™i^
craniumorcerebralcnmitL/todisintukh'ff "'^"'"'■'' ""^ '^e neuro-
head skeleton, the sptanctaicranh!^ n. l^ T " ^""""^ P°"'"" "' the
the series of visceral rrcherJu^^THH T'l™"""' "hi^h includes
neurocranium. The addhLn^r.'^h "" '^"^ ''™"'^' ^"^'ace of the

number of mentbrane bones results' fnTo"' "^f ''''^*'?" "' " '^'^-
original divisions since th„ L k °" '"' ''"''s confusion of the

are' with the ScepuJn o^'thri'ndibie'^unlt'd U '"^ "^"'^'" "^"-"
the cerebral cranium, while the true car'tiW ^ f ture with those of
of the former, occurring as the audltnrv ^^"' ™;"'aSf bone portions
(in part) (Plate U), altLuVh h.Jwr^L°f S'"' """ ^^"'"^ ""<■ 'arvnx
independent relation '^ *'' '' """i-fied, remain in a more or less

de4'e^\i'c:Li:t;^gTfTctiii^pUir rih " '™"=" -"— > ^<^

a facial portion, the latter inc"Zi n, 'f ^ , T^"'""" P™?^"'' and of
and the mandible, and as cereSruc ures'tL n"'.'"? l""^ "PP'^''^*"'
bones and the associated secondarv" r„/^ . P'"''' "' ""^ turbinated
nasal fossae. In a mammar^he in? '"P'-'atorv tract formed bv the
are largely associated wUh a great exteSon T.'^''""'^ ,'"'"" "' '"e face
portion of the primary skulffrom wS ,h ^ k*"^' "^P^"'^^' °^ 'bat
formed. Thus, as illustrated in thl ,r " 'urhmated cartUages are

nasoturbinals and max lloturb.nilsare form' H "^'T" °', """^ '"• ">=
the primary septum (mesethmo?H ™ , ^f v°" ^^^""^ extensions of
directly, and in'^the aZfwMy bv hf '^ .''"■' ^"PP°^"^d more
(nasals, maxillae and premaxillae)' '"vestmg membrane bones

?TTrtZ:V'"' '''' ^''^''"■" "-^^ "-^ ^'--fi^O as follows-
inclidilg'? *=^'^^'^'' ^«^«™ ("anium cerebrale or neurocranium).

^^' ^.SrUV!^^Jt"^'-^^. enclosing
auditory capsules (embryonic); olfactory and

32

Anatomy of thb Rabbit.

Ih

!l

(b) The secondary bone skull (osteocranium), replacing fa) and
comprising the occipital, sphenoid, ethmoid, ii&erior ttirbisal,
and periotic bones;

(c) The associated derm elements, comprising the interparietal,
parietal, frontal, nasal, vomerine, lacrimal, tympanic,* and
squamosal bones.

2. The VISCERAL CRANIUM (cranium viscerale or splanchno-
cranium), including:

(a) The primary mandibular and hyoidf visceral arches (embry-
onic) ;

(b) The secondary elements, replacing (a) — the malleus, incus,
and stapes of the auditory chain; the hyoid bone and its
connections with the skull;

(c) The associated derm elements of the face and palate, com-
prising the premaxillary, maxillary, zygomatic, mandibular,
palatine and vestigial pterygoid bones.

The anterior and posterior portions of the appendicular skeleton
include each a proximal or girdle portion and a distal portion, the free
extremity. In each the free extremity is divisible into proximal, middle
and distal segments. The proximal joint of the limb, either of the
shoulder or hip, is an enarthrosis, although it will be seen by examination
of the rabbit that the glenoid cavity of the shoulder is not greatly
elaborated as a concave surface. The distal joints of the limbs conform to
the type of the ginglymus. and with minor exceptions the movements are
restricted to one, namely, the sagittal, plane. In each limb they are
described as movements of flexion and extension, since the general effect
of movement is to bend or straighten particular parts on one another.
Similar motions are observable in the limb as a whole, but are not spoken of
as of flexion and extension, since the shoulder and hip joints are of a totally
different type. In the limb as a whole, the chief motions are of pre- and
post-traction, but it is convenient to recognize also movements of ad-
duction (toward the body) and of abduction (away from the body). In
both cases the axis of the upper arm, or of the thigh, is assumed to be
parallel to the median vertical plane.

In mammals, as in other terrestrial vertebrates, the anterior and
posterior limbs are equivalent part for part. They are said to be
serially homologous or homoplastic. There is, however, particularly in
the mammalia, a pronounced difference between the anterior and
posterior limbs in the respective positions of the different segments.
Consequently, in studying the related musculature, it is advisable to
consider not only the functional relations of muscles, but also the equival-

•The identification of the tympanic as a derm element has been questioned.

tThe thyreoid cartilage of the larynx and its connection with the hyoid
(greater comu) are modified branchial arches, but the structure as a whole is not
included with the head skeleton.

The Sksietai. System. 33

in the accompanymK diagram by shaded lines. The angles b and c

ii^s=i. -?srj^ s^:^^tr-^r£S^

34

Anatomy o? thb Rabbit.

the sole of the foot resis on the ground. Thus the mnscles described as
flexors in the foot pass over the heel. They are functionally flexors of
the toes, but extensors of the foot as a whole. Those described as
extensors, lie for the most part on the anterior surface of the tibia, and
are turned from their original course to the dorsal surface of the foot.
They are functionally extensors of the toes, but flexors of the foot as a
whole.

THE NERVOUS SYSTEM.

In the central nervous system, the more general features relate to the
form of the whole structure as a neural tube, containing a central cavity,
the neurocoele. This is differentiated into two portions, nameJy, a less
modified portion, the spinal cord, or spinal medulla, containing as its
cavity the central canal, and a prcatly expanded portion, the brain, or
encephalon, which is divided into a series of paired and unpaired seg-
ments, and contains in its interior a corresponding series of divisions of
the original cavity, known as its ventricles.

Although the internal structure of tht brain is a matter of the dis-
position of its ner\'e-centres and fibre-tracts, it is customary to estimate
its primary divisions by reference to a general plan, the latter being in
most respects one that is common to vertebrates generally and thus
appears in a less elaborated condition in the embryo, or in the adults of
lower forms. The main features of this plan are indicated in the ac-
companying diagram (Fig. 23).

The brain as first formed in the embryo appears as an anterior ex-
panded portion of the neural tube, or rather three expansions
arranged in a linear series. They are described as the primary cerebral
vesicles; or, as primary divisions of the future brain, they are designated
in anteroposterior order as the prosencephalon, mesencephalon, and
rhombencephalon.

The first of the primary divisions, the prosencephalon, or primary
fore-brain, becomes divided during development into two portions,
namely, an anterior portion, the end-brain or telencephalon, which 's
largely a paired structure, and a second portion, unpaired, the dience-
phalon,oi inter-brain. The larger paired portion of the telencephalon is
the basis of the cerebral hemispheres. It contains, as divisions of the
primary cavity, a pair of cavities, the lateral ventricles. The anterior
portion of the telencephalon, moreover, becomes differentiated, so that a
small terminal olfactory segment, the rhinencephalon, is more or less
perfectly marked off fiom the rest. In the mammalian brain this part
is chiefly identifiable as the paired olfactory bulb, the latter being the
anterior portion of the olfactory 'obe or olfactory brain, and containing
in its interior an extension of the lateral venlriclc.

The unpaired portion of the prosencephalon is consifltred as belonging
in part to the telencephalon and in part tc the diencephalon. It?
cavity, the third ventricle, is connected with the lateral ventricles through
the interventricular foramen. Its anterior wall is formed by a transverse
connection of the cerebral hemispheres, the lamina terminalis. In a!l

The Nervous System. 35

.. a s.e„ae, funnel-.S^ure^.t Z^^ZX^^lX":?^

■ A. embryonic; B, adult.

«o. mesencephalon; K

pnalon; S, spinal cord ' ' "'■ ""^wntejin

aicsua pc.Uon of mas., i„t,.rm.J 1 '.."r?.'?' Wduncle; l-. f-r- '

■"dultary velum: v.q., fourth ventricle

™tifed'»^^^'a^rl;^e^?L'::;';i?„^^^^^^^^ -d .s base

36-

ANATOHY Ot THE RABBIt.

I I

J'
III

ventral portions of the optic tncti join to form the optic chiuma, and
immediately behind it the floor is thickened, forming externally a pair
of rounded protuberances, the mammillary ttodies. In the brain of the
rabbit this structure consists superficially of a larger median portion with
faint lateral elevations appended to it. Collectively, these structures are
considered to form a major division, the hypothaLunus, the latter con-
sisting of two portions, namely, an optic portion, comprising the in-
ft<ndibulum, tuber cinereum, and the optic chiasma, and a mammillary
portion, including the mammillary bodies.

The more dorsal portion of the diencephalon, containing the major
part of the third ventricle, is known as the thalamencephalon. Its
lateral walls are greatly thickened, while its roof is extremely thin,
especially in its anterior part. Here the actual roof of the ventricle is
formed only of a thin layer of tissue, the epithelial chorioid lamina, but
the latter has associated with it a series of vascular ingrowths of the
investing pia mater, the latter being described in this relation as the
chorioid web (tela chorioidea). The two structures together form a
chorioid plexus. This extends downward into the third ventricle,
reaching out also into the lateral ventricles.

The dorsal portion of the thalamencephalon bears posteriorly the pineal
body, the latter together with certain related structures, the habenulae
and babenuhir commissure, forming the epithalamus. The general
portion of the thalamencephalon bordering the third ventricle, and
broadly connected across the latter by the massa intermedia, is the
thalamus. In the brain of the rabbit it will be seen that the thalamus is
chiefly indicated exttmally by a rounded protuberance, the pulvinar.
The latter is dorsal in position and is imperfectly marked oft from a
second protuberance, the lateral geniculate body, lying on its postero-
lateral side. To the medial side of this is a thirdaprotuberance, the
medial geniculate body. The medial and lateral geniculate bodies as thus
defined constitute the metathalamus (Fig. 53).

The second of the primary divisions, the mesencephalon, or mid-brain,
is noteworthy in a mammal as lacking a ventricle. Its cavity is a
narrow canal, the cerebral aqueduct, leading from the third ventricle
backward to the fourth ventricle, or cavity of the rhombencephalon.
Extcnally, its roof is differentiated into four rounded elevations, the
corpora quadrigemina, of which the anterior pair are much larger than
the posterior ones. Its floor is chiefly formed by a pair of divergent
cords, the cerebral pedtmcles.

The parts of the mesencephalon and prosencephalon together con-
stitute the large brain, or cerebrum.

The third primary division, the rhombencephalon, or primary hind-
brain, is a greatly elaborated portion from which arise the majority of the
cranial nerves. The constricted area joining it with the mesencephalon
is known as the isthmus rhombencephali. It includes the anterior
medtUlary velum and hrachia conjunctiva (Fig.55). The rhombencephalon
itself is divisible into two portions, especially well defined in the
mammalia, namely, the metenceplialon,or hind-brain, and the myelence-
phalon,or after-brain. The former includes the small brain, or cerebellum.

Iff
O G

Thb Nesvous SysTeic.
Cerabnim

37

I

5 a

f- -^ lii

I

■ e

t

St

la
It

1°

S

V

ss

g 2

■3. S is

8 ; i

J3^

1!

ft 4* '

8 "
a ■= I

38

Anatomy of the Rabbit.

and a ventral structure of a commissural nature, the poni. The my-
elencephalon is a transitional portion connectiuK the brain with the
spinal cord. The cavity of the rhombencephalon is the fourth ventricle.
It is a peculiarly shaped space, the floor and lateral walls of which are
very Kreatly thickened, while the roof is for the most part thin. The
roof appears at first sight to be formed largely by the cerebellum, but is
in reality formed by two membranes underlying the latter. One of these,
the anterior medullary velum, is connected forwards with the mesence-
phalon, while the other, the posterior medullary velum, covers a triangular
space over which the posterior margin of the cerebellum does not extend.
The posterior medullary velum has the same structure as the chorioid
plexus of the third ventricle, but is much more poorly developed.

Apart from its principal divisions, which, as indicated above, are more
or less common to all vertebrates, the brain depends for its external form
on the elaboration of certain parts in comparison with others. In the
mammalia the cerebral hemispheres andj the cerebellum are the chief form-
determinants, although the pons and the corpora quadrigemina may also
be considered in this connection. It will be seen also that the form of
the brain is more or less dependent on the existence at certain places of
well-marked flexures (cf. Plate II). The first of these, the cephalic
flexure, is in the region of the mesencephalon, the anterior portion of the
brain being bent downward . the second, or pontine flexure, is at the fourth
ventricle; while the third, or cervical flexure, is at the point where the
myelencephalon passes over into the spinal cord.

The peripheral nervous system embraces two groups of paired and,
for the most part, metamerically arranged nerves, namely, the gpinal
nerves^those arising from the spinal cord and leaving the vertebral
column through the intervertebral foramina; and the cranial or cerebral
nerves— those arising from the brain and passing through the foramina
of the skull. Of these the spinal nerves are less modified, both in
structure and distribution.

A spinal nerve (Fig. 21) is a product of two roots, one of which, the
radix posterior, is sensory and arises from the dorsal side of the cord,
while the other, the radix anterior, is motor and arises from its ventral
side. The posterior root bears a root'-ganglion. The combined nerve is
distributed in three chief parts, of which two, the anterior and posterior
rami, are distributed as mixed nerves to the skeletal muscle and the skin,
— the anterior ramus being in practically all cases the prominent nerve —
whiJe the third, the ramus communicans, is connected with the sym-
pathetic trunk-

1 he sympathetic trunk is formed on either side by a series of ganglia
joined together by connecting cords. It is connected not only with the
spinal nerves through the rami communicantes, but also with a series of
prevertebral {cceliac, superior mesenteric, etc.) ganglia and plexuses
from which nerves pass, chiefly in association with the bloodvessels, to
the peripheral ganglia and plexuses of various organs.

The anterior and posterior rami of the spinal nerves contain both
senbory and motor components, and are typical somatic nerves. The
ramus communicans is a visceral connection containing similar com-

The Kervol's System. 39

side ed as part7of an exlcn, v^ !.^^ ' "? ""'"•" J^'"' ''^^"^ •"^'^" in-
vertebrate!^ al»»„"afn rep es^^I^^^^ "'"',•'■ '" '°»"aquatic
is distributed widely to .ZZ7,lf^r,[i!':,';:^^'''"'"- ^^'^^ """

I. ".*i,sr3!;,°„ts rr si'" r' * ""~- « »>- •"'..

40

Anatomy ot thb Rabbit.

THE DIGESTIVE SYSTEM.

The dic«tiT« lyitem comprises as its chief portions the dlfntiv* tub*
and the digMtiT* gbmdl. The digestive tube is divisible into several
parts, which, with the exception of the caecum and its vermiform
process, are arranged in a linear series. The digestive glands comprise
the oi»l glandi, the liver, and the pancrwi. Thev are parts of an
extensive series of epithelial glands, otherwise contained within the wall
of the tube, and for this reason not appearing as gross structures.

The parts of the digestive tube may be classified as follows:

Oral Cavity

Oral cavity proper,
Vestibulum oris,

. I'haryn.v.

Xasal portion.

Oral portion.

I ^ryngeal portion.

, Oesophagus.

Stomach.

Small Intestine.

Duodenum.

Mesenterial intestine.

Jejunum.
< Ileum.

Large Intestine.
Caecum.

Vermiform process.
Colon.
Rectum.

In its most general features the digestive svstem is significant as an
epithelial tube, in which the food during its passage is subjected to the
action of digestive juices provided by the epithelial glands, and is
modified, by solution or otherwise, so that it is capable of being absorbed
through the epithelial surface. In the form of the digestive tube as seen
in a vertebrate, however, a number of gross mechanical features are
evident, such as, for example, the increase in capacity, or in absorptive
area, through the folding of the mucous membrane, or the expansion of the
wall ; or again, the presence of a special muscular tunic, and its modifica-
tion at certain places, as in the oesophagus, the pyloric limb of the
stomach, and the first portion of the colon. Moreover, many features of
the abdominal portion of the tube, and, indeed, certain of its recognized
divisions, depend on its relation to an extensive serous sac— in a mammal
the peritoneal cavity. In this connection it is to be considered that the
digestive tube is primarily a median structure. It has this relation in the
earlier stages of embryonic development (Fig. 20), and in many of the
lower vertebrates it does not deviate to a great extent from a median
position. In all higher vertebrates, however, the tube becomes greatly
elongated in comparison with the cavity in which it lies, and thus becomes
extensively displaced to one side or other of the median plane. This
development, while advanced in all mammals, may be said to reach an
extreme in the herbivorous mammalia ; and in manv cases it is further
increased by the independent elaboration ot the blind intestine or caecum.
In the rabbit the combined length of the small and large intestines is
approximately eleven times that of the hodv

^y]

Th« Diubstut! System. 4.

portion exhibitin^a vaSy of een^aTZm™*"!''" '",' '"'" '' « fi"'"
with the organiialion ofthe head •»«"""«'■«" feature, connected

the phlr'^J^S: lto''n,tch''",'„''i\f ™"^"^«"«'"^""« '™'""'f '™">
neck and the thorax a3 in hi?h r 'T™*' backward it traveri, the
In the thorax (Plale VII Wtwil^ti„Ki''!.T"P'" " "'^''''"' l»«'ion.
"nd the dorsa aor a thu, exh iiHn. .h"'' • ''^' ","" '*'"'«" '"^e heart
tube .0 the aX"'Sof't'rvaL"ulL'r'"::r^''''"^l''''^ •'''="•!-
portions of the diEestivp tiitJ „rL .fc system. The succeed njf

cavity, and with he excemfan „7,h f ''''°^',""'' *'"■ ""e peritoneal
displaced from a medTn^r^shi^l r """*' ^''T' "'^ "''»"'■ "'
are recognized are baSd oa^tlv Z .h, ^.r*''''?' >\.""= •''''''""^ "'hi''-

intestine, "^l t^^^iLZ 'sUTm'k'^dU' ^ror.T"'""" ™"'l
intest ne as an extensivp in/ir, '""W .""arKed off from the mesenterial
and its duct^and lv"nron^rri^h^'5'J''"? It T'"' P"" °' 'be pancreas
The mes«ntiri«l totMHn^ i. * .,^* °' ""^ ■'"'■"' *»" "' »he abdomen
on thel^ sW^oT "^abdomin^lrI^."'"™i"!''' P°"»"' >-™8 ^bieHy
broad, frill-like mesentery FrnlTh^',*"'' '""^'^ '"PPo^'ed by the
there is no abt^pTc^^^g/in fhe chlracf/r /fX^J",! ^f"'" V"'""'''"
portion of the mesenterMl intesHn. .^ . i ■ ™ *^"' although the first
the duodenum mrybe'tisd^'e/^^^ftht?'!,"'''''' "" ">' i'r"™. and
with thicker walls in comDaris^n w^ih 'iT a.n>°re vascular portion

wliich the wall is less vaSTnd^more't^rpSf.n^"""-' '"^ "•»»■ "

speiteTmaTbrcon i^dT ^^t. €^^1 '"'"r ^-"^

on the caecum fcTward to a ™i„T^h^'" fflT*^ '™!? "=■ P"'"' "' 0^8™
the transverse coIonT the lattS crors^s thl i^^'""!.*'-^''!'' '" '^e left\s
as the descending co on In the ™hhif S ^ ""^ " ""^'^ backward

as the ascendinf ™C is^reaHy e^oLa^.T""'^"'" P"'""" <''^«"»ble
principal limbs, united by flSres ZToUhZ'^r"'^^ "' ««
ventral surface, are concealed by th. h.\ li ^*' '•" dissection ficm the

tbede..eudi„gmei^L';t^lX^/4r^^^^^^^^^^

r

42

Anatomy or tiik Rabbit.

I i

ij.j

of the aKcndinK limb of thr duodenal loop. The course of the catcum a>
it lies in the body ii comparable to two turns of a left-hand spiral, its blind
termination, the nrmifonn procMi, being dorsal in position and directed
for the most part backward. It may be ot>served at this point that in
their vascular supply the more typical divisions, namely, the transverse
and dcsccndini! colons, have arterial branches, respectively, the middle and
left colic arteries, comparable to those of man ; while on the other hand
the riijhl colic relation, on account of the great complexity of its parts, is
represented by a large number of vessels, branches of a common ileo-
caecocolic trunk.

The form of the anterior, or cephalic portion of the digestive tube
(Plate II) depends on its fixed relation with respect to the enclosing
parts of the head skeleton. In the rabbit, as in mammals generally, the
oral cavity is divisible into two |»rtions. of which one is the oral cavitv
proper, while the other, the VMtibulum orii, is a space enclosed h<'tween the
alveolar process of the jaws and the teeth on the one hand and the cheeks
and lips on the othn. As in other vertebrates, the tongue is a muscular
structure projecting upward and forward into the oral cavity from its
base of attachment on the hyoid apparatus, but its greater elaboration,
as well as the differentiation of special processes, the circumvallate
and foliate papillae, for the accommodaticn of the gtislatorv organs, are
features of mammalian significance. The roof of the oral cavity is
formed by an extensive palatal surface, c-omprising the hard palat*,
and the membranoui, or soft palate. These structures also form the floor
of the accessory respiratory tracts of the nose, the posterior aperture
being thus carried backward to a point more directly above the aper-
ture of the larynx.

As accessory structures the teeth present two mammalian features:
they are heterodont, or difTerentiated according to particular regions, and
the adult series, excepting those designated as molars, are permanent
teeth, replacing deciduous, or milk teeth of the young animal. The
condition is thus described as diphyodont in comparison with that in
lower vertebrates, where there is usually a multiple tooth change, new
teeth being developed as required (polypliyodont type). Moreover, in the
rabbit, as in all mammalia, the number is restricted, so that, considering
the differentiation of the teeth, it is possible to express their relations
by a dental formula. In the mammalia generally the teeth are differen-
tiated into incifon, canines, premolars and molars, and in placental
mammals the full dental formula is indicated as i. 3, c. }, pm. J, m. 3.
In the rabbit as in other rodents, however, the dentition is greatly
modified by the elaboration of two pairs of incisors and the corresponding
obliteration of intermediate teeth, the place of the latter being occupied
by an extensive gap. or diastema in which no teeth occur. The dental
formula of the rabbit is i. if, c. g. pm. J, m. 5. It will also be observed
in this animal that the absence of the intermediate teeth allows the lips to
be approximated behind the incisors, and since the lips are in this region
also provided with hairs on their internal surfaces, the oral cavity is
separated almost completely from a small space enclosing the incisor
teeth. This adaptation, however, is not so perfectly developed in the
rabbit as in certain others of the rodent order.

ThX RiSPIIATOtr AND \'A«ClTtA« SVSTEUS. 4J

THE RESPIRATORY SYSTEM.

In all air breathing vertebrates the luon arise embrvnni<iilli n.

nected «ith the outside of the bo.lv through spi-cial k" or" <.n?of

indicated above, this connection in a mammal is represenu. by an

organs. It is distinguished as an tccMury r«ipir»tory talct from the

e%7S"' theTeUrT'" '^ "'^' '""'» ""d""' tei^m^Jf ilvlTio'i^s'
r.l!.t.^^ K ■ '<^'.P'ra'"0' system as rcpresinted bv the lungs and

L Meflv mie oaheTrrf-' 'T'^l '".""^ "'-Phagus. but this relation
iscnien> true of the trachea. In the thorax (Plate VII) the bronchi are
m general. .nterix>si.d between the oesophagus and the hearf "he lungs
being expandetl laterally into the paired pleural cavities. ^

THE VASCULAR SYSTE.M.

In the rabbit, as in all vertebrates, the vaicttlar system embraces a
^Ees .'hThJ^"' organ of propulsion, the h«rt, and a «ries of "ranched
w^lhA 1 ?^'^r*",l""^'''"" •*'"« "' three different kinds (a)7hick
TaS'in t ''^ '''f "''"""« vessels-arteries; (b) microscopic term nal
ves^U-vil^.'!'"''^"^''"'*""''"'*''^'*""'"'' '^) "■in.walledcolle"t."rg
„f ,l!!V''^' ""»"""«»'"' f'^^""-'' in this svstem consists in the division
cLifl, 'T^ '"■" P?"'™' "''^'^ VII), each consisting of a receivh^g

™,„T f,°h •'^""•r'' * ''"^in« chamber, or ventricle, and the arrange
ment of their vascular connections in such a wav that two com nW
circulations are established. One of these is the long, or%r,t2ic cScuU-
^r,i, \L'^ """/""l with the distribution of blood to t^ v^ous S^s
Uft V ^^T' T*' ""^ ««ption of the lungs. It is cstablish"d bv the
i„H .I,"'''- "'f '"'«». .the carotid and subclavian branches of ilsarch

S^'iont '"Th?bloo"d is'^S"', "iT'^'V' "^ '""^-'^ and abdominal
fhrn ^JL „ I ■ . f ™"«"'d froni the anterior portions of the body
through paired interna and external jugular and subclavian ve ns rem
mun eating wi h the right atrium of the heart through paired su«ri™r
cavals; from the posterior portions of the bodv through he unpS
?he rt ri^T.i:'""^' '"l"'"' '=*™' "''"■ 'he latter passing f^rwarf^n
i^rium Thl '"•^''''"'.P'»"e and entering the posterior end o° the right
atrium. 1 he second, short, or pulmon«y circtJ.Uon, is concerned with

44

Anatomy of the Rabbit.

■H

the distribution of the blood to the lungs for purposes of aeration. It is
established by the right ventricle, the pulmonary artery and its paired
branches, and by the capillaries of the lungs. The blood is delivered to
the left atrium through several pulmonary veins. A similar division of
the circulatory organs occurs as a homoplastic modification in birds,
which, it will be observed, are also warm-blooded vertebrates.

Many of the peculiar features of the mammalian circulation which at
first sight do not appear to be general, but are so in reality, depend on the
circumstance that the complete partition of the organs is a final stage of
a general progressive development, observable in air-breathing verte-
brates, in which the lungs and their vascular connections become perfected
for pulmonary respiration. On the other hand, the vascular system as it
appears in the embryo, more especially its aortic portion, is arranged
according to the type of branchial respiration as found in fishes. In this
condition the blood is sent forward from
the heart through a ventral aorta. The
latter is connected with a series of paired
branchial aortic arches, traversing the
rudimentary gill structures, and thus
passing upward around the sides of the
primitive phar^-nx. The dorsal aorta is
formed by the junction of the branchial
aortic arches, and passes backward as a
main distributing vessel on the ventral side
of the axial support. The heart itself is
formed primarily on two-chambered plan,
similar to that in fishes, where all the
blood is received by single atrium and is
delivered forward to the gills by a single
ventricle.

The definitive condition of the chief
arterial vessels is arrived at by an extensive
modification of the branchial plan. As
indicated in the accompanying diagram
(Fig. 24) the arch condition is retained by
the aorta and by the pulmonary artery,
and it is interesting to note also that the
primary connections of these vessels, repre-
sented in the embryo by an open canal, the ductus arteriosus
(Botalli), is indicated in the adult condition by a short fibrous
cord, the arterial ligament. The adult aortic arch represents only the
left one of a pair, and since that of the right is only represented
imperfectly by the innominate artery and the base of the subclavian of
that side, a condition of asymmetry results, which is mainly expressed
by the sinistral position of the arch with reference to the oesophagus
(Plate VII). By comparison with the embryonic plan, it is seen that the
primitive features of the heart and the arterial vessels include the
ventral position of the heart itself, the equivalence of the two atria and
of the two ventricles — these structures being partitioned internally but

Pto. 24. Plan of the brarchial aortic
arches. The adult nuiiTiinalian vcbbcIs
ere indicated in black (syRtcmic) or
chadcd diulmonary). 10. primary
arches; ao.. aorta: a. p.. pulmorary
artery; c.e. external carotid; c.i.. in-
trrnal carotid; d. a., ductus arte rioeus
(Botalli): i., innominate artery: a.d..
right subclavian; s.d., left subclavian.
(From Weber, after Boas.)

The Vascular System.

45

imperfectly divided externally— the forward position of the first portion
of the aorta, and the position of the aorta as a median vertebral trunk.

The vascular system is noteworthy for several departures from the
condition of symmetry, one of these having already been mentioned. In
addition, it is seen that in a mammal, as in terrestrial vertebrates generally,
the base of the pulmonary artery is rotated in a spiral fashion about
the base of the aorta, so that from its beginning on the right ventricle it
passes across the ventral surface of the base of the aorta, and divides on
the dorsal side of the latter into its two main branches. Moreover, the
separation ■al the ventricular portion of the heart into two chambers is
associated with an enormous increase in the muscularity of the wall in
the left ventricle, or, in other words, in that portion which is concerned
with the larger, systemic circulation. The inferior caval vein (Plate
VIII), a highly specialized vessel, is asymmetrical, since from its begin-
ning in the pelvic cavity to its termination on the right atrium it lies
wholly to the right of the median plane. The azygos vein of the thorax
(Plate VII), a vessel uniting the majority of the paired intercostal
veins, and interesting as a remnant of the primitive circulation, is also
asymmetrical, since the trunk lies to the right of the bodies of the
vertebrae, and is connected at its base with the right superior caval vein.

In general, the blood which is distributed to the various parts of the
body passes through but one set of capillary vessels, and is then returned
through the systemic veins to the heart. In all vertebrates, however, a
special portion of the systemic venous circulation is set aside as the
hepatic portal system, distinguished by the possession of a second series
of capillary vessels ramifying in the liver. Thus, in the rabbit, the blood
distributed to the stomach, spleen, and intestine through the coeliac,
superior and inferior mesenteric arteries, is collected into a main
intestinal vessel, the portal vein, and the latter, approaching the liver
through the lesser omentum, divides in that organ into a series of portal
capillaries. The portal capillaries, like the systemic capillaries proceed-
ing from the hepatic artery, unite in the tributaries of the hepatic veins.
In lower vertebrates, although not in the mammalia, a second svstem of
venous capillaries occurs in connection with the kidneys, and is known as
the renal portal system.

The lymphatic system, both in its functional relation and in origin,
is an appendage of the venous portion of the vascular svstem. The
system is an important one, of which, unfortunately, little may be seen
by ordinary dissection, the structures which appear in this way being
the lymph glands, or lymph nodes, centres of cell formation, occurring
in the course of the conducting vessels. These as superficial structures
are found either singly, as in the head and neck, or more or less grouped,
as in the axillary and inguinal spaces. As deep structures they are
conspicuous in the intestinal mesenteries, and in the walls of the digestive
tube, occurring in the latter chiefly as continuous masses of lymph
follicles, as, for example, in the walls of the sacculus rotundus, the
vermiform process, or the tonsil ; or, again, as aggregated lymph follicles
(Peyer's patches) at various points in the intestinal wall.

The conducting portion of the system comprises an extensive series

46

Anatomy of the Rabbit.

^Il

III

1'

of canals, beginning as lymphatic capillaries in peripiieral organs, and
ending as lymphatic trunks which empty into the great veins. The
lymphatic trunks of the anterior portioil of the body are designated
from their association with the corresfjonding veins as jugular and
BubclaTian. They enter the venous system on either side at the point
of junction of the internal and external jugulaf Veins or of the common
jugular and subclavian (Fig. 52).

The lymphatic vessels of the posterior portion of the body,
including the intestine, unite to form a common canal, the thoracic
duct. The latter lies for the most part between the aorta and the verte-
bral column, and traverses the thorax in this position to enter the
venous system at the same point as the jugular and subclavian trunks
of the left side.

The Ivniphatic capillaries are terminal, absorptive vessels, differing
from blood capillaries both in the character of their walls and in their
relations to other portions of the system, since they are not interposed
as in the vascular system between vessels of a larger order. The lym-
phatic vessels connecting the capillaries with the lymphatic trunks form
extensive plexuses, in connection with which the lymph nodes are dis-
tributed.

THE URINOGENITAL SYSTEM.

The ttrinogenital system comprises two primary systems — leproductiTe
and urinary— differing widely in their central organs, but associated to a
certain extent by having common ducts. In the rabbit, as indicated in
the accompanying diagram (Fig. 25), this association extends only to
the presence in the two sexes of a urinogenital canal, or urinogenital sinus
connecting both urinarv and genital structures with the outside of the
body. This canal is designated in the male as the urethra, but in the
female as the vestibulum, since the structure known from the human
relation as the female urethra is only a urinary canal leading from the
bladder, and in man is not associated with the reproductive ducts.

In general, however, the relations of the urinary and reproductive
organs involves two chief features. First, in primitive vertebrates, the
urinary and genital ducts open into the posterior end of the digestive
tube, the latter forming in this relation a common canal, the cloaca.
In terrestrial vertebrates, the urinary bladder is developed as a ventral
outgrowth of the digestive tube, and, except in amphibians, both sets of
ducts undergo a migration from their original position on to the wall
of its canal, the latter being thus transformed into a urinogenital sinus.
This development reaches its extreme in the higher mammalia, where
the urinogenital sinus is completely separated from the digestive tube, and
where the urinarv ducts are also transferred from a posterior or hypo-
cystic position on the wall of the urinogenital sinus to an anterior or
epicystic position on the dorsal wall of the bladder.

Secondiv, there is a more fundamental association between the
reproductive and excretory organs, depending on the circumstance that
the former are primarily in the vertebrates organs connected with the

Thb Ubinogenital System.

47

lining of the codom and dischar^ng their products into the cavity, while
the kidneys are primarily tubular structures communicating also with
this cavity, so that they become modified in part as reproductive ducts.
The coelomic connections of the kidney tubules are with few exceptions
only seen in the embryonic condition, since the definitive kidneys in all
vertebrates are structures in which the tubules are connected with the
vascular system, and have either lost, or, as in the specialized permanent
kidneys of the mammalia, have not developed, the coelomic apertures
The embryonic development of a mammal includes the formation
not only of a final kidney or metanephros, but also of two embryonic
structures, one of which, the first kidney or pronephros, is embryonic in
all vertebrates, while the second, designated as the mesonephros, or
embryonic kidney, is one occurring in the adult condition of intermediate

FlO. 26, Diasraim of the male (A) and female (B) urinosenital
Byitemi uf the rabbit, b., urinary bladder; k.. kidney ur
-ureter: r. rectum. '*

<A)--C-P.. crua penis; d.d., ductus deferens; en., epididymis.
■■■,S'.^"**^"'"™ = ^:'**?^i»' v.a-. seminal vesicle; u.v.. male urethra

(»)--«.<•.. crua chtondis; o.. ovary; t.u.. uterine tube; u.m.,
female jrethra; ut., uterus; va.. vagina; vs.. vcslibulum.

forms. It is from the ducts of the primary kidnevs that the reproductive
ducts arise. Thus, in the female of most vertebrates the oviduct opens
by an expanded funnel into the coelomic cavity, usuallv at some distance
from the ovary ; and, although in the rabbit the structure is said to arise
as a secondary development, it exhibits here as in other mammals the
feature of a coelomic opening, coupled with that of close association with

i

48

Anatomy ot the Rabbit.

Ifi

the ovary, so that the products of the latter, while nominally discharged
into the coelom, are actually received directly into the uterine tube.
The oviduct itself is phylogenetically the oldest of the urinogenital ducts,
since it is identifiable in the embryo as the duct of the pronephros.

In the rabbit, as in all mammals, the testis is connected with the
urethra through the canal formed by the epididymis and ductus
deferens, these structures comprising in a modified form a portion of the
mesonephros and its duct. Since the excretory functions are fully
provided for by the development of a permanent kidney and its duct,
the ureter, the ducts of the embryonic kidney have in the adult no urinary
connections ; but in intermediate vertebrates, in which the mesonephros
occurs as an adult kidney, the interesting condition is observable in the
male that the duct of this' structure serves both urinary and reproductive,
functions.

It will be seen in the rabbit that the female genital ducts, apart
from the common urinogenital sinus, include an unpaired portion, the
vagina, and a paired portion, comprising the uteri and uterine tubes.
In all vertebrates up to and including the monotrematous mammalia
the oviducts open separately either into the cloaca, or into the urino-
genital sinus. In the higher mammalia, however, a process of fusion is
observable, extending from the partial coalescence of the vaginae, as
in marsupial mammals, to the complete coalescence of both vaginae
and uteri, as in man. Thus, there are recognized in the mammalia
the types of (a) unpaired uterus— uterus simplex; (b) semi-divided
uterus — uterus bicomis ; and (c) compleiely divided uterus, such as that
of the rabbit — uterus duplex.

In the respective positions of the central organs, as exemplified by the
rabbit, there are several features of general significance. Thus, the
kidneys (Plate VIII) are paired structures lying on the dorsal wall of
the abdominal cavity, where they are interposed between the peritoneum
and the dorsal musculature. They are covered by peritoneum only on
their ventral surfaces. As indicated above, the permanent kidneys ot
a mammal are highly specialized structures, but they show in these rela-
tions features common to lower forms and dependent in both cases on
the primary position of the intermediate mass, froir which in the em-
bryo the kidneys are formed.

The gonads are primarily associated with the dorsal lining of the
coelomic cavity, although certain observations on the development of
these structures in the lower vertebrates appear to indicate that their
elements arc assembled from other parts of the embryo. In somo of the
mammalia, as in all lower vertebrates, the testis occupies an abdominal
position in the adult condition ; but usually it undergoes an extensive mi-
gration, passing from the abdominal cavity into a special sac of peritoneum
enclosed by the scrotum. This change— described as the descent of
the testis— is effected through the agency of a muscular cord, the guber-
naculum. In many cases, as in man, the cavity enclosing the testis is
completely separated from the abdominal cavity, but in the rabbit a
more primitive condition is retained in which the sac of the testis is
widely open to the abdominal cavity, and the organ thus passes freely

The Senous Cavities.

49

from one cavity to the other. It is also observable in this animal that
the gubernaculum is represented in the adult as a short thick cord
connecting the end of the testis with the wall of the enclosing sac (Fig. 26).
In the female the round ligament of the uterus is a structure similar
in a general way to the gubernactilum, and in the rabbit will be seen to
be inserted in a depression of the body-wall resembling both in form and
position a rudimentary vaginal process. The ligament is continued,
however, beyond this point, ending in the wall of the urinogenital aper-
ture. The presence of this structu.i: is an indication that the ovary,
as well as testis, is subject to change in position. In the adult condition,
however, the ovary occupies approximately an original position on the
dorsal wall of the abdominal cavity; and it will be observed in the rabbit
that the position of the structure is one also defined by the points of
origin of the spermatic arteries and veins of both sexe's, with the ex-
ception, however, of the left spermatic vein in the male.

THE SEROUS CAVITIES.

The organs collectively described as visceral are those associated
with the serous cavities. They belong to several systems, but present
the common feature of being projected into the membranous linings of
these cavities so that they are more completely invested by them.

The serous sacs are extensive body-spaces, derivatives of a primary
body cavity or coelom. They are usually considered as containing the
visceral organs, but the condition is more accuratelv described as one in
which the visceral organs encroach, chiefly from a dorsal position, on
the enclosing membranes. The latter are thus divided into two
portions, one of which is distributed as a parietal or peripheral laver,
forming the enclosure of the sac, while the other is disposed as a visceril
layer on the surface of the visceral organs. The serous sacs are enclosed
by thin, moist, serous membranes, consisting chiefly of mesothelium,
which give to the visceral organ, their characteristic appearance.

In lower vertebrates, where ihe diaphragm is absent or imperfectly
developed, the coelom is divided into two chief portions — the
pericardial cavity, enclosing the heart, and the pleuroperitoneal cavity,
lodging the remaining visceral organs, including in terrestrial vertebrates
the lungs. In the mammalia the pleuroperitoneal cavity is completely
divided into two portions by the diaphragm, the smaller pleural portion
being again divided into right and left pleural cavities through the
presence of certain structures filling the median portion of the thorax.
There are thus recognizable in a mammal four large serous spaces,
namely, the pericardial, peritoneal, and paired pleural cavities.

The pericardial cavity, the smallest of these spaces, is situated
between the paired pleural cavities. Its enclosing membrane, the peri-
cardium, forms a capacious sac for the heart, and is reflected directly
over the surface of the latter as a thi:; membrane, the epicardium.

The pleural cavities are those lodging the lungs, the latter being pro-
jected into them from a medial position. The lining membrane or pleuia

i

N't

50 Anatomy of the Rabbit.

is divided into three chief portions — the pulmonary pleun, investing the
greater part of each organ, the coital pleura, lining the internal surface of
the thorax, and the diaphragmatic pleura, covering the anterior surface
of the diaphragm. The latter is broadly connected with the pulmonary
pleura through the pulmonary ligament.

The peritoneal cavity, the largest of the serous spaces, comprises in a
mammal a general portion, the abdominal cavity, and its posterior ex-
tension into the pelvis— in the male also ^nto the sac of the testis. The
general relations of the cavity to the abdominal organs is indicated dia-
grammatically in Fig. 21. Its lining membrane, the peritoneum, is
divisible into two portions, the parietal peritoneum, lining the abdominal
wall, and the visceral peritoneum, investing the visceral organs. Of
the latter the kidneys encroach only
to a minor extent on the serous
*/ lining, so that they are covered by
If peritoneum only on their ventral sur-
ilj faces. The digestive tube, on the
III other hand, is removed to such an

Ay // extent from the abdominal wall that

'■/ // '^^ peritoneum forms a complete

^ /' III serous cqat, and is connected with

* ' the parietal peritoneum of the wall

j^^ through a thin transparent mem-

'^i >!•)'/ ,'/// j brane, the mesentery. The latter

i//\l consists of two plates of peritoneum,

/ e.«\'\\ enclosing between them a thin layer

I f\ \\ °^ connective tissue, the lamina

// V \\ mesenterii propria, for the trans-

vtv 111 ill I t Ml mission of nerves, bloodvessels and

**"^*" ^ / I lymph canals.

bt-v .. M\ \\\\ / ^ As indicated above, the relations

"" w^'A^Ov Um - of the abdominal portion of the diges-

tive tube are greatly modified by its

by. ^^^^^\a\JEE elongation and displacement from a

^3ks^ wr# median position. Thus, while in the

embryo the common mesentery is
Pic 2fi. Diagmm showirg fche relation of rccognizablc as a coutinuous median
the t«t» to it« invesimeriu: a.i., inguinal vertical fold, in the adult it foUows

TinR; c.c. caput epididymidu: cr., crtmattir ,, ... c .i •• .- ■ «

muscle; d.d., ductus defei^nc: r.. gubtr- the COUVolutlOnS of the dlgeStlVe tube,

"r^'^^ii^taTand v^.^'^ty"^ oi^tL'^iunTc^ ^ud is therefore considered as divided
vaKinaiwpropm: ii.v, cavity of the vagiriBi into correspouding parts. In many

proress; b., integument of the scrotum; ,, \ ,. c .t .• ■

■ v., spermatic vi«sck; t.. tesiii. cases the relations of these are greatly

complicated bv secondary adhesions.
In the rabbit the mesoduodenum, mesentery, and descending mesocolon
will be recognized as parts in which a more typical arrangement is
retained. Moreover, in the anterior portion of the abdominal cavity the
peritoneum is concerned not only with the investment of two large visceral
structures, the stomach and the liver, but also with the formation of a lining
for the posterior surface of the diaphragm. Thus the general condition
is less simple than in th? ^mall and large intestines. The peritoneum,

Th« Stioi's Cavitiks. 51

passing from the dorsal wall, successively invests the spleen, the
stoinach and the liver, and is reflected from the last-named structure

Iri.^^.i.J"'' /!"? •?"'' ',•" '■^"'"' '»<'>■■«■«" through the coronuy,
Wangular, and falciform Ugaments. Its gastric portion is differentiated
™.li „™ t?"'""? fPh^n-cosplenic and gastrolienal ligaments), the
(TMter omentiun and the lesser omentum. Similarly, in the posterior
part of the body the peritoneum passes from the rectum to the urinary
bladder, enduing also m the female the vagina. It is then reflected to
the ventral body- wall as the middle umbUical fold.

In the male as indicated in the accompanying diagram (Fig. 26), the
pentoneal relations of the testis are greatly modified bv the migration
of the organ from an abdominal to a scrotal position. The entire sac
lodging the testis IS an evaginated portion of the abdominal wall, and

XhL'JI, 1 '■..'.. "i? ■""'"'■ ■' "''**'>' "?<■" throughout life to the
abdommal cavity, the lining membrane-that designated as the parieUl
tayer of the tumca vagmalis propria--is continuous with the STrietal
£!"'^r"T.?' "!f abdomen, and thus represents a permanent vaginal
procew. Like other structures of the abdominal cavity, the testis itself

L^r^!^ J peritoneum the latter being designated as the visceiml
tayer of the tunica vaginaks propria. 1 his investment is ccnnected with
^J^T,^ M" ^l "'? """"""i"". and in the rabbit it will be

r fi.U'"' ""^ '^'!*'' '^ -■'"^''y attached fcrwards en the dorsal wall
the testU i°S7' '^ ' '" " '"""''" '"''''^a"''8 'h^ original situation of
In the female the ovary is closely associated with the dorsal wall
S Jifi. . t!"' f^. '-^ supporting peritoneum, the mesovarium, is in-
si^n ficant Its duct m passing backward, however, becomes greatly
displaced from a dorsal position, and thus comes to be supported by a
broad fold of pentoneum. The latter is considered to consist of two
portions, one, the mesoulpinz, being the support of the uterine tube
the other, the mesometnum, that of the uterus. The entire fold how^
braid Sam^t"""""""^ structure, and is known in this relation as the

REGIONAL SECTIONS,
nf JilS'r'."^ plate-figures (I-VIII) are from characteristic sections
?L M 1 ? ."' ^^"""■' *"•* ""^y ''^ "*•' either in connection with
the general features of topography as outlined above, or for the identi-
hcaticn of various minor structures appearing in the dissection

Lertain points regarding the sections are perhaps worthy of notice
first, in the longitudinal section illustrated in Plates I and il it will be
Th f » !l > ^u"^ structures frequently appear; this being because of
the fact that the section is not exactly median, at least in certain places

f^ZfZ: '" "T"^ T"°,r' °' ""^ '""'"^ '"' «"» anatomical features
t is necessary to make allowance m some cases for the different propor-
tions of organs, and consequent slight differences in position, in the
foe al as compared with the adult condition. FinallyTmanv of the
features appearing in the original sections are such as could not be repro-

skelt^n^fii;" ^ ^ *'"'"i;^'' '.■"">■."" indicated in the accompanying
skeleton figures, and may be referred to in this way. «~ J s

id

hHO[OZ> S-

II ill

if?

Ill

nil.

E

sil- e ■ ■

■3^-2 « i 5 c E •
^ S 3 " S'S-SII'S

UKSICNATIONS VOU PLATK II

, TraiiHVcrM «lnu* of dura niHUT.

. Utira mater.

. Pallium of ccrtliral hi'miNphrrr.

. LaU'ral vt-ntrU'lf.

, OlfactiM-y Imlli

. OKMctury trait.

a. UlviJcil ul(HL'it>ry mrw in ihi' c

t>lBti<.

. Choriuid iilexti* nt third vfnlri.lt
, AntfriDr commiiiNiin:.
. Thalamun.
. ()|itic chlaNnm.
. Tiil« ■

lary 1
K'Hur L-oIlit
rnfen<M- o.llici||i.«.
AiiU-rior mtdiiilarv win

:i2. Mftxtlla.

:M. Hard iwlatr (falaiirir and maxilU)

iH. PrfBiihenoid.

'M. Intc raphe noiflal HynihtiiidrtwU.

M. banUiihrnuid L hyporihyaial fnua.

't7. 8|ihrno(Kci|iital nym-hiitiilroiiiH

■AH. HaNlitcciiiital.

:iHa. StiiiraiM-cipltal.

M. Naul )>(>rliun of iiharynx.

W. Soft palatr,

41. Oral jKirlion of ])harynx.

*2. EiiiKluttlR and eiilitluttic cartllBKf,

4;t. Tnyrrind cartilaicr of larynx.

44. Laryniteal cavity.

4.V 4.1a. Cricoid cartilairr.

4t(. OfophaKiix.

47. CricuthyreoidruH mitNtk:.

. Cerebral iit'dtindt; epphalic fltxu:

. Isthmuti rhomtienccphali.

. Fotirth ventridp,

. Pons; jHjntine flexure.

. Cer.>lK-lh

. Pcisicriu: •(liillar>' vcitim,

. Cirvkal . ire.

. CViitral canal of siiinal tord,

. IKpo]ihysis

. 1-ronlalUnf.

. N'usal bone.

. Nasal fossa,

. MtRFthmoid cartilaKe.

. CartilaKe of vomeronasal orfian.

. Premaxilla.

.. Thyreoid Kland.

'. SternohyoidL-us muscle.

'. OenioKlosstis muscle.

. Cicniohyoidtius muscle.

. Mylohyotdeus muscle.

. Mandible.

. Occipital musculature.

. Semispinalis capitis,

. Rhomboideus minor,

. Suiicrior portion of trapezius.

. Atlas.

. Epistropheus.

a. Odontoid process.

. Third cervical vertebra.

. Median vertebral vein.

. Body of hyoid bont.

A Median Vertical Sectki.v or the Head.

DESJC.NATIONS FOR PLATE III.

, Nasal bone.

, Lt:viitor olai' noNi must;

. Nasal seiumn,

, Nanoturbirial carlilatH-

. Maxillulurbiiial (luikIi.

. Nasal fu«Ha.

. NoNolacrimal diiil.

. Vomtrnnasal urKun am

. i'remaxilla.

. Small iii>i*r incisor.

. LarKC upiier invisur.

'. Na&oi>Blatint: duels.

;. Oral c-^vity.

ixUlary i

. TonKHC.

. Vihiiasae.

. CuiiinuH muKClt'.

. Terminals of (tiiitri

>, Buccal Klands.

. I'liccinator miistle.

. Terminals of infirior alwular nvrvi,

. Uuadratus labii infirioris nmsck.

. Mandible.

. Meckel's caililuKr (primary mandibular

arch I.
I. Mt'ntalis musclp.

HI.

A Transverse Section op thk Anterior n

ASAL Region

DKSTr.NATIONS FOR PLATE IV

. Superior satiittat sinus of dura

. Lateral ventricle.

. Cerebral hemisphere.

. Pia mater.

. Frontal bone.

. CartilatfE of orbital v-mn.

. Menethmoid carlilaKi'.

. Cupula iiosierior cartilaKO.

. Obliiuus superior musck.

. Ophthalmic vessels and nerves

. Levatnr iwlpebrae sinicrioris n

. Rectus medliHs miiNtle.

2."). Nasal tract: choanu.
2fi. Palatine iMine.
'J7. Oral cavity.
■2H. Palatine n

2'.l. Sphenot«l

.JO. Infraorbital v___.
■'II. Internal maxillary a
■.iJ, Maxillary ntrvc.
:i;t. Ma.\illa.
;M. /.ysonmtic Iwne.
;i'i. Submaxillary duct.
■iti. Buccinator muacle.

l'.1. Retractor buibi muscle.

U. Rectus inferior muscle.

Wh Sclera.

IB. Retina and choriotdoa.

17. Vitreous Ijody.

IS. Uns.

19. Posterior chamber of eye.

20. Anterior chamber.

21. Cornea.

Zi. Ciliary body and iris.

23. Upper eyelid.

24. Lower eyelid.

'. Masseter muscle.

I. Parotid duct.

I. Facial nerve.

I. External maxillary artery and ve

(anterior facial vein).
. Platysma muscle.
'. Inferior labial artcrv and vein.
. Mandible.
. (lenioHlossus muscle.
. Diftastricus muscle.
. Quadratus labii inferioris muscle.
. Geniohyotdeus muscle.

i)l

A Transverse Section- of the Orhitai. Reoiox.

DESIGNATIONS FOR PLATE V.

. Parietal bone.

:. Transverse ainus of dura matLi

I, Sii|ierior colIiculuN.

. Cereliral a'liiediict.

I. IsthmtiH rhomlK'nct^hali.

. TriKcminal nerve.

. Basilar artery.

. Facial nerve.

'. Cartilatiinous auditury cajisiik-.

'.'■i. Lontcns cat'itifi.

'SJ. Kecius capiti!< antcriur.

2'-t. Oral tmrlion of pharynx.

'2\. Thyrcohyoldeux muscle.

^■1. Stemoh^oideuH muscle.

2ti. (Ireater com-.i of hyoid.

Li7. StvluhvoidckiN major muscle.

'in. LinRual artery.

2H. HypoRloKsal nerve.

3l». Tendon of dixa-stricis muscle.

;n. Exlemal maxillary arteiy.

Itt. Tri;.iiUTi s of |M>sterior fatwl vun.
17. S'luamusal lionc.

in. Ci'iihaii,- |>ortion of median vertebral
m. NbmI jioiJon of i)har>n.x.
•-''t. OriKiti uf Iwsiuilavicularis and 1< va
Kapulac major muscles.

:12. Stvlohvoideu:

;«. SlvloBloHSUS.

■'14. Internal inaxillar>- artery,
■i.'i. Tymi«nic lone.
III. Mandible.
;t7. Submaxillary gland.
;iH. AnltriOr facial vein.
.'HI. Internal tarutid artery.

A Transverse Section (,f thk Aiiditorv Reoicn.

DESIGNATIONS FOR PLATE VI.

1. Rhomlioideus niimir.

2. Superior iKirtion of tra[«7iuit.
2u. Levator scapulae mirair.

:). Sijlenhta'.

4. SetniapinaUri capitit.

J). Kectnn capiti:( (xKitFriur shiktIi

6. Ohli'mufl capitis major,

7. Arch of epistropheuH.

N. (lanfiUon of iKWterior root.

U. LoriKistimus cervicis.

Ill, Ocfto|)hagtiH,

'2X\. Infurior ihyreoid nerve,

21. Inferitif thyreoid vein.

«. Trachea.

a.1. Thyreoid irland.

•24. Cardiac liranch of vaKi» (n. depreuoi).

2'i. Symiialhelic trunk.

aa. VaKus nerve.

27. Common curotid artery

28. Internal jiitiiilar vein.

10. LonKisdimus capitis.

11. Vertctiral artcr and vein.

12. LonKus atlantis.
i:i. Vertebral body.

14. TransverM process (anterior root).
1.5. Median vertebral vein,
10. LonRiDt colli.

17. Longus capitis.

18. Fat ■

igus ca):
-body.

. Sternohyoideus muscle,
. Slcrnothyreoideufi muscle.
. Stcmomabtoideus muscle.
. DeacendinK ramus of hyt^oRlossal r
. External jugular vein.
. Baaioclavicularis muscle.
. l.«vator gcapiilae major muscle.
. CleidomaHtoideuB.
Platysma.

A Transverse Sect,„x of the Axteri„r Cervical Rec.u

DESIGNATIONS FOR PLATE Vll.

i. ScmiH|iinalM JurNi.

2. LonjiiaaimuH doni.

:). IliocMtalU.

I. Spinal cord.

•*>, Ganitlion of iKMtcriuT

fi. Tulicrcle of rib,

7. Head of rib.

S. Symtwthctlc trunks,

1). \f,yKf» vein.

10. Thoracic aorta.

11. (X^BophBKiia.

root and IntiTcoi^tal

24. Cottul pleura.

'2!i. Bone tiIm.

W. Coctal rartilnKe.

27. Sternum.

28 C'.itaneuH maximum muitclc.

29, Interior iiortion o( trair^zint.

30. Khombcrideiii major.

31. Inferior anfflo irf Kcaiiula.

32, Latissimus doryj.

33. Sermtus ponterior.

34, IntercustoIuR exterri and inttrr
;i43. ! nte re o« Valla inlcrnu,i.

12 12a. Right and left vaRi.

13, LiinR,

14, Bronchi.

15, Branches of imlmonari' artery,

16, Pulmonary veins,

17, Right atrium.

18, Tricuspid valve,

19, Right ventricle,
2U. Lc7t atrium.

21. Left ventricle.

22. Pericardial cavity.

23. Pulmonary pleura.

I. Thoracic portion of scrratus anterior.

(. Obliquus extemus abdominis.

'. Transversus thoracis.

1. Pcctoralis major.

t. Rectus abdominis.

), Anconaeua lotixua (i^aput lunKtim of

triceps). t

I , Extensor antibrachii jwirviis.
i. Anconaeus medialis,
t, Anconaeus lateralis,
k Distal extremity of humerus.
>, Proximal portion of radiiis.

VII.

A Transverse Sectkin op the Thdrax.

DBSIONATIONS POR PLATE Mil.

iHle.

:i. Verteliral Ixxly.

4. SAcroHvinaliH m

A. Ouadratuti lumborui

n. PaoMi major.

7. PaoAK minor.

K. SymiAlhetic trunk.

{). Altduminal aorta.

18, Itte. Posterior and anterior lolnilM of left

lolw of liver.
lOJfta. Right lol« of liver. _

3o.*Obli<|uuH'internu« abdomini* and trani-

vervuH ■bdomini^.
HI, Ohli'imia extcmuH alxlomiriii',
22. Rectkia alidominis.
22a, Cutaneus ma.timus.

10. Inferior caval vein.

11. Descending meaocolon.

12. Ureter.

n. Renal pelvU.

14. Renal papilla.

Ifl. Left kidney.

16. Parietal peritoneum.

17. Viaceral peritoneum.

2H. Middle vimlnlical fold.

24. L'rinary bladder (canal of foetal allantoU).

25. Umbilical arteries.

26. Duodenum,

27. Pancreas and mesoduodenum.

28. DescendinB colon.

29. Parts of mesenterial small intestine.
:'.Q. Caecum.

VIII.

A Transverse Section op the Aiidomen.

PART II.

OSTEOLOGY OF THE RABBIT.

For a practical atudy of the rabbit'a slccleton, a thoroughly cleaned,
but otherwiK rough, unmounted (keleton will be found moM convenient.
The >kull should be divided with a fine aaw at a little to one lide of the
median plane, or a second skull may be provided for this purpose (cf.
Fig. 33). The mgst. useful specimens for reference are: (I) a well-
mounted skeleton tff the adult animal, showing the natural relations of
the bones; and (2) a rough skeleton of a young animal of from one to
five weeks, showing the primary composition of cartilage bones. For
the special study of the skull (pp. 85-07) a disarticulated specimen may
be empkyed, but the majority of the features may be made out in
the intact or divided skulls. The general account of the skull as
given below will be found to cover most of the osteological paints
noted in the dissection.

DIVISIONS OF THE SKELETON.

The skeleton is divisible into two main portions, namely, the axial
■kttotoo and the apptndlcular skeleton. The former comprises the
vertebral column, the ribs, the sternum, and the skeleton of the head;
the latter, the supports of the anterior and posterior limbs, and the
associated pectoral and pelvic girdles.

THE VERTEBRAL COLUMN.

The vartoteal cohunn (columiyi vertebralis) is formed of a linear
series of segments, the Tartabraa. In accordance with its function as a
general support of the body, and also its relations with the nervous
system and the spinal musculature, the vertebrae, with minor exceptions,
are constructed on the same plan. Those of particular regions also
present certain features in common, so that it is possible to classify
them into cervical, thoracic, lumbar, sacral, and caudal groups.

A typical vertebra — for the characters of which any one of the
thoracic or lumbar series may be taken (Fig. 27, D-F) — consists of a
basal portion, the vartabral body (corpus vertebrae), and of a dorsal,
▼ertabnl arch (arcus vertebrae). The two portions enclose a large
apertiu-e, the vertebral fotamen (foramen vertebrale). The successive
foramina form an almost complete tube, the vertebral canal (canalis
vertebralis), for the accommodation of the spinal cord.

The body of a vertebra is a cylindrical, or somewhat dorsoventrally
compressed, mass of bone, which bears at either end an articular surface
for attachment to the adjacent vertebra. The articular surfaces are
borne on thin plate-like epiphyses, the epiphysial lines being evident
even in older animals, especially in the lumbar region. The dorsal por-

~-. iiuwnar imtpa» of the pcdUc an aotdNd. cuk oatdi

thi

■atcfior

f^-

70

Anatouy or TH« Raiiit.

i

The trch of the vertebra in noteworthy for iti pmjectioni or |
On either tide ii a horiionul plate of bone, the truntrM procMi (pro-
r«»"" transversus), and, dorully. a median projection, the ipinooi
proem (processus spinosui), all three serving for the attachment of the
vertebrae to one another by ligaments, and for the attachment of the spinal
muiculatiire. Special articular surfaces, borne on low articular pro-
CMMt (processus articulares), are found on the anterior and posterior
itiar^ins of the arch. The anterior, or ninrior articular nirfacn are
directed for the most part toward the dorsal surface, and are overlapped
m the natural condition by the infarior articular iurfacM, which are
directed toward the ventral surface. A certain amount of movement
IS permitted by one surface slipping across the other, the mechanism
Illustrating the arthrodia, or gliding-joint.

The cervical nrttbna (vertebrae cer\'irales) are seven in number.
The posterior live are similar, while the anterior two are speciallv modified
m relation to the skull. The posterior vertebrae (Fiij. 27, C) are dqrso-
ventrally compressed, their arches low, and the spinous process short.
In the seventh vertebra, however, the spinous process begins to be elon-
gated as in the succeeding thoracic vertebrae. In each vertebra the
transverse process is perforated by a coato-lnasverM foramen (foramen
transversarium), the latter serving for the passage of the vertebral artery
forward to the head. Through the presence of this aperture, the base
of the transverse process is divided into two parts, namely, a dorsal,
or postarior root (radix posterior), and a ventral, or anterior root (radix
anterior). The anterior root is a coalesced rib, and is comparable in its
general relations to the normal ribs of the thoracic vertebrae.

The first vertebra is the atlai (Fig. 27, A). It is peculiar in lacking
the vertebral body, the latter being represented by the odontoid process
of the epistropheus (cf. Plate II); also in possessing special articular
surfaces, and in having its transverse process greativ flattened in the
dorsoventral direction. It consists of a ventral half-ring, the anterior
arch (arcus anterior), a dorsal half-ring, the poaterlor arch (arcus pos-
terior), with paired lateral manes (massae laterales) uniting them.
The lateral masses also form the bases of the transverse processes. The
anterior arch bears on its ventral side a small backwardlv-directed
process, the anterior tubercle (tuberculum anterius). A similar
posterior tubercle (tuberculum posterius) on the dorsal surface of the
posterior arch is comparable to the spinous process of an ordinary
vertebra. The anterior surface of the atlas bears on either side an
extensive concave smooth surface, the superior articular pit (fovea
articularis superior), for articulation with the convex occipital condyles
of the skull. Its posterior surface bears on eithe5 side a somewhat
triangular inferior articular facet (facies articularis inferior) for articula-
tion with the epistropheus. These surfaces take the place of the arch-
articulations of ordinary vertebrae. Through the compression of the
transverse process, the costotransverse foramen is converted into a
canal. The anterior aperture of this leads by a shallow groove, the
sulcus arteriae Teitebralis, into a second aperture perforating the
posterior arch.

The VKiTKa> \l Coli'mk. 7]

• ' ' u tupwiar articular facets
'■• ■. IIS vertebra and the trans-
-11' r three main points of attach-

'horaiales) are twelve in number
1 ^session of articular pita for the
nh 15 articulated at two points,

the odontoid pnii<-., urui t> 1,
borne on its base Iht .wn.,11. , •,„
verse processes 01 'ho all. ■ 1 ,ri.. i^,-
ment for the o«i|Mlii mi.-,(ul:. mp "
The thoracic Ttrtebr* I ('fM.ra-
They are distinguishes! ihic-llv .)■■■ I u
attachment of ribs (Fip ■>!'■)' \

SI^e« Th.°? "" ^ ' ' ^•""•■""' 'he otheVon "the'tr;n7ve'r«
S borne wholly on'tS^ 'v"^b™ri,dv"o wh ch thrri^Mors "'inTh '

devetowd^'Th^r- °' ""^ "?°T''^ *"" "■* spinous processes are well-
a lusea rib. At the posterior 5 de of the base of each i« a «h„r. n .. i

=™' ^^r-^ifrsLxd^ JSSPir

articular processes are rotated upward, so that ther^^es are direcT^

72

Anatouy op the Rabbit.

more nearly toward, or away from, the median plane, instead of to the
dorsal or ventral surface. The anterior articular surfaces are borne on
the bases of stout, upwardly-directed mammillaiy procesiei (processus
mammillares). The latter are most characteristic of the lumbar verte-
brae, but may be seen to arise in the posterior thoracic region as small
elevations of the transverse processes. Each of the first three of the
lumbar vertebrae bears a median ventral projection, the anterior spinoui
process (processus spinosus anterior), for the attachment of the lumbar
portion of the diaphragm.

The sacral vertebrae (vertebrae sacrales) are four in number. In
contrast to the true vertebrae— those united by ligament and articular
surfaces— of the remaining portions of the vertebral column, they are
fain vertebrae, united in the young by synchondroses, and in the adult
coalesced to form a composite structure, the os sacrum (Fig. 28). The

Flo. 28 The oas»cnim: A, venttmJ (pelvic) surface; B. doraal surface:
c-v.. bodie« of coalesced vertebme: £ a„ .luricuUr surface; f.s.a., anterior
sacral loiamina; f.a.m., median sacral foramina; f.s.p.. posterior sacral
foramina; p.a.s.. superior articular process of first vertebra; p.m., mam-
millary process of firet vertebra; pr. promontory; p.s., spinous p

axis of the sacrum forms an obtuse angle with that of the lumbar ver-
tebrae, the angle being indicated by a ventral projection, the promon-
tory (promontorium), formed by the last lumbar and first -acral ver-
tebrae. The sacrum is the medium through which the vertebral column
— in other words, the posterior portion of the trunk — is supported on
the posterior limbs. Its anterior dorsal portion bears on either side a
roughened area, the auricular surface (facies auricularis), for articulation
with the pelvic girdle. This surface is borne for the most part on the
transverse process of the first sacral vertebra.

The Ribs.

73

P.IT.C .urf,c. (facies pelvi„a)^he line, onuncH^- °''u"" ^™'"'. »'
between the bodies, or between the ranfj,il°" '"^^^ "•»«'' """er
apertures on this surfac™ The „,.„" "'~>^— ™'^'*'' ^""^ P^'" »'
anteriora), lead into thiZ"'n!brThlI^^i'°'^'°^^^'^^i>^
the sacral spinal nerves. On the do~l •"rf-^/f''" ^"^ P*'*«« '°
of posterior „cral foramto. UeTn th^Tine^? ' ^ *.•'" 'l"*'"'' » P^"
second vertebrae. ThTlDino, ? Ir Junction of the first and

vertebrae. The comb1ned'^a"°rcnir;Tn7Va™ T''""' '" »» '°<"
conspicuous only in the first tvro hnt .,. niammillary processes are
two by low, roughened tub^Tcles In ,Jf/'^*H"if'' •" ""= ^""ceding
vertebral arches are separated by cln '^"'^ '"'•" ""^^"y'hf
^uous apertures, the mSlian «.cSi fZ'

are^sl■x^e1n"'^ T:^^; '^Ttf"^ ^""'"'■"^
of small size, incr^a^ingsligm y .r.re'S'
?he''c^uln^'"'Tte' dfcrealn/ 1'„" tten'd^o'f
firstTvTn Th.^'^''^' "' ""P'^'^ in the

THE RIBS,
on ^emief'si^r^Xr '"^'^^ '" """">-

^:tdiS^7?S'°?-^^

veralfanTf^^^i^^'^^-J^ul^

l°™r'™H""P"?"« the anteTi" tvel^ '""""■ '"'"

£f r«--r L"d&-ua J,^----«'™™the
Generally spea.ing, the bone-ribs a^c;l«;drical ; but the anterior

minubnumsterni; o.c bon- rih'

i

• 6

74 Anatomy of the Rabbit.

five or six are more or less flattened, with their main surfaces respectively

mXl knd laTeral. The compression is most marked m old animals^

Thf first rib is extremely short The succeeding ribs increase m length

To the sixth and thTn decrease to the twelfth. The arch formed by

«ch rib has its greatest convexity, or uigto, at some pomt toward the

TrSal surface Passfng backward, the point of greatest convexity

changes from a medial to a lateral position. This, together with the

elongation o" the more posterior ribs, results in an enormous mcrease

in the oosterior extent of the thoracic cavity. .■ . . j

X'^erXal end, or he.d of the rib (capitulumcostae),.s articulated

with the bodvof the Vertebra to which it belongs and also, in the case of
The first tVn with the vertebra immediately in front. The art.culat on
luh a transverse process is marked by a small smooth devation, he
r«Ul tuSrde (tuberculum costae). It is present only ■" th* fi'^' "'"'
ribr Except in the first rib, and in the last four, the tubercle bears a
Tharp dS v-directed process for muscular attachment. The slender
K,rtfon of The rib intervening between the head and tubercle is the neck
(S,ium costle" the remaining larger portion being distinguished as

'■'^ r^^b^; 'tUr irrrmed'b? the ribs and the sternum with the
assis-TrnW the thoracic vertebrae. It enc oses a large ^Pace, the
A^ekavity (cavuni thoracis). The latter is conical m shape, «ith
!^ra,^x""ected forward. The dorsoventral diameter of the av.ty
s conSeraWy greater than the transverse diameter. Apart from the
ntwcMtal SD«c«, the cavity is open at two pomts: antenoriy, the first
SLrac^ verTbr? the firsi rib, and the manubrium stern, together
enc ose a sman opening, the «.p.rior thoracic aperture (apertura thoracis
suSrI ^slfrioriv the seventh and succeeding ribs, together with
!hr»>sterioMhoradc vertebrae and the xiphoid process of the sternum.
encir« a much larger opening, the inferior thoracic apertur, (apertura
thoracis inferior) In the natuial condition it is largely closed by the
^rXagm The curved boundary formed by the ribs m this region
fs the CMtal arch (arcus costarum), the angle formed at the point of
attachmenTof the xiphoid process being the infr»stem.l angle (angulus

'"'Through Uieir articulations with the vertebral column, and the nature
of the "o"tal cartilages, the ribs are capable of being ■T"'. "^ ™„'f 'f,^^
forward. The movement results m an increase of the extent of the
thoracic cavity, and is of importance in respiration.

THE STERNUM.

The rtemum consists of a linear series of six segments, the stornebrae.
The firs, tgrTni ,s the manubrium stemi. It is about twice the ength
of th mSdle seKment* ll .s *mewha, trianRular in section, two of
Us sur,a";Tbem^ent,a».eral, Ibe third d.rsa. .-«« ^-^^^^'-^
the thoracic cavitv To i»» a«en..r tip is attached «be Hgrooclavicuiar
lig^«rb> wtoch the .Wiv reduced clavicle is united with the
Sternum.

The Skeleton of the Head. 75

bodrMZs^sfemil**'?^" *:r™"" '" appearance, and form the
•"•Of (corpus sterni). The sixth seirtnent described as th.. irli.i.»u
procMi (processus xiphoideus). is an elongated J rio of bo^I ,^ ,^
■"'^r fir,"," "'.",'■"'■ ■'' f "''^'■^'' » broad.^rhrn pC of cartulge" ""
m„ J K • T"*' ""^'a""" is situated at ab^ut the middtf of the
Five of Th""' ""^ «■»»'" "8 ^^ a' 'he points of junction of The 4ments
le attached tortLr^'Ii,'"'"' l^'V'"'" «"'' -venth costal ca?tTC
»rpus st^l wTh'^Se xiptd^^rL^"""-'"' "' '"^ '^^' -'^"-' °' '-^

THE SKELETON OF THE HE.AI)

the'^Jl^^^lnt'/'jThe'raHT^ '" .'!!'-.«^"<^'=°f -'ements constituting
UK mm, ana (J) the hyoid bone, with its connections Thi. ..loii „,
cran.um-using that term in a general sense indues [he ^u^
rS' "' P^"'™ en-^'o^nK 'he brain and containing mitl ^Z
auditory capsues. and the bones of the face (ossa facii?^) the iauer in
eluding the series of elements related for the most mr in .h ,

^late. The primary relations of the ^nstltuTt " he I .tl':,:!';"'
have already been indicated above (p. .31). u'^d sKelelon

A. THE SKULL AS A WHOLE.

.1™'"'. ^''"u'l" "^■nposi'e structure, consisting of a large number of
elements, which, with the exception of the mandibie a?e "mUed I v
L"nH hr^'' "" """ ""'>■ P™''"" ""■ -«"■' "' a contiguous mas The

:rSdA?tr^^ ^t:i^^----- arti^ated- -thTi;:

f.ciIl''Mrt!l.'i''„r^'"^' f'''"^" '"'■" •"■° '"'•""'•s- """"-I^-. an anterior

iJ^VLT .u ! """ '^™aining special sense organs, the eve is not

apex being formed by the anterior extremitx ,>f the upper iaw ami the
mcisor teeth Its base is fornied in part bv th connSiin with he
cranial.portion. asalready described, an":! also by theTntemr^aUs of Z

(nlJ,!'l''"°t'i''?'^"'° "''"'''' ■"■ ^"'ensive posterior, nuchal surface
(planum nuchale . situated in general at risht .nries J!, 1 1^ sunace
portion of the vertebral column and ali to thTSorsaT L e ^1 a, d v™,'ra1
^iita toL w" , ,V''' '"'"" '"''""'' '"e external tr'uc.f"h
ktter iKdoVs, ^' '■f'^P'""' '•hiefly. of the basilar portion of the
latter lis dorsal portion forms an area of attachment for the soin-,1 -.nrf
special occipital musculature. Its ventral portion is ;:eri;,raT«l by a

ilJlU

76

Anatomy of the Rabbit.

lari^e aperture, the formmen nugnum occipitalCt for tlie passage of the
central nervous system from the cranial cavity into the vertebral canal.
On either side of this is a smooth, ridge-like projection, the occipital condyle
(condylus occipitalis), for articulation with the superior articular pits of
the atlas. At a little distance lateral to the occipital condyle, the
nuchal surface is continued downward through the medium of a some-
what triangular, pointed jugulftr proceis (processus jugularis). This
structure is separated from the occipital cond\ le by a pri nounced notch,
the posterior boundary of a deep narrow excavation, the jugular fossa
(fossa jugularis), which lies between the condyle and the tympanic bulla.
The jugtilar process serves for the attachment of muscles belonging to the
tongue, hyoid, and mandible, namely, the styloglossus, stylohyoidei
major and minor, and the digastricus, the suspensory ligament of the
lesser comu o* the hyoid also being included in the ligament of the
stylohyoideus minor. Toward the dorsal margin of the nuchal surface,
the dorsal surface of the skull is projected backward as a shield-shaped

iM^

3n. Lateral surface of thr skull : AS. alinptxrvoid (aJa rnatmB): BO. laKioccipitai
(bwilar t>ortion of occipiul). *8 bfcuwpKtnoW (tiodv ol j>o"terior sphenoid'; F,
frontal: 1, hiterparittal; L. lat^fMuil; M. maxilla. fcfS. magf^ tM-jirii'is of t>ctr'jsal
( petromaBtoid) ; N, nasal; US. orLHoepht nuid (ala |«rva): P, i<arielsl. PL, palatine;
PM, pT^maxilla; SO. sujiraoccipital <&'|)«>inoua jK^ttion ut occipitali; sy. s'luamtisal ;
T. tympanic; ZV. xysomatic.

a. p., piriform apiirture of noee; d.i. incisor teeth; d.m, molara. d ptn , prenn .ars;
f.i., infraorbital foramen; t.mx., maxillary fonsa: f.o.. ojrtic foramen; !.».. btylomaKtotd
foramen; f.t.. temporal fosna; I.I lateral lamina of ptcryifoid pruceM: l.ni.. medial
lamina; m.a.c, ckscdus jiortion ui cxtrrnal acoustic ntratus; p.*., alveolar [iroceKB of
maxilla; p.e,. ethmoidal portion of orbitoaphenoM p.f., frontal procew of premaxilla;
p.j,. jt^sular process of occipital: p.m., ntMtoid i/T'icess at maitotd: p.mx., maxiljarv
process of frontal; p.j., orUuU process of niaxilU, po.e., external occiptt«i jn-otubw'
ance: p.s.. squamasal iirucess of parietal: p.i.a. and p.R.p.. anterior mv4 j-n-trrior
supraorbital proccKBes of frontal: p.«,. lygomatic process fk f i\iamtMit\ . p z ni , «y«o-
matic proces.q of maxilla : s, sphenoorbilal process of maxilla, «.m.. Bjiina mafiMterica:
sq.. squamosal pro(%st^ of M|uamusal.

promontory. The lateral margin of this projection is the mperior nuchal
line (linea nuchae superior). It forms a curved ridge, the position of
which indicates the dorsal limit of the occipital musculature 'I'he
posterior, somewhat tri-rudiate tip of the projection is the external
occi|Mtal protuberance {proluberantia occipitalis externa), an important

Tiis Skull as a WHoie. 77

and internal pterygoid muscles oTthetandible '"'"'"' "' '"^ '""""'''

of thf ;a?erar^^ins"LTet°' "' '"fT^V^ "^''' '^e external surface

11

's^''^mmsm^mm&.. .

n

ASATOMY OF THE RaBBIT.

rclatiuiis kA which are more fullv dealt with below (p. 90). The
dorsal portion of the tympanic bulla is continuous with a short bony
tube which opens at a short distance dorsad by a large oval aperture.
This tube is part ot a more extensive canal, the eztemal acoiutic HMttuf
(meatus acusticus externus) which, in the natural condition, leads down-
ward through the base of the external ear to the tympanic membrane.
The tympanic bulla does not form the lateral wall of the skull in this
region, and is not exposed to the cranial cavity. It is applied closely to
the external surface of the periotlc or petromutoid bone, which forms
the lateral boundary of the cranial cavity, and contains the structures of
the internal ear. The external
ormastoid x.:;rtion of this bone
appears in the space enclosed
between the tympanic bulla and
the jugular process of the occi-
pital bone, where it is readily
distinguishable by its pitted
appearance. Its ventral portion
bears a slender projection, lying
parallel to the jugular process,
'the mastoid process (processus
mastoideus).

A series of foramina, lying
partly within the orbit, and
extending thence posteriorly
along the boundary between
the lateral and ventral walls to
the occiput, put the cranial
cavity in communication with
the outside, and serve for the
passage of nerves and vessels.
The first and largest of these,
the optic foramen (foramen
opticum). occupies the middle
portion of the orbit, and trans-
mits, in the natural condition,
the optic nerve. Following this
is a vertical slit-like aperture —
not to be confused with the
perforations of the external
lamina of the pterygoid process
—the superior orbital fissure
(fissura orbitalis superior). It
represents both the superior
orbital fissure of the normal
mammalian skull and the
foramen rotundtmi, and provides for the passage outward of the
third, fourth and sixth cranial nerves, together with the first and
second divisions of the fifth. The lateral lamina of the ptervgoid

p.o.t.

FiH. 31. Dorsal surface of the skull F, frontal;
I. inUrpariei&l: L, lacrimat; M. maxilla; MS.

iBJ (tx'iromastuid);

.ocoipiLal (s.^ua

squamcMal :

P. nariet
portion oi occipital ) ;
KyKomstic.

f.mx.. ma-tillary fossa; f,t,. umiioral fodKa;
l.n.s., superior nuchal line; l.i,. temporal line;
p.f., ironLal process of pn;maxillfc: p,mx..
maxillary procc-M of frontal: p.o.e., extpma)
occiplial protuberance: p.s.a. and p.s.p.,
anterior and pt>iterior supraorbital processes trf
frontal; p.sc., subcutaneous proc-iss of lacrimal ■
p.;;.. xyKumatie process of snuamoxal: p.s.m.,
zVKomatie process of maxilU s.f , frontal spine.
;..m., spina masseterica

The Skuli. as a Wiidijj. 75

.he auditory con,pl„"C oMhesT^ har.rwaVd Ih" rrtdrr""" "'
he mt.mal croUd fo«n«, (foramen caVm cl rm.rn.mT ? *is Jh' .l'
tenor end of a canal transmitting the internal crr'HrfTrL 'V''"' »""

=?,=^;^';sLaaSin ■sStFH' "-

eavtty and in the natural condition the tube pli"sth^°a\^tvTTJ
muntcafon w„h the nasal port»n of the pharv^^^ .^'^da ed' «Tth the

^ril^'". '''"'" '^"'^'"«''' by the cranial portion of the skull is the c™ni«I

80

Anatomy op the Rabbit.

small division lodging in the natural condition the olfactory bulbs of
the brain. The middle cranial fOHa, the largest division of the cavity,
lodgfs the enlarged cerebral hemispheres. The poiterior cranial fossa is a
small division extending backward to the foramen magnum, and lodging
in the natural condition the cerebelhim and related posterior portions of
the brain. It is partly set oflF from the middle cranial fossa by a fold of
the dura mater, the tentorium cerebelUi which projects inward from the
dorsal and lateral walls of the skull. This fold is usually found adhering
to the intt-rral surface of the
skull, nntess the latter has
been vcrv • 'orouRhly cleared,
and in ">ses its posi-

tion is . '-'Uted by a low
ridge ,ne. The marked

diflferei ,■ in diameter between
the miildle and posterior cra-
nial fossae is accounted for by
the sreat thickness nf the
auditory portion of the skull.
The anterior surface of the
periotic bone will be observed
to form an extensive posterior
wall for the middle cranial
fossa.

The floor of the middle
and posterior cranial fossae is
not smooth, like the external
base of the skull, but presents
in its anterior portion a pro-
minent elevation, the aaUa
turcica, which is Ijorne on the
body of the posterior sphe-
noid . 1 1 con tains a large
central depression, the hypo-
physial fossa (fossa hypophy-
seos), which in the natural
condition lodges the hypo-
physis or pituitary body. The
aperture of the fossa is partly
enclosed laterally by a pair
of pointed posterior clinoid
processes (processus clinoidei
posteriores), the tips of which
arc directed forward ; and a
corresponding pair of anterior
cliroid processes lie at the
anterior end of the fossa, with
the tips directed backward. The posterior, and also dorsal wall of
the fossa, described as the dorsum sellae, leads by an abrupt curve

Fig. 32. Ventral surface of the skull: AS. ftli»phenotd
(h1« maKna); B. b||iflttUlilil (basilar (lurtiun of oc*
cimtoi;; BS, 'MiiinThn""" "^~"- of pobt^rior sphcnuid);
KXO, cToccipital: mT maxilla; PL, i^alatint-; PMX,
Iirenmxilla; PR, pnmphenoid (body of anterior sphe-
noid); SO. "upraoccipital (siiuamoui portion of occi-
pital): SO. sqiumawJ; T. tympanic; JEY, zygomatti:.

ch, choana, c.hy.. hypoglossal csiul; c.o.. 'ocdnttal
condyle: f.c.e.. external carotid foramen: fin.. iacin««
foramen; f.j, jugular foramen; iM. foramen Uamm:
f.m., mandibular fot.' a: t.m.o., forai^.en tnasnum;
f.p.m., creatcr paiatine foramen: f.s.a.. anterior splM-
noidal foramen: m.a.e.. osseous portion of external
acoustic meatus: p.i.. jugular process; p.o.e.. external
occipital protuberance: p. pi., palatine proctss at maxilla:
)>.l'm.. palatute process of premBiiilla: p.pt., medial and
lateral laminae of pterygoid process of iKHterior sphenoid:
!>.m., spina massetcrica.

THg Skui.1, as a Whole. g,

the po„, and „,^„,i. oWo.^^'u ^70"^ ,h, /n.""'""' T""'"""
middle cranial fo!«aahel«ieraJwan, of thr«ir,,l '"'"'?' ™'' "' "•«
» thai the anterior portion of ihrhL.^,- " *" «""">■ eompressed,
anterior sphenoid, if larTcrv exdudTd from ' ,'h'*'"'"^ ,""= ^y °' '"e
usually paired optic foramiiu »■•- h.r ^ ""^ "*""»' ™vity. The
apertureTor the traLSn ^fZ XZ^T '' rtl'?'"'^ ^ »""'■'
boundary of this aperture contain. .iJrI,j . Posterior ventral

Which lodges in thrnaturaTrd" til'Z'ol-r^hiltr'" ''-'••™"''

and ser^i„g for thT^^i^^ ^l^T<^^''J:"f'7T\?' ''''' '"^''^ *>«>'.

median portion ptojectsStll ?„.o ,h '■''w "''"'•""y nerves. Its

crittag^. whicrs'im^rttdMi^cn ihTtiolM^f "Ir" '""■ "''«^' '"e
. In the ventrolateral ^rUon of the cr»n Lf ?* "Ifactory bulbs,
internal openings of the foramrnade^rih?rfil, ''''''>' ""^^ ^ '""'"^ "■«
orbital fissure, the forame"b"e™,^The^lfl^7' "*■"''>•• "''^ '"Perior
glossal canal. The superior orb™2^' fissured .li"'^""'"' ""'' ""= ^yP°-
to the foramen opticum and is «^n„r, h I ?°'';'^"'''''' "' 1"^"^"
lacerum by a broad gr<Sve thf .Xi »h.„„M''ir''''.*'L'' ""^ '"'^"'^'^
natural condition the^rootso the fift"n??« ''?^' "''""' '"''«" '" '"«

t'e^rr^;^'c:ret^i°^ ""^ '^''""^ ^- "^- iHrb^rgirvTbrth':

com°p:cfwrrU™»'p:,''rt^^^^rJSe'SJrn """ ''"''°-'' "^ '"^
apertures leading into its subs™nce oSl „?th..^ '' ■\»,«^"" °f 'hree
remaining two, is the subarciitS or flMcX ?^ T'*' '"Sf ""*" ""^
floccularis). It lodges in thrnatur,!^^.- ...''"i'" subarcuata s,
stalked appendage ol the cerebenum Te' raTt^ fh"T"'"'' " ^"""'
somewhat in front of it, a thin leTe of bon. .v ^ ^" ''"'^' ""'' ""'^
mg, the internal aperture T the facial ^n.i ."''','?'''?*" °™' "P*"-
yrves for the transmission of the seve^fh ^r^, ?f"*''^ '''"''"''■ "'«'='■
diately behind and below this awrture if^h * *""" V'- ^"""^■
•courtc ni«tu. (meatus acusUcuf ^nt/mus) ?or X".'"^ "'■"'.'' "••™"
eighth cranial (acoustic) nerve The two . . ^ tratlsmission of the
by a shallow bonv ridge largelv foTmert hv T''""^ '^"'' '" ^ «^"'^'°«^d
above, and resembling suSianrtheL^nr?''"'"^ '^^^ ''^«^"'«^<»
-nted by the internal' acoS m'eat s'^of^tKuma"""^? '""= """'■
^n^o/Tu^'rJX''1U'J,7;'^ fopr'the investing
entire olfactor/?:giirofThe timarv skurf,;cl,"H"' 7.**^ "'» '"e
and associated tufbinal bones Th? n„^' '?''''«''"8 "-^ "asal fossae
human skull-is formed of two primary'^Tnd'InTh^' '^^ °' '"^
elements, the maiilla and pnanaSta Thev tnl.th T''''''"- *Parate,
portion of the facial region^TVhelduh t^nnf,- 7 '°'"! ""' 1^'^^^"

alveoli Of the ^^r^^TZ^^r^tl^-^ "^^.^^^

82

Anatomy of thk Rabbit.

■M

M

s

root of the zygomatic arch, the Utter being formed partly by a short
xjgomatic procan arising from its lateral surface, by the lycomatic boa*,
which is fused with it, and by the corresponding lygomatic process of
the squamosal bone, constituting the posterior root. The anterior root
of the zygomatic arch is perforated by a deep narrow infraorbital canal
(canalis infraorbitalis), which opens on the facial surface by a vt-rtical
slit like aperture, the infraorbital foraman. It serves for the trans-
mission of the intraorbital vessels and nerves from the orbit to the face.

The ventral portion of the maxilla is associated with the palatine
bone to form the hard palate (palatum durum). This structure is repre-
sented chiefly by a bony palatine bridge connecting the two sides of the
skull between the more anterior cheek-teeth. It forms a portion of the
roof of the oral cavity and a portion of the floor of the nasal cavity.
Immediately in front of it, the palatal surface is perforated by a pair
of large inciiiTe foramina (foramina incisive), which arc broadly open
to the nasal fossae.

A considerable portion of the anterior and dorsal wall of the orbit
is formed bv the facial complex. Dorsally, the roofing element of this
reeion, the frontal bone, bears a curved lateral projection, the tupra-
orbital proceif (processus supraorbitalis), iMhich overhangs the orbit.
Its narrower base expands into anterior and posterior tips, which lie
parallel to the adjacent portion of the skull, and enclose with the latter
corresponding anterior and poiterior lupiaorbital inciiuie*. The latter
are converted by ligament into foramina. The anterior wall of the orbit
is formed in part by a loosely articulated element, the lacrimal bone,
the lateral margin of which projects from the orbital rim as a blunt aub-
cutaneous process (processus subcutaneus). On the ventral side of its
base is the orbital opening of the nasolacrimal canal (canalis nasola-
crimalis), the bonv enclosure ot the nasolacrimal duct, which in the
natural condition leads from the corneal surface of the eye to the
anterior portion of the nasal fossa. A smaller projection forming the
ventral boundary of the nasolacrimal aperture is the hamulus lacri-
malis. Finally, in the ventral anterior angle of the orbit, the bases of
the three posterior cheek-teeth encroach to a considerable extent on
the orbital space. Thev are separated from the orbital wall by a deep
infraorbital groove (sulcus infraorbitalis), which leads forward into the
canal of the same name. Thev partly conceal two important apertures
of this region, the orbital opening of' the pterygopalatine canal (canalis
pterygopalatinus). leading to the palatal surface, and the sphenopalatine
foramfn (foramen sphenopalatinum), leading to the nasal fossa. The
pterygopalatine canal opens ventrallv in the palatomaxillary suture of
the bar-! palate by a rounded aperture, the greater palatine foramen
(foramen palatinum majus).

The nasal cavity (cavum nasi) is enclosed by the maxilla and pre-
maxilla, with the assistance of paired roofing elements, the nasal bonei.
Apurt from the incisive foramina, which are closed in the natural con-
dition, the cavity is open at two points. Posteriorly it communicates
with the ventral surface of the skull bv the choanae, which, in the rabbit,
are incompletely diN-ided. Anteriorly it opens to the outside by the

The Skvul as a Whole. gj

the division is effectedX.fl?Th.;u.E 1 t, i '^ '''""." '' **" "'•»
plate, the Dual WtSm (wntu™ ~5^ « n>«)i«ii vertical. cartilaKinoii.
•MMtlimolilThirir™,!^'^ •"'• °' ""aamiious portion of the

the ethm'l.id to„r^rhe tr^^Sflr** ''"Tr P:'P'"diculari,) of
» also the terminal elem^nf ff .h • * ™*''!.h">o'<) and the latter
the basicraS Postrirl ° .'J"' "".",''' '"'?"»" >»"" constituting

cartila,? sup";!,"" i„ Jh/n^tS inl du^faVeT",'"' ''^"^" ■•' "' ""
animals (cf Plate III) ^'P"'"'"" <"»'^'' "« best seen m very young

the ISLfcaWty I^l"^™": „*?,""'''. '"'"»•'« •»"-. characteristic of
■««« cavity, are tiome on its posterior and lateral walls. Occupying

a]v«olar procpss ol maxilU; pd hard laufJ ■ I!^ J meBtiis, o„ optK- foramen; iT.

P.PI . Pierymid proca. of pctcrio;- ,ph°„„3 ,„ '\^ ^'„,'!1 occipital protul«ra„cc I

.. luHw Kpium. t.c. tentorium ccrebclli.

mtror^;r^rii^'Sor7itli!;s.rii^^

"laocafT nsounnN tist chut

(ANSI onl ISO TEST CHMt No. J)

I in ^L&

\_U_ l*^ I
^ "" I

1^ 1^ I

1.8
1.6

A

IGSJ Eait Main Str««)

RochMtar, N«b 'grii U609 USA

(716) *8! -O300-Phon«

(716) JSa- S9B9 -Fa.

84

Anatomy of the Rabbit.

I

IT I

shorter folds decreasing in length from above downward, in the natural
condition the turbinated bones bear a considerable portion of the nasal
epithelium, the surface of which is greatly increased by the folding of
the underlying bone. That covering the ethmoturbinal contains the
olfactory sense organs, while that covering the maxilloturbinal is non-
sensory and possesses the mechanical function of freeing the air of the
respiratory tracts from foreign materials, as well as of warming it sligMly in
its passage. On this account the respective structures are conveniently
distinguished as sensory (olfactory) turbinals and respiratory turbinals.
The mandible (mandibula) is composed of two portions, united
anteriorly by the symphysis mandibulae. Each half comprises a hori-
zontal portion, forming in conjunction with that of the opposite side
the body of the mandible (corpus mandibulae), and a posterior, vertical
portion, the ramus mandibulae, the latter serving for the insertion of
the muscles of mastication and for artticulation with the skull. The

Pig 34. Lateral surface of the left r»mu» of the mandihle; a.in.,
angle; cm., Iwdy of mattdible; cp.m.. articular portion (head)
of mandible; d.i.. d.m.. and d.pm., incifior, molar and premolar
teeth: f.m., mental foramen; i.m.a. and i.m.p., anterior and
posterior mandibular incisures; p.c, coronoid process; p.cd^
condyloid process; t.m. and t.pt.. masseteric and pterygoid
tuberosities.

body of the mandible bears on its dorsal margin the alveoli of the lower
teeth. The mandibular ramus forms a broad plate, the lateral surface
of which is occupied in the natural condition by the masseter muscle,
while the medial surface forms an area of insertion for the external and
internal pterygoids. The surface of the ramus is greatly increased
in its posteroventral portion through the expansion of the bone to
form the angle (angulus mandibulae), or angular apophysis. The elon-
gated articular surface is borne at the end of a vertical, or slightly oblique
condyloid process (processus condyloideus). The nerve and vessels of
the mandible enter at the mandibular foramen (foramen mandibulare),
the latter being situated on the medial surface of the bone immediately
behind the last cheek-tooth.

The Bones of the Skl-li..

85

B. THE BONES OF THE SKULL.
1. THE OCCIPITAL BO\E.

for the most part with the nuchal surface but a^rUonnhfn "^
the horizontal plane of the basis cranii Thp int^rf^i r • ""^ '"

™J„n ,"'P"1^ ^■,'"" '''"^'"'^ *"'° fo" porUons,nameTv the basilar
portion (pars basilaris , or basioccipital, the paired literal nirSil!^!

^Hnf,'.'"!""'"'' "' ««"P'tals, and the s,u«L"us portira ^Z
occp. a hs) or supraoccipital. All four portions take part in the ^orTa
tion of the foramen magnum. In the voune animal (Fil in .V
represented by separate elements, fo^me^i^a confinuous ma sTf
cartilage and united for a time by synchondroses, but inThe c^ri o

The basioccipital ,s that portion Iving below and in front of th^
oramen magnum. Its main surfaces are%espectivelv dors^? and ven

rhe^-n-tS'Znda-T^hlr'-" '" ^ '"- "--re'dgrwhlch s
bArX'rfp^Sclt I-nd rtrfaTe™al p^r^n^'i^ ^ ^^^
The dorsal surface bears a median groove deener^in it. „,vi]u °™P'.""-
where the lateral margins of the bonf^e raised ta for™ f P""!? ".'

bosses fo. articulation with the p^"rotvmDanic Thr« ^ °' ™""'''^''

c'd^d'th: ^.::rjT^^%^ ''?d"f Fir-

borne on the exoccipital, with illf^ce'pt^rhow^ver^X's ™S' Up^
^fl^-^-Z-c-^n^-r-S^S

13

<T il

86

Anatomy of the Rabbit.

boundary of the jugular foramen, the remaining portion of the latter
being formed by the petrotympanic.

The supnoccipital is the dorsal portion of the bone. Its dorsal
margin is bent sharplv forward, so that it tends to fall, like the basi-
occipital in a horizontal plane. Its external surface bears the 8ttp«rior
nuchal lines and the external occipital protuberance. A pair of lateral
wing-like expansions rest upon, and partly overlap, the dorsal margins
of the petrotympanic bones. The anterior boundary is formed by the
interparietal, parietal, and squamosal bones, but in young skulls the
squamosal connection is represented by a vacuity. The internal sur-
face bears a longitudinal groove, lodging in the natural condition the
median vermis of the cerebellum. It is crossed at its anterior end by
a shallow transverse groove (sulcus transversus), which marks the
position of the transverse sinus of the dura mater.

2. THE POSTERIOR SPHENOID.

The sphenoid bone, as identified from the human condition, is a com-
plex of elements belonging to two segments, namely, the posterior
sphenoid (os sphenoidale posteiius) and the anterior sphenoid (os
sphemidale anterius). In the rabbit, as in mammals generally, these
segments are separate throughout life. . .. v j

The posterior sphenoid comprises; (1) a median portion, the body,
or basisphenoid ; (2) paired dorsolateral expansions, the greater wmgs
(alae magnae), or alUphenoids; and (3) paired ventral projections, the
pterygoid processes. .. u ■

The basisphenoid continues the basis cranii forward from the basi-
occipital to the body of the anterior sphenoid. It is united with the
latter bv the intersphenoidal synchondrosis. Its surfaces correspond for
the most part to those of the basioccipital. The ventral surface forms
the chief part of the bony roof of the nasopharynx. It is perforated in
its middle by a round aperture, the foramen cavemosum, which leads
into the interior of the bone. The dorsal surface is occupied, as described
above bv the hypophysial fossa and related structures, namely, the
dorsum sellae and the posterior clinoid processes. On the lateral surface
of the base of the posterior clinoid process a faint groove, the sulcus
caroticus, marks the course of the internal carotid artery. The interior
of the bone contains a cavity of considerable size, the sphenoi^ smus
(sinus sphenoidalis), which communicates both with the foramen
cavemosum and the hypophysial fossa.

The alisphenoid extends at first laterad, but soon changes its direction
so that its axis becomes dorsoventral. At the same time the bone is
rotated in such a wav that its surfaces tend to fall in a transverse plane.
It is bounded anteriorly by the orbitosphenoid, dorsally by the squamosal,
and posteriorly bv the petrotympanic. The anterior margin of its r<)Ot
encloses with the basisphenoid, and to a certain extent with the orbito-
sphenoid the superior orbital fissure. The foramen lacerum is formed
by the posterior margin of its root in association with the petrotympanic.
The external surface of the alisphenoid is convex, both toward the

The Bones of the Skull.

87

n-gn... The in.er„al"urface frrms\'rrf„„''„7t!;'°"fl '"= '1?^ ^.a

nerve and th"e re.a.l^.ilfr "c'at^;' 7„"/h„'^^^ -' "' "■' «""
the meXK^^rSumrrTh"!^ 'w^p.a'^terdescribed above as
surface i^d.^ecte^ Tia^d^S^'na Jpha^vTx" 'rh^l'^'' '"V' '"^''»'
jontal. The medial lamina ends^enfraHv in It ''t^V " * ™°'' '«'"-
hamutar procM, (hamulus pterygoideusj^In the v°^ '' P':°)«^f «°.». "-e
tion is formed of an elpvaii™ f !<,' ■ ™''"S animal this por-

brane elem"^, tL ptt™ d^le'^TSf Jir'n^''/ '^"^'"'^ •"""-
part by the uiedial and lafeml u^i„. ^'"^P'"yK»"» f<«»a is formed in
terior end of the nalatine h^ni tI "^ *"''■'" P*" ^^ "«^ <"^ided pos-
is exten";.ely excavateS inL ;h h' ■"""'" ''** °' "«^ '^'"''' ""^na
It bears a 'shaHow ^ro iVe e^res nS "f '1"^ "(''■' alisphenoid.
ptervgoideus), and is MrforaieH hv fh .^^ Pterygoid canal (canalis
as the .n..ri4. «Iddl.ratd''';^,.'„;;^,;,r^l'f„;™;-'^^^ above

3. THE ANTERIOR SPHENOID.

tion^Lmltf : I'd^t^ioT'the h^' anterius) consists of two por-
lateral expansionrthe W win« r»i^' °" P«»P»"»>«M. and a pair of

The pr«ph.nod is a^nsTr^i i^" P^"^'' "' ""itosphenoids.
basis cranii forward fiom tT„ h • u ^"/ ^P''"' "''''•'> continues the

the perpendic™arplItrof' h?:Zord"°a„'d Jil,;^^"'^^T'"'°^'^ '^■"'
septum. In the divided .iknil „rT«f. ? , ""^ cartilaginous nasal

been removed, the acfualdl-ril If '" ""Z '["^ "■''''^'' 'h^ ""' has
exposed to the cranial cavity oSl In^^'j', '^' '^"^ '^ *'" '" ^e
occupied by the sulcus StosLtis anV h ^^ «"7 P°'."™' "''""^ " '^
of the floor immediatelv^f^tnfthl t ? '' 'onunina. That part
coalesced roots of the orbitosnhen 'in! K" ^"^"I"'* is formed bv the
sphenoid being thus excluded "^'^ "" ""'*' ^'f^*^"^ "' '"e pre-

tion'o''f^S:''orb^a"„S"div■™d bv a"fhl7 '"^'r,!''"^ '" ""^ -'-' P"-
foramen into a ^ster or i«rtfnn ^h k^"^*" ." '' ''^^'^' °' "-e o^ic
anterior portion, XeZ.ffi^;„iiLT'"'°'P''"' " ™P*^- and an
orbitosphSioid prZr l^b^„r?^rt 'P™^""' ' ""'idalis). The
dorsally with the ortitarocrtion nf ,h ? " /°'"""!,"- " '^ '" °>"'act
alisphenoid; it asslts theTat ter in fh f """f'' *"? ^'^ntrally with the
fissure. Its posterior tp is i"S„',"acfJ?h";h°" °' ""^ f"*"" '"•''"»'
surface formra considerable mrtfnn n J^J ^quamosi.]. Its internal
middle cranial fosS ^^'^'°" °' ""* anteroveutral wall of the

doriJ'^iliSt' LTufat'erwtVThr" i^l"? ""^ "^"^ '-''"'™ "»
anditsventLlmar^^withtheo WtalL«'^'''''rP,?''''T °' "'^ f^'al,
it projects toward^he l^r^'^'S^'^it^;^"-^

88 Anatomy o? thp Babbit.

which, in the typical mammalian skull, is filled by the lamina papyracea
of the ethmoid. Its internal surface is associated with the ethmoid bone
and with the nasal cavity. It falls for the most part below the level
of the cranial cavity.

4. THE SQUAMOSAL BONE.

The temporal bone, or temporal complex, as recognized from the
human condition, is an association of three elements— iqiumosal,
tympanic, and periotic — which in the human skull are coalesced to form
a single bone. It is usually described as consisting of four portions,
of which the squamosal and tympanic portions are two, while the periotic
bone is considered to consist of two others, one of which, the petrous
portion, is a solid white portion lodging the internal ear, while the
second, or mastoid portion, is a mass of less compact character appear-
ing externally in the wall of the skull. In the rabbit the original
elements are not coalesced, but the periotic and tympanic bones are
so closely associatet' that it is proper to describe them as forming a
petrotympanic bone.

The squamosal bone (os squamosum) is a rectangular plate, forming
part of the lateral wall of the cranium, and bearing the posterior root of
the zygomatic arch. It is articulated anteriorly with the orbitosphenoid
and with the orbital portion of the frontal, dorsally with the frontal
and parietal posteriorly with the supraoccipital and petrotympanic, and
ventrally with the alisphenoid. Its posterior margin bears a prominent,
slightly decurved squamosal process (processus squamosus). It lies on
the lateral surface of the petrotympanic immediately above the opening
of the bony external acoustic meatus. The posterior root of the zygo
matic arch is formed by a lateral and afterwards ventral projection, the
zygomatic process of the squamosal. Its base bcnrs ventrally the
mandibular fossa, and dorsally, in association with the body of the
squamosal, the temporal fossa. The internal surface of the squamosal
forms a considerable portion of the wall of the cranial cavity, the middle
cranial cavity being, in fact, broadest in this region.

5. THE PETROTYMPANIC BONE.

The petrotympanic bone (os petrotympanicum) is a somewhat oblong
bone lying in the lateral wall of the cranium between the posterior
sphenoid and occipital bones. It is chiefly indicated externally by the
tympanic bulla and the bony external acoustic meatus. It is articulated
anteriorly with the alisphenoid and squamosal, dorsally with the supra-
occipital, and posteriorly with the exoccipital. Except for the presence
of the squamosal process of the squamosal bone, the lateral and ventral
surfaces are exposed to the outside of the skull. The internal surface
is exposed to the posterior cranial fossa, with the exception, however,
of 1 small ventral portion which is articulated with the basioccipital
bune. Only a small portion of the anterior surface is in contact with
the squamosal bone, the larger part being applied to the tentorium
cerebelli and forming with the latter a posterior wall for the middle

Is

The Bones of the Skuil. gg

posterior surface is applied^o ?h, »^ ■ ^ " " ^"i-^ulaled. The

and is ihusexcluded toth from Iht !" ^"''^"^ "' '^e exoccipital.

surface of the skull V e«?nK ,h. skun"tam''h"r 'lV'°'" ""^ "'"""'
that a small dorsal portion nrn.r,,!- ^"''""''' '"'"'ver. it is seen

the dorsolateral mar^n o? the exocciDilal''a„d?H*"'''' ^P^ '"'""--^ ^^
of thesupraoccipital win^ This ZC is dfs, n'' "."'m'^^"''' ■""«'"
character. It form, the nuutow'^^rtrj. f'^'-nR^'shable by its pitted
guished from the ^MlZI^t^tr^^'Ziii^? mastoidea) as distin-
exposed to the cranial cavity a^dwTio^f -^'l I*"™«). «l"<-li is
internal ear. The inastold ^;or?L r ~"'?''"» 'he structures of the
tympanic cavity but it iralS^.^'"" ""^ •""*' P"" ''bove the
acoustic mcatus'^and the 1x^0^?,.'^?^ "'"''/^ ''^■'"«" '"e externa!
-stoid ,or.„.„ lies mC^/^ ^ ^ TJ^^Tx^- J ^ ^s't^

ob.^ ^Jp^5:^"o;;ii^^er::i[l,'xi::e"^'l:r^- " ™^'^'"^

a^Te^x^rd^„?^oVeTutrofTf ''^ -^^^^^
depression than is indicated bvthi J^L,""' Z"™'"^ " '""-■■'■ '"■•«"
dorsal margin of the bone is occuni.ri T. °' '" "" ^he related
a canal at its posterior marKin nmd^.^ *i™"'". "■'■'<^'' '"^^ds into
portion of the transverse stnus of .h„ h ""^ P""""" °f ""e lateral

portion of the b^e ™cks^LVh„ ^^^"'^'"•^ '"'■<= ventral, thicker
meatus and the fac ikl 22^1 fs ' ,L fh" Th °' ""J """«' «»•»«<=
cochlea of the internal e^ A smalT=.nh ^'"^ ""• ^"'ibulum and
only visible when the P^' otv4™nic fsCd fro '"r"'""^""'^''' ""«'«•
sents the hiatus canalis fackUi of th„ h , ",f connections, repre-

shallow oblique groove" the n^Sn^n ,'"" .'^'"dicated externally bv a
the tympanic membrane wlthT The m'H'"' '",'''?'" '""SMy [hat of
s articulated with the basToccipital but ,h«°™", '■^' "■"'?'" °' "«^ bone
from the latter bv a broargrXe term nn Mn '." ''''^"°" '^ ^^P^-'^'ed
fossa and the jugular foram^ I^T^ f posteriorly m the jugular
fossa, the roundidCr,ureTtheertZ';i."f'-H,'" ''°"' "' '^e ju|ular
the natural condition tl^^ interLuZ ^r l..?""^'"- '■'''"^■"'"'"^ '"
canal of the interior of tvmpanTc porTion A,' h ', '""' ""^ """"•
groove, communicating with the forSl.^ ?' -^ anterior end of the

of the carotid canal the iate^«,^,t?^''"'""' " "'" anterior opening
the much larger aperture of "S aSrv?p'"f°V""''.°" '" '^•■=™' ^'""^
..ons of these ape^Jtures afe '^^en't'bTst* ^^^f^f ^h^" ^^^^^

90

Anatomy of tiik Rabbit.

tympanic is disarticulated from the associated posterior sphenoid bo .«.
The auditory tube is then seen to lead directly into the tympanic cavity.
A fine bristle may be passed through the carotid canal from one foramen
to the other.

6. THE STRUCTURES OF THE TYMPANIC CAVITY.
The relations of the tympanic cavity and associated structures may
be studied with advantage in a skull from which the lateral wal of the
tympanic bulla and external acoustic meatus has been removed, the sur
face displayed being as indicated in Fig. 35. The tymptnum or middle
ear is enclosed by the tympanic and petromastoid portions of the temporal
complex. The attached margin of the tympanic bulla encloses a roughly
triangular area, into the ventral part of which the petrous portion of
the petromastoid projects as a smooth, white, convex ridge, the prom-
ontoiy (promontorium). Above and behind the promontory the
tympanic cavity is extended toward the mastoid portion of the bone

Pic ■^l Petrotvmuanic portion of the auditory complex of the left side -<3.
The 1 Jil iJSSSTthe ,7mp.»ie Ml« ""d .«er,..l .jcoo.t.e m..lo. h.». l«n
re"oS exwita tl.e .tractor., of the tytnianic cvity. MS, mutoid portion.
P Detroua portion; T. tympanic ixirtion (bulla tympani), i„„,...

cm mSSd cill.' c,t.' tympanic cavity; tc. cochlear fcintra; to. Incu.;
ma?" Semal SouJtic mc.tu.; mm., manubrium of the imillco.; m_.o..
^■praiccipital marsin of pctroma.toid . p.m., ma.loid proce..; .t.. .tape., t.a..
aperture of auditory tube.

as the tympanic or mastoid antnun (antrum tympanicum), and the
interior of the mastoid portion is partly occupied by small extensions
of the tvmpanic antrum, termed the mastoid cells (cellulae mastoideae).
At the anteroventral angle of the area already described, a deep notch
indicates the point of entrance of the auditory tube. The exposed
surface of the petromastoid presents two apertures one of which,
situated posteroventrally, is open in the dried skull, and is the cMMear
fenestra (fenestra cochleae). In the natural condition it is closed by a
thin membrane which separates the tympanic cavity from the perUym-
nhatic space containing the membranous labyrinth. The second
aperture the vestibular fenestra (fenestra vestibuli), lies above and in
front of 'that just described. It is closed by the base of the stapes.

The auditory ossicles (ossicula auditus) comprise three elements,
namely the maUeus, incus, and sUpes, which bridge the space inter-

The Bdnes or i hi. Skull. 9,

angle of (he triangular area alread de^rSn »nrf ■ ^"^^ "l' ''°'»»'
the promontory. The malleuru .h!^ . , ?^ '" ""™«''"lel.v above
tion. termed the h6.d,is™Sed hv the n™' "'.^""'"i ■^'" ■""'" P"^-
acoustic meatus. It he^rs a sto^,', '^.^^P^f <^""« <-d(fe of the external
maUei, which in the natural ™,Sn Tf'*' ^'?^'^^- ""^ ""ubriiun

r;^sx:^witi^e^25S- i?T "^

7. THE INTERPARIETAL BONE.

surrIS'ndedTlr,l''o' paSttl tdTH""' '"""^-'haped element,
first of the membrane rSgelememrof.h'e'.?'^""'""^'- i' '^ "-^

8. THE PARIETAL BONE.

covIring'?t!^e'Cio'„"of'?htmiH'H,'' " ^l-ff"™'- roofing bone
rectangSlar inThaw and is ^nn?.? JV^"'^' '"'^ " '^ somewhat
rounding elements^id with ks ?,.nll ''/.*"*"^ '«"■■" "-i'h the sur-
produeing a chamcLristl pattern o„,h '^ °PP?«'%«de, the sutures
The sutuTes are medial an^rinr I ? f' * j'""*' ""•f^« "f ""e skull,
are designated res^iSivelvanilri^"''""!'?'''"""' '" r'"°"' """

skull. ""' "P"**" '" ""e external surface of the

9. THE FRONTAL BONE

anterior portion of the roof of the crnnill /f . °' '^e opposite side the
portion of its lateral orWtalwaH V^l??,^- ^"1" "" * "nsiderable
skull, the two bonesart -*™rrte thrnrJL ."l^, "-"d-'ion in the human
manent frontal sutS.t*art«nsUunf, '."'?■ "" ■"" """* '^ « P*^"
the external or doTi'l surface of X V-tin^effhar^

!i'

•■« (I

If

92

Anatomy of thk Rabbit.

thus formed, one medial, the other lateral to the nasal. The medial
process is associated with that of the opposite side to form a triangular
frontal tpinv, while the lateral or maxillary proc0H (processus maxillaris)
projects forward between the nasal and prcmaxillary bones, on the one
hand, and th? subcutaneous process of the lacrinial, the orbital process
of the maxilla, and the body of the latter, on the other.

The orbital portion of the frontal forms a considerable portion of the
orbital wall. Its anterior margin is in contact with the lacrimal bone,
its ventral margin with the slender sphenoorbital process of the maxilla,
the ethmoid process of the orbitosphenoid, and the orbitosphenoid
proper. Its internal surface is divided by a vertical ridge into anterior
and posterior portions, in relation respectively to the anterior and middle
cranial fossae. The anterior cranial fossa is enclosed by the frontal
bones, with the exception, however, of a small portion of the floor which
is formed by the cribriform plate of the ethmoid.

10. THE ETHMOID BONE.

The ethmoid bone (os ethmoidale), the *chief representative of the
embryonic cartilaginous nasal capsule, is a delicate, greatly sculptured
structure, almost completely enclosed by the membrane bones of the
face. Its features may be studied either in the divided skull, or in one
from which the roof of the nasal and cranial cavities has been re-
moved. It consists of three main portions, namely, the cribriform plate,
the perpendicular plate, and the paired lateraf masses, or ethmoidal
labyrinths.

The cribriform plate (lamina cribrosa) is exposed to the anterior
cranial fossa. It is somewhat heart-shaped, with its apex in contact
with the ethmoidal processes of the orbitosphenoids. Its lateral por-
tions are perforated by numerous foramina, giving passage in the natural
condition to the branches of the olfactory nerves. Its median portion
forms a low vertical ridge, the crista galli, continuous in front with the
perpendicular plate.

The perpendicular plate (lamina perpendicularis) is the bony, pos-
terior portion of the nasal septum, and as such is exposed to the nasal
cavity. It is united with the cartilaginous nasal septum and also with
the presphenoid. It forms the terminal member of the chain of bones
lying in the basicranial axis.

The ethmoidal labyrinth (labyrinthus ethmoidalis) occupies for the
most part the posterior portion of the nasal fossa, but the nasoturbinal
extends forward to its anterior end, and is attached for the greater part
of its length to the internal surface of the nasal bone. It is broadest in
its middle portion, where it projects into the space left between the
ethmoturbinal proper and the maxilloturbinal. and contains at this point
a pouch-like cavity, termed the marsupium nasale. The whole struc-
ture is comparable to one of the folds of the ethmoturbinal proper;
but it is frequently seen to be divided into anterior and posterior parts
by a thin vertical line of cartilage, the anterior division being probably
allied to the maxilloturbinal. Its middle, ventral, portion bears a

The Doxks of the Skiu..

93

cnbriform plate, the Derfor»^ [„,,?> ""^^ »''■ ""ached direo.v to the

•kun opening into thrjtaS liZ^'Ic^uT' "Th "•'". '," ""' '"""''d
contained bv them Thi.r»T!i iT '"""'"c flhrnoidalcsl or soace.
middle turbinated bones of IheTu^'-nT!?*^!!'* •" "•^' »"Ixrior'lnd
most mammals, the ethmoturbinarw ""' *"" '" "«^ "'>'"'• ""in
extensive than in man '"'*"' ''"' relatively much more

-bi^w^r^S.rr;E^'X^^^-'/-°^e is expo^d to the
rabbit, however, the soace u...r,riv. -5 '*'»^ P«pyrace«. In the

"partlv filled by the EaT^"e theXlT ,""' '""■'"' '^P""""
sphenoid and the 'phenoorbitaiTr^-e's onrmaxijr"' "' ""^ ""'"°-

11. THE INTERIOR TURBINATED BONE

t-rbl^.^XellT^'^^'^.r^J™^^^^--"^. '"/"-'•- nu^-
and supported bv the maxilla and ''""'"^•'.""'"'"rly in the nasal fossa,
arly-named structure oTthe human /kuTTh''- '' ^'■P'''^'*'"^ <he simi^
Ike bones, of which thr rmSntwn/r"™'''' "' '''re^ scroll-
turbinated bones, belong to the eh™ , u- "'.'' '"P*""'' ""'' ""'"die
ditionitiscoveredbvanonolfl. "T,*"""' '" the natural con

able in function as '.^ciirin-Srfl^.Ste^urr'''''"^''''""^^^^^^

1-' THE MAXILLA.

its fellor^e'SfrJdttorm .'h^'"""' '«^«»"' '"»«-"«' -'h
It consists of a cenTral p^rHoL the b^St T-t' " P°^''™.°f the upper jaw
processes, namelv, alveitar Miltto. Zk-ffP"' ■""""'»••). and of five
orbital. In the adult conditSrr.' "'"*^>.^yK»'n«Uc, and spheno!
maxilla, so that the extent of th.,! ^>'«"""''f<' h<ine is fused withThe
increased. "'"' °' ""<= ^ys°-natic process appears to be greatly

faee";L''K.e'';ari'i^e';rdK!.yr™fr'^. "" "' -•--' ™-

orbit, and thus including the Sta^ f~l ilu""^ ^""■™' ">" "f the
The dorsal boundary of the b^SfSr^Tf K"'lu'"^,'°'"»'''"«"»"m»-
premaxilla and bv ihe maxillarv nr™. f ;''u"'f '™""'' '°«ss of the
« united with th4 premSa h P™?',°f ""^ f™"""' Anteriorlv, .1
in the diastema se'^rTuflheindS,. t"^" °1 '''^ ^"'"^ appear ng
ventral portion of the bo"? form pLTof "tr /^ ^''r'''^*^''' ^hf

-und to be co„cea.^^;^^J:ig- S;- 5^^r^^- — jj'

94

Anatomy or tiik Rabbit.

dinal excavation, the maxiUary linus (sinus maxillarit), widely open
to the nasal fossa, but only seen to advantafce when the ethmoturbinal
is removed. The lateral wall of the sinus corresponds in position with
the fenestrated area of the external surface. It bears the chief part of
the nasolacrimal canal.

The alvaolar procaw (processus alveolaris) is that portion of the
maxilla lodRiuK the sockets of the cheek-teeth. In the rabbit it is
separated by the diuHtema. in which no teeth occur, from a corresponding
but imperfectly difTerentiated process of the premaxilla.

The palatine proceu (processus palatinus) extends toward the median
plane. It forms with its fellow of the opposite side about two-thirds of
the palatine bridge.

The orbital procaw (processus orbitalis) is directed obliquely toward
the dorsal surface of the skull. In conjunction with the lacrimal bone
and the maxillary process of the frontal, it forms the anterior orbital
rim. It is continuous with the fenestrated portion of the body, and its
te^pearance us a process is largely due to its solid character as com-
pared with the perforated surface lying in f^ont of it.

The zygomatic proceu (processus z /gomaticus) forms the anterior
root of the zygomatic arch, and in the adult condition has fused with it
the anterior end of the zygomatic bo le. Its ventral angle bears a
prominent mauateric spina for the attuc'"nent of the ligament of the
masseter muscle.

The iphtnoorbital proceu (processus sphenoorbi talis) lies on the
medial wall of the orbit, in a position opposite to the middle portion of
the ridge lodging the posterior cheek-teeth. It forms a stout buttress,
the tip of which is applied to the anteroventral angle of the frontal bone.
In this position it is visible from the orbit, lying l)etween the lacrimal
bone and the ethmoidal process of the orbitosphenoid.

13. THE PREMAXILLA.

The premaxilla I or inciiive bone (os incisivum), forms the anterior
portion of the upper jaw. It comprises a central portion, the body —
including with the latter the scarcely differentiated alveolar portion con-
taining the large and small incisors — a frontal proceu, and a palatine
proceu. The body forms a portion of the palatal surface of the skull
and of the lateral boundary of the incisive foramen. Its dorsal surface
forms part of the boundary of the piriform aperture, the remaining por-
tion of this being formed by the nasal bone. The palatine proceu extends
backward on the medial side of the bone, closely applied on the palatal
surface to its fellow of the opposite side, and forms in this way a medial
boundary for the incisive foramen. Its dorsal surface, in conjunction
with that of the corresponding process of the other side, bears a broad
palatine groove (sulcus palatinus;, lodging a portion of the cartilage of
the vomeronasal organ and nasopalatine duct. The frontal proceu (pro-
cessus frontalis) is a thin bony splint, extending backward between the
nasal and maxillary bones, and terminating between the former and the
maxillary process of the frontal.

Tiie lloNKs or TiiK Skui.1..
14. THJ! ZYGOMATIC BONE.

9S

matic procM, „f the max llo .h, ^ '?■ "*^ "niiTiorly «iih the ty^o-

t^e lyKomatic arch arise" fm™ ,1^. ! ''"■ h»ri»ontal porljon of

form, an almost 4ittal „la.?of ^i '""">'* .^Vxomalic pro«.s,. I,
•he attachment "the ma^^r/r^l I *;"?>.''''■ "''" »'"' *""•" '»'
margin form, poste "or " a sm^T h ■"' "", ""'"'"'•''• I'" <l..r,al
«yxomatic procewof he squam"^ Ih^"-^" 1"'.''™'''''"" «'"• ">=
"derably behind the articu?ati"n "" •*"••■ ?«•)""■•« "»■■

18 THE NASAL BONE.

of .^na"tt'«l"a' ?n"'^]ut''tiot'"v;.i&'^;' '"T 1"""'"'= ""^ "»'
the dorsal bo.mdarv of the niT."fnr™ ,? ^ '''l"": °' ""' "PPos'te side,
with the maxilla and with thlZ'^r^'T' " '» '«■*'>■ •'"iculated
(harmonic) sutures The me^i ^"^in' ""■ "^^'l'" ''"'■ ">• ™"<"h
of the nasal septum. tL^I:^:^^::^-^^^^;;^^

16. THE VOMER.

J»n^;;rd;^'h''e^:„ta7■po";ro7s'•o^' ,t'"-''?M. -r.ical plate o,
from the palatal surface hmu% he i^ ?""' ^""""^ " '» ^'^ible

best shown i„ ,he divfded kuU "■* '"'■'■^«' foramina, but its extent is
border of the nasal septum and it, L^,"" " '"''>"" '°' ""^ '""^'^'
pro ection, the tl. voierb ' whieh . P9^}<'r}or portion bears a shelf like
turbinal. "■»•«», which assists m the support of the ethmo-

17 THE LACRIMAL BONE.

waiuf tt'^,'t'~7, t I'rXiVtJcul Tf "'T'"' »•"■« '" "■- -"'-
and in the dried sku I s ?Zuen,.v ™. '' ""'■ ""^ ^•"•""nding bones,
to keep it in place. t mn^sts of I h»">'"* 1"" ' ""^ *"" ^'" '*■«■"
on its orbital surface^3 of two „* """'""• """^what renangular
proc«, and the h.m^« I.criS.'^ Thf'^.h"";"'' ""^ «"«''«•"«>.»
prominent hook-like pro^ct3 ik.Ji^ ™'«-">a"«'"s process is the
The hamulus lacrimalis is 1 small nr!, ^^""^ ""^ °'^''^^ "">■
cavity. I, bears a «r^ e whSh iJT"'- 1'"^'"^ """""^ 'h^ nasal
groove of the maxillarrb^ne form-Th ^T"""- "'"" " corresponding
canal. "^ '""''■ '"'■"» 'he first portion of the nasolacrimal

18. THE PALATINE BONE

pa.a^ineCd'^'a'T'th'e m'So^""p:;?L^„?'.h""^, T'^'r""" "' "-'
pharynx. It consists of two mr Hon, I.^ *'"*.' "■"" "' "■« "aso-
^. The horizon., portion'^ars-hro^Tall^^Tt' 1^, iS^r^S

96

Anatomy op the Raxbit.

of the palatal surface. It is articulated in front with the palatine process
1 M '°?'""'». "le suture between the two bones rnclosing the grwter
palatine foramen, tho ventral termination of the pterygopalatine canal.
i he perpendicular portion (pars perpendicularis) is the vertical plate
extending backward from the palatine bridge. Its medial surface is
divided by a low ridge into a dorsal portion, in particular relation to the
nasopharynx, and a ventral portion, in relation to the oral cavity, the
ridge indicatmg the position of the soft palate. Its lateral surface is
partly applied to the maxilla and partly exposed to the orbit. Its
oorsal margin IS articulated with the presphenoid and with the ethmoidal
process of orbitosphenoid, but a small posterior portion is free, so that
tne anterior portion of the basisphenoid is visible from the orbit. The
iree ventral margin forms posterioriv a thick projecting angle, the
pyramidal process (processus pvramidalis), the base of which is cleft
wnere it articulates with the medial and lateral laminae of the pterygoid
process. Between the pyramidal process and the alveolus of the last
cneek-tooth there is a conspicuous palatine notch (incisura palatina),
connecting the orbit with the palatal surface. In the entire skull only
tne J. sterior portion of the lateral surface is visible from the orbit the
antenur portion being concealed by the projecting bases of the posterior
cneek-teeth. The ridge of bone on which the alveoli of these teeth are

0 irne IS separated from the palatine bone by the infraorbital erooTe.

1 He medial wall of the latter, formed by the palatine bone, contains the
orbital opening of the pterygopalatine canal and the sphenopalatine

19. THE MANDIBLE.

The mandible (mandibula), or lower jaw, comprises the two dentary
nones (osM dentalia), which, in the rabbit, as in mammals generally,
are united by a fibrous or fibrocartilagiuous connection (symphysis
mandibulae) ; not coalesced, as in the human skull, to form a continuous
^5'j'"^'"^'^-. -^^ indicated above, each of the dentary bones comprises:
t 1? ''°"™"''''' tooth-bearing portion which, in conjunction with that
'"f opposite side, forms the body of the mandible (corpus mandibulae);
and (2) a posterior, vertical plate, the mandibular ramus (ramus mandi-
pulae), for muscle attachment and articulation. The horizontal portion
IS deep posteriorly, where it lodges the alveoli of the cheek-teeth.
Anteriorly, m the diastema separating the latter from the incisors, its
dorsal surface is rounded and depressed, the space thus formed corres-
ponding to a similar space in the upper jaw and serving chiefly for the
accommodation of the lips, which in this region encroach medially on the
oral cavity. The medial surface of the horizontal portion forms an
acute angle with that of the bone of the opposite side, except anterioriy,
where It bears a roughened area for articulation with the latter. Run-
ning backward from the svmphvsis there is a broad horizontal ridge,
representing the mylohyoid line (linea mvlohvoidea), the line of attach-
"^"1 ■ "** mylohyoid muscle. The mandibular foramen, through
which, in the natural condition, the inferior alveolar nerve and artery
gam access to the interior of the bone, lies on this surface at the junction

Ths Hyoid.
of the horizontal portion with «,. ^^

s^'iSs tt^ p'^oiKi-™ 'itsroTi r

nmsseteric fossa occmS,th» '"""^"'•'at similar, but iL h P T
its raised v^ralTa'in ,"""'»"'""« 'a'eral surface of th/ '*,''•

tuberosity (tuberosi.rZss^LrTcai' "I. ""^'"-"'y i" 'he ^iU?^^^^^
the mandible is greatly elo^L/,^^'-- ^l'^ a^icular portion ^^a ,

Theh V.K ^- ™^ «^OID APPARATUS.

and connected through the stvlnh, -5 "■"""dorsal angle of the hv?^'
process of the skull *ti, L ^1 "^'''''^''s ni nor muscle ^;.i. .1. .">""'.

i

98

Anatomy or thb Rabbit.

process by the stylohyoideus major muscle. The connection of the
lesser cornu with the styloid process through the stylohyoideus minor
replaces the stylohyoid ligament of the human skull and the chain of
elements commonly occurring in mammals and other vertebrates in this
region. The muscle tendon contains near the jugular process a small
ossification representing a detached styloid process. This connection,
together with the hyoid bone itself, indicates the relation of the em-
bryonic hyoid arch, from which the skeletal structures in question are
derived. The greater cornu belongs to the succeeding visceral arch,
and is connected with the superior cornu
of the thyreoid cartilage of the larynx
by the laterftl hyothyreoid ligament. o./C..

THE SKELETON OF THE
ANTERIOR LIMB.

The skeleton of the anterior limb
is divisible into two portions, namely,
a proximal portion, comprising the
scapula and the clavicie, and a distal
portion, comprising the supports of the
free extremity. The scapulae and clavi-
cles of the two sides together form the
pectoral girdle. The pectoral girdle is
lightly constructed, and, apart from its
muscular connections, which constitute
its main support, is directly attached to
the axial skeleton only through the
sternoclavicular ligament.

The skeleton of the free extremity is
divisible into proximal, middle, and
distal segments. The proximal segment
contains a single bone, the humerus;
the middle segment two elements, the
radius and ulna; while the distal segment comprises, in addition to
the accessory sesamoid bones, twenty-eight elements of the regular series,
of which nine form the carpus, five the metacarpus, and fourteen the
phalanges of the digits.

THE SCAPULA.

The scapula (Fig. 37) is a somewhat triangular plate of bone lying
in the natural position on the lateral surface of the anterior part of
the thorax, with its apex Jirected downward and forward. In the
rabbit, as in quadrupedal mammals generally, the main surfaces are
respectively medial and lateral, and differ in this respect from the
human condition, in which, from the transverse widening of the thorax,
the corresponding surfaces are more nearly ventral and dorsal. Of its

Pio. 36, LateiU Bur(ac« of the
hyoid and l&rynx: c,a., arytenoid
cartilage: c.c, cricoid cartilage: c.i.,
inferior cornu of thyreoid cartilage;
cm., leaser cornu of hyoid: c.mj.,
greater cornu of hyoid: c.8 , Buiierior
cornu of thyreoid cartilage: c.t., left
plate of the thyreoid cartilase:' e.,
epiglottic cartilage; f.t.s,. thyreoid
foramen; I.h., lateral hyothyreoid
ligament: l.h.m., median hyothyreoid
ligament ; m.ct., cricothyreoideui
muscle; o.h., hyoid bone; s.m.,
stylohyoideus minor muscle: B.mj.,
stylohyoideus major muscle; tr..
cartilaginouB tracheal rings,

i ■

The Ante«io« Limb SKewTo.v.

99

tf"f p4";.; 'l.'HreretrS„^-3 '«). <^ disced

•caputar .pine (spina scapu ae) whTeh »ri "*'/' * "°'" """V P'^te, "e
through about two-thirds oTts' extent ZT ?"" ""^ '»''>' <" ""^ bone
jection, the acromion. The^!. • ' "^ '"^^ ventrally in a free oro

backwardly-directed pJess the ir^^""- •" ""= ^™""<"' "'»«»
Through the presence of7he scaouUr ""? (processus hamatus)
bone is divided into two areas Jt,. ".'""' """ '^'"^' '"^^^ "f "he
the nipnupinou. fore, (losT-lZ ^^"s «"a<^hnient. One of the«
the other, the WraS^ino^lo^^S"' ' "" '" '™"' "' '"^ ^X^!

ihi^^rLXu^^tsTSr'"^^^^^^^

* m'°infcri!^*T'f '"'*«« Of the left scapul.-
inet«rmmi™. ' .^- """^ '»- Supraspinous .

meticromion , ,„ a r.
P.C., coracoid prt^M

«-. acromion; a.i. ml anri
---. ™P™i;in™,-:;/'f£j««;">'i ■■■. neck

Mcupies practically the entire surface Th

the scapula, sometimes termed the hwd oJ^h T" " '^'""' *"?'^ <"
considerable extent in comparison whh ^L . ^"^' " ^'=P^"ded to a
called neck of the scannl^ tZ^T "" ^'ender portion— the so

body of the bone nXirs^T Zca^'d"''-^""*'^""^ '' ^^ 'he
(cavitas glenoidalis), fo7aAicuS with'^I'T"' "" «"■"•"• "^^^
atmg surface is borne chie^y on th« M to,' 'th IT'"'' '^"^ ^"''^"■
the axillary border, but it also ext^Lf ■ ^^ "^""^ corresponding to
base of an overhanging proTeCfonth-" ^" *"■!"" '"■•'"»" '" 'he
coracoideus). The free UtZ of "he latter'^"'"' '"^•" 'P"^"^"'
projection lying toward t^e medial surfa^ofMr^n: """' """-'"''

100

.\\.\TOMV OF THE RaBBIT.

THE CLAVICLE.

The clavicle (clavicula) is imperfectly developed in the rabbit, con-
sisting of a slender, arcuate rod of bone, tipped by cartilage, which lies
in the interspace between the manubrium sterni and the head of the
humerus. It occupies only a port'on of this interspace, being attached
medially by the sternoclavicular ligament and laterally bv the deido-
humeral ligament.

THE HUMERUS.

The humerus (Fig. 38) is typical of the long bones of the proximal
and middle segments of the fore and hind limbs -n consisting of a central
portion, the body or shaft of the bone, and
of proximal and distal extremities for muscle j.^.

attachment and articulation. The proxi-
mal extremity bears on its medial side a
smooth, convex projection, the head of the
humerus (caput humeri), for articulation
with the scapula. The articulation is
nominally a ball-and-socket joint, or enar-
throsis, but th° articulating surfaces are
somewhat restricted, and the muscular
arrangements of the limb are such that the
ran£;e of lateral motion (abduction and
adtluction) is small. Immediately in front
of the head of the bone there is a small
elevation, the lesser tubercle (tuberctilum
minus). It is separated by a longitudinal
furrow of the anterior suiface, the inter-
tubercular groove (sulcus intertubercularis),
from a much larger lateral elevation, the
greater tubercle (tuberculum majus). Ex-
tending distad from the latter is a tri-
angular area the humeral spine (spina
humeri), the i.^ of which reaches almost
to the middle of the bone and forms a
pronounced angle on its anterior surface.

The distal extremity of the humerus
bears a grooved articular surface, the
trodUea humeri, for articulation with the
radius and ulna. On its lateral side is a
smaller surface, the capitulum humeri, for
articulation with the radius alone. Im-
mediately above the trochlea the medial and
lateral portions of the bone are thickened to
form two areas for muscular attachment.
One of these, the lateral epico lyle (epicondylus lateralis), is a general
point of origin for the extensor muscles of the dorsal surface of the
hand, while the other, the medial epicondyle (epicondylus medialis), is

Pig. 38. Anterior surface of the left
humerus' c, capitulum; c.h., head of
humerus: e.l. and e.m., lateiMl and
medial epicondytes : f.r., radial fossa;
s.h., spina humeri; s.i., intertuber-
cular groove; t.h.. trochlea humeri;
t.mi. and t.mj., le««r and greater
tubercles.

The Aktmio. LiaB Skewtou.

epicondyles the extrJ^i, , between the

frreatly ^excavated i'Th^.-.V" "^"^ »
portions of the rirlili. ■ \ ^ Projecting

ulna behind [rl r«e ^d In .?h' """ !" ""^
the surface when the f?r. ■ •'^P'^ssions of
extended On tie »i? ■? greatly flexed
niiUalfaaaff '" H- i^"'"""' ='de is the
side ehe^ec«n?„7^", • °" '^ P°^'"i"
called becausT." Tc^l^ 'f olecrani), so-
Procers of the ulna "*'" "le olecranon

THE RADIUS AND ULNA

^^•^^tTT&IHJ.' ""^ ''"''" "' '"e
extremity does not eS T'v '•^P™''i•>'al
the front of the elb^'r/oinr »m1 "^r""
dorsal m its general noJ,,- " u . *"'""-
on the ulna in such a^av ih»?" . " "°^*''
extremity tends to be irteraWh/l P/"5 ■"»'

te''rreTThi^-SLrof4~^^

J^^^tdSS-----

portion of the e;£,''^.j5™"'8,»^ considerable
bone is solidly unitedTith Sf ^""^ u°' ""^
interosseous l4«ni.„» „r.? . '"* ''^ ""e
distal ext"emhr^r,a°rL ^^ /o""™- The,
epiphysis, which is well m.;i, 1°""^ ""^ an

"-Tii^'i^SlS-'^'^r-

Sr^^^iSSr^^."^^?^
faceof\herTdTst,nt"„rs',H''^ "''^'''' '<"
of the extensor muSles of he h"?."'"*'"
lateral epicondyle ot ,hJ u ^*"'* '"■""" the
to the foLrm^whSc the ,',^7/ •"^'?''.°"
function with resn...t V„ ft, „^''' * s™ilar

The proxima?,ir,b„ of the'hf "'"?'• ."'"«^'"
compressed. It bear^ °V^ '*'?'^ '' laterally
the swniluMT 'oteh ^i"^"""'"^ depression',
notch (incisura semilunaris)

"Piute; ■■c?"'ffL'»",'' =P.

" . uwr»i phliini?,:"'™' i*™.

ft

I

102

Anatomy or the Rabbit.

the articulating surface of which continues that of the medial
portion of the head of the radius, and is received into the trochlea
humeri. Behind the elbow-joint the bone forms the large projecting
portion of the elbow, the olecranon, which is a strong process for the
insertion of the extensor muscles (anconaei) acting on the forearm. The
distal extremity of the bone is formed by an epiphysis, similar to but
much longer than that of the radius. It is immovably articulated with
the radius, and its tip is formed by a blunt styloid process (processus
styloideus), which is articulated with the triquetral bone of the carpus.

The elbow-joint is formed by the trochlea and capitulum of the
humerus in conjunction with the semilunar notch of the ulna and the
corresponding articular surface of the head of the radius. It is a hinge-
joint, or ginglymus, permitting motion in one plane, i.e., extension and
flexion of the forearm. The trochlear surface of the humerus, however,
has a slight spiral trend, the anterior portion bemg medial in comparison
with the posterior portion. '

Through the immovable articulation provided by the respective
proximal and distal ends of the bones, and also through the interosseous
ligament, the radius and ulna are unable to change their positions with
respect to one another; in other words, the radius is unable to rotate
on an axis formed by the ulna, the fore foot being fixed in a position
comparable to that of pronation in the human hand (cf. p. 33).

THE CARPUS.

The carpus (Fig. 39) comprises nine small elements, the wrist or carpal
bones (ossu carpi), which are interposed between the forearm and the
digits. They are arranged in two main rows, namely, a proximal row,
the elements of which are articulated with the radius and ulna ; and
a distal row, the elements of which are articulated with *he five bones of
the metacarpus. Enumerated from the medial side of the ..rist laterad,
the proximal row contains four elements, namely, the navicular, lunate,
triquetral and pisiform bones. The navicular and lunate are articulated
with the distal extremity of the radius, the triquetral with the styloid
process of the ulna. The pisiform bone lies on the ventral surface of
the extremity of the ulna, and is therefore not exposed to the dorsal
surface of the wrist. The distal row contains five elements, namely, the
greater multangular, lesser multangular, central, capitate, and hamate
bones. The first, second, and fourth are in association respectively with
the first, second, and third metacarpals. The central bone lies to the
lateral side of the articulation at the base of the second metacarpal.
As its name implies, it is originally an element interposed between t^-e
proximal and distal rows. The hamate is a comparatively large element
associated with the fourth and fifth metacarpals, but extending also
to the articulation of the third, where it tends to replace the greatly
reduced capitate.

^ SESAMOID BONES

^^THE SKELETON OF THE POSTERIOR LIMB

The coxal ™^ '^°'^'*'' ''°'^^-

104

Anatomy or the Rabbit.

excluded through the development in the acetabular depression of a
•mall triangular element, theoaaceUbuU. Although completely coalesced
in the adult condition, and showing but few traces of their origmal
separation, the three chief elements are nevertheless described as if distinct.

The Ilium {os ilium) is the anterior,
also somewhat dorsal, portion of the
bone ; that part extending forward from
the acetabulum. It comprises a basal
portion, the body (corpus oss. ilium),
which includes the anterior portion of
the acetabulum and the cylindrical part
of the bone in front of it, and an ex-
panded portion, the iliac wing (ala oss.
ilium), for muscle attachment and
articulation with the sacrum. The body
is somewhat triangular in section, its
surface being divided into three areas,
which are respectively medial, or sacral,
ventrolateral, or iliac, and dorsolateral,
or gluteal. The corresponding borders
are respectively ventral, or pubic, lateral,
or acetabular, and dorsal, or ischial, c p
The -cetabular border terminates a short
distance in front of the acetabulum in '■ P
an abruptly truncated projection, the r.s
inferior anterior spine (spina anterior n '
inferior). The ischial border forms the
anterior half of a long depression of the
dorsal surface of the coxal bone, the
greater sciatic notch (incisura ischiadica
major). The pubic border presents on
its medial side a faint, ridge-like eleva-
tion, the iUopectineal line (linea iliopect- ^^^ ^^ ^^^ ^^^_^ ^, ^^ ,^,,
inea), which connects the sharp anterior „„, \„^, jl, iiiom; is. tachmra; p.
border of the pubis with the articular ^"^^f'Sm"'c"S.:bi!yo^tach";S:
surface for th. sacrum. f,4S-°'.'S£i.c.T- It 'SUiif

The wing Ol the ilium forms a shovel- i^. fo,. obturator foramen; ,i.a..

like expansion, the natural position of :=«h'"'rmin'5i."'AJ'^ichri'r
which is almost sagif il. I'^ 'a'"^' !LXr.':S',i?.^v &.t1o?«ia
surface provides a fairiy extensive area !„hium; rip., iohrior ntratn. of puIiU;
for the origin of the gluteal muscles. ;„"irt™''^t;,T puS.r?aT,' i4'rfe
Its medial surface is a muscle surface ^^z;'^< '^Ij'^S.uS'.i^i-T"
onlv in its anterior portion, the posterior ,^„^„is ^m,- •■'■^■^^'"tf^Sl
portion bei ; occupied by the roughened .pj™^,.... ---i <»•«"-". • » • -»>>-
auricular kOtface (facies auricularis), .... j . •„!,.

?oT™Cection with the sacrum. The dorsal margm is thin andfaight^
Posteriorlv. where it is associated with the greater ^^'^'J^ ""'^^ 'f"f
is a small projection, the inferior posterior spme (spma posterior inferior).
Anteriorly it passes bv a broad angle into the anterodorsal margin of

The P0STE1..0, L.MB SKEtETow. ,p5

•S;^ « it^-sisf ^^Er/is-^ ^^^^ "■« »'■>- -"-ich i, ai..

h.ck.r than the related dorUl a'd vemral Ljr '?°""'"J' """'derably
in.!"*?,^ '"'* " somewhat hook shared n^^*^""' ^""^ *'» l"™" "n
angle is the superior anterior wta. f,rii^ P"^'** '" "nteroventral

ral margin is slightly longer tha?H,lS„r„i'""'°'' '"I*""^). The ven
It IS associated with 'the puhic Cder of .T^lliy*'"/ »"'' " "'» "'"ca™

r^'r^f^^T^"-^'^''^^^^^^^ the acetabulum, it,

tertt^KI.-rc:£F^^^^^^^^

part of the acetabulum, and weLu "'f "^''' '? '"'"'' the posterior
deep .cetabtxtar notch (incisuri^ac^tabum wh.Vh'V"."'"' '"e latter a
articular surface. The acetabular notch Ldf '"^' '" '"terrupt th-
of the centre of the articular basfn, "he .«tab^°7"'' Y. '° ^ depression
In the natural condition the combined rtl™- '°~ dossa acetabuli).
ment of the round ligament of the kTm TP/"/">ns serve for the attach
of the bone, belonghTg T„ ' "rt to ,h.^^H"" ^"'"' The dorsal ma?g?„
ramus, bears a shor? hoSk like or^i^, '' ""!'" »«"•' '° 'he sS?

formfr^- '^•■^^^'"''''^desthis'^mTrgnntot'"'*^ ■"»• ^P^^
forms the posterior half of the grea^r TL" Z P*"^' °"e of which

"hie the other forms a similar! and ^tKhh^""^''' ^'f"^'"''' described,
posterior depression, the lewr sciiurnoteh rinci' *""•«'>'•'"=' extensive
,. T^^^'uPfriof ramu. of the ischium ,°s thi , " '^hiadica minor),
the bodv of the bone It i. « i!^ i "^ contmuation backward if
thicker dorsal poS o which^rrminaJ '^''^'"!"' P'"'^ of b^ne th°e
One of these, the ischtal tubor^ti rn.h " L" i'™ '''''"' Projection,
tertor end of the bone, whfle tKheexYeid ^'"'"T""' '"'">' "-e ^s
IS described as the lateral orw^/nf^^ '?*'*'"»' direction knd
««u, is that part of the^hiumThich «r„"; ^'"^'j.'' ^he inf.ri„
downward and forward between throbturrttf """ "" '"P*™r ram^
to rjiee, the corresponding ramus of , he pubis ^*'^"' *"'' '*■* 'yn-physis

diatp;^j^t rc"etLruml^°ul£' -"^°- - "-^

to the symphysis, and an iS;^™?;^" ""•» "'-"ding firom theZ^y

^^•"P^y^s to its junction w,Tth?S^hiumTh^ ''*"''"'"'' ^""^ 'he
the bone, described as the necton n.. i" • ^^^ anterior margin of
the symphysis it bears a min'^e e°e^.-i„''„"'';?' "^ '!"'; ?"" ^harp. ^al
pubicum), and laterally a morrextenLl f"''''.*"'»«'« (tuberculum
•mmmce (eminentia UiopectTnea) Th, Tf,. ™"°"' ""^ 1iop«tineS
older specimens, where it is Sv 7 ^''t"! " "«"■- conspicuous^
Its lateral margin is ^onllZ^^^'^^^^yJl^,,^ ™""" "

THE FEMUR.

verJ"'4X" rTufie^'ihl'or^hr?"' ^ -^haped bone, the body being
•^nt downward, forming thr/rtlc^^larn-'r^- Z ^-^J

106

Anatomv of ihr Rabbit.

with its various proctsscs, slightly upward in association with the pelvis.
In considering the general form, it will be remembered that in the natural
sitting poaturi- o( the rabbit, the position of the femur is approxi-
mately horiiontal. the convex surface of the shaft, which is equivalent
to the anil rior surface in man, being uppermost.

The jiiuximal extremity of the femur bears an extensive rounded
portion or baad (caput femoris), for articulation with the pelvic girdle.
This portion is separated from the main part of the extremity by a con-
stricted area or nack (coUum femoris), so that, unlike the case of the
anterior limb, the points of muscle attachment fall a considerable
distance from the point of articulation. The actual extremity of the
bone is formed by a large process for
muscular attachment, the gnat trochanter
(trochanter major). It is divided into two
portions, one of which, the firtt trochanter
(trochanter primus), forms the large termi-
nal, hook-like projection, while the other,'
the third trochanter (trochanter tertius), is
the smaller lateral crest. On the medial
side of the bone, immediately distal to the
head, there is a triangular elevation, the
lesser, or second trochanter (trochanter
minor s. secundus). I'osteriorly, these pro-
jections form a smooth surface for muscle
attachment, except, however, at the base
of the trochanter major, where the surface
of the bone presents a deep, though narrow,
depression, the trochanteric fossa (fossa
trochanterica).

The distal extremity bears an extensive
surface for articulation with the tibia. It
is divided into two portions, known as the
medial and lateral condyles, through the
pr.'^sence of a deep excavation, the inter-
condyloid fossa (fossa intorcondyloidea).
Immediately above the condyles, on the
anterior surface of the bone, the inter-
condyloid fossa is replaced by a broad
groove, the patellar surface (facies patel-
laris), which, in the natural condition,
accommodates the convex internal surface
of the patella. The medial and lateral
portions of the bone, intervening between
the distal portion of the patellar surface
and the tips of the condyles, provide
slightly elevated, roughened surfaces, the
medial and bteral epicondyles, for muscular
attachment.

Pin. 41. Anterior surface of the left
femur: c.l. and c.m., late raJ and
media] condyles: cl f, neck of femur;
cpf. articular portion (head); e.l.
and e.m., lateral and medial epicon-
dyles; f,p.. patellar surface; t.mi..
trochanter mmor; t.mi.. trwhanter
maior. including t.p. and t.t., the first
and third truchantetv.

Th« ToSTIUIO. L,mb SxgWTON.

THE TIBIA AND FIBULA.

IV

half of ill length. Its proximal rxtn.^ . '."*'«"<■■• '"r more than onc-
mam .urfa«. being re.^ti^v "mS ",'"""«"'" '" «ction. th.
•""The «nterio*r bori^r , form^ bvT; »"'«"•"«•')'■''. «nd po.-
th. tulMnMity of the tibia (tubero»it« lihi ! "°V' '."'K'^ "ike elevation,

"f the articular torde he bo.t,teT"
condyloid foun i posterior inter-

dis.i;.,„ishable e^; i^^rerrnt^lr' "^""^

v,rJ^^," / PO"'"on presents a trans """»"»"y of ,«;
PrCet o^.%riaTer:rijr;fS- ""= — '"-e-

fontendonsof the Aon;:Y;"„I,Ye, "^ "'""'"''" '""^^^ '"« i"--

1 tT'°.'^- Anterior surface of the
l""i^ IT) .nd fib.". ,F|

sunace lor the femur: m 1 anil
t.. tuberosity of titria """'•'oil.

lOB

Anatomy or riii: Rabbit,

THE TARSUS.

The tartuB (Fig. 43) comprises six elements, the tariAl, or anklt-booM
(ossa tarsi), which, like the corresponding bones of the carpus, are
arranged in proximal and rii^' <t rows. An excptkin is to be made, how-
ever, for one element, tti icular. which occupies an intermediate
position. Thf proximal row L^ntains two elements, the taJuB and cftl-
caiMUS. The talus is medial and also slightly dorsal in position. Iti
proximal end, described as the body (corpus
tali), Iwais an extensive pulley like surface,
the trochlM tali, for articulation with the tibia,
these two surfaces together forming the chief
portion of the ar.'-le-joint. Its distal end,
termed the hcadol the talus (caput iaii), pro-
vides a convex articular surface for the navi-
cular hone, and is separated from the larger
trochlear portion by a slightly constricte'd
intermediate portion or ntck fcollum tali).
Us ventrolateral border is extensively arti-
culated with the calcaneus. The latter is a
cylindrical element, fully twice as long as the
talus, since it is extended backward behind
the ankle-joint, as the tuber catcaneii ur bone

of the heel. Its dorsal surface bears a prom-
inent elevation for articulation with the
fibular side of the tibiofibula. Its medial

surface bears a flat, shelf-like process, the

■uitentaculum tali, which forms a ventral

support for the talus. The distal extremity

of the bone articulates with the cuboid and

also with the navicular.

The intermediate element, the navicular

bone, is a somewhat cubical bone, lying on

the medial side of the tarsus between the

talus, on the one hand, and the proximal end

of the second metatarsal bone and Lhe second

and third ctmeiform btjups. on the other.

Its {xisition is more nearly that of a central

element than is the case with the bone called

by this name in the rabbit's carpus. In this

connection it will be remembered that the

carpus and tarsus, like other parts of the limbs,

are primarily constructed on the same plan.
The distal row of the tarsus contains

three elements, namely, the second and

third cuneiform bones and the cuboid bone. The two former and

especially the first, are smaller bones, articulated respectively with

the second (first developed) and third metatarsals. In the rabbit the

first cuneiform bone — the first element of he distal row in the usual con-

Fto, 4.1. The bonw of thtltft foot,
viewed from the aorM) surface:
T, tanui; H, metatkTTui: p
ph«l«ni(«. H V, the four me-
tatanal bono: cb.. cuboid: cl.,
cftlckneu*: C.B., lerond runeiform;
c.t,. third cuneiform: f.m

artuuUr surface for fibular side or
the tibofihula: n navicular; t,
talu*: t.c. tuber calcatiH; t.t.,
trochlea tali.

^^ THE METATARSLS AND PHALA.VOES

fully d':.v"Cn'ni''gfe.1?^ Tx^ln ^ 1^"'^- "' »••-•• four .„
mttacrpui, while one, the first n,..i? , " "'""■"Pundini! bones of
riemen, lies on ,he pl.n Ur^u^7L"o T?Jo,'V"'«»'- -^"'e ^^^ii'
•o the navicular and at the base nt ih ' I '"^ ""'»• P"ft ventral
developed metatarsal there ma ZdUtituiT?" ™."""«^ In each
a proximal extremitv or bu. and a dS ^'''' ' !""'" P""»>> "' b«lT
named portion arLciilatiniT h ?h. "' T'"''^""> "■■ ^*»i the W

.-e^nalX^r;^^---^:^..
SESAMOID BONES
andoI^.htXmifrs'S'r^ro'r.tC r"' "' '"' ■"- i"-'

tit>ia. The sesamo ds of the foot »r„ .". . j ""* '*"""■ and that of the
^.n.s and at those ^nJ^^^T^ulV^Z^lir^l^^/Zu-^^^^^^^

PART III.

i|:ffi

DISSECTION OF THE RABBIT.

The plan of dissection as ouUined in the following pages presupposes
in the first place that the entire dissection is to be made on a single
Lcimen, la secondly that the latter has been prepared for gross
duiction according to the method given m the appendix These
points may be mentioned as explaining many details of procedure and
also to a certain extent the selection in preference to others of those
9 ^ctures which are more readUy made out by the "'^''■"d e'fP'^f.d^

Because of the convenience of dissecting \n circumscribed regions, the
plan has been divided, although of necessity very unequally, into several
Sarts The order of these is such that the visceral dissection is introduced
at an early stage. The somewhat more logical plan of completing first
tie disictton of the anterior and posterior limbs may be followed but on
account of the fact that it involves a lengthy muscular dissection to
beein with, it is perhaps not to be recommended.

The account itself aims at a statement of the various structures as
met with in order of dissection and the features by which they may be
SentTfied, rather than . t a full description. The student should make
his own observations and prove them by personal drawings and de-
scriptions of selected parts. In this connection he will do well to bear
in inind that whUe dissection is nominally a means of obtaining anatom-
ical information, its chief value as a laboratory exercise consists in the
training to be acquired from critical observation and analysis It is
therXre of quite\s much practical importance that he shou d make
his observations extensive and accurate as that he should employ only
good instruments, or maintain the proper sequence m dissection.

I. EXTERNAL FEATURES.
The external structures, subdivisions of the body, and superficial
skeletal points may be made out as follows:

1. The division of the body into the head (caput), neck (collum)
trunk (truncus), t«U (cauda), and the anterior and postenor lunbs or
extremities (extremitates).

2. In the head: , ^ j

(a) The division into a posterior, cranial portion (cranium), and

an anterior, facial portion (facies).
(b)The mouth (os), bounded by the cleft upper Up (labium

superius) and the undivided lower Up (labium infenus).

The large sensory hairs or vibrissae.

EXTERNAI. FeaTIRES.

Ill

(d) The eye (oculus), and its coverines the evelirf« i„ i j-
the upper eyeUd (palpebra superiorUhe loW^eui p^ " irf
.nfenor), and the third eyelid (pal^bra tertilr The U,ird
eyelid occupies the anterior angle of the eve and is pLl
able to the conjunctival fold of^the human eve '^ " """P""

(e) The external ear (auricula), and its canal the eit«™.I
acoustic meatus (meatus acusticus cxternus) leading ?.?T
tympanic membrane. >^Aiernusj, leaamg to the

'''^ t^h°rou^h''?hI\'"'"' '■'"'■""■"■■ '" ^ '"'^""fi'^'' bv feeline

exJernil "'^'^'": zygomatic arch, supraorbital- process

external occipital protuberance anirU n! ,u ^^ " ."'■

symphysis of ?he mrndible and ihehtid bone '"'"'""'^'

In the trunk ;

(a) The division into thorax, abdomen, and back, or dorsum.

iTihl" tI'"" "■'."'/'"^ "•""'^ °' 'he proximal portions of the
limbs. The angle formed by the anterior limb with the Lnk
s^^rh""""??"^""" (fossa axiUarisl. The depression
IS much less evident than in man on account of the dSnt
positions of Its enclosing folds formed bv the pt^toralf, and
ktissimus dorsi muscles. A corresponding i.^aS4?™
f-Parates the posterior limb from the abdome7an7i.1T"

Lr-Ti, '"i*"^* '""H^'' ""^ "" "'h" 'ide of it the iLuinal
gS'o^*" depressions, on which the ducts of the 1^1

(d) In the male: the urinogenital aperture at the extremitv of
o«„Sr7/ ""^^ '""".-"'^lo^d bVafold of interment \he
prepuce (praeputium); the scrotal sacs (scroti) "atera^
sacs of the integument lodging the testes *^™"""'' '^'"'''

'"' o? th^ 'fT'"' ""■ """"K^ni'^'l aperture, enclosed bv folds
of the integument, forming the vulva. The clitoris th^
homotogue of the penis, is contained in™ ventral waT' The
«^°™«y nipples (papillae maramarum), eight (to ten) in
number on the ventral surface of the breast and abdomen
The fol owing skeletal points: on the axial skeleton the
manubrium sterni, xiphoid process, cosUl arch spinous
processes of thoracic and lumbar ver ebraeronThe pectoral
girdle, the acromion, clavicle, and respecive borders and
angles of the scapula; on the pelvic giVdle the iliac crest
pubic symphysis, and ischial tuberosity '

4. In the anterior limb:

*^' I^ ^k"1°" °! }^' '""^ •»"'"" i"'" ">ree segments the
ann (brachium), forearm (antibrachium), and hald (manus)

k^.""' °" ' •""" *™''""^^ '" ^mparison with the

(f)

^I'-J

112 Anatomy or the Rabbit.

(c) The five digits, designated from the medial side as: fint
(d. primus), or pollei, second (d. secundus), or index, third or
middle (d. tertius s. medius), fourth (d. quartus), and fifth
(d. quintus s. minimus).

5. In the posterior limb :

(a) The division into three segments, the thigh (femur), leg
(crus), and foot (pes).

(b) The knee (genu), and the popliteal fossa of its posterior
surface, the latter not well defined. The projection of the
heel (calx), and the angle formed by the foot with the leg

(c) The four digits (dd. secundus-quintus). The vestigial first
digit, or hallux, does not appear above the integument.

The Abdominai, Wai,i,.

113

n. THE ABDOMINAL WALL.

symphysis to the tip of the mandible, being careful not To cut throuA

sTrthrr ";' ''rJ'"".. ''"^^ "-^ '-"-rse i„ciions™ thTS
ebow ,h °"^ 'he med.al surface of the arm and extending to the

elbow, the second midway between the anterior and posterior limbs he

Work Z San"?''"" f'^'V '"' "■''^'' "■"» "'-"^i"8 "o he knee
unta the%?7 T ™'", '^* '"'*"■ "»'"« 'he handle of the Lal^l'
until the side of the trunk is well exposed. On the right side nf S

^/.nls: ^•"'"^"' '" ^'^"^ '"' -^'^'^ '■-■ Ide„Uf7?hVtul're:

On the skin :

.M It" "'k'!.?' ^l?"''' connective tissue forming the corium.
(b) The imbedded hair-folUcles.

''^ ?"he^ll^"Ts:uttd.""" """• '"^'^^ ^"•'™'--) ">• "hich

''"^ la"ver ™X^^ "" f^"^^ S^^^ (mammae), forming a

ahn^^f fh "" '"''""• ^"'' """■'^ °f 'ess closely aggregated

about the mammary nipples. -^ "SBregatca

On the exposed surface :

^''' 1!^;"°" "l*"'* ''■''"' aponeurotic line extending from the

pubic symphysis to the xiphoid process of the sternum
(1) The cutan«us maiimus muscle, a thin sheet of muscle fibres

Orie'r^Th' ?"'"■' 'il'""' '""''•' "' 'he thorax a^dTbdomeT
Origin. The linea alba, the ventral surface of the sternum in
Its posterior portion, and the ' humeraf spine TheTs,

ln"rl?^The ^iET?.? '^ "f"^' ^"''-'^ "' the hum ru.
Th^ fii? The skm of the dorsolateral surface of the trunk

llr"' "^ "^'""^^"^ "P""»^d and backward. The muSle
IS continuous across the back with its fellow of the op^^te

branch of the femoral (p 149) ' " ■•'P'™':'*' epigastric, a

.a.erI';„'^oT^f''o:ra,,S;Sr„'Sf frTm','? '"^ '=">")=/"—>' 'he
axillary fos.,a, Iving on the eSemalsuV^^^r ,h '"^'""'" '""''■"" '° ">«
is a tri&utary of thS inferior epSricJnmf '>' V'"""^"' ma.x,rau.s. It
with the external maSma,?.'^vein o?' the*'ax?lla''°¥ir"-'''' '""'i"''

LTt^hra-bd'otrr^rixTtr ?„f >■ °' ^'^" '-^^^

directlv from an extemaT^pel'af ttX ''"^"'"'=- '"' '""" "-■"«

'V.-.I. brownish U.dies iy.ng m the .nguSlfuiS^.

JJ4 Anatomy of the Rabbit.

2. Remove the eutaneus maximum from the surface, "entify the
following points of attachment of the abdommal muscles proper.

(a) The linca alba.

(b) The linea semUnnaris, a slighUy curved line situated laterally
a short distance from the linea alba.

(c) The ribs and the costal arch.

(d) The lumbodorwl fascia (fascU lumbodorsalis). a broad, white
sheetTf connective tissue extending o«r the posterior
thoracic and lumbar regions.

M The inguinal ligament (ligamentum inguinale), a stout white
cord, stretched between the symphysis pubis and the iliac
crest.

3 Identify on the surface the external obUque mujcle (m. obliqmw
extern" aMominis). Origin: The posterior ten "b^^^y-P^-ie in'S
ihp xinhoid orocess and the lumbodorsal fascia. Insertion, the linea
IL anS the?ngu^nal Ugament. The fibres ar^ directed from an anterio
dorLTDOsition downward and backward, the more dorsal ones almost
SvTackward S^me of the anterior slips of origin "•t"d'8"ate
wUh tho^ of the thoracic -ortion of the serratus anterior muscle. Some
are concealed by the frf:toral muscles. „„,„„,:.

where they conceal the external oHiqu-s.

4 Taking a line between the Uiac crest and the xiphoid process
divide the muscle, and then separate it fully f™" '^e n«t, wh^h may
be distinguished by the cross direction of its fi^^^^^^^ote the separate
sliDs of origin and the difference m appearance between the Heshy ana
aponeurotif ^rtions of the muscle; then remove it from the surface.

Examine the following muscles, proceeding in a similar ^'\'^^'-

(a) The internal obUque muscle (m. obUquus internus abdomm^.

'''* 6rigi":^e ingSinal ligament, -^""'i'^'''°l'^^'''%,

dorlal fascia, and the posterior four "b^- .I°^^''°"- Rl

linea alba The fibres pass downward and forward, ine

ventraTa^neurosis is much broader than that of the external

oblique. It contains the rectus abdominis.

(hi The transverse muscle (m. transversus abdominis). Origin:

' ' Lvei "sle^r ribs, third sheet of the lumbodor^l fascia

a^d thnnguinal ligai.ient. Insertion: The linea alba. The

fibres areTrected downward and slightly backward.

(c) The rectus abdominis muscle. Origin; Lateral border of the

^ ' sternum, including the "ipho'dprocess; also the ven^ra^

surfaces of the second to seventh costal f^'.-l^S"; . '"^^

ion ; At the anterior end of the pubic symphysis. " « » J^in^

rap-like muscle, enclosed by the aponeurosis of the mtemal

The Abdominai Wall hS

with theSernaJ mammar^ (D 1%) Xiivif J-.l^*' ..'' ''?"'<''"°«''
•rtery, a small vea^l wS Eerfori't« flS .Jh «'»,««^ni«l iiMmuitie
backward, supplviM the S^ ^ ,hl ! .' ' "Nominal wall and extends
female in the wKf' ,h,^„?^a ' in abd"o,^1: ?i' "k^ "J''^' " "»
passes forward on the abX,;?SwaltLt^Sdatev"''' °' '"" ""'''

116

Anatomy of the Rabbit.

If-*

111, THE STOMACH AND SPLEEN.
The cavity disclosed ^v the divi^on of the abdom^^^^^
peritoneal cavity (cavum 1*"'°"*^'; '"j* 'f '^"„ ° c«lom (p 49). The
MCS representing the Pr>"'?"'>. ^l'^„Tu^'t UcxtVnds into the pelvis,
„ajor portion of the cav.ty .s abdor^>^^ **" , 'i „Y„rmen.brane iVthat

rp^p^r/oTrp'^iirafrp^^,,^--
£rir ^r^^T:::<^:^^^^^ -ior^tions of

the digestive and urinogenital systems. ,,,„„irt first be

"^he general relations of the viscera P^^ -^ ,?„tetft'"de of
examined bv raismg a portion o the ^ma" mttsune

, ,e visceral mass. Note i'"""^'"""''^ „* T^bodv waT and 'the ex-
i„ appearance to the 7<'""';^ne co^r ng the body^ ^^.^^^ ^^^^^^^^^

tension of the 'f'" ■".'", 'i"«^„'^^*V parallel arrangement of the
from the dorsal body «all. ■^?'% '".^.l? „_„_,oniose5 Lymphatic

dorsal attachment, or root (radix mesenteru).

1. Displace the po^teroventra, portio^ oUhe U-/or«ard »pos,ng

r„cfoiUperr:urei:m^^^^^^^^^^

" '°"°Ta" The greater curvature (curvatura ventriculi major), its convex
(b) d:L7':^atur. (curvatura ventricuU miv.or), the
contracted concave anterior surface.

the intestme (d"°denum). It is marKe

~^r tf^hr^rctmb,Tno^ril rpVoric antrum

(antrum pvloricum).

Thk Stomach and Spieen. 117

""' JunXri'"!™"" f" TC'^^'l'' '""^''»"<' f™" 'h= greater

usually contams fat. It is composed of four eaves „f which
passTo^a/dTn"/;"'^ "'■ "■' ^""""^h »ndt»o Others

gsJ"[ru^,e"„..VrL'rs :;z^''- «

cTrvatZ' """"'""^ "" ™'«^''"-- '"•'e with ZTsser

and'thT b;'JvS:';rvfs:mci::rof'rh''"'"' f"^^"^*- °' "■-= ^'■""-'■

first portion of the abZn^Ll aorta ..it P^"'™'"'" '» -^"Pose the
Passing in the direction o^The stomach is "T'T '"■" .'"^ ."'-Ph^S™-
coeliac artery, the distribut on of wWch m k "" ''J'"'''' ''''""■''• "'<=
structures, ri'o'wever, shouldfirst be "j^kntS " '"'''■ ^"^ '""""'"«

'''^ ^^eIlow!?h"H"""^^'"'? [«'■ ^-P^^'^nalis) of the left side a
'^ .??hl"?vrpau"if:v','"''f"'''' '«■ "--""icu,u superius)

pcrior^--!^------™;^;;;^^;;-

118

Anatomy ot the Rabbit.

11'

(I) The nerve, proceeding from the coeliac and superior me-

sente?'c ganglia accompany the corresponding arteries,

S™"ng the c«li.c and .up«lor m««.t.ric P .xu«..

<„) Thrcneater) tptanchnic nerve (n. splanchnicus major) of

**" Ihe leHde Pas«.s baclc«ard from its origin in the thorax

S c^rolIf^gXrort'a^^S '^^J^^^^

Trace the p^n of branching of the coeliac artery, beginning at the
n'h°e^Xc■S^rt^U-)lTlU"rt^'^^;.,its first ^^^^
.he?pLr'^te^*?eLggiv.noffne^

remaining port.cn of the ves^' f*^^' " ?," Vh" ef" K"'™ »°'' '"=P*"'^
'Trir^SmalT rets^rthe iS.rio^'^i^cV.rf.s (aa, phrenicae
arteries. Small vessels ">^ "^ anterior wal" of the coeliac and are
ilfstSl^d"' .r^aphrlgr ^l^t-Jibution of the main branches is

ir;lrfci^"e^X^^etfV^rtrnT^^"

^th^t organ, and also several more branches, comparable to

Hr::db;|5^;:.r-i^-~t

(h) ThrS^stricart^^.^jca^^-a)^^.^^'^
"JasTinrsoTe;* , raS mann^f toward the lesser curva_
fure of thT™ mach, reaching in this way both dorsal and

S ^:^^ JrtSt^^e^r ^-V ?^

ntho left distributes small branches (rr. oesophagei) to the
ramifications of the v-ikub (p. lia).

Ths Stomach and Spums. „j

distributed chieflv*7,he nS tLrtin^T '^'' . ''^'"'. '"»" »

alis superior), but a smaujec^!^ h Pancreaticoduoden-
trcplploic «it«T (a Tas,r™n^'r"' 'Y""'^'"' "-e right gu-

branch of the left gaTrfc arten "*' <^""="--« »ith a

tnbutaries of the iDlenic ».ln T ,' f'"""^ ""ery aretho

ais. "^^j-^^f"'^ tri;::;^^'4i"; 'f^.^ts'S

enter, .he right »^aTnf t"e''"'^.a?v. n ' "Th"'!";;'''"""^'' "^ch

llip abdominal portion of the >.««i. .

> vagus) mav be t"aced fromTh^„e"°lf' ' °' "«"« -•"•
of the stomach. The left mTd/n^P"*"! '° ""^ ^""•fa™
the oesophagus; crossing ^e veSf," "", ""= '''f' "••'" of
obliruelv to the ri/h t i7ra„% "' u""''^" °' "■« 'alter

the I.s=er curv^tuf 'The rSt^'en"",'"' ™""'^ P""*™ "f

^'-'ar manner on the^d^o^s^fLrjJT/o^e^^Xus'"^
oesophagL,^:;d"rem:ve^r''stonrach't:;;t"'L'i"'™'"- ^""''^ '-e
o^^soXg^s"' - '-'''"" e.te„rg-?o!irti^e\ttr c^J^^t^The

^|^S^Mrm:ti!^aiKl:SsSr ^;Tr -" "'»"^'

by divtdmg the loose tissue of the tela subrn?^?"'',^™"'.™" «"""'"
the mucous tunic mav be seen the gastric ^nT.T °" ""^ ^'"'^'^^ "f
by the longitudinal folds and imMrfecTtr^^ 'areae gastricae), formed
connect them. They are well Sed onU fn ,T "''^^ "''''''' '™d «<>
°f "".^Stomach. The mucous t"^ c of the' st^^.%™""?"'"'^ "'"'"""''
tmted from that of the oesophagus ^'"' " ''"''P'^ diffe.-en-

ill

120

Anatomy or TiiK Rabbit.

!l|

IV. THE LIVER.
Th. IW« (hcDar) is noleworlhy, first, as hting the Urnest of the

^d!^:ii^'^«'rn.cti:,n^T,h th'eYa.ter being through the common

bile duct. , „

1 Examine the general contour and plan of division as fo lows:
(arxhe convex anterior surface, applied to the d.fPh™f!™j
' ' the cXIve posterior surface fitting the convex.^- of the

ItomTch? the thickened dorsal portion of the organ, and Us

thin posteroventral margin. j t „>,

(b) The division of the organ into right and Wt lob-, and of each

lobe into anterior and po.t.rior lobul«.
(e) The g.11 bUdd.r (vesica fellea) situated on the postenor

surface of the right anterior lobule. , „ a,

(d1 The QU«di»t« lob« (lobus quadratus) an ™f ri*^''> ^'-
' ' velop2riobe ivingto the medial side of the gall bladder
(e) The caudat. lob. (lobus caudatus^^^ a small mdep^^^

ffi,'?nd'':rmt„i:rd in\he"ra.u a. condi£in the
space enclosed by the lesser curvature of the stomach.

'■-'^'^r^^-S^.^Zt^:^^'^ the hepatodu^lena.
(b) ThrfaTciform ligament (Ug. falciforme hepatis) a broad

line of division of the liver mto right and left lobes, ine
free a cuate border of the ligament contains a thin cord, the
ro^S S^^ment dig. teres hepatis), which marks the position
of the umbilical vein in the foetus.
In^ The coronary ligament (lig. coronarium hepatis), a short

'rS^r-riJ^'^riSe^siiasnrihi
<^)SS]s:;^t!:^t^ir;trJ-gr^^

with the diaphragm.
s"de by side and their branches are similarly arranged.

The Liveh.

121

Sbull tT '?," "'""■ """'"duet from tho riX aSr
duct through > .h!,,. '^?''^' ""^ common he

proper divides nto right and lift r.ml n ' . . "

'■' «.rZT:{. SS^S^. S„»ftJS

Divtde'^h^tronarvrd'JriaTuUr r ''■ ""^ ^'T'"" '''■'""'«^'' ""^ve
Ihe central Zn"on .Tflu'dSZ^^'^Tl '"•"I' "-'^M not ,o .njure
ligament. Rem™c V liv^'^f™/"' "''""'•. ^''^'nbles the coronary
following "^ '"^" ""•' examine Us dorsal surface for thi

I

il

!:!

121 ANATOHY or TIIK RAIBIt.

V. THE INTESTINES.

The poatcrior portion of the digestive tube, or that portion extending
from the pyloric aperture of the itomach to the anal aperture, is divisible
into two main parts, not wholly distinguishable in calibre, namely, the
•null IntMtlnt (intestinum tcniie), and the largt IntMtint (intestinum
crassum). Ik>th are greatly elongated and convoluted. In examining
them care must be taken to avoid injury to the bkxMlvessels and me-
senteries, especially the dorsal attachments of the mesenteries, in which
the chief plexuses and related ganglia of the sympathetic system will
afterwards be traced.

Pot the general relations of the intestines and mesenteries ice pp.
41, 5U.

1. Beginning at the pylorus, trace the < jurse of the small intestine,
as follows'. Its first portion, the duodeniun, forms a U-shaped loop
lying on the dorsal wall of the abdominal cavity to the right of the
vertebral column. The end of this loop, when traced from the right side,
disappears in the peritoneum and may then be picked up in a forward
position on the left side of the mass. This point marks the beginning of
the second portion, the mewntMial small intestine (intestinum tenue
mesenteriale), which may be traced to its termination on the greatly
enlarged caecum. The connection with the caecum is through a rounded
semi expanded sac, the Mccnliu rotondiu. The terminal portion is
somewhat more difficult to follow on account of the adhvsions of its
peritoneum with that of the large intestine.

2. Examine the divisions of the duodenal loop and related structures,
as follows:

(a) The superior, descending, tnnsTerM (horizontal), and M-
cending portions of the duodenal loop.

(b) The comm m bile duct, opening on the dorsal wall of the
superior portion.

(c) The mesoduodentun, a fold of peritoneum joining the various
parts of the loop.

(d) The pancreas (Fig. ,3 D, p. 11). Its principal portion is here
seen as a diffuse brownish mass lying in the.mesoduodenum.
Us duct (d. pancreatis) opens into the posterior portion of
the ascending limb.

(e) The superior pancreaticoduodenal artery, a branch of the
gastr<!duodenal (see p. 11!)), passes backward on the first
portion of the descending limb.

(f) The inferior pancreaticoduodenal artery (a. pancreaticoduo-
denalis inferior), a branch of the superior mesenteric (p. 125),
enters the mesoduodenum from the left side and supplies the
major portion of the loop. An anterior branch an-
astomoses with (e).

Tug Intejiinm. 12^

.he »n,e„uT,l"rr,ht";, " z tz^ :t'' "'■«•'• «»-

the terminal or caecal poJtbn il„ i"''''^ vasinlaritv of
Utiua (inle,ii„„m j,^„"', •■,"": "'"' ."""""({uished a, the
sparable Al«, ,1^ cicul^; fo-'irrT"" ''"•■'"'•''«'"'' '
valvulae connivente, of th? ,„„ ''"'"'f"' ''"■■'I'Tes), „>
mammal, contribute ,,',' 'Z^"' •■■-k-. which in man*-
duodenum and i..i„„..!„ '""'''ness of the wall in ,i„.
^^^ expre,«d. """'"'"■ "^^ '" the rabbi, not'de^^.t^^;

' r"'"~°^^'i»'disSr'>""'''^" "' "«■ "'"n.erial
•"■oa-I frill like ehara T wh h" '.!' """'"' """'"" '" "•■
movement to this portion of Ti?^- """"' «"■"' f^^'^om "
Porfon however, bc^K m"i„. Jf tV T 'i"'"' '"^ "■™'""

'" ^aTers 'n?/i'';!:,«zi"'T'tr"""'^ "-'«"-^'

oM.vmph follicles, .^mirar"^ "tn . L "r °^ ? '''^«'- ""mlHT
"hout 3mm. in diameter andlmmr', '""^•"X "vul area,
along the intestinal y^M(X^^Z,Tj'y^ ?">■ '«^ ^'md
I he finger like processes or vim r u ' °'^"'" "' ^V")-
^all intestine ma^ ^ «;„^f .' "' ^e mucous tunic of the
wall and examining itVinTern,.! /'"*■' "" '""^''"' "' the
the wall mav be excised "„,, ^'"f^'^"- ^ ^mall portion of
■I- Trace the course of thr, «'''amined under wate?

(f)

ill

124

AXATOMY OF THE RaBBIT.

In the caecum the following features may be distinguished :

(a) The wall, which is otherwise smooth, is divided by a spirally
arranged constriction, the latter denoting the position,
internally, of a fold of the mucous tunic, the spiral valve.

(b) The vermiform process is a narrow, light-colored tube of
about five inches in length, the wall patterned externally
by Ivmph follicles, in the same way as that of the sacculus
rotuiidus, and greatly thickened in comparison with that of
the caecum proper.

m ' '

i4 •■

Pi«. 44. Plan of the connections of the targe and small
intestines c. ascending colon; cae.. caecum; h.. haustra;
i,. ileum; s.r., sacculus rotundus; t.c. band of the colon;
v.s.. spiral valve.

6. The colon is divisible into ascending, transverse, and descending
portions, the relations of which may be traced as follows;

(a) The ascending colon (colon ascendens) passes from its origin
on the caecum to a point forwards on the right side of the
dorsal body-wall. This portion is greatly elongated in the
rabbit, and instead of passing directly forward follows a
tortuous course. It is composed of five principal limbs,
united by flexures. Three of the limbs are directed for the
most part forward, the remaining two backward.

The first limb of the colon bears three rows of small saccu-
lations, the haustra, separated by three longitudinal muscle
stripes, distinguished as the bands of the colon (taeniae coli).
Two of these bands are free, while the third is enclosed by the
supporting peritoneum, the mesocolon. The two free
bands run together toward the anterior end of the first limb.

(b) The transverse colon (colon transversum) is a short segment,
beginning forwards on the right and crossing the middle line
transversely to the left, where it bends sharply backward,
and is replaced by the descending colon.

The Intestines.

125

rectum. ' "• "'' ' ' ^^ lenlaced by the

The descending mesocolon wh -i, „ „
with the dor^I bodv-warshou- ' ,, .;r ' " '' •»"»"
Its relation to the inferior mesent" c ^i rl 7 "'^"""'^ °'
plexuses. It is connected for a consiX-lh h"' ->"'P'>thetie

7 Disor^:'"' "' "^ ^"^"'''"^ ''^^"^ttiz:r "-'" ""=

mesenteriS'T^rinTeS' ^"Zf tt^" '"/"'^ ^'^•"- ^av out the
are exposed. Remove the iTmoh V ^ndT r*"'"': ''"'' "^ Woodvcss^ s
n.ese„teric artery and trace'\rSanth"ef.st^„:.t°*" '"^ "^ "^ ""e'

(b) The inferior pancreatirrde al t.e?v"rT.»;'™'-

the same level, but from the right wau" ^"^^ '"' "'*^ ="

j;;,tirs";h:t;?;rt tiXri-'r'.^ ;-- "---•

to the terminal portion'Tf thrS Th "''' ■^distributed
the vermiform pr^ess), and the as^nH.W T"""! ('"'^'"ding
are arranged in two 4^7 a Dro^ /"'"?■ .''^ branches
near the point of orig™ of fJe^n^^^P ^'"K Siven off
group, including the terminal m.rt,'^^ f 'I'"^'' "'"' ^ ""^tal
two inches from%he p^[n7o?oS '"*'• "' "''°"'

The proximal branches include-

"* ofTlll'/SX^cotn *"*'''• '<"•""• -" fif'" "mbs

''' verUr;tr^ss"'rbri^„ ^^'7"^,-'-^^) to the
off near the'' p^I^t of^r^" ^ ^e, ■^. «->..«iven
anastomosmg with a bran^ch' oHhTsu'^rt ^ITn-

''' ahird"'S,"o*f°tS:'=^:e''c?mVo4'^ 'T'"^' 'o"'"
tion of the ileum ^ °'*'' ""'' ''''ated por-

'■" ^hr/r^^fd^^'jlimbf 7,^" '"^ «-"- •-"-«

-di:;r;£'-:^--s^^

portion of the ileum. anastaSnTwi h^S^*'^"'
'" L"bXrc7ecl""^ '»^'"'- <»"""■ -"He third

126

Anatomy of ths Rabbit.

It
\i

(8) Terminal branches to the parts about the sacculus
rotundus: anastomosing with (4).
(d) The intestinal arteries (aa. intestinales), about twenty in
number, are given off from the superior mesenteric artery,
and are distributed to the free portion of the mesenterial
small intestine. The successive vessels are connected by
anastomoses. The end of the superior mesenteric artery has
the relation of one of the intestinal arteries. It anastomoses
forwards with a single branch given off from the side of the
vessel opposite to the intestinal arteries, and the latter in
turn anastomoses forwards with a branch of the appendicular
artery.

8. Locate in the descending mesocolon the inferior mesenteric artery
(a. mesenterica inferior), a small median vessel arising from the abdominal
aorta. It has two main branches— the left colic artery (a. colica sinistra)
to the anterior portion of the descending colon (anastomosing with the
middle colic), ami the superior baemorrhoidal artery (a. haemorrhoidalis
superior) to the posterior portion of the colon and the rectum.

9. The superior mesenteric vein (v. mesenterica superior), the chief
tributary of the portal, collects the blood distributed by the superior
mesenteric arterv, its tributaries being similar in arrangement to the
branches of the artery. The inferior mesenteric vein (v. mesenterica
inferior) collects blood from the descending colon and rectum; it -nay
be traced forward in the descending mesocolon.

10. Sympathetic plexuses. In the descending mesocolon will be
found the inferior mesenteric ganglion (g. mesentcricum inferius), a
narrow curved body situated ii. front of the interior mesenteric artery.
Surrounding the abdominal aorta and appearing in the mesocolon is the
aMominal aortic plexus (plexus aorticus abdominalis). It is connected
anteriorly with the coeliac and superior mesenteric plexuses (p. 118)
accompanving the corresponding vessels, and with the renal plexuses
accompanying the renal vessels to the kidneys; posteriorly with the
inferior mesenteric and spermatic plexuses about the inferior mesenteric
and internal spermatic arteries, and with the hypogastric plexus about
the pelvic vessels.

11. By dividing the rectum close in front of the pelvis, and severing
the peritoneal attachments, the intestines may be separated and laid out
in an extended condition. The relations to one another of the ileum,
caecum, and colon are studied to much better advantage than in the
natural position.

Ths Ubinogenital System. J27

VI. THE URINOGENITAL SYSTE.M.
A. The Urinaiy Oigans.

antJrtSnT,redl4r;irof t'.*;: lir*^' ''»")■ -™pv ««

« placed a little farther forwtdthan the left r;"' , ''^', "«"" '''''"'^v
the right postirior lobule of the Uver „ H.?-t ''''«^''>' "^'d bv
immediately surrounding the Mney substin. ?" "■ " ^^""^ «=»«'t
>n a mass of fatty material the adL^^™"!' T'' "?"" '^ '^bedded
IS also held in position by he m*rto^m^?"J^''P'"''> ^*posa), and
ventral surface. ' P<^"toneum, which is stretched across its

^''^"^^'>^'ZZJt^'^^^'^°^ -P-e fro™ the left
out as follows: "" vascular connections may be made

(a) The general conyexity of contour.

* ' /ac:orhe''i'r"^i"''""™^"''' -™-ityof '"e medial sur-

''^ wardTo^%he1,ilu's''' •"' '^"'"'^>-- " «"*"^ '""e passing back-

''^'o'rla're„re?l?gtSt'at^tTi/™";^^''''''™-'
vessel, the twelfth intercMtallA-J^^' ■ '^ ''""'^'' "^
passes to the body- "?„"„„? o^Thi'tid"'''™''""' ''"'■
small supraretui. artery toMiT'suptr^^S" '"'"" °" "

''' a^d^S^gTc [.Iferi^tla'^^^'"^ '"^ '^■"'->-' '"^ "ilus,

mow„g''rhif:,nti'ifair'E:fS'th''" r'7" "'/'- '■"- -<< -■

the following: *"""''""- ™t surface of the dorsal half for

^:ct^^^'ss!,-£li?^i^«^

stripped from the surface. ^^ "^y Ije

IS imiierfect y expressed Th. ~ j ii >^ sutatance into reul Dyramfd.
" sligl„ly divided'^S^^fn. ^' '"•dullary substance, however, IZT^s

I

128 Anatomy of the Rabbit.

The distinction of medullary and cortical portions depends on diFer-
ence^ in the arrangement of the minute tubules which compose the kiu .ey.
The medullan- substance is larijely composed of Itriight coUecting ti:Dutel
converging on the renal papilla, while the cortical substance is occupied
by convoluted portions of the tubules and their vascular connections, the
elomeniU. In the natural condition the two parts are also distinguishable
in coloration, the cortical substance being darker. In embalmed animals,
however, the color leatures are usually reversed.

3. The urinary blaiidw vesica urinaria) lies in the ventral posterior
portion of the abdominal <:;.vitv. It is a muscular sac, capable of a
considerable amount of dis. n'sion, but usually found in preserved
animals in a greatlv contracte ; condition. Its rounded anterior end,
the vertex, nrojects forward into ti.e abdominal cavity, while its posterior
portion or fundus, narrows to a canal, the urethra, which receives on its
dorsal wall the apertures of the genital ducts and those of the related
glands. The connections may be made out as follows :

(a) The peritoneum is reflected from the ventral surface of the
rectum in the male an-', fiom the uterus in the female, to the
bladder, and after investing the latter passes to the ventral
abdominal wall. Vhe dorsal peritoneum forms in the male
a double rectovesica." fold (plica rectovesicalis), and in the
female a similar vesicouterine fold, a recess of considerable
extent (rectovesical or vesicouterine pouch) being left between
the adjacent structures.

The ventral peritoneum forms a broad median vertical sheet,
the middle umbUical fold (plica umbilicalis media). The free
edge of this iold, extendinj; irom the vertex of the bladder to
the umbilicus, contains a slender cord, the middle tunbilical
ligament (lig. umbilicale medium). The latter marks the
position of the peripheral portions of the umbilical arteries
in the foetus. • i

(b) The umbilical artery (a. u-nbilicalis), a branch of the hypo-
gastric, passes along the side of the bladder to the vertex.
From the base of the arLCy branches are given off to the
ureter (a. urelerica) and relat2d portions of the genital ducts.

B, The Male Geniuil Organs.

1 . Continue the median ventral incision of the skin backward along
the symphysis to the penis. Reflect the skin on both sides to clear the
attachments of the penis to the ischium, and on the left to a point
beyond the scrotum. Note the cremaster muscle (m. ciemaster), a thin
layer of muscle fibres forming the outer layer of the sac of the testis.
It is continuous with the internal oblique muscle of the abdominal wall,
and also contains fibres from the transverse muscle. Make a longi-
tudinal incision through this muscle, cutting forward into the abdominal
cavity. On spreading apart the two fiaps the following features may
be made out :

(a) The parietal layer (lamina parietalis) of the ttmica vagmaus
propria, a layer of peritoneum, continuous with that of the

The L'ri.vogenitai, Svstem.

he.ng suspended from its dorsal «4,r "" '^"' ""^ '""^
(c) The gubemaculum, a short thi,-!.- ,.„„i . • ■

.use^^h.^ -- 'He posle^ ^ J^ ^^S^rt

Imuous with the mMorrhinm K J '"'"* "'"' 's eon-
J^eunt conneet.n^»'^!r5o;i^S:;^^r I^L^'^
(e) The first portion of the diirt nf '!■„ . .■

forms a th ekened mass at t^,e ,m^r- "';'••'"■ epididymis,
extends backward as a ,1 inn i '"J'' ""^ ""= "^^tis, and

thickened anterLr nortionU^^"'"' "'""» "^ ^i''^'- •'he
the contracted posteHopotion ,?""" 'f "idJ^nidis and
The second portion! the du'^te defer™, ^''''' •P'<"<'y"'idis.
its posterior end. where it I firniiv •,,, 'h '^^\" 'J"" '""'^ '"
culum. The connection wth.^' attached to the guberna-
by carefullv iparat r.he due^ ^■P-d.dym.s may be shown
and tlie side of tl'e testis "^ "'<^ gi.bernaculum

(f) The internal spermatic artenr I-, ...^.,~ .•

from the abdominal aoruXofl^T^A'™.'"!"""' ""«''

^Sr^^Zt^^'-— "^^-

foSsK^^Sr bS- fF"--
latter with the renal ar°erv mat o' *,h^'' '^™"j ''>' "''^

ot":::::: ^^™' " ^'»"' '^^ •-.^^"s;e7m'L\i:* ^^^^^^^^^^

a .p.rn..,ic cord (funiculus ^,^I^S^>'^ l^/f^Z,^^^' T

physis and dissecting in tte interior of th''^-?''- ^^ '^'"'""S ""e svm-
attachments of the p'enis shojfd fct bl e.LTned" ^"^ ^'"^'"^^ ''""

J»d^XVeTni/ilX"flt' fCij-d of'^p^rof'^^jf- ^l"-"^ -""ra, the
cru, penis, -^heltter ^^^^:L:^:^^-^.:^^^^^

130

Anatomy of the Rabbit.

nosiis muscle, the origin of which occupies a similar position on the
ischium, '.he penis is also attached to the symphysis by a short but
stout suspensory ligament (lig. suspensorium) and by a small pubo-
cavemosus muscle lying between the latter and the ischiocavernosus.

The attachments of the penis should be severed and the symphysis
divided. By pressing apart the two sides of the pelvis the urinogenital
tubes, with the penis and the pelvic portion of the rectum, may be
dissected out and removed from the body.

The middle haemorrhoidal artery

(a. haemorrhoidal is media'), a
branch of the hypngastric, passes
to the side oi the rectum and to
the seminal vesicle. The internal uu.-
pudendal artery (a. pudenda inter-
na), accompanied by the corres-
ponding ner.e and vein, passes to
the side of the ;>eni>i, jjiviiijj off the
inferior haemorVhoidal artery to the
terminal portion of the rectum and
to the associated rectal or anal
gland. The rectum is connected
with the root of the tail bv the
rectocaudalis muscle, a somewhat
spindt shaped aggregai..'>n of
smoot. iTiusile fibres, aiisinji from
the body of the second caudal ver-
tebra, and inserted a short distance
forwards on the dorsal .surfi'ce of the
rectum. The sphincter ani externus
and sphincter ani intemus are two
closely related muscles enclosing
the r&L-tumand urethra, the former
arising from the dorsum of the tail.

The fcllowiiig parts of the
urinogenital system may be
made out :

(a) The connection of
the bladder with
the outsirie of the
body through the
urethra. It com-
prises a short pros-
tatic portion in rela-
tion to the genital
ducts, a much
longer membranous
portion traversing
the pelvis, and a terminal cavernous portion in the penis.

(b) The seminal vesicle (vesicula serainalis) lies on the dorsal
surface of the base of the bladder. It is a flattened median
pouch, the anterior, slightly divided tip of which is directed
forward.

Fio. 45. The male urinogenital ducU and related
structures, viewed from the lateral surface. After
Kauther: a., anal aperture; bu., bulbourethral
gland: cc, corpus cavernoaum; d.d., ductus de-
ferens; g.a., anal (recUl) gland: K.i. inguinal gland;
g.p.. gUna penis; par., pareproatatic glands; pr.,
prostate: r. rectum; ur., ureter; u.v., urettira
(membranoiw portion); v.3., seminal vesicle; v.u.,
urinary bladder. ^

The Uwnocen.tai, System.

(c) The deferent ducts lie h#>t
dorsal wall of the bladder Th.""". *'"•'"''' '"''^'^ ""<< the

(d) The r«' *"""*' ''^'^" "'""" '" "" '■'""■"'

glandSS^'uMuifhesYn'^h-'J!''!''' " yellowish mass of
wall of the semtaf, ves?deP°Vu"°r Portion of thrdors^
number on either sde oMn ii, '^f!""' "'''' <" four in
P«aprostaUc glands g?.' ZaV„,t° .""^ ^""•'"•'' AccesLry
projections of 'the uretLrwan f """'*?^' ™'"""= finger-like
of the seminal vesick ""' '"' "" ""-er side of the basi

of the mmute apertures of .he^^s^r!;?; ^J'^^/J^jf;, of «<.ich "^m1

C. The Female Genital Organs.

, Th *""*' Organs.

as filoT^^ --- -V be traced from the abdominal cavity backward
(a) The ovary (ovarium) is a small_in ,

elongated structure of CTevTsh „r " ^^'^u^"™"'^ minute-
on the dorsal body-wa I Emedi.t '^'"e":'?'' «"oration Iyi„,
IS readily distinguisCTy /h'"? ''?'''"'' '''^ Wdnev.^ I?
representing the larger vesicVrnv'^'T 'ranslucent dots
cases the darker radiate i^r,.""*™" follicles. I„ some
extruded eggs are Sernrr"'™^ <""'"'" "•««» ^effby'

Jtrfr'^--;.t- ""' "' '-''"'-m suspending the

''' 'ro^ ttTid'^^^'tr'Tmtrr"- '"'"-) arises
of 'he inferior mesenterfcirSvInn"'' """''"' 'he orig*
r^. '"J-^ersely to the ovary ^' ^"^ ""=*' 'he body-wall
(aj The spermatic vAin /■..

'he ov^ry'a^n'dT^ij-P^™-^-) ^-- 'he medial side of
Tu "'"■ bodj-wall enters the inferior

''' ^^f^^^irsr^z f n.-"™ °' '-e ovi.

number of short folds and^ ^^ "^rgin bears a large

xrm::^^---3:^--e- -'»^:

second portton of the oviduct: dis,i„g„i,!„d

(f)

132

Anatomy or the Rabbit.

r i

by its Rreater diameter and muscular walls. The size of this
portion is enormously increased in animals which contain or
have borne young.
(h) The mesometrium is the supporting peritoneum of the uterus,
and is a continuation of the mesosalpinx. The mesometrium,
mesosalpinx and mesovarium together constitute the broad
ligament (lig. latum uteri).
(i) The round ligament of the uterus (lig. teres uteri) crosses the
broad ligament, and may be traced from the anterior end
of the uterus to the body-wall below the posterior portion
of the inguinal ligament where it is inserted (cf. p. 49).
(j) The vagina is a flattened median tube with muscular walls;
it receives anteriorly the apertures of the right and left uteri.
2. Preparatory to dissecting the urinogenital structures of the pelvis,
the median inciMon of skin of the ventral surface should be continued
backward to the base of the clitoris, the structure and attachments of
the latter being then examined as follows:

(a) The cavernous bodies (corpora cavernosa clitoridis) form the
bodv of the structure, as in the male, and are attached to
the posterior border of the ischium through short fibrous
cords, the crura clitoridis.

(b) The suspensory ligament (lig. sus|>ensorium clitoridis) is a
short median cord joining the base of the clitoris with the
posterior end of the symphysis.

(c) The pubocavemosus and ischiocavemosus muscles pass from
the posterior border of the ischium to the base of the clitoris
on either side, the former being medial in position.

The attachments of the clitoris should be severed and the symphysis
divided. By pressing apart the two sides of the pelvis the urinogenital
tube mav be dissected out and removed, together with the terminal
portion of the rectum.

The related structures, tlie middle Imemurrhoidal artery, etc., appearing in this
dissection are as in the male (see note p. 130).

In the urinogenital ducts examine the extent of the vagina back-
wards and its connection with the canal of the bladder to form the
common vestibultmi. The latter is comparable to the male urethra
(cf. p. 47. I'ig. 25). The bulbourethral gland (gl. bulbourethralis) (cf.
p. 131) lies on the dorsal wall.

By slitting open the vestibulum and extending the incision into the
bladder and also forward into the left uterus the apertures of these
structures may be examined from the interior. Ihere is an external
uterine aperture (orificium externum uteri) for each division oi the
uterus.

Till! Abikjmi.vai. Aobt.,, ktc.

133
VII. THE AE DOMICAL AORT4 ,.,.

.SVMPATHET.C T^ •"- '''"''' ^^^

b* cleared firs^ tZ^rT "^""^ ""' »""•" '"oojlu ,rih, ,''>'?'P'"''Hic
I Th. kT ^'" "^'"°^«''' »i"> the liver '""" P""'"" of

paired ri^-on't^irie^^r^"'^"-' "^"- "s rZ'S b" .'t-^

m The twelfth intercostal .w. ,

disjria'„\«:;i'^^/-^>mbales, seven pairs of vessels
body-wall. Six pairs ar i f L ^h '!""''f Po^'on of The
the seventh from the meL„ f ''"'^' »""" of the aorta

;> common trunk. ""^''■^" «""' ""ery (d), each throigt,'
(<i) i he median sacral «rt..^ ^

dorsal wall of the a"r'7 ntrlr"' T''''" "'«^» f^om the
buck rd on the ventral s"face of th"°' ""^' """ P-^'
portion IS concealed from the vemr i f '^""'"- 'ts f.rst
hypogastric vein ""'""'"' ^""-face by the common

. "=• "ic common iliar art.™ / ■.

^^^:l^^ "ir ^"^'-^'Sne'^al^:,^^' '?"^. '-^

"■hich passes l"erad to th h^°'^ ">' '"»''™b" arteiv L r f '"'u' "'"'
- eonnecti„„^X-J^';^^;^^n<, ^_dffii- ^i;^— ^

• ti ! i

134

Anatomy or the Rabbit.

(al The .xttnuil lU«c «rt«nr (a. iliaca i-xterna) is the larger
*" lalerarbranch, directed '.oward the '""f"'"" '•^^"•f,'"' " h"
which it passes to the medial surface nt the lim^> as the
Cora aVterv. It gives oft the inlerior epig»itric «rt.ry
a ep^astrka inferior), which passes forwarJ on the medial
portion of the abdominal wall (see note p. 1 15).
(b) The hypog..tric .rtery (a. hypogastrica) is 'he smaller medwl
branch directed backward on the dorsal wall of the pehis^
At "ts unction with the external "'"'''^V^*'"'"'"" t'
\^mLl .rtery (a. umbilicalis) to the "•'"I'l". - ■■• ^^e
fi.male first to the vasina and ute ils (a. uterma). 1 ne
obTtito^^rtery (a „l,tSra.oria) passe.s laterad to the ^Iv.c
wall and the middle haemonhoidal (see note p. .10) to the
Tide o^the rc-ctum. Ihe main vessel leaves the ,k.1v,c cavity
passing to The lateral side of the abductor caudae anterior
and reapwars posteriorlv as the internal pudendal (note
p 13") The intermediate branches pass to the posterior
limb and the side of the tail (p. I4!»).
■1 The inferior caval vein (v. cava interior) is formed on the dorsal

'isi:^:^ :j^;h:^:ii t r;s oiix ^^ht ^X^^^^r.

Tsviscwa roots or tAbutarie, (radices viscerales) comprise- the paired

vein (v. iliolumbalis).

i The external ilUc vein (v. iliaca externa), the continuation of the
, T,f..inof^eX2h approaches the inferior cava from the dorsal

Zr.r including in the female also the veins of the uterus.

«; Th,. svmoathetic trunk (truncus sympathicus). Its lumbar,

TiiK Ante,,,,, Limb.

IJ5

scapula and clavicle. "'' """^l ^^''-^to" and inserted on the

(a) The cWdomastoideus. Origin ■ \,..., ■ ,

In*rt,«n: .Middle |«rti„n"T7he dav.°k! '""'"" "' "•'^ s"""'.

<^) T^'£Sr£i?- = "-^^ -

^'^^•r'S!:„»tL-^n. Sphen»ccipital .,„.

.1) The trapezius. Origin in two portions

supraspinous fascia nscrtion, Metacromion and

Infenor (thoracic) portion o ■ •

thoracic vertebrae and 'the llfrnhnl"'"?", P''°'^<'^«-s of the

Dorsal two-thirds of the scai^uHr.^""^' i^^'''- '"*rtion

" ^'"f '™"S"'''"heet„^Z^ , Pi?urfn"'%T^^'^ f"™^
The levator sapuLw mai„r h, , '•""ace of the shoulder

*The stnictures of G ->

™ uu lUcd luKfiher with

136 AsATiiMv iif TiiK Rabbit.

(e) rht rhomboidmu minor. Origin; Ugamentum nuchar.
Inwrtion ; .Anttrior two-lhirils <>( the virli-brttl border of the
scapula.

(f) The rhomboideui major. Origm: hpinouj proceMes of the
first seven thoracic vertebrae. Insertion: Posterior third of
vertebral Ijorder.

Bv dividini! the rhtimlmiJei the «ii|mla may lie di.<placcd lulerud.
Thei>iier»lion i> (militated by dividinE the lati»»iinu« donii, the re-
latiunH •>! which •h.)uld. hi.wever. lirHl lie noted (2. a ).

(g) The lavator tcapuUe minor. Origin: Mastoid and supra-
occipital portions of the skull. Insertion: Medial surface of
the inferior angle of the scapula.

(h) The temtut «nt«rior. Origin in two portions:
Cervical portion: Transverse processes of the posterior live

cervical vertebrae and the anterior two ribs.
Thoracic portion: Third to ninth ribs by separate slips alter-
nating with those of the external oblique.
Common insertion : Medial surface of the vertebral border of the
scapula.

The transverse artery of the neik (a. tranaverHa colli) lies on the
medial side of the i-ervieal jmrtion.
2 Muscles arising from the axial skeleton and the pectoral girdle and
inserted on the humerus, for the most part at its proximal extremity.

(a) The l«ti«iimu» donl. Origin: Lunilwdorsal fascia and four
posterior ribs. Insertion: Humeral spine. A long flat
triangular muscle, covering a considerable portion of the
lateral surface of the thorax ; having its dorsal angle covered
by the thoracic portion of the trapezius. Its insertion end
passes to the medial side of the humerus.
Cb) The pectoraliB primus (p. tenuis). Origin: Manubrium
sterni. Insertion: Humeral spine.

A liranch ol the thoracoacromial artery appears between this muscle
and the dettoidens.

(c) The pectoralis Mcuntlus (p. major). Origin: Entire lateral
portion of the sternum. Insertion: Anteromedial surface of
the humerus, beginning below the head, and extending to the
boundary between the middle and distal thirds. The anterior
fibres are covered by those of (b). Some of the posterior
fibres are inserted highest on the humerus

The two muscles should 1« separated and cut across.

(d) The pectoralis tertius (p. minor). Origin consisting of two

Hnst porUon : Middle line of the sternum between the attach-
ments of the second to fourth ribs. . , , e

Second portion: Manubrium sterni, extending to the level of
the urst rib. ^ . .. u j

Insertion : The superficial fibres of the first portion are attached
to the clavicle. The remaining fibres, combined with those

TiiK Antkiikiii !,„,„

"Itudmu.,,, of ihV first ™",'„, '■'";. »"•"'""> at th. p.,i,„ „f
he semnd ,»,r,i„„ ,„• (d) 1„ J, "", '"'"■"' ""■' '"t.rul lo
""■ ""' P""i"" "f (d) should t^.'diidi.r'"' ""' '■" '•'"™'

BloodVESSKLS and \ki,VI!S

crosses frotn Z- nilZb^thZV'!'-' '-""'i""-'-"" of ll.c su.Klavi.n

;-f the humerus. ^"ulrfi'/;,V''"^"'''''"'™''"f•h^hea^
H'lween the pectoralTs' primus .''nH"."^ J"'^ ""'"'■ l-a^*,
'"■Ks on either side '^ "' ""'' ""^^ d^ltoideus; git-ing

-elude short anterior vesil ''.rTh""" "■""■ "^ "'""-1"
'■">; (external mammarv) b a„ehes es^'^f/*' ."■"«■'" ""d
the female. ,„ ,he side of the 'ho?a"' P'"''"^' ''"•'■''"^■■' '"
ic; I lie subscapular art«n, / ^

p^r^'^^xr'-hS£--^t^':^
'ri^;^r:j^:^""-sj^i---

(d) 1 he deep artery of the or™ /

at about .he7..n. of ^.^in'" fT/""''^ ''^^'^''ii, is given off
lo the posterior surface of "he hn^ ^ubsrapular. It passes
the shoulder, and is eontinued dis.Td"" *".''"'' ''ranches to
of he anconaeus medialis and aft,^ T '^ '="""' ^"^face
of the brachialis as the r\m cl^^f'J '"'■• '"'"»' "^ad
accompan.es the branches or.ht°;^d!"'n:r'!^- ^"'^ *"^^

If

jjg Anatomy oe the Rabbit.

**The .lillaiy vein (v. axillaris) begins at the medial side of the
hume^s annSJsTh^axUIary fossa '° '^e fi,.^nb «hen« .Us con-

maior and subscapular muscles near the neck ot the scapuia.

.»*The brachii plexus (plexus brachialis) is the network of ner.es

the formation of 'he more general c«^c^^^^^^^^^^ ,,,

Tr Sl^^he" il'U itenta^ are distributed to the subsca-
Dular teres major, and latissimus dorsi muscles.

Tie Hillary ly^P^ S"*"*' (lymphoglandulae axrllares) are pmk or
brownishT^s lying in the fat of the axUlary fossa.

•oTt and e^lpt f^rThe unimportant difference in origin are s,m.lar to

'""The^rsrof the cephalic vein (p^ 143) should be traced before
seDaratingthemusclesof the front of the forearm.

Tote the Bupraspinou. and infraspinyu. fascia, covermg the corres-

rK.nding portions of the lateral surface of the shoulder.

rK>namg po q j ;„. Lateral portion of the clavicle and

'"' Ihe c1edohSm;ral liament. Insertion: Anterior surface of

Ihe humerus in its distal third. The muscle .s a contmuation

of the basioclavicularis.

(b) The abductor brachU superior. Origin: The acromion. In-

sertion: Distal portion of the humeral spme.
M The abductor brachu inferior. Origin: Infraspmous fascia
* * ^he eTo the muscle forms a curved line over the dor^
nortion of the infraspinatus, leaving only a small triangular
Tr ion o the latter exposed. Insertion: The distal portion
S^ the muile passes beneath the metacromion, wh"^h »'»
^ries a?a mint of attachment, and is replaced on he lateral
furlace of tKumerus, beneath the abductor brachn superior,
bv the long thin tendon, through which It IS inserted.

The abducta,.B are also considered aa second and third portions of
the deltoideus.

The Antesior Limb.

139

Insertion: hrea.er ^Se?f' the' humerus'""'""" '""'^•

(g) The teres major. Origin ■

Dorsal portion of the ,.,„

axillary border of the

scapula. Insertion : In

common with the latis-

simus dorsi on the ante-
rior surface of the

humerus,
(h) The teres minor. Origin :

Ventral portion of the
axillary border of the
scapula. Insertion:
Greater tubercle,
(i) The coracobrachialis.
Origin : Coracoid process.
Insertion: Distal portion
of the upper third of the
humerus on its medial
surface.

5. Muscles arising from the
scapula and humerus and inserted on
the proximal ends of the radius and
ulna (extensors and flexors of the
forearm), (Fig. 46).
_. ^- Extensor (anconaeus) group.
The muscles arise for the most part
behind the axis of the humerus and
are inserted on the olecranon.

(a) The extensor antibrachii
parvus (anconaeus quar-

j;he muscle should be divided, or detached from its orig.n, and re-

140

Anatomy of the Rabbit.

Origin:
Medial

(b) The incoiutua minimua (epitroehleoanconaeus).
Medial epicondyle of the humerus. Insertion;
surface of the olecranon.

(c) The triceps brachii. Origin in three portions:

Caput longum (anconaeus longus): Ventral portion of the

axillary border of the scapula. . , j

Caput lateiale (anconaeus lateralis): Greater tubercle and

related portion of the lateral surface of the humerus.
Caput mediale (anconaeus medialis) : Posterior surface of the
humerus.
The three portions are practically separate muscles. Insertion on
the olecranon. ...

B Flexor group. The muscles arise in front of the axis of the humerus
and are inserted on the radius and ulna in front of the elbow-joint.

(a) The bicepe brachU. Origin: Anterior border of glenoid
cavity Insertion: Ventromedial surface of the ulna and
medial surface of the radius. The muscle possesses only one
head in the rabbit. >

(b) The brachialis. Origin: Anterior and lateral surfaces of the
humerus, divided unequally into a larger lateral and a
smaller medial portion bv the insertion tendons of the
deltoideus and abductores muscles. Insertion : In common
with the biceps.

6. Muscles arising from the distal end of the humerus and the radius
and ulna and inserted on the hand (extensors and flexors of the hand
and the individual digits). The long msertion 'f"!""^..?*^ "l""f
perforations of the dorsal carpal and transverse (ventral) canial liga-
ments (Fig. 47). , . ■ ,

A Extensor group. The muscles have a general area of origin from
the lateral epicondyle of the humerus and the anterodorsal, or antero-
lateral surface of the radius and ulna. Insertion dorsal.

(a) The extensor carpi radialis longus. Origin: Lateral epi-
condyle. Insertion: Base of the second metacarpal.

(b) The extensor carpi radialis brevis. Origin: Lateral epi-
condyle. Insertion: Base of the third metacarpal. The
muscle is partly fused with the foregoing one, and the tendons
are closely associated on the wrist.

(c) The abductor poUicis. Origin: Anterolateral surface of the
radius and ulna. Insertion: Base of the first metacarpal.
The muscle is partly concealed by (e). Its tendon forms a
conspicuous cross with those of (a) and (b).

(d) The extensor poUicis et indicU. Origin: Anterolateral
surface of the radius and ulna. Insertion: Ungual phaUnx
of the poUex and the head of the second metacarpal. Its
tendon is the first of five in the centre of the carpus.

(e) The extensor digitorum communis. Origin; Lateral epi-

The Anterfor Limb.

|ad^^^.He «.H »etacarpa,t^ ul ^nhe t. plTafro-r

(h)

a-u., Ulnar artery en. -i. ' *'^' radiaj arterv-

'ID., extensor dtoiti oS.rt? J^- Wllici. e, indg;!

Ventral surface ofiherS '"«''^' ^P'^ndyle. Insertion:

(c) The flexor digitonun .ublimis. Oriiri^ r

ulnar portion of the prohmdus frnS .^ wmmon with the
proximal portion of th^e ulna In«rTio„ ' T'"'^' /Picondyle ;
phalanges of the friur latera di^iH *"' ""* «»■«>

142

Anatomy oi' the Rabbit.

Ill

(dl The p»linari«. Origin: Medial epicondyle. Insertion: Siiper-
ficiallyoTthe volar fascia. This extremely slender muscle
lies between the superficial portion of the profundus and
the flexor carpi ulnaris.

(e) The flexor digitorum profundui. Origin in four portions:

Superficial portion: Medial epicondyle.

Radial portion: Ventral surface of the radius.

Middle portion: Ventral surface of the ulna. ....

Ulnar portion: Medial epicondyle in common with (c)
Insertion: By five tendons on the bases of the ungual
phalanges. ... j

(f) The flexor carpi ulnaris. Origin: Medial epicondyle and
medial surface of the olecranon, forming two short but
separate heads. Insertion : Pisiform bone.

7 Muscles arising from the bones of the hand and inserted on the
individual digits: . , j

(a) The flexor digiti quinti. Origin: Pisiform bone and tendon
sheath of the flexor digitorum profundus. Insertion.
Sesamoid bones of the metacarpophalangeal joint of the
fifth digit, extending i j the ungual phalanx.

(b) The lumbricales. i^ '.'in: From the point of division of the
tendon of the flexor digitorum profundus. Insertion: first
phalanges of the second to fifth digits.

(c) The interossei. Origin : In pairs from the bases of the second
to fifth metacarpals and related portions of the carpal bones
Insertion: Sesamoid bones of the metacarpophalangeal
joints.

Bloodvessels and Nerves of the Arm and Forearm.
'The brachial artery (a. brachialis), the continuation of the axillary
passes distad on the medial surface of the arm between the b'ccPS and
the anconaeus medialis. Crossing to the anterior surface of its d.s a
extremity it passes beneath the head of the pronator teres to he media
surfacTo^ the radius, dividing at this point-a short distance in front of
the elbow-into the radial and ulnar arteries. Its chief branches on the
arm are the ulnar collateral arteries (superior, middle, and mferio.) to
the muscles and ihe elbow joint. . _, j: i

The radial artery (a. radialis) passes distad on the ventromedial
border of the radius, in company with the median nerve, lying at first
between the flexor carpi radialis and the radial portion of the flexor
SfgUomm profundus. Toward the distal end of the radius it crosses
thi ventral surface of the tendon of the flexor carpi radialis, and appears
n a superficial position on the medial border o the carpus. It reaches
the volar surfacVof the hand after passing obliquely across the tendon
of the flexor digitorum sublimis. ..i- i t _ :i.

The utaar irtery (a. ulnaris) crosses the ulna obliquely from its
origin readying in this way the lateral border of the flexor carpi ulnaris.

The Anterioh Limb. , .,

tt"p^lS 'ZTM"XTtT' 'Tr ^"■' "' ">^ "-r side of
and .hen, urns across '.h';r^dfc^™^„7'J:lr:^^°f the fifth digit!

arter/a^ndSeSlUS'^^ -^st^dll^^^^^ -e hracHi.,

latter The radial vein anastomoses w,htf°"" J"', "P^"'"""" °f 'i==
"Thrc™^r'"^'''r''''"'''^S:of'ttea7m''' '"""'" "' '•'"=
on tltVo^^SrCe ? thettarln'^ %S tf 'S' --' ^P'--'-^

a ir::;;^^ rSh:SF ~r^ -' - -'ar 'vf

""ve. It passes to the frnn. f ?i ""^ ^"I^-^ficial ramus of the rad ai
'ying at firs?o„^VeVnterrml'''or,hera^"/^ 7''' °' "«'''•-''
and afterwards on the lateranXe of fhl "*' k'"'' "' ""^ brachialis
brachn superior and the anconaeus lateraHs Tt Hi ■'™ '"e abductor
surface m the triangular space enclosed bvlLJ ^'^fP^^^^ from this
tion of the evator -irant.ia. ™, '^"'^'os^a ."> these muscles and the in«.r

from the shoulde . ranpe^rfonTe'rS"! ""^,P°'"' ^ '"^^e tribSv

-s^^aH£l£?^:^^^^'^^L=i:

eompanvwiththecoIlaterXadiaTarte ' 7 ^■■*^''/,"'- brachialis in
on the distal portion of the Lr.^ " ^ superficial ramus, given off
passes along the sZce o theTxte'Z'r""'^"'" 'H^ cephalic vefn:"t
branches for the dorsum of the hand Th/""' '^•'"^"'' ■""•""« '"'o
d.s^nbuted as the ramus proftl^ t .L^LTur m^uS^™f '^^^t^

f^ Jo'r trZ,T:/"a, firs1t''ft„^l1^h''"b^'' HT '"^ -"^"-l sur-
on Its medial side." It accomDanies ^hl h t"- ?'''"'''"" """v and then
the head cf the pronatorTeTes and then ?r'^"^ artery passing beneath
pany with the radial artery to the v^l.r '"^"Y"'^'/''^ '""'"'"■ '" ^om-

The ulnarnerve rn ,,!„„■ ?i- J?. ^"^ surface of the hand
the distal ex,Sv'"oft:"htmer'/irac^^''™'^''''''-'"y.- toward
collateral arterv. it passes from fh. "cco-npanies the inferior ulnar
tween the ancinaeus m n*musT„d Th^ k '"' '7^T "' '"^ "bo-v, be
dorsal surface of the olecranon head of th^ fl "" "'^"''non, to the
hen crosses the ulna obliquelv in «mL„v T'.u"^"?' "'""ris, and
the lateral border of the muscle LT ,^ ^- '"" "'<' "'"^r artery, to
At the wist i, crosses th? do sal sur&f'.h '^ i"*"'"" 'cndon
between the tendon of the sublim s rnrt ,h / ''"?•'"■ ""<• Passing

volar sutface of the hand ^ ""' P'"'°™ bone, reaches thi

144

Anatomy of the Rabbit.

IX. THE POSTERIOR LIMB.

Dissection on the si'' opposite to that of injection. The dissection
is largely a muscular u„c; to be conducted in the same way as in the
anterior limb. The corresponding muscle groups should be compared
with respect to the difference in orientation of the equivalent segments.

1. Muscles arising from the ventral surface of the posterior thoracic
and lumbar vertebrae and inserted on the pelvic girdle or on the lesser
trochanter of the femur. These muscles are chiefly distmguished bv
their vertebral position, on account of which and the fixed condition oJ
the pelvic girdle they combine the characters of vertebral and appen-
dicular muscles.

(a) The psoas mlaor. Origin: Bodies of the four posterior
lumbar vertebrae. Insertion: Pectcn of the pubis. The
flat, pointed tendon forms a square cross with a pofs^'
(sacral) continuation of the inguinal ligament, which is
stretched transversely from th^ middle of the inguinal liga-
ment to the centre of the body of the first sacral vertebra,
and on which it is also inserted.

It is necessary to divide the inguinal ligament and reflect its sacral
continuation, together with the tendon of the psoas minor.

(b) The psoas major. Origin: Internal surfaces of the bases of
the last three ribs and bodies of the corresponding thoracic
vertebrae; also the lumbar vertebrae. Insertion: Lesser
trochanter.

(c) The Uiacus. Origin: Bodies of the last lumbar and first
sacral vertebrae, extending to the sacroiliac union. Inser-
tion : With the psoas major on the lesser trochanter. 1 ne
two m-.scles together form the iliopsoas.

The lumbM portion of the lumlwiacnl plexus, beginning with the
fourth lumbar nerve, lies on the ventral surface ot the psoas major ■
a,rbet""Tthe latter and the iliacus. The «* 'T"" ' Wr'^ed
root of the femoral nerve, (p. 149), the trunk of which may be traced
from a position between the two muscles distad over the do^al
surface of the inguinal ligament to the media surface o the thigh^
The remaining four nerves crossing the dorsal body-wall obliquely
are the twelfth thoracic and nrst three lumbar. „,„ .„j „,_,h

The psoas major should be treed at its lateral malgin and turned
toward the middle line, the fourth lumbar nerve being divided.

(d) The quadrat™ Iwmborum. Origin: Bodies ot the posterior
five thoracic vertebrae and the bases of the corresponding
five ribs; bodies and transverse processes of the umbar
vertebrae. Insertion: Triangular processes of six lumbar
vertebrae and the posterior ventral angle ot the Uiac wing,
together with the adjacent portion of its medial surface.

2 Muscles arising from the pelvic girdle and sacrum and inserted
on the femur, for the most part at its proximal extremity.

The muscles of this group enclose the proximal portion of the lemur

The Postekioh Limb.

• ■ l'»5

on Its lateral, posterior, and medial sido. Ti,

the flexors of Group 3, namely the httn. ^^- "' P'"'>' ">^"^d by
must be divided. To begTn ihe dis^"f„; "* 7'' *"'' «^''""'' ^^^^
tH-iceps (P. US, T^^^Z^T^-^^ ^T'^S^'^

Dissection on the lateral surface posteriorly

"" ly^^Z'^ul^'"- "^'^ "■ - «"hy portions, joined

7hi'^r„,'sxrfhi'^T;d"r"''"H"''^^'™'='''-

by the first head of the biceps "^^ "'' " ""■"<^<' posteriorly

"tvTtrtE^'lrsortirLt^'a^/te"/ ?l "r "'"«• '-'■
femoris; also from the dorS ^rdeJ throlh'^h °' """ '^""^
mentioned above. ooraer through the aponeurosis

Iiisertion: Third trochanter. The axis of .1, r .
.s transverse, that of the second horizo" t^f ""^ ""' P""'""
Both portions of the muscle should be divided

(b) The glutaem medius. Ventral border „f .1.

ilmm and the ilUc crest Inserdon r ? """« "' ""^
Some of the fibres pass around ThprnH-^*""," "•"'chanter,
of the greater trochanter and JJln^^' •""''«''= °' "-e tip
of the trochanteric fossa *"■'"* '" ""^ '»'"«' "all

The muscle should be divided.

(c) The glutaeus minimus. Origin- Pn.,v 1 . .

body and wing of th?ilium.^ "user" o^ c^"f,^"/-l''f 'he

Remove the entire muscle The^rif " trochanter.

dorsal margin posteriorly "" P'"''"™'^ ,s m contact with its

(d) The tensor fasciae latae. Oriirin- i-. ■

ventral border of the wing of tl^" ilitm ?' P°'"°" "' ""e

fascia of the lateral surface nf.h.T- ^I"*"-'™: Broad

fused with the first head of the rectus fLmo ■^'^%'"''^^- -

^ with the second portion of the vlmi^? ™""^ '" '™"'' ""d

(e) The pirifoimis. Orig^ Lattj f"' "^i"™"' behind.
third%acralvertebrS Ini?,fon ??nT,t°' '^' *"'"" »""
, The muscle should be divided ca^' Ifn .t'^'"' '"'^'"'"'"■
the nerves and bloodve.ssels Snea^Mt ^ ■"" '° "'"'d '"J^ry to

*'' 'pinerrflTsh;;'^-.He°Sy oTr'iT '""■ '"^ -"ial
jnjront of it. ^nsertio^n^ rafe^il t.ro^X rhattS

aJu'c'to'?"c^^dS''a=nS/(risSr"''-' ^""^ '° '^^ — i» the

(g) The obturator intemus Oriinn. i». ■

obturator foramen I^Urtion^Troch™?' '^'"r""' °' ""e
muscle passes over "re i^hium in ,h '? '°'^- ^^e
notch, only its insertion porUo-tlTpp^^Hn'g^'^fro'^X S^l^

146

Anatomy ot the Rabbit.

(i)

J . Tn ««■ its oriein reflect the tendon through the
fest «iaac n^ch'ld e^ Jne the mu«le from the internal
surface of the pelvis. ,„ „, ,h,

"" - r^s'TJ- i«sr anS°rM'^^.i^

r:»d.I;;'''f»^''"ori.in: Ventral surfa^ of the

ischia?^uberosity and the 'T^hT^wI h (i)Tn th"
immediately in front of it. Insertion. With (J) in tne

trochanteric fossa. . . t .i,„ „!,„.■•

(i) The obturator extemus: Origin: Extc, > "''"' "M.^X is
'" itor foramen. Insertion: Trochanteric fossa^ The muscle s

Dui^doToi^r medial surface posteriorly, after division of

(k) ThTl^toeus. Origin: Pecten of the pubis. Insertion:

Immediatelv below the lesser tibchanter.
(1) The adductor brevi.. Origin: Anterior portion of the
^^ svmphvsis pubis. Insertion: Below the pect.neus.
(m^Thp adductor loneua. Origin: Posterior portion of the

end of the femur, extending to the medial condyle of the

on v^t^^^rJ'^ri^^^^^^

°' t '?^U; (r--/Ztiur ^^TheThlre T ^r!^
rrVofon'-tllrulial ^^^^^^^^^^ ^^^ ^nd the patellar
ligament.

(a) The rectus femori.. Origin in two .portions :

First portion: Superior anterior spine fused with the tensor
fascia? latae. and ventral border of the iliac wmg
Sd portiin: Bv a stout round tendon from he mfenor
rnterior'spine, immediately in Irc.t of 'he acetabulum^ This
part is cylindrical in shape and is practically a separate

muscle. : , .

The two portions ot the muscle should be dividea.

(b) The vastus tateralis. Origin: Anterior surface ol the great
trochanter and the lateral intermuscular ligament.

The muscle should be divided.

TiiK PosTEnjoii Limb.

Ulml

iA\ ^'^^ P<"-"on: Antmor surface of the femur

''*'^no-i:s^,-sr.-->;,£^.«of.e

muscles). With the exception of '—

he sartorius.the muscles lie behind
the axis of the femur, and are in
serted on the medial and lateral
surfaces o the knee-joint and the
corresponding proximal portions of
the leg. They form the bound
anes of the popliteal fossa.

(a) The saitoriui. Origin-
Posterior portion of the
mguinal ligament, espe-
cially its sacral exten-
sion Insertion: Medial
condyle of the tibia.
Ihis IS an extremely
thin and narrow band
of fibres. lying on the
more anterior portion
ol the medial surface of
the thigh. The muscle
■s fused distallv with
the gracilis. It has the
position of a rotator
muscle, and is only a
flexor through its con-
nection with the latter
(b) The gracilis. Origin :
the entire extent of
the pubic symphysis.
Insertion: Through a
broad tendinous expan-
sion ending in the fascia
ot the proximal portion
of the medial surface of

tlf^\ The muscle —»■ v ..»,.«„., ..„^„„„,„,„:

te™r porUo°n of'^;re'^'''i!T'y '>•■" ^^eet. covering the pos-

tion ZZl ^r Sra"d tX^" "• ""-""^''- '" '"*'"
vein and the g?:at"tphenoLs\f"e' "''''™""^ "^'"^ -"
diviSId'"""""" """ ^™"'» -h""'.! he rai«dfr„:„t„e surface aid

Haphenous nerve- n t .iKi„i "■■■'"■. greater

media^is: v s m Krcli^. ;?),.„■ V""- vastus
.o.iii., Krcai saphenous vein

148 Anatomy or the Rabbit.

(c) The bicfpt fimorli: Origin in two portioni:

Ftnt portion (caput breve) : Spinous processes of three posterior
sacral and three anterior caudal vertebrae. This portion is
triangular in shape, the distal end, or apex of the triangle,
passing into a thin flat tendon which is inserted on the
lateral margin of the patella.

Second portion (caput longum): Dorsal surface of the ischial
tuberosity, fused with the adductor magnus, and the
lateral process, fused with the second, or deep portion of
the semimembranosus. This portion is also triangular, the
base being distal and providing a broad insertion on the
fascia of the proximal third of the lateral surface of the
leg. The first, or superficial head of the semimembranosus
covers this portion at its origin.

To free the biceps a'.id divide it : Incision along the aponeurotic
line joining the tip of the great trochanter with the sacrum ;
also distad along the intermuscular septum of the lateral
surface of the thigh from the great trochanter to the knee.
The sciatic vein lies on the lateral surface towards the ischial
tuberosity. An incision along it will free the superficial
head of the semimembranosus from the biceps. Raise the
biceps slightly by working the handle of the scalpel under
its distal portion. Divide the muscle from its posterior
margin, being careful not to injure the slender tensor fasciae
cruris muscle and the branches of the sciatic nerve which lie
beneath it. The first head of the biceps may be separated
and reflected in order to expose the short muscles of the thigh.

(d) The tensor fasciae cruris. Origin : By a long, slender tendon,
from the transverse process of the fourth sacral vertebra.
Insertion: Lateral fascia of the leg. This slender muscular
slip underlies the biceps femoris.

(e) The semlmembranostis. Origin in two portions :

First (superficial) portion : Fascia covering the first head of the
biceps.

Second (deep) portion: Lateral process of the ischial tuberosity.
Insertion: In common with the gracilis on the fascia of the
proximal portion of the medial surface of the leg. This
fascia is contracted into two ligamen one of which carries
the insertion of the muscle to the o-..al end of the tibial
tuberosity, the other to the distal end of the leg, where it joins
the tendon of the heel (tendo calcaneus).

(f) The semitendinosus. Origin : Ischial tuberosity. Insertion :
Medial condyle of the tibia. The muscle is completely en-
closed by the adductor magnus, which must be split to
expose it.

Th« Postuioi Limb.

Bloodvessels and Ne.vbs of thb Th.ch.

m

contmues the external iliae aHer ?mi,.Hi ".*V'"3 ""S"""^"'' "here it
hgament it give, off the d^p ,rt«ry oT^rhe .h^lT r"*'""' J" 'J'" '"«•"""'
The latter passes to the dorLl s^d7of ih/1 ? '"• P™f"'«'a femoris).
tnbuted to the posterior nrnvimrt .L .■ pt^'meus muscle, and is dis-
the totorl circS^flriS^Tr'S'rcumV''''? "■"''. ^ s..^nd branih
forward from the anteriw^ll h.,^ "^2''''.'' '""^"^ lateraiis), passes
and the origin of the' valrml^ir"! sVrsrbr "" u' ""= >»"- ^^'
medially to the vistus medialis and r„',„ ," '"?"<^hes are distributed
to the lateral side of the head of the J ^ ''"""' T*"^ ^'""^ Passes
and is distributed chiefly to the fisth1S"of?^"'°"."' ','"' "-tusfemorT,
tensor fasciae latae. A third branch „? u ?""" 'f '"°"' ""■* '" the
•pigaitric .rtwy (a. epigastrica suwrfidllii^ """'"'i ""= •"P'rtci.I
Pa»?mg to the abdominal "all ha? h^n ]■ '^^f ,"" ""dially, and
begtnnmg of the distal third o the th^,"'n''K'P "*' ^' 'he
•nprem., passes over the medial ™L i5„V "^u'T" ^"'"'^- ""e «. genu
and at about the point of or^^ ""thU «,l^' '"r"' 1° ""^ '"■™J"int,
Mphenoiu .rtery (a. saphena n,»L'.i • *' f '"«■= ""'''""^h, the gnwt
It passes across the Si LZ^e Jf thTl T '?* P"^'"""- ^
longus, and through the tendon of ^h^ .■•'"*' """^ °' ""= adductor
the leg. The femoral arterv™si,bet«^en'f^ '° 'J^' "■^'"'" »"^f«« °
magnus continuing as the po&' ^Ta'tpllfea'/"" '""^^ "'"*

The hypogastric arterv rii iqii •' T P^Pl'tea),

continuin^ThLce asXTcilPtic'Si.^T.iJlL'!^ f^i^' -atic notch,
backward to the dorsal surface of the ,u!^i^™* ^""^ ™^*' Pa^es
where it divides into lateral „,^ ' I superior ramus of the ischium
smaller branches are di"ri"^ f"^fj*7" PV"'''! branches. l7s
muscles. siriouted to the glutaei and biceps femoris

thi/hTc^r^L'll'/^i^h^-^^™-^"^ traverses . "-^dial surface of the
end of the low'^r third of the thW. as a -n";- " ^«'"^ *' '^e proximal

V. poplitea), which accompan Ls the c^r^e "n!!'""" °' '^' •»'«•«• »•!"
taries comprise the great saphenLi .u™iS^?'^"V"« «"ery. Its tribu-
flM, and profunda femoris Ti" ' '"l^"*' epigastric, latenU circian-

^l^ ;^!-r l^il^t^^tsi'^ ^'^-' r^- <" 'He
Mmimembranosus and afterwards on th.„. ■'''"''™ ">« biceps and
At the dorsal border of the ischium ilfrCf'^u ""f" "' "-' f°™er

plexus, chiefly from Ihrfiflh lurbr""„rj-.'™". ""^ lumbosacral
major and iliacus muscles has aJre^dti. '^1 °" '"^'"■'^" ">' ?»»»

oth„, the gr«...r saph^iS d'.^: tn'TpUt^iltVe'^^-t tt

150

An.xtomv or TH« Rabbit.

fffi

medial .urf»« of the Ihixh »nd Irg in company fir.t wuh the femoral

arterv and afterwards with the great japhenoui artery.

The ictatle narrt (n. i^hiadicu.) appear, laterally in the greater

Kiatic notch It paMM backward beneath the piriformi. muKle. and

Then turS^ di'tad to the thigh, where it tie. on the lateral «"face. °f
he adductore. magnu, and longu.. It di.lribute. branche. to he

Msterior mu««lature of the thigh. In the proximal portion of the

{high it divide, into two chief branches, which are cloKly connected a.
a) a" he knee The anterior branch i. the pwonwl twrr. (n. p.ronaeu.),
the ™.lerior branch the tibial n.rv. (n_tibiali.). The le«er »phenou.

nerve (P IM) i. a .mall branch given olT from the tibial above the knee-

'"'"por the oriijin of thi. and related nerve« ««• P 1»»

The •uperior glutaal nerve (n. glutaeus superior) appears in the
greater T^" notch, leaving the sciatic clo«. to the inferior posterior
Se of the ilium. It passes between the glutaeus minimus and the
Uteral surface of the ilium, ending in the ten»r fasciae latae^ Its
branches are distributed to the glutaei mediu, and minimus and the

'''"The'toS''^ut..l nerve (n. glutaeus inferior) perforates the pos-
terior poVUon of the piriformis, and is distributed to the glutaeus maxi-

"""rhe ooeterior cuUneous nerve (n. cutaneus femoris posterior) accom-
oanies tErhviSgastric arterv backward to the ischial tuberosity, where
H wrns to thr^sterior margin of the thigh and the meduil surface of
ihi. viatic vein ending in branches to the skin. ...

The p^eidij nerve (n. pudendus) accompanies the sciatic artery
anH afterwards the internal pudendal to the penis or clitoris.
" In p" para ion for the muscular dissection of the leg, the insertjon
tendons of the biceps femoris, tensor fasciae cruris, gracilis, and semi^
mrmhrLosus muscl^ should be removed from about the knee_jomt _ 1 he
Sctor magnus mav be detached from the medial condyle of the
?emur buHhe popliteal vessels must be kept intact. Tlje ™perfic,a^
bkodvessels of the leg should be noted, since it is necessary to clear them
awaf'n separaUng the muscles. They include, medially, the great
Chenous arte" and vein, and laterally the sciatic vem, together with
Us «nti"uation, the anterior tibial vein, and the accessory small saphe-

"""r Muscles arising from the medial and lateral condyles of the femur
and from the proximal portions of the tibia and Abu a including the
H^hia COTdvles inserted on the foot. The group includes the typical
extensor" and flexors of the foot, together with the peronae. muscles,
wh'chlndivXallv are extensors and flexors, but collectively have the
relation of lateral tractors (Fig. 49).

A Extensor group. Muscles occupying an anterior position on the

leE and inserted on the dorsum of the foot. „, ,i,.

leg »"« '"^^ ^„,i, ,0,^. Origin. Middle portion of the

anteromedial surface of the tibia and from the medial con-

Ths PbsTKiioi Limb.

LSI

M Thr»xteiiiordljitoniin

lonpu. Origin: Bva ■"—

flattened tendon frbm

the lateral margin of

the faries patellaris of

the femur. This ten

don passes throu){li

the capsule of the

knee joint, and the

fleshy portion of the

muscle lies on the

anterolateral surface
of the tibia. Inser-
tion: The distal ten-
don passes beneath
the crural ligament,
then beneath the cru-
ciate ligament of the
dorsum of the foot
dividing into four por

"•••"":K""o'ourpor. no M.rr,„.„,^ „„,„

tlons for insertion on ':^r^i.:!rJ:\^%r.~' "-- "-■■

Thed?^.!""''"'^" "' f^ «^«;n:;^-;;;f 5^r',.r.rs

plared hv dividing the """"i™ iSSI) ?: "^'Sl"""'":' "■ I'r-ciSi
crural litiamem. J"",- '"".' ••i.h.n„„,-„™'" "rtf"™- ntr™:

1 ne peroneal and ante- unterior: tfc t*t.^i '..tibia; t.a.. tibialii
ni.r tibial arteries lie " » • -ei^'i-- >Ji'n^Tj*"j^ '"■"" """rtta"
behind this muscle, the I,' "■ ""ll "Plimmi. vSi; M ih'J'i',""'". ""i:
f<™er in a medial pos"! """l"""" ' ' *' "" """"■ 'wl

^ ^ 'll'mp-a-nrrirh' tt ''^^iSVer.""" ™ "« >— ' --e^ in

the leg''rX,ri5S?.''ed o'n'ln sTrf'Jjra'J'h'T, '"l ""i,^"" ™^''« »'
The insertion tendons reach '"e f^^^^ t„tt^t'hri.^*,^J^tfr

proTimal

II

152

Anatomy or the Rabbit.

of the tibia and head of t"?,"™'; . mosses the plantar
if^^J'lL-'^'^^^I^ro:^^^"'^^^' end of the

cuboid bone. ......

Th. muscle should be dmdrf. j^ ^^

^•» s^dXT? rtir™d ^^ -S ^^a"^
srn.^s^loi;^'T.f=^Trbr^^he ^th .eta.

the crural interosseous l^ament, fused w» ^^^^tarsal.
^iSSr-'n^ted irrten^: V^e extensor digitoru.
longus, on the phalaJiges "t thj^ dipt. .^^^^^

(d) The peronaeu. «17rt»-0"P°„T^^^Xevis and with the
osseous ligament Jusedwth the r«ronaeus^ ^^ ^^^ ^^^^^^^

extensor digitorum longus. Inseruon n»
metatarsal. medial and lateral

C. Flexor poup. The nm«Jes an^ Soi^m Tubtois from the

^^'SSESlSe^«'r femur and
g;:.f^S^Mrdr~ndyle of thefemur audits sesamoid.

irSXo it: l-eXlXe"" TVe''te':rn is covered b.
that of the plantans muscle. ,.,„ ,^.^,„riorma.xinoftl.e

(.) ThTpUnUriB. Origin Lateral " tVn'do'n'^pLrs' ov«
associated sesatnoid. I"^™"",' ^ 'J^t and divides in four
rart^ri^'i^nr^rsera V°°Ha\aVs of the four
developed digits.

The two muscles should be ^'^"^f , ^e femur: The

c) The popUt.™ Ongta: Late™l^»-dyle^,°: STeJ'oint. The
tendon passes through tne »^ y ^ ^^jes the pos-
S''suXl'°o1 tt tlSrSy. and i^ i-rted on the
proxImTportion of its posteromedial angle.

The Posterior Limb.

of the interosseous Iwament „nH ^ •"'* P°*'*™""rface
tibia and fibula. LZZTn^ttrST^ P°'k"°"' "' ""e
sustentaculum tali, reaching the oW« '^^f*' '*"'«"' ">e
where it is partly roveredby^heDlant^^^^^^^ °' ""e foot,

into four parts for insertion on P'^"'^"* ''""^on. It divides
four developed digits ^ ""^"^ phalanges of the

' t)th73r„!''^c5xr i"er -^ 7 '^ '-'-<•- «>«<-

^.^:sa,dS^^'^---pJs^

^'^ o?th'?rdt.irsrof ■t.o-^f;^; ^zi? '"^ -^-^ pcion

sert,on: Heads of the four metaUrils. ^ °""" '™^'- 1°-
Vessels .no Neeves oe t„. l^g .no Foot

leg,and^P?o'n';'„t*3rrrtSt/n''°r''^-''''-rf-e„fthe
around the medial malleolus Tth" plantar !^P '^ 'i."""^ '"''"ior)
the ankle-jomt it gives off the iMU.oUr '^ ? °' ""' '«>' Above

the me,|a« rf ^e ttrrnrmTusTnl''^ '"T"' ^^^^ l^'ween
^lit*"'* ""^Pl^ntarison the^?he7 reachiL/,r ''f"^ ""'' ""e latera"
popliteus, and afterwards the anterior «.!?*^ ^ anterior surface of the
by passmg between their proximal ™ds 1?^ ?i "'^ '""^ ""d Sbula
the anterior tmial and perineal arteries It H' ?-k' ""° "«' branches!
muscles about the knee-inint ti^i j- . ^'stnbutes branches to Ih.
the vastus laterafis'Th/c" ' T.nZ^'i'ZlV "-'"^"t'o?
the small saphenous artery " *'""' ">« Pomt of origin of

The small saphenous «rt«rv Co

s^c^^f-jh^E^ d5rS^<^'-=.ni^

nerve to the dorsum oUbl f^*" """ ''"'"'" ""'al vein and the ^roneal

Hi

154

Anatomy of THg Rabbit.

„pHenous nerve, and is continued - th*^" Ub-. via (v. Ub.al.s

rlfe';JW"^e'PeH^r ='oC .He late.. Head oi

the gastrocnemius. . ■ , „i surface of the leg as the

The .ciatic vein is «'""""'d„°°i'J^' it rec^Tves the .ccwsory snuJl

„t«i« tibial v.in (V. t^fl^Xac^ssori^) from the posterior surface

r^^Zre^^toTheTrs^rof^'S^t passing to the hbular s.de of

nerve, accompanies fi-^^^''*^^.'*."" the medial surface of the leg.
saphenous artery, passmg d«'».° '^' isi„" „, the sciatic, passes between
The tibial QMV.. 'he poster "divisiono^^esc ^^t^^^^^ ^„^f^^^

the medial and lateral heads °' 'h* f*,'J;^"th?Teg, Iving on the medUl
of the head of the plantaris. >' "Xmards of the flexor digitorum
surface first of the P°P"»^"\»"'*„XarmaHe.Sus reaches the plantar
rre rthrSo? ^T^he ;™x.rr^nion of the leg it distrrbutes
muscular branches to the A""' K^^P^-henus minor) accompanies the
.jrU'hXuTSrran^'^Int re^erior margin of the lateral

lying at¥rst between 'he >nsert.on of the blceps^a ^^^ ^^^^^^,

tlelastrocnemius, -"^ thus ap^armg on the^surf^^ ^^^ ,^^^^^, ^^^ „f

of the former. U P^f .^"-"^'^^^^^rthr^^^ heads of the peronaeus
the castrocnemms and ""^'T*™* ,,„..„,:„„ the leg at first behmd
lertiSs and flexor d'S^'Xthei^rund U meSfal margfn to the front of
the peronaeus longus a""* 'hen arouno us ugament and thence

its tendon. "P^f^^'^^'fJ^t The n'rvx distributes branches to the

tYbillTs anurio" and exten-^^'ri^exuT-y be examined by break-
The structure of the '"™hoMcral fuex j ^^.^ ^^^ sacroiliac

ing away the ventral P°;»™t°h, two sides of the pelvis may be pressed
articulation in such a »a> that me I"" „crum being thus exposed.

---^fS^^"---- '^ .rmed by the

U is divisible into a lumb«^<^-"^^,„, sacralis), from which
the femoral nerve, and a Mcrai pia"" vh

"'^hl'-Arrlrn^-i^formedfrom^^^^^^^^^^

S'^ieSerra^Hratri-aCobtil;^- u.rv. (n. ob.uratorius).

IfFi

Ths Postehior Limb. jjj

^to^-sj^i^^r --- Si,-" '^ '''^'-'- - ".e

nerves (ansa lumbalis iii), * lumbar and first sacral

The internal pudendal nerve is fortnoH fm™ n, i
second and third sacra. nerves^U^nl^'^ct/innrSn^^^^^^ {H:

The Articulations of the Posterior Limb.
The more perfect development and lareer size nf th. . ,

art^^.:;:;--- --^-„^^v._^m about the

head on'reSurwit'h"tttrrsX''he' HZT^^'^' IT"-'^ "-V '"e
bull enclosing the acetabulum oge.h^rwUh the ' .'«t'^ "' "'^'''-
(capsula articularis) and accessorv Ii|ame„ts '"'"^' "P'"''

prox?m\i'':rorthXt„rrfeLu;"",;t r'"""'" ™^«'" '° ""=

The external supports of the ofnt comnrii ,1, ".'"I^Sest on its dorsal side.

artic^lf r^r^:?e^;a^'?''be"':xa•mined"'\"/ile''^^'"H• =■"" '"^ --"■
of the femur to the wall of X acetabut^fl V..*'^'''"''-' "l the head
ment (lig. teres femor ) The gtenoM LoTh ''™"^? '^^ """" ««•-
ring of tibrocartilage surroundingThe m^ViL ofThe' '"71"'!' '^ ""=
connecting with the articular capsule acetabulum and

with''aI,i^hl^";i?tn'd^'7t'i"?ofrd'b: f^-'T^r'' •" «^'^-

medial and lateral condvles of he f"mur and Hh, '"'f^ T'*"' °' ""^
articular capsule, ligaments, and^^Irur"«J;„^- -^'es't?^;!^;':

of clSne^Jl'^'e "^'"feSK^ th^'i^lr',^ ""^'f' ^l " ^'™' ^-d
the posteromedial angle of Z mXl"con"d\1r'of";"he-^t^b:' '"^ '"""' '"
lateJal ™'n'd"^^ o?te?em'i«'^rh' t^l T 'f ^ structure "connecting the
diately in front of 'the lead of Ilie fibula ""' '"'"" "' ""^ '■'"'' ™™^

.aki^gV'rf rJhetrmarL"':f ^^J^S That"='^^H""™J" '-'-«

nemi. and the pla^taris, a„^ ^a"t ■"„ Z lal^Sl t-iSaVc^„t.lfT„-;;-

The common tendon of the quadriceps femoris, the patella, and the

fit
'U

jjg Anatomy or thb Rabbit.

patellar ligament are a3«,ciated *ith the capsule, forming the anterior

wall of the joint. ^ . . „f ,i,, mndvles in the interior of the

Between the apposed surfaces of '^^ ~"°y'\';,^°t„„ thin plates of
joint, there are two short, "»<^" \'«^!^ The Ulterior crucUte
ibrocartilage, the .«»«^^^"li„^ f^,^^ the lateral wall of the
ligament (Ug- ^^'^'^'^".''"/fZrtrthl anterior end of the intercon-
tatercondyloid fossa of ^hf^.f'"" *" ^^.rf", "ruckte ligament passes
dyloid eminence of the tibia, ^he l»»t.nor craoare HS ^^ ^^^

from the medial wal of the """<^''"^>''°^>'^he „^U1 meniscus
posterior in'"r?V°'nnthTartLlar surface of the medial condyle.of
(meniscus medialis) lies on the ?."'"J'" "[J? "u, anterior and posterior
'the tibia, and is connected ^l^^^'^'^'XX^ri^"^'-^"'^^''^ °°
intercondyloid j<>f^%'>/ '>■,«; hU ^nd^s atSche'd by ligament anterioriy
lS^l^e';1dr'^Ai:n^^^t^Sullr sXe, aid posteriorly to the
Se^lS r^tK^Te intercondyloid fossa of the e^^^^^ ^.^^ ^

C. The ankle-joint (articulatio tal"'^™"'''''':*,^^,':"^- surfaces are
considerable amount of spiral o'^'o-Jl^^The^ ^X^'f^^^l^r side of the
chiefly formed by the t.bia ^^'l '^'f^'/.'^^^f^id/the calcaneotibial lig.-
tibiofibula and the calcaneus. O" 'fj, ''^J^ maUeolus with the sus-
ment (Ug. calcaneotibide) connects the medh^maueom^ ^^

tentaculum tali. On the fib"'»"'^^ '^\^t^'7 tteV^ for the
calcaneofibulare) connects "if. IT'^^rsuTce of the calcaneus, and
peronaei muscles forwards with '^e later^ sunare ^^^^

?-rto-t&Maror£r^^^^^^^^^

^Vt ;IS: wUhl^lrXr^ of^ -icula. bone.

The Head and Neck.

157

X. THE HEAD AND NECK.

- IS: ^t^ferSH r {^ -«-

skull. The insertion of the plaWsZ ^^ thl I, T"^' ."".^'^" ""^ "' 'h'

riioi^^^^i's d?Sf " ?'-'^- ^

platysma, arises rrm the kterllZtr'ortt'L'^HKf '^''"'°" '° '"e

trated at the anterior and poLrioranrfes Thp iT.', ^ '"''"« ™"''<^"-
muscle arising from the zieomatir »rfl, =n7- *!'!,'' !' * '"y ^'«^nder
the lower evelid The c.!rr?smnZ. and inserted into the skin of

arises from the orbitafwX aris hfre c^'l,c°/ale^'r''Jr '"^"""^
supraorbital process. concealed by the projecting

the, mucous membrane of the cheek oAns" fntr/rS

(c) The chief part of the Mventh crani.! or faciid n.r™ t„
facwlis) appears in the anterior pontaTof the oSotW^f.iH'
Us branches crossing the masset«. Thev ar^ dtsTrihl.fin '
Te'^iarm^' '° '"^ ""'^"^"^ "-'« oT.r/fattrin^'

158

Anatomy of the Rabbit.

the superficial temporal (p. 102). .

i,\ Th, .nterior facial veto (v. facialis antenor) accomiMmes the
^'^ . ™»f m»,XTv aVTerv It begins in front cf the eye as

triS^ vl^. and "«ives as tributaries the .»p«i.r and

inferior labial veini.

Tthe frontal. Insertion: Skin of the dorsal surface of the

(c) Tl^iygomaticns mtoor. Origin: Anterior end of the lygo-

matic irch. Insertion: Skin of the angle of the mouth.
M^ The tavatoralae nasi. Origin; Maxillary fossa. Insertion:
^ ' late ml cartiTge of the no'se. The muscle .s very sender,
and 's inserted by a long tendon which uuderhes the m-
irUon portion of the quadratus labi. supenoris.
M The bucdnator is a broad stout band of fibres enclosmg the
^ ' Iheek anHLhed to the alveolar borders of the upper jaw

((, xt^c^^! Origin: Lateral border of the upper jaw.

^ ^ L^rriM^ Hairy ^rtion of the mucous membrane of the

mo^Ih Th"m/sck is very broad, but short and extremely

(g) T^he quadratu. tabu inferiorU. Origin Ventral border of
^ tbo m"dible. Insertion: Skin of the lower lip.
(h) TtrnUi™ THe -scle sur^tinds t^^^^^^^^^^

the "»f*'^h^tk?n„ftL7ow« lip through the insertion
P*t™nof the quldtrnflatilnferioril which largely overlies

angle of the mandible by '^e union of the antenor an po ^^
rhtr^cic'a'pe'^^S^ -'r,?ec'^onsinTfiow1r^par^

-TS:^;;;^^.^ -,;. ana .ygomaticu. minor muscle, may be considered to
be subdivision.s ol Hub muscic.

Ths Hisad and Nkck. 159

W. jugularis transversa) (Fig, 52) ' ""™"ne jugular yein

basJof Cl!°h"fi^ ""^ <^; '?"""' P°""'<") '^ f"™ed below the
portion of the orbit, and the .nterio? auri«Sr vSi rom he'^ar '?;^

paroiid'gTanT'^'''^''"'""" "■^'' "^ *v.deda„d turned forward together with the

.ur,tce^o?rhrhea°d"a";d'n':cr" "'*"^"'" ^'™'^'-- °' "■« ventral

**' I'l^^'".'"""^ «'"•' <«' submaxillaris), a somewhat
compact rounded or oval gland lies at the medial sld^nrthi

ducrrd%rh'"''"r''r °' "-^ '•""'^ °f the maid ble' ^

(b) The angle of the mandible is covered- bv two muscles of

rh/l't?rl""\H"""^'" '""8 ™ 'he lateral surface and
the pterygolde-js mtemus on the medial surface

(c) The digastricus. Only its insertion portion is visible It
passes forward a^ong the medial surfa« of "he mandible to
the anterior portion of which it is attached ""'"'"'''<^' '°

' The mylohyoideus is a transverse sheet of muscle ari,in»

^^Si^:^^^ -^ -""""^ "■> eUhrr'side-LI

"' JJ=^^n<^fLnXrr„r'j„--

Mastoid process of the skull insertion.

g|»=ii^!on--^--^}i^

(!)

I

jgQ Anatomy ot tiiE Rabbit.

Wng bn the side of the trachea. It « 7»""" ™M « he
thyreoid cartilage to the greater cornu of the hyoid as the

(h) The"teac^*^'cupies a iredian position, and is supported by
cartilaginous tT«ch««l rings. j „.,:

« 7a^e,r;^t«i.°inri«~«r^^«r^

»j:^-trS'cartS^qj^f'ilSS
U i^ ^nnected ventrally with the thyreoid cartilage by the

cricothvreoideus muscle. . , . , ;„„ii.

^v> Th- deen cervical lymph gland (Ivraphoglandula ceryicalis

<"' l^A "'X.J^LA^ '^f'''t^°y^id'ca"r''tilage'''
upper portion of the neck, opposite the thyreoid cartilage.

m Thrthwoid gland (gl. thvreoidea) lies on the ventral surface

'" If' he Sef behind the cricoid cartilage. , I' « "TC'e by

right and left portions connected across the middle line by

a narrower median portion, the Uthmiu.

to the l"r nxTnd to the sternohyoid stemothryeo.d muscles.

neck from the jugular foramen of the skull to the superior

(o) rlTuntS «^ or vagu. n«v. (n. vagus) is the largest of

'■"^ Srr-°ves"^panyiSrthe carotid arte^X^ /'""J" ^e

lateral side of the common <^?""'>' ''^''!«"i'^"^' ^ZAor

internal jugular vein. It gives off the n. "^•VJ "^T^^c

to the larynx, the latter passmg to the dorsal side oi mc

common carotid artery. i.„™,i».«.i

(„-\ The ramus descendens of the tw«afth cranial or hypogloMal

^^^ Ime^^s rt^e^ooTof the vagus from a lateral to a med^l

^Hnn 1 1 oasses backward on the ventral surface of the

^t"ry, and is^Sy distinguishable >,y its branches to the

sternohvoideus and related muscles.

«•' SL^-iSie^cl'-Sonro^Sdt^X »ei^
(r) 'TV;';ii:;*^^'""f the vagu. (n. depressor) lies on the

Tne HgAD AND Neck. jgj

margin of the thyreoid cartilagr Po.terior

»verotth7i;:>^roid^^^-r^^^^^^^^

the n,a„S,'°" °' "" """^'" °' nu.stication and related structure, of

•urface for the deep dissect "no the v™™? r™"^; '? "'d'r to expose the
-eve one ha.f of tL .and^e eitS/^TicrS^oKLi^A'^de?"-' """• '°

paSnVa to^LX^^d'^rS'L'Si^^!;"" "'' 7«™t''^ -" -^
fce divrded anteriorly and oosterioX =„!"''"!?"'"' '"^'' may thei
wh.,le insertion of VL mLSer mSle ""°"'"^' "«"''" "'"■ "■«

medi-a1 sW " of fh^r^H '^''^ " '°!"/ ''°'" tendon on the
uieuiai siae ot the reduced coronoid process The m., Ji«

To remove one-half of the mandible:
m^^l \^r7a«''ort'i:eirtri^;r'' •""h ' !5-f ^ "'""^ '"^

veloped. ^ ^°"' ""'«^" »« strongly de-

^'' ^ween'li^^l'^T'" '?"' ^^^ »'^«''"« inferior) lies be-

162

Anatomy o» the Rabbit.

(0

The correspondinK toI«ior tlTwUr ttUi l«ve. the mandible
at this point. . ■ ■ , ■ ^ ...^m

The tofwior riT«rf« n«T. (n. »'v~'«"' " ^.^'VEfSS:
panies the inferior alveolar artery '° *^"»"f ^^„ J, 'X
tinuation of the nerve is the mental n«rT». It appears at me
mental foramen, and passes to the lower Up^
The origin of the inferior alveolar >>="'™»> "^ ,''*{* .hi'J
arises from the mandibular nery. (n. mand.bulans) the third
3"*^nTf the «fth c.«^ or trig."^' "'J^ ^'JJJ,
minus), which also gives off anteriorly '^e stout lta«ajlmW
to the tongue and posteriorly the slender "»y'0'>y™f "n'-
The« strue'Tures. toother with the '" "■°; ^^y^'^h"; " ^J^l
mav be freed from their loose connections «••'»"« P'"y
goidei. so that they may be left in P'"" '" '»''f;"in" of
The two ptervgoidei may then be detached at their point oi
origin from the skull and removed.
6. The branches of the common carotid may be traced in the anterior
portion of the neck as follows: .

(a) The intern^ carotid (a. caroUs >" er>ia « a small ve^l^P-n

"p^sie'^Tor'wtd "a?t e"^e.iSS c'^id\"'car„.is externa).

(b) ThetcipiUl art^y (a. occipitalis) passes from the dorsal wall

the hyoid, should lie divided. ,„„,„1 wall

(c) The Ungual artery (a. lingualis) arises from the ventral wall
and oasses forward into the tongue. .

mandible to the lateral surface of the face.
(e) The internal !»«f^ 'H'S tt "xTemaVc ™ X^"- ?n
Z recr'o^rotinp.''l6l),Tving o^ the'lm^lor
alveolar artery to the mandible. _j:„i„i;,-i

branch of this^ vessel.
7. Dissection of the tongue and hyoid :

(a) The stylohyoideus major muscle. Ongin. juguiat v

Thb Head and Nkck ,,,

base of Ihc tongue im" a broarf Ihf ?,: '''S""'''"" «' "•«
extend to it. anterior tip. "* '■"" "■"' «"•" »' "hich

n,7dwLT;!'„d"5?vyj'' ""'"">• «P''™"1 fr,™ ..„ other. u„i„
(<•) The itylohyoldMu minor. Oririn i. ,

jerion: Les«r cornTSnhe hvo S AT'"i' P"^"' '""
•o the medial side of the "tvloKus "''" '""''" '>'"«

* 'i«iorA':;;'et^TuVra«T.he^''H"'''^"l" »>"P-"- '""

immediate, beWndKmpi'^,:' 'Th''?^'" ""^ ""'"''"'le
and slightly backward into"he,?.h.. l-^'!' •"" "P"»'«'

(f) The hyoglcu.. Origin Th?^^? "'''"' '""^""^

greater Tnd lesser ro?m„ u ^^■' "' "'"' hvoid and the
The muscle ,!::S ZTtlL^^! V?' ^P^'^"' "'''''
either side bv the styloglossi """^ enclosed on

(«) The Unju«li«, or intrinsic muscle nf ,h. ,

mass of fibres with no skeSr»l 1, u '""«"'' «>"'«•« "' a

(h) The lin««l nenr, rn li , "'""'"""'"'s

'he tongue and enteTs Us"ubsta^l °"'"^^''' '° "■' "de of

Jtylohyoideus majof. It ^distributed' '"''''''' ^'"'^ "' "«
the Imgual muscles d'stnbtited as u motor nerve to

HtoidSnrn^" tt X E- fcvt'xr

nerve of the tongue "J'opharyngeus. It is a gustatory

The«r:.:rtht\1o?trrs[°:'\r' -'""■ - '-mh nerve,
raay be traced to their origin in .hi P"',''*^'^ '"''eady been exposed
bulla should be exposed by^removiSt 'Tl" '"'™"'" ^he tvm'^^c
.^d are stil, in place. ^Th:TnZVar\Tpo'?S^°ir^4'' £°t'

1^ ANATOMY OT Ill« R*»MI,

dorsal to the vagu, with which .t '» »"'"°,^^d„;^'d to the medial
formU by a r«nu. IntMnui. J.^' ,X ste^nXoideu, and cleidomas-
.ide of the mastoid ^''^-^hments o the sternohyomeu ^ ^^^^^

toideus muscles. K-vmK branches to he '»»^^ "^"j/^,' di^ribu.ed.
to the ventral surface of ">e trapezius to wnic , i„^ „efves,

The twelfth (hypoglossal) nerve »"7j*^"f of the .K-cipital. It
.ince it come, from the hypogIo»al 'o'-ajma of the ^^^p^ ^^ ^^^

crosses their roots, forming a b"»^ ^J"^.™, tL ha»- »' 'he tongue.
'■rt ;iLtdSlT;i^nX. a"l^uTtr;,int where it crosses the

"The crvicia po,ti» of the .y»|-«f'''^r^„rhfr:edia;''sid"o'r?h':
..rvic.lg««Uon(gjrv,calesupe^.usV •' -^o ^^e^». p, „e,

;redS'g"t°m treVngU™ ac'mpany the branches of the externa,
knd internal carotid arteries to the head.

9. The oral cavity and pharynx. ^^^

The glossopharyngeal nerve and the sui^^^^^^^ ^^^ ^,^.

artery may be d'v.'le'l. and the^^ern-^^^^ ^^^ ^^^^^ ^^

ated nerves separated from the oesopnagu jj y; the loose con-

be displaced downward '° ». XVa« of the ve teb?al column An
nective tissue along "le ventral surlaceoi me .^^^

incision extending from the <'f"'?\^''^f^^s°^'^thi digestive tube
the oesophagus will «,|»'f,''|^X™ The ta"^on divides the con-

posterior portion of the pharynx.

f uir.

iih tic

Vi in (s
:n Jl., I.

Tb« Hkad and Nkck. 165

In the oral cavity:

*'" I""™^' "'"• 'P?'*'"" "">"') i« the Ihin. narrow r
inembranou, portion of th. roof. It i, very long in I
« ending from the bony palatine bridl-e bSc" ,
point above the laryngeal aperture, where it c, ,
concave free margin.

(c) The DMOp^tta. duct! (dd. na»palatini) o'. .,
apertures immediately behind tie «nall wu,. -.
mo"u"" ■■"^ri"' portion of the nasal -^nay

basal attachments on the hvoid into the floor ..f li-
lt, connection with the latter is extended forvv ml In „„.
m^e Ime by a vertical membranous fold, the f'rnLtm
BniMt. Its dorsal surface is divided into a p„, ,i,
™ooth and hard portion, and an anterior «,fter and'^^ougher
Miuta.'r™nT"'f ''-r""' I""' «>"«tions, the fuiriS
JSSvTh 'P^P'""' '""K'fornies). At the posterior en™ The

SiDSSIirr"'"^" 'r '"»" 'P''"''^"' 'fevation, he
vuute papUtae (papillae.vallatae , partlv sunk in the mucous

foS^li .he.,^:^'' •■\"'h" .'Me aroval area. Re «pZ

SS, J u.V'l ?■' *'■"''' '" '""''«' by fine parallel ridgcT

t«Ee bud* ""'' '°'""' P'P'"'" "* '"^^P'^d by microseop'c

In the pharynx :

'"' Mili"?^"- "°"'"'?' »PPea" as a rounded mass of Ivmnh
^on the l[ISSiZ '.In ""/'"" """ of " O^P 'ateraT dipTs
Hke awrt^^.J^" (""f^'""''''*"')- The vertical slit-
Dostertor f^H^ ... "">'" " '"""'''^^ ^y low anterior and
posterior folds, the glo«op.l.tia. and plu.yngop.l.,in,

^""^ Jn*'.™!?'*!"'^' f '"""«"'«' valve.like fold guarding the

the"p!;:V4e'arcaX' '"'''''' "'-"' '""^ '"* «"""'°

^'^ n/r,?'"°'f"?i.""' P°""ior portion of the soft palate the con-
nection of he nasopharynx with the nasal foSae w«rbe

•J«'^"f the auditory tub. (ostium pharyngeum'^S)
10. Examination of the larvnx

By cutting around the base' of the tongue on the opposite side of the

166

Anatomy or the Rabbit.

body, the whole structure, together with the hyoid, larynx, and a por-
tion of the trachea back to about the end of the thyreoid gland may be
removed. This affords a good opportunity of re-dissecting on the oppo-
site side from the medial surface of the mandible outward, also of cleanng
and examining the hvoid apparatus, which is not usually available with
the prepared skeleton (p. 97). The laryngeal cartilages should be
cleared externally and the parts made out as follows:

(a) The thyreoid cartilage (cartilago thyreoidea) (Fig. 36) forms
the largest portion of the structure. It is a unpaired saddle-
shaped cartilage, described as consisting of right and left
laminae. Its anterodorsal angle projects forward as the
comu superior; connected by ligament with the greater
cornu of the hyoid. The corresponding posterodorsal angle,
the comu inferior, overlies the dorsolateral portion of the
cricoid cartilage. The anterior dorsal portion of each plate
bears a small thyreoid foramen (foramen thyreoideum) for
the entrance of the superior laryngeal nerve.

(b) The cricoid cartilage (cartilago cricoidea) is an annular carti-
lage, partlv enclosed by the posterior portions of the thyreoid
laminae and surrounding the first tracheal ring. Its ventral
portion, the arch of the cricoid cartilage, falls some distance
behind the thyreoid cartilage, the intervening space being
largely occupied by the cricothyreoidel muscles. Its dorsal
portion, the lamina of the cricoid, forms a greatly expanded
plate serving for the ipport of the arytenoid cartilages.

(c) The paired arytenoid cartilage! (cartilagines arytenoideae) lie
one on either side of the anterior tip of the cricoid plate.

(d) The comiculate cartilages (cartilagines corniculatae) are
slender curved terminal cartilages supported by the ary-
tenoids.

(e) The epiglottic cartilage (cartilago epiglottica) is a triangular
plate supporting the epiglottis.

(f) The rudimentary Tocal folds (plicae vocales) may be seen as
vertical folds of the internal surface of the larynx, especially
prominent when the thyreoid cartilage is bent downward on
the cricoid. Each fold forms the posterior boundary of a
shallow pouch, the laryngeal ventricle (ventriculus laryngis).

In addition to the criothryreoidei the laryngeal cartilages are
connected by several small muscles, including the cricoarytenoidei
posterior and lateralis the thryreoarytenoideus and the arytenoideus
transversus, the last named being an unpaired muscle connecting the
arytenoid cartilages.
11. The eye and related structures of the orbital cavity.
The eyeball should be carefully separated from the bony orbital rim-
The first portion of the nasolacrimal duct (d. nasolacrimalis), passing
from its aperture on the medial surface of the lower eyelid to the lacrimal
bone, will be divided. The muscles and glands of the orbit may be
made out as follows :

(I)

The Head and Neck. jg,

™cT:1',LXo? of'.h'e';X°ir''°"''' ■" •"•"""• '-■" 'he underlying

then beneath a fibrous cS^d fh' "?.'''*"'""''''''* "■'''■t.
small portion of The orbhaf'wLn .„T^i™' ""'"u" """«*' »

tJr-?So^^,t.r;;j£-^"Si."?s-^::-

;;; po-^&'^'^j^'nopfc.^r- >»- •--.»:

S^!ar^'?ro""?SX™r'"'r'^"^'"- »««»«». -d

are*^;t:?res;™c"v'e,;^n"?h'e"i;ri,'^S '°7™"' ^
pos,e..or portions of th'e periphery ^/'threveba^n'"""' "'"'
(e) The retractor buibi fbest v-n <.f.., .^ eyeoaii.

arises in common with ,h^?*''" "" ''^'n''^'^' °' 'he eve)
inserted on "r media, Mrt ^^Ti "■""' J""^'"' ""^ 's
optic nerve. It «n1S's o^'frd^^'n^ct plrt" ""'"" '"^

two portions, one of Uich is B^yis? ed h'.' "Jh'""*." "'

(g) t': J4r"r" '!"^ '-"- -'f-' <" t^^t'ifi^d" e";-^-

''' d\'rle'?^'rtu^r^rv'i„Ln,otTttV^,,^ -r- ™«""' ="»
of the orbit. It commumV^, k "" '7 ""^ "^niporal angle
inner surface oV tTuT-^'e^'Sid"' "^'"'" '""" ""^'^ '^'"' ''e

ate y medial to the zSgomatic "rch^ Th. 1 "J""' ""^ °''''i' '"""edi-

^X n^"hS WiSSI^f f -^s

nerve outward from the optic foramen t'oThe'ev^S ^""""P-'" "-e

hemiste^r^tf^^ift^ispC"':; ■""''"" 'r "■^''-' -» '=""->
divided vertica'lv. The Mr7s sSrf '^"'^"■"•.« the lens, being again

chief strictures (Fig. 50, cCprfii ""' ' "'^""""' ""■>" "'^'^ The

'"' ™at?,!3rsir^i'"Xo1e"^trture"'i;''^ ^^-^^ ^'^^'"^^
medial portion, the schr. or ..flt^.! ' " ''"■'""''« *""> »
investment of fibrous conne'rlk.r"' "f*' ^ ""ick white
part of the evebal" and a smi ler ,f"^ ""'^"'"^ *'"' S"-"^"'"
the c,m«. ^veringThe ex^lld suS""' '^'"^' P""-"'

16B

Anatomy of the Rabbit.

(W The nsculu tunic (tunica vasculosa oculi), the thin middle

^"^ loatT^he eye; pigmented, except '" '''W»° »?i;^''^ 'Vn

divisible into: (1) a general portion, the choiioidM, lymg on

rie .mer surface of the sclera; (2) a muscular P?rfon, the

ciliMT body (corpus cUiare), forming an annular ndge about

S^riptery of^e lens; and (3) the iri., the latter forming

a cir™lar fold suspended about the periphery of the lens and

on its outer surface.

fcl The retliui, the innermost layer of the eye, forms a thm soft

^' membrane covering the inner surface of the chor.o.dea It

UdTvisible in a larger op«ic portion, the «n»7 P"' ."' '^=

eve and a smaller ciliary portion, lying about the periphery

of the lens and distinguishable by the radiate ■^''""f "■

its surface, the latter formed by the projecting ridges of the

ciliary body. , . ^ /=, ..

(d) The transparent lens of the eye is suspended by fine filaments
the zonuUir fibres, reflected from the margm of the ciliary
body.

(e) The vitreous body (cor-
pus vitreum), a trans-
parent mass, of gela-
tinous consistence,
occupies the large space
enclosed by the lens
and the retina.

(f) The space enclosed
between the surface of
the lens and the cornea
is divisible into a larger
portion, the anterior
chamber (camera oculi
anterior), lying outside
of the .ris. and a smaller
portion, the poeterier
chamber (camera <x:uli

C;n""he .ris'"a'nd '^.e lens The central space enclosed
bv the free margin of the iris is the pupU (pupllla).
12 Following the removal of the eve, the hloodvessels and "erves

1 Ihp Merveoid process .\t the pomleriw ventral angk "f the
:!^'!^ if^n efc* Cirterior ophttalmic artery (a ophthalmia

Pir. 50. Diagtam of thf pf.rte rf the eye in
,ertiSj KCti™ c.«.. ai.u..or ch.ml«r; c.c.
cU^ry body; ch.. chorioide»; co.. oornei; «■?■.

VWtina' c v., V treous body d.h.. Hardenan duci.
dK%itto of the Ucrimid ducO; iij ""^:
irimiiduet; i.. iris; 1.. ten.; n.o., optc nerve.
or optic portion of the wtina: (M.. Iweer
eveid p-.V upper eyelid; pt... third eyelid,
"l" retractor liiEi; r.i. mM ■"f«"°'i„J^
recto. .u[»rior; .c . «lcra; «-. lo.penraT
zonular libn-n of the lens.

The HgAD AND Neck. .gg

It divides iato twrbtlXs "the CSS'alJi^ T IfV"'-
the orbit through the anterior foV^^ ^T?' ''^"''' ''"'"'
process, and thi IwrteSu Xv Xh 1 f"Praorbital

srrziTh^ oT'trrr^n ^^^ =''arrrv!\'

'■'b^indarT'orrhlt'St^a'^^art^V^™-'' t^' '-^ «"«-'
canal gives off a branch tL^,T"'"^ ,°' ^*" infraorbital
tinning' as the Infra^biia f arrerP'^Tl',!,'",^ ^"'1 ™"-
•uperior dental arterv ra \ir„. i= ^ bmall branch, the

lat^IlytotheaCTofThet^fLeT""' '^ «'^'" "^
^^^^""rc1'„*,?o'ThiVe^'^"'''"'"-^> P"-^ "■-"«" -e

"ard''Sratd";;:eT;^U;aEra£^^^^

nasal cavity by the sph^noTfTatinffcraS ""'" ""'''' "■•=

''\H';4':=:.':ii/hX?,^p';-rtr'bT-''"-' -'">''>'

and the rectus lateralis. ""^P""" "' ""e obliquus superior

nene.s parsing through the mirfrfl. .."'''"'""'' <'• 0- The small
of the ptervfoid pTe,, are thJ M^l.i'r"^r'"' sphenoidal lor^„l
-^nen^.hUhSt^.tSSSl^'^S^'^™^-

"' ?^5^"^ ^-sicr-^ — 1^ •"'^'"--'- ■' -■

■'^ Sb^u?:?^o t^'c.u-la'J^'rr* "'"' '" ^'■<'— )■ *^ 0*^-

through the .^s\rri:??o'raZ'ort"e',"up4';r'SS^"P"'^

anterior supraorbital foraJ^In; whi ^ ,he oth r fc' '"'

fhe-o^ "Tn'dls-'c^lL'l^^'^r.rth'" '^^ ^"''™' ''-"^
lying on ,he oprn^^^ft:; "„Vu: rsi^n. rl^T'' fr'^l!"-;
portion leaves the orbit throu^h the n^h!!^ J^ , ' "'"^f
the orbital ^rtion of the frj^.'^bonc af tri't^LtSi^^^J

170

Anatomy o? the Rabbit.

(f) The branches of the BMilUry nerve (n. m«'ll»"»)- ''■e
se^nd division of the trigeminus, traverse 'he ventra por-
?Sn of the orbit passing forward in company with the mternal
maxSary artery'^ Thiy include the .ph«.op.l.tUie nerve (n.
XenoMlatinus) and the infi.orWtia nerve (n^ mf raorb.tal.s)
The "Xr pTis forward through the infraorbital groove and
foramen to the face. • j k

The connections of the sphenopalatine nerve may ,>>« "^^'-^^"^

^^ tsx^;h^,^atr:r; ^^r'TfB

"'Ttthenopalatine nerve ends in t^^^^^

rSSfewTeh nd The sphenoTatitin^™ amen. The nerve, proceed-
immediately oeniiiu ure ^h r ^^ . ^^^yj membrane

ingfrom 'he ganglion include^m«^r«n^ to l^he^ ^^^^^^ ^^ ^^^^

f^ra^-n to the anterior portion of the hard palate, and (3) the »>»""
^to. nerve, which pSses through the pterygopalatine canal to the
posterior portion of the hard palate.

XI, ..m of the oterveoid caiul (n. canalis pterygoidei) is a slender

^SfinCrwKrr^es and onThe lateral surface of the palatine bone
PostericTlv it enters the groove representing the pterygoid canal.

This nerve is composed of two parts, separated posterioriy. One ot
1 "^."'I^LlfoJS^ nerve (n petrosus profundus , is connected with
hn-vrnpatZc'l^^sTthe inS^rnal cafotid artery. The other, the
Xt'^tkcW p^teoid «rv. (n. petrosus superiicia is major) en ers the
SS aTJSrforarn lacerum, pacing into the Petrosal bone in t*^ '"'enor
,rf which it is connected with the trunk of the facial. 1 he nerve con
"titutefthe motor root of the sphenopalatine ganglion, the sensory roo,
being that provided bv the sphenopalatine nerve.

The sphenopalatine ganglion is one of several representing the sym
patheticTvste^ln Ih. head, and having motor and sensory roots from
fhe cerebral nerves in addition to their sympathetic connections. The
the '^'^'^"r","'- ,1. ciliarv BUielion, which lies on the optic nerve, the
"'"l^^'J^l^^Z^^bf^e^^. associated with the mandibular
^'e'vri^X^'t&^r^Sl^'^. associated with the lingual nerve.
13. Examination of the middle ear.

Bv breaking awav the ventrolateral portioi, of the tymnamc bulla
^d ckarmg the surface, the structures of the tympanic cavilv may be
«ud.>d Thev arc chieflv those already described '" ™"'-«;;.''"7''''
the skeleton (p 10), but the Icllowing soft parts may be identified.

The Head asu NgcK, ]7j

on the manubrium mallei. " is mserted

(c) The •tapediut is a minute muscle arising from the Derin.i,

(d) The chorda trmru, ,s a delicate nerve which cros«., \h,'
tlTanuSnlXT'^'"^- '^^ '-^ crus^of L"S a'n'd

rhenen'e is a continuation of tlieinteni»di«fen.r.. , „„

.Tr^tnLnr-'^"- ^" "■'" ^^^ '"ntaYn^n.eTna"?h^-Hn,i:;!
(c) The internal carotid artery
traverses the carotid canal
of the tympanic bone. Bv
breaking away the posterior
portion of the bulla, the
entrance of the vessel into
the external carotid foramen
may be seen.

The disfrection of the parts of

the ear as het« outlined includes

only the e.xtemal and middle

portions together with the asso-
ciated acoustic ner\-e and its

entrance to the periotic bone

The parts of the internal eir

(Fig. 51) am not readilv made
out without the use of special

methods, though their position
may be estimated bv carefully
breaking away the surface of the
ventral portion of the periotic
They include (1) the bony l,by-
rintll, consisting of a series of con-
nected spaces lodged m the in-
tenor of the petrous bone, and
comprising the cochlea, veitibu-
lum, and the bony semieirciUar
can.!.; and (i) the mem-
branous labyrinth, consi.sting of a
.second series of spaces contained
wilhm the first, and comp.-lsinir
the duct of the cochlea, the

.51 Diagram ...
Mr in verti. ,^i projection, "to show ,'ti^
R'K' S^SZ^ *• ..ruelai^'lZeS
, 1|. peero,,, portion ^ ,t,, petrolymranir
^|. > . tymi.„„io portion (bull, tyrn-

mae ^-i .r^=i " '"™?' m malleuB:
"itt.e exumai acousiic meatuH tn-

S™"T„;' if' '""f'' ™S;™n .

iii.«,i internal ocouhUc mpattis- <

starie*. t.a . aiidilonr tul>e; ii.. itrici.kis'
; VIII, acoiiMk- nerve

c"sss,i5'a:rtt"%.^^,;i«pS''/'r''r''"««''""''''«''->

ous laby.mth contains ?^Sfs^''^,t°Sn■■'of^h'"■ T''^,"'^'"''"-
is occupied bv » fluid niat.^,ri ' ^ "™ ','',»'i' ?'r and its csvin
■separated from' that of the bon^^:,,.'.;" ?V''"y"P'' T''" 'all is
phatic space also « . o .ied by a flutd ■,f,'", T "" "^''"^^'^ P«rilym-
1 leo oy a nmd material termed the pefilymph.

»jr^

.*. "^r

172

AWAT04»y '>f THE Ra»»T.

XI. THE THORAX.

1. Examination of the thoracic wall. For this purpose the 'ateriil
surface of the thorax may be conveniently cleared, on the side from
wh ch the interior limb has removed, by dis«cting away the attachments
of the muscles already examined in the previous dissections. These
tacladeThe orUs of the pectorales, pectoscapularis, serratu, anterior
(thoracic portion), obliquus externus, and rectus abdominis.
^ The dS portion of the exposed surface is occupied by the spmal
musculature; to be examined at a later stage. On the ventral port on
Tpt^ar the ribs, and between them, filling the inlercostal spaces, the
XSstaf muKles. The .itemal intercost^ (mm. intercostales
externi) arise from the posterior margins of the bone ribs the fibres
SS oblkTuely downwaVrt and backward to be inserted on the anterior
mareZo the next succeeding ribs. The internal m ercostals (mm.
Ster^stales interni), the fibres of which are disposed in the opposite
di ecUon are concealed for the most part from this surface but appear
ventrallv between the costal cartilages, where they are not covered by
The externafintercostals. They are best examined at a later stage from

"^n'—ticn forS removal of a section of the thoracic wall, tlie
pectoraks'^rhould be divided on the opposite side of the thorax, close to
the sternum, so that the limb may be displaced.

The nerves »nd vessels of the neck must b. kept intact unt,l the folio, mg

rtestrov their costal insertions.

A triangular section of the wall, including the sternum and the costal
cartilages may be removed bv making three incisions, one on either
sfde of Se "ernum, extending from the middle of the first nb backward
to the end of the ninth bone rib, and the third across the ventral surface
close in front of the diaphragm. , , .

The tSnsversus thofacU muscle appears on the inner f jface of the
sect on removed It is a thin sheet of fibres arising from the body and
XhcW prressof the sternum and inserted on the ribs, from the second
Tr the sixtlTat the junctions of the bone ribs with the costal cart, ages
The artery passing along the ventral wall between the foregoing muscle and
the internal intercostats is the internal mamoMiy (p. 174).

2 Dissection of structures in the superior thoracic aperture.
The nerves and bloodvessels of this region are concealed by the
thvm™ gUnd a large triangular flattened structure of fat y consis_
ten" ex?" ding forwird from the base of the heart to the anterior end
of" he thorax The thymus should be carefully scraped away, all vessels
excent those of the structure itself being kept intact.

/he foltowing structures, including the aortic arch and the arteries
arising from it, the superior caval veins, and the vagus, phrenic, and

iO^«e£?/M».M

The Thobax. j^j

m.^fli''*""' "TPi """"* ** <i'»«cted in the order given below hut
must be separated from one another and identified as tli« apiaT'

^^ Il"','ir\'^ V" f"*" <"™' "<"'«*) Beginning at the' base
of the heart, the aorta passes at first forward and the^

Iefr„f T ' ^"'' T "■' ™"'* "f "O^h i' lies sllghtlv to
left of the median plane, turns backward along the ventral
surfaces „l the bodies of the thoracic vertebrae W ,h the
a^tCVa,". '^' ."""■«••>• -"eries (p 178), the first branches
are the large paired vewels arising from the anterior wall
They comprise the common croUd and •ubcl.»i«i™rt«rt»
On be right side the carotid and subilav""a^ r„!™-
shor common trunk, the ta««nffl.t. artery (a "llTil)
vetTorriHtV^:"" '""' --edia:^. .V Mt .^fTJi^
The branches of the common carotid arterv have alreadv been

^^ii^^'^r "' ""^ '"'"-""""" '^'^""^^

The subclavian artery (a. subclavia) is the first portion c,f the

^l7„^", "!f ^"'r°' "■"'" " 1»««>^ f™™ i^s point of
origin laterad to the anterior margin of the first rib, where U

t .ivl\ ff^-' ""^ ?"[""'>■ "■■'">• ^^^' "^ point of origin
iLlL^r. *.™™' branches, the relations of which fe
subject to considerable variation. Thev include ■
(1) The vertebral artery (a. vertebralis). This vessel oasne^ into
the costotransverse foramen of the seventh cervrcif^meC

fng ;oram?„a''o^\'h''"'' '"''""' ''^ '^*' ""'' "-^ corr:rptd'
ing loramina of the remaining cervical vertebrae reache.

surface of the medulla oblongata with its fellow „f the

stTeTp mi° '""" "' '"'""" "'"y "'" "^ *^''' " « '"•"

' div^L"!^*"^ ""'"S". "**^ <^ cervicalis superficialis)-
whd ™ * ?''"'°'lf 'J'^*'-"™ (P- 135)--is a small vessel
which passes forward and outward beneath the insertions
of the cleidomastoideus, basioclavicularis and levator
scapulae major muscles, ramifying extensiveh in the a
mass of the side of the neck under cover of the su4r or
portion of the trapezius. Its ascending cendMl Knch
lies on the lateral side of the external ju^ar tX^ """"

divTd^^f^™*! "*V " *• »«'' <"■ transversa colli) also

?he neck o? Th'T? "^r""?" ^P' '^«>' P«'*^ '^'"=«i « ™nS
the neck of the first rib to the wall of the thorax. It passes
hrough the loop formed by the eighth cervical and fi^t
thoracic spina nerves. It runs dorsad, first on the med a

^rvicil r!.^^"""? r'"'"- ""^" ™ 'h^ "^dial side of The
cervical portion of the serratus anterior. A strong branch
passes to the inferior angle of the scapula. The arterv sup
plies the serratus anterior and the rhomboidei " "^

174 Anatomy ot thk Rabbit.

(4) The 1. Inttrcottdii nipnma paswi backward to the internal
surface of the thoracic wall, giving off the first three intw-
cottal artarlM in th- intercostal spaces, and also small
branches to the ocsoi'liagus and trachea.
(A) The internal mamioary artar; (a. mammaria interna), the
first portion of which has been removed with the ventral
wall of the thorax, passes baclcward to the ventral abdominal
wall as the iopwior tpicaftrtc artarjr (a. epigastrica superior)
anastomosing with the inferior epigastric (p. IIS).
(b) The iupmior caval vain (v. cava superior) is formed at the
base of the neck bv the union nf tlie internal and external
jugular veins, the latter vessel re.- i 'ng at this point the
subclavian vain (v. subclavia) i ''Tht superior caval
passes almost directly
backward, crossing the
ventral surface of the
right subclavian artery,
and enters the anterior
portion of the right
atrium. The left vessel
crosses both the left
subclavian artery and
the arch of the aorta,
reaching the right at-
rium from the dorsal
surface of the heart.

(c) The vagHB n«rv«. On
the right side the nerve
crosses the ventral sur-
face of the subclavian
artery, passing dorsad
to the wall of the oeso-
phagus. It gives off
the recuTT«ttt nerve
(n, recurTens).the latter
curving around the sub-
clavian artery and
passing forward along
the side of the trachea
to the larynx. On the
left side the vagus , , . , .u
passes between the arch of the aorta and the base of the
heart to the ventrolateral wall of the oesophagus The recur-
rent nerve passes forward on the dorsal side of the arch.

(d) The ramua cardiacus of the vagus. In front of the subclavian
artery the nerve is at first closelv associated with the vagus
trunk. IvinK on ils medial side. On the right side it passes
to the dorsal surface of the subclavian, and on the left to the

After McClure »nd SUv«t«r.

k ksygon vein; ao.. Boita: c.a.. left supenor
cav»l vtin. d th . thoracie ducU j.e.. ji.. »nd
j tr.. cxtemeL mternal. and iransverie juKtilar
veins; s., left Bubclavian
scapular vein.

Th« Thorax.

175

(<■)

(I)

dorsal surface of the aortic arch. It ends in ih. - _•■
Itou. (plexus cardUcus). a network of svmpL,he,L~'??'

^:««f?::r^ce?l;s-l----^^|.^
f paiJ£,~/';;;raC^r^£r?T^

»rthe^S?^r^^^tif--"S""™Hl^

The sympathetic trunk. At the base of the nn-lr .!,•„. ■ .
portion of the sympathetic trunk enters the W,ri^o^ Z^^l
ganchon (g. cervicale inferius). The latter HeJTfr^
and somewhat dorsal to the subclavian arte t The U
thoracic KMKUon lies behind the artery and is conL^A
wth the inferior cervical by the u^ ^llliTl f^t
formed by two cords, c. ,» of which d^sTT?? h ' ■ ^P
other to the ventral s.„. of the subcrvTaV^rle'r;""^'- '"^
The nerves proceeding from the inferior cervical Kanclion enter

3. Dissection of the heart.

thatof the peritoneum and p'eura investh^l "th^r viLeS " ""!"" '?

^rrm^^t^a'SiitSl.'ii' r ^S-^^^^^

investment for the ^ar.^bs\anS''^rpkrltt,'°™rmr"r''''''^
capacious sac. the serous membrane being Sv srren<„hr.H K "Jtf '
presence of a thin layer of connective t4Se whih forl^ / ,

'"rrSir, '^ r"""^ """''"'' ^ P- of^rp^r^card^um^'"""'"

vertebrae, and "also bounTd \ll^nyly?h^2Z T^he L.-.^jf" "' "l! "'''■•'«^'<'
It IS ocfupie,; in- several stnicturei namelv ,h. l^ poWeriur nwdtaltinum.

the bronc-fii. and the pulmcMn bT^dviS: "'»?'■"«>»■ th' thoracic aorta.

The pericardium should be removed and thf .vt.™„i i .
heart and its great vessels examined SVoltows '™^' ''*'"" °' ""^

(a) The posterior, somewhat conical, y«itricul«r Dortion nf fl,.

ter of Its wall^ The ngfat ventricle (ventriculus dexter) is less
muscular, and the wall is readily pressed inward The line
ol d,vs.o„ IS mdtcated on the ventral surface bv a faint de
pression. the antnor longitudinal sulcus

ITS

Anatomy or thi Rabmt.

(b) The pulmonanr uinf (a. putmoiulis) le«vn the base of the
right ventricle, passing forward and to the left in a some-
what spiral fashion around the aorta. On the dorsal sur-
face of the latter it divides into the right and Mt pulmoaur
utnlM, one for each lung. At the point of division the
pulmonary artery is connected with the aorta by a short
fibrous cord, the arterial ligament (lig. arteriosum), repre-
senting the foetal connection of the two vessels through the
ductus arteriosus (p. 44).

(c) The left coronary artery (a. coronaria sinistra) passes back-
ward on the ventral surface of the heart, lying in the anterior
longitudinal sulcus. A corresponding right coronary artery
(a. coronaria dextra) passes to the right side of the heart,
lying between the right ventricle and the right atrium.

The two vessels supply the substance of the heart. They are the
first branches of the aorta, arising from the aortic sinuses at its base.

(d) The left atrium (atrium sinistrum) is the thin-walled chamber
lying to the left at the base of the heart. The puUnonory
veins (venae pulmonales), several on either side, enter th*
left atrium, passing from the medial portions of the lungs.

(e) The right atrium (atrium dextrum) resembles the left in the
character of its wall. It receives the right and left superior
caval and the unpaired inferior caval veins.

The heart may be removed by dividing the great bloodvessels. The
arch of the aorta should be removed with the heart by dividing the
vessel at a point beyond the origin of the left subclavian, and then
severing the carotids and subclavians at their bases. This exposes the
surface for the subsequent examination of the posterior end of the
trachea and its connections with the lungs.

Open the right ventricle bv a longitudinal incision of the ventral
wall, extending the incision forward into the pulmonary cttery; also
both atria bv transverse incisions. By washing out the cavities,
the internal features of the -wall, including the arrangement of the
valvular structures, may be examined as follows:

In the right ventricle;

(a) The trabecuUie cameae; muscular ridges of the mtcrnal sur-
face of the wall.

(b) The tricuspid valve (valvula tricuspidalis). The thin
membranous flaps composing the valve enclose the atrio-
ventricular aperture, and project into the cavity of the
ventricle. Their margins, which i.ic otherwise free, are con-
nected by slender fibrous cords, tbe chordae tendineae, with
the papiliitry muscles (mm. paf-illLics), the latter being thick
muscular projections, of somewhat conical shape, arising
from the opposite walls.

(c) The semiluiur valves (valvulae semilonares) of the pulmonary
artery are three extremely thin folds guarding the entrance
to the vessel from the right ventricle. Two of the valves

i
■Wi.

Thb Tiioiax.

177

JhJ v^Jl'l ■ '" ** '"'""'■ "" "■'"• ■*'"« «'"'«>y«l on opening
In the atria :

(«) Tht rr.pective poiitioni of the pulmonary and sy.leniic
„ veins at their points of. ntrance. y »na sj.iemic

(b) The complete separation of the two chambers. In the par-
tition separating them may be seen a thin fibrous poriton
denoting the position of the embryonic fonmn oral*

through" the IId ^f'Th'^t '■'"ventral longitudinal inc,«on, cutting well
inrougn tne tip of the ventricle and extend ng the incision ai-rn™ ih.

right ventride '""""' """""' " "°' » "^'^ """■i-'d «» m the

(a) The Ucuipkl tiIt* (valvula bicuspidalis) is similar in general
stnicture to the tricuspid valve of the right ventrick

are'siZ^lT^h"*"'","!! """ .»■"■'" "' "•«•' *° "-"be^ »nd
are similar to those of the pulmonary artery.

4 Examination of the lungs and their connections.
^Jttl h!T?" °' ""^ '''"'™' "■^" °f 'he thorax opens the pleural
^h7.i ■ L *^'"^ '"?•'■ " ""'iderable portion of the costal Seura

the lining membrane, or pleura, being distributed over the

S« of the"; '"h ""•' >"•.""• •»"'>■ °'" 'he anterior
surface of the diaphragm as the diaphragmatic plran, and
over he surface of the lung as the pihaSuiry plJunT Pos
terorly the pulmonary pleura passes from U«^med^margTn
of the left lung to the medial lobule of the right and TheSe

(K^ ?r Pu'moMiy ligament (lig. pulmonale).

surfa^f'whiT""' f "^ '"''"'* "P»""''"e ^'mctures. the
suriaces of which are free, except posteriorly, where thev
are attached to the diaphragm through the pu monarv liga

ouTmontrvhTn'H"'"' ,*''*'? i'«>' "^ "'""^''^ "i'h fhe
pulmonary bloodvessels and the respiratory tubes

'"' fn^d^iS,' fVl^^ '^° "■'" P""'""'' ""'e »up«rior, middle,
fef? l^f Yhe "^^ .O-.^P^V". °f 'he smallfTsiz; of the'
lelt lung, the superior lobe is imperfectly developed On

he' ™!5.' !'V^\ '"'?""' '•"« " "^'ded Tnto two ^rtions
betw"e1fh:m' ""^ """^^ '"^ """'" --' vein'"passi"^g

'"" ri!lh.'"^J'^!.?'v'''''^^' "^ posterior end into two portions the
nght and left bronchi, one for each lung. Each bronchus is
again divided into smaller portions, the bronchial ..Z, which
tXs ^"'■st^-ee of the organ and redivide into Smaller

MOIOCOn HMUniON TIST CNAIT

(ANSI ond ISO Test CHAUT No. 2|

11^

LO
I.I

1^

125
12.0

A

/1PPLIED IK/MGE Ine

178

Anatomy of thk Rabbit.

(e) The branches of the pulmonary artery and the pulmonary
veins may be traced for a short distance on the medial por-
tion, or hilus, of each organ.

(f) The vagus nerve passes to the dorsal side of the bronchus,
giving off a number of branches, which accompany the
bronchus to the lung.

The lungs may be removed, together with a portion of the trachea,
care being taken to leave the vagus nerves in place. The lungs may
then be examined to better advantage, and the surface also prepared for
the next dissection.

5. The following structures may now be traced on the dorsal wall of
the thorax:

(a) The oesophagus. It traverses the thorax in a median posi-
tion, entering the diaphragm at the hiatus oesophageus.

(b) The vagus nerves. The right and left nerves pass backward
along the lateral walls of the oesophagus, and are connected
with one another through nerve plexuses lying on its dorsal
and ventral surfaces. The left cord is that appearing at the
posterior end of the oesophagus in a ventral position and
passing to the ventral surface of the stomach. The right
cord occupies a corresponding dorsal position and passes to
the dorsal surface of the stomach (p. 119).

(c) The thoracic aorta (aorta thoracalis) passes backward on the
ventral surface of the vertebral column, leaving the thorax
through the hiatus aorticus, the latter being the aperture
enclosed by the crura of the diaphragm. Its branches in the
thorax are the intercostal arteries (aa. intercostales), beginning
with the fourth, which are given off metamerically in the
intercostal spaces, and pass laterad to the thoracic wall.

(d) The thoracic portions of the sympathetic trunks lie on the
lateral surfaces of the bodies of the thoracic vertebrae. The
posterior ganglia give origin to the splanchnic nerve, the
latter passing backward into the abdominal cavity (p. US).

(e) The levatores costarum; a series of small muscles arising
from the transverse processes of the vertebrae and the heads
of the ribs and inserted on the anterior margins of the next
succeeding ribs.

(f) The intercostal nerves (nn. intercostales) accompany the
intercostal arteries to the lateral wall of the thorax.

(g) The azygos vein (v. azygos) is a small, asymmetrical, venous
trunk lying to the right of the dorsal surface of the aorta.
It receives the majority of the intercostal veins, which
accompany the corresponding arteries and nerves, the
tributaries extending backward to the first lumbar veins.
It opens forward into the right superior caval. The more
anterior intercostal veins are tributaries of the right and left
supreme intercostal veins which open into the corresponding
superior cavals.

Thr Thorax. j^^

for™i„JV"^'^:f»/^^-Ph7.-a^ and tendinous sheet

cavities from the peritoneal cav tv Ui «^Paratlng the pleural

the relaxed conditio, but in ™ntrac,i„„ i/l'™'^'"^' dome-shaped in
way that the space occupied by C'"- '™"'" -""""' '" '"'='' »

>-f^v^.tci'nlisto^?[rm:;i:L;"anr4^ "-'-i ^--^ «-. -r

nght much larger and stronger thf„th?yf.°"' "'^'''' "'^ '^""»- "-e
spmous processes of the firsf th ee lumhir ' Tk"« ^""^ '^e anterior
cost, portion, arises from the Tnterna^ M^rf '""T. ^""^ *™"d. <>'
The third or sternal portion, arises from h "'u*! P"''"'"' ^bs.
sternum. Its insertion is represL^ldT. ^ "'P''""' P™«ss of the
portion or centrum tendineuZaiThourt^h i „""'" '^dinous central
forwards to the lungs and TjicardhZ ,V '"."." '■'""^"^- attached
.gament. The eentfum tendlneum HhanT^" "'"".'"•'"«' P""nonary
the fibres of the costal and ster„a"ir&l^''";r«'hat like a trefoil!
■nargm. """' portions radiatmg outward from its

'' tatr^^'"^ "' '"^ '=""f-™. "^narv, and left triangu.^r

;;;g2^rr;r-rro;--^.-twocru.

arii f™T?Je''^rat''r:? [h" ^''"''''^^ ^P""-")
e.^en.h intercostals or^^o-nl L-J^hriSltet a°n?tt"e; tt

*^itr1*r:''^f''?H"et,:rn'';^-a?^-'-^ '"'"--)• o- on
enter the inferior cava * '^''™'^' "' "hich point thev

180

Anatomy of the Rabbit.

XII. THE VERTEBRAL AND OCCIPITAL MUSCULATURE.

ii

Dissection on the dorsal surface of the body from the occiput back-
ward ; also on the lateral and ventral surfaces of the neck.

The serratus posterior muscle lies on the dorsolateral surface of the
thorax. It arises from the ligamentum nuchae and from the lumbo-
dorsal fascia back to the last rib, and is inserted on the lateral surfaces
of the eight posterior ribs.

The splenius muscle is a somewhat triangular sheet arising from the
ligamentum nuchae and inserted on the supraoccipital and mastoid
portions of the skull, extending also to the transverse process of the
atlas.

TJiese two niiistles should be divided, the serratus posterior being removed
from the surface.

1. The long muscles of the vertebral column.

Apart from the iliopsoas, psoas minor, and quadratus lumborum —
muscles of appendicular insertion lyintf on the ventral sjrface of the
vertebral column — the vertebral musculature comprises chiefly modified
segmental muscles lying on the dorsal surface, for the most part in the
area enclosed by the spinous and transverse processes of the vertebrae.
They include the sacrospinalis. semispinalis. and intertransversarii.
Their insertions are extended in part laterad to the ribs. In the cervical
r^ion they are represented by short muscles, separated for the most
part from the thoracic and lumbar portions, and arising by accessory
bundles from the anterior ribs, the corresponding thoracic, and the
posterior cervical vertebrae. In the cervical region the muscles are
easily separated from one another, but in the posterior part of the body
it is necessary to dissect away the tough investment of lumbodorsal
fascia whiclrcovers them.

(a) The sacrospioalis. Origin: Crest of the ilium and medial
surface of the iliac wing; mammillary processes of the six
posterior lumbar vertebrae; investing lumbodorsal fascia.
This muscle is the largest and strongest muscle of the body. It
extends forward over the surfaces of the ribs. Its medial
border is separated from the middle line by a space of con-
siderable width, in which the semispinalis and multifidus
muscles are accommodated. In the lumbar region it is
inserted in a continuous mass on the long transverse processes
of the vertebrae and in the interspaces. In the thoracic
region the muscle divides into two portions, namely, a slender
lateral portion, the iliocostalis, and a thick medial portion,
the longissimus. The latter receives in the posterior portion
of the thorax strong accessory bundles from the semi-
spinalis muscle en its medial side, the two muscles being
inseparable at this point.

The Vertedrai. Ml-scvlatire.

Tl, r ■*•

™edlr f'rt tt'ri£?l':r"^- °" '"^ ""- n receives
are inserted forward^.o "r^^.^J.^ZT'^ "'"'"^^- ""ic"
The longissimus is inserted bv broad flesLvh!' '""■■'''*■
niargms of the ribs, medial to th.^ ""''"'" ""^P"^'"'"'
■hoeostalis, this port on ofThe mu!',/^"*^^ ""^'"^ <>' 'he
Oorsi. ContinuinK to the neck ^t ™'"^ ''"'' '""BiMimiu
verse processes of the four „, .'"'*■■'"' °" "■' '™"
medial to the origin "f , he 'rvi^ll '''""'''' vertebrae,

anterior, but a number of acassorv ,r"™ °' """ *™'"
forward to the transveriS procc'sL of . I '^ .?''''' ""■ '"^-"'"n

chtefly from the transver": procesS ,h f "' t''"" "■''''"R
vertebrae joins the medbl v^^^ ? "^ ^'"^ ""'ec thoracic

and forms\he lo„|isS^t capiS^' P""'"" °' "»^ "P'™'"^'
(b) 1 lie semispinalis and multifidus 'ti,„ k ^ ,

between the longissimus and t^f,'. J t, f""^ °' ""^^'e King
partly fused slips, arising for ,1,,™'? ''"'' '' "mposed of
tendons from the man mnii"": "' ""^' P"" ''y verv long
inserted forwards on l" spinous nm ""'""' V"""'*^^^''' ^"d
■nto two portions, whi h a " suDerficM"'' " '' '''"^''''le
constrictedarealvingatthelnv,.rf . V^"-'' «'Pamtcd bv a
this being also the poLt tVer/ he H"f '^T"' ^•""=''^''.
longissimus. The interior portion Th ' " "^'' ^"'^ "-e
■smsertedbyaseriesoflieshv,7"s' "^H '''^''P^^'^ dorsi,
more anterior thoracic vertebra burJf T"""' '"'"■•'^'' "^
process of the third or foitnh ee^.'.v ",' ^"'T''" '° 'h^' ^F • s
Porfon, the multifidus, reread, ', 7- "''?■ ,T'"--post. ..r
-™m,^ Where it is cjn.in "^^ wlu, X '^^^ ^:.Z

'th:'arulTpr;rse"s1?,tl«-f!^7«"api.is.arisc.sfrom

protuberance. The moTe ^osw- for and' '''Tr' °'^"P''^'
the muscle is composed of « r'"' """^"'> Portion of

«!th the longissimus capitis ] ^'T ''"','"« '" ™n.mnn

ever, at the free margin of . .Zil' "PP''"'' ^"P^' •>o»-
semispmalis dorsi and the longissimu" """"^ '"•'"" ""'^

that of the epistropheus "'■'™' ™"ebrae, chiefly on

(c) The intertransversarli are short m„ ,

lateral portions of the vertebrae Th eonnecting the

■n part by their darker coSonT^. ''''-■- •''''"■^'"■^'■able
baekwards, being most con^^Tus in^^L Tu^ ^J^

182 Anatomy of thb Rabbit.

where they form thick muscular pads interposed between
the mamniillary and accessory process. The last slip is
attached to the crest of the ilium.

2. The following muscles constitute an occipital group, composed of
short muscles arising from the atlas and axis and inserted on the atlas
and the occipital portion of the skull.

(a) The rectus capitii posterior superficialis. Origin: Spinous
process f the atlas. Insertion: External occipital pro-
tuberance.

(b) The obliquus capitis superior. Origin: Transverse process of
the atlas. Insertion: Lateral surface of the occipital pro-
tuberance.

The foreRoing muscles should be divided.

(c) T: .e rectus capitis posterior minor. Origin : Posterior tubercle
of the atlas. Insertion : External occipital protuberance.

(d) The rectus capitis posterior major. Origin : Spinous process
of the epistropheus. Insertion: Laterally on the supra-
occipital bone.

(e) The obliquus capitis inferior. Origin : Spinous process of the
epistropheus. Insertion: Dorsal surface of the transverse
process of the atlas.

(f) The rectus capitis lateralis. Origin: In common with the
obliquus capitis superior, which covers it. Insertion: Base
of the jugular process of the occipital.

3. Muscles of the lateral and ventral surfaces of the neck.

(a) The scalenus anterior. Origin : Transverse processes of the
four posterior cervical vertebrae. Insertion : First rib.

(b) The scalenus medius. Origin: Transverse process of >.hc
fifth cervical vertebra. Insertion: Lateral surfaces of the
third to fifth ribs.

(c) The scalenus posterior. Origin: Transverse processes of
the fourth to sixth cervical vertebrae. Insertion : First rib.

(d) The scalenus medialis. Origin : The sternum at the point of
attachment of the first rib. Insertion : Middle of the ventral
portion of the first rib.

The foreKoine muscles, comprising the scalenus group, are destroyed
by the removal of the ventral thoracic wall (p. 172).

(e) The longus colli. Origin: Bodies of the first six thoracic
vertebrae. Insertion: The muscle passes forward on the
ventral surface of the bodies of the vertebrae, giving off
insertion fibres, and also receiving strands of origin. It
terminates on the anterior tubercle of the atlas.

(f) The longus capitis is partly fused with the foregoing muscle,
but its origin is in a more latc.'al position from the trans-
verse processes of the first six cervical vertebrae. ' "~
Sphenooccipital synchondrosis.

Insertion :

Thb \-erti;biiai. MuSClLATfRE.

183

vertebrae. Insertinn ■ Tr-T ""^'' '" ^"'"' «rv cal

"'™- Transverse processor the atlas

The .o„K„, cap,tis .h„uld he divided ne^r it, in J,il„

'"^^rS'.r'fJ^rr'pror^.C^i - ventra.
Basioccipital bone. H'"i«^» oi tne atlas. Insertion:

poIt'e;riore',t™'„'^'„f7hl%'„^«a„t''!„™"'''"-^'J" ?"'>'''"•' "■ '^e
muscles: "" '"'"neus maximus. the following a.xial

^P^^'^n^TZ^r'^.Z'TiJM'^ i" '"^ '''™»- '«— 'he
and IS iaserted on the Irrntve,^. ^l:'^"' ■'"'' '^■""'•'l vertebrae
the caudal vertebrae '"""''"^^ processes and dorsal surfaces of

mi''.k5u^^:'fh"etroo^'"b:uv^n thf ","^r ■" " "-""'inuation of th.
and is inserted o/surceeSS; tm'ebrae"'™'""' ""'' '""«^"» P~-'^

LaSJ's^ure^oftrst'ruT^'n";- t^eTin'""' " 'P'"- '-«-:
caudal vertebrae ™ '"^ transverse processes of the

anJ%T''c\«5rv'e?!*et^,, "Stio^^-'^.^'rl'^^w"' "" -""■ -^
vertebrae. insertion. Ventral surfaces of succeeding

184

Anatomy of the Rabbit.

XIII.. THE CENTRAL NERVOUS SYSTEM.

1, The spinal cord and nerve roots,

To expose the whole cord or a portion of it from the dorsal surface,
the muscles should be removed on both sides of the vertebral arches and
the latter broken away with the bone forceps. The following features
may be made out according to the extent of exposure:

(a) The spinal cord (medulla spinalis) is a thick cylindrical white
cord traversing the vertebral column in the vertebral canal.
It is oi almost uniform diameter, but exhibits two slight
enhifgements, one m the cervical, the other in the lumbar
region. At about the middle of the sacrum it contracts to
a slender filament, the filtim tenninale, which may be traced
backward to the middle of the tail.

(b) The enclosing membranes or meninges of the cord are three
in number, of which two are readily identified. Lining the
internal surface of the bone is a thick fibrous investment,
the dura mater; on the surface of the nervous matter a
thin vascular membrane, the pla mater.

The dura and pia are connected by a loose web of connective
tissue, the arachnoidea.

(c) The regional distribution of the nerve roots — eight cervical,
twelve dorsal, seven lumbar, four sacral, and six caudal.

The cervical nerves r-^ numbered from the vertebrae lying behind
the inter\'ertebral forai; .na from which they proceed, the remaining
ner\*eB from the vertebrae lying in front of the inter\'ertebral foramina.
The nerve transmitted by the intervertebral foramen between the
seventh cervical and first thoracic vertebrae is described as the eighth
cervical.
(d)^The origin and primary divisions of the nerve roots may be
worked out by removing carefully the lateral portiuns of the
arches of one or two vertebrae. The posterior, or sensory
root (radix posterior), arises from the dorsolateral surface of
cord, and expands immediately into a spinal ganglion (g.
spinale). The more slender anterior, or motor root (radix
ant( rior), arises by a number of filaments from the ventro-
lateral surface. The combined roots give origin to the
posterior, anterior, and communicating rami. The posterior
ramus is an inconspicuous branch (except in the first two
cervicals) passing to the dorsal musculature and skin. The
anterior ramus is the chief poition of the spinal nerve, the
successive rami appearing as the components of the cervical
and lumbosacral plexuses or as individual spinal nerves.
The ramus communicans is a slender filament which passes
ventrad to join the sympathetic trunk.

TlIS CgNTRAI, NebvOUS SysTEI

;n.eHo., ana .He p^^^Tjt^^^'^^, ^^^^S:
(b) The division of each half ini„ .i„

grooves, the anteriorand Lt,rior uf ?^T^' •>>■ shallow

.he .„t.H0, U^XTd p^-StSu"^'^ °' '"^ -"-

2™'?o%r„,^at;U™r!"^!'err" f^""^'^-"' »»«') «

stance (substantia jrr^a) of th ';'"^'°»'"K 'he grey sub-
grey portion is wi^ewlm. H.h J"-'" "' ""= ™fd 'he
being composed'^aneror wS ;n".'''''°"'. ''"''' >"^"
masses, known in section as M,h^™.f''.,P"""'°' ™^"e>-
as complete strurturls the aS.JSL"' "'^ '^'^^ """'"■ "'
columns. In thp m^rfi i *"••"" and posterior erev
the ven;ral"su?;acT'''irthf "„";„';■' "-^",'^0 dorsal .H
centralis), the cavity oaheVrnarcord*""^ "^ (--""lis
3. The brain mav be exDoscri l.v Kr„,i •
P^"';"^^°f 'he frontal bone'^and ,hen remo'vLTh'-' ""f l''P^='°'bi,al
«.th bone forceps. In order to clear thrhV» i^ ^ "■"^^ °' "''^ si"""
cerebral nerves, it is necessary to r,!mn, .k " ■""'' ""^ ™<"s of the
skull on both sides. The chUToart oMh ""■ "^""'^ ''""''' "'"" "f the
the temporal portion of the skull bvsucf,.T""?" ""^'"^ '" ''''■"ov n|
flocculus of the cerebellum a smaM\talkedhn7''l'^ rP"^'"" «"' 'hf
pletely enclosed by the dor^il p"rUon o th. ^f' "?"''i-i' "'"'°^' '^"">-
tympanic bone is easilv detached a„d if re™"^ ^°*"- ^""^ ^"^'"^ P^tro-
and^probably also the roots of^hrfa^lTX^-us'l'ne'rt^^iJl't

the previous dissection '^ ™'^<' has been exposed in

tebrl*; ^IJS^J^^'i^rt^,:^^^'^ '"^ >^r',°' ""^ "■'^'' V"-
nerves are strongly a.^at-hed at h".i;Zm"o?e".";'7'""'- ,™^"'-- ^'"- 'hT

With :Si°' n^s-^^r s^'S^^'^;'::^'" "'^>- "^ -' --

the longttudina, fissure between the^etb^al'L^nll^pher^r-thTo^hir;;;?

186

Anatomy up thk R.vnnrr.

tentorium cerebelli. These parts contain the luparior sagittal and
tramvcrw vanous sinuses.

On the ventral surface of the brain as removed appear the basilar
and internal carotid arteries and their branches. These vessels should
be kept intact for examination at a later stage.

For the primary divisions of thf brain see p. 34.

4. The superficial features may be identified as follows:

IN THE PROSr.NCEPHALON

(a) The greatly enlarged cervbral hemisphere (hemisphaerium
cerebri) forms with its fellow of the opposite side the largest
portion of the brain. The two structures are separated by the
longitudinal cerebral fissure, but are connected with' one
another by the commissures indicated below.

(b) The olfactory bulb (bulbus olfactorius) is a small expansion
lying at the anterior end of each hemisphere. Its cut end
represents the point of origin of the first cranial or olfactory
nerve, the various divisions of which may be found on the
skull, where they may be traced into the perforations of the
cribriform plate.

(c) The olfactory bulb is the anterior portion of the olfactory
lobe, or olfactory brain. When traced backward on the
ventral surface of the brain it is seen to be replaced by a
white band of fibres, the latter forming the olfactory tract
(tractus olfactorius). The tract ends posteriorly in an
expanded portion of the brain, which, from its shape, is
described as the lobus piriformis. The olfactory brain as
thus defined is separated superficially from the remaining
portions of the cerebral hemisphere by a longitudinal furrow,
the limbic fissure (fissura limbica), which passes along its
lateral margin. The anterior portion of the furrow, known
as the anterior rbinal fissure, separates the olfactory tract
laterally from the narrow anterior portion of the cerebral
hemisphere. The corresponding posterior portion of the fur-
row, the posterior rhinal fissure, separates the lobus piriformis
from the posterior enlarged portion of the hemisphere. The
slight angle formed at the junction of the anterior and
posterior rhinal fissures is the point of origin of a faint
depression extending upward on the cerebral hemisphere.
It represents a rudimentary, lateral cerebral (Sylvian) fissure.

(d) The corpus callosum is a broad white commissural band
passing transversely from one hemisphere to the other. Its
median portion may be exposed by pressing apart the
medial margins of the hemispheres at the longitudinal
cerebral fissure.

(e) The pineal body (corpus pineale) is a small somewhat
conical structure lying between the dorsal posterior tips of
the cerebral hemispheres, and connected by a hollow stalk

TiiK Ckntral Nk«v,)is Svstem.

(f)

(g)

1H7

pigmented .a«.ulur tUsue h " k "'"«"'''' >>>■ » mass of
plexus of therh""lveZi.|..„„H '■*'"",',"« "' "•'' ''""'^'i''
portion of .he <lura^mrr''-,ruai„r/'^.|":; 'lu " ™'"'

pineal bod'^^^the do £ surface 7ihe In 'I """ ''T"'"« "■'
be sn^cien.,, expo.., ,„ ti^t^l^^^^^^lZ:"'
r?m'ov of^.K'";,-; ?ir;-^ i" '"e middle line :f"e '.he

.he third v.mrirv.mreu;uT[m'iuoa-i'''"^' "r'"" "'
which i, formed anterior vbv he .^fi' r "^ ,'"• ""' "•""' "'
chorioid plexui (plexuTch,rioiH,l>T T''*' P""'"" "' 'he
ventricle at this S '' '"' '""" ™'"""f 'he

.he itonutar commiZl (com ''"''"''''""•'■'*■ ''''■■''•
missura habenularum) The fibres
of the comtmssure are faintiv trace-
able forwar. , where they form a pair
striae" " '' '"'""™'^ (medullary

"" sT,r!^ P<»««ri»f commiMure (eommis-
sura posterior) crosses the posterior

b^h ;,T "'. 't", ■•'"" ™media.elv

behmd and below the habenular

commissure.

The walls of the third ventricle are

formed by the thalami. Thev are

broadly connected bv the tater-

m!Sjf. """ '■""'^'^ in.frmedia), or
middl. comnussure, which mav be

(j) "" ^i'her side of the middle line, or

of he ?'',™"''«'i "«' dorsal portion „„,„,,; - ■■

of the thalamus forms a low, some
what oval projection, the pulvinar or posterior tubercle
The anterior tubercle of the thai™ • i. f ■ . ""■''■"■
small dimension., IvniK m the ani, e ™T ',1 , '"' 'l''^"""" -< verv
the anterior portion of the atS^ of .h 'l «-'"'™ ""• I'"lvn.ar and
/l■^ TU ai«riure of the third ventiii-Ie

(i)

,j, ■'■ "Mitram, showing

vitwcd from the dureui sur-

thalamic tiibrrcle: ,. h

habenular commiNaure; c r> '
r«>*tenor I'ommiNsure' v s"
su|*riwcollic,.lus (of mwcnce-
(.halo,,,; „i. andK.m.. Uteral
ana medial Kcnctilale Itodies-
h.. habt-nula; rti,i.,rTms<a inter

'** Ana )mv or thk Rabbit.

sion of the surfair The maditl gtnicttlaW bodv occupin a
more |K>»liTior and mrdiiil position.
(I) The optic tract (tractus opticus) ronnects the lieniciilale
lx)dii-s, especially the lateral one, with the ventral surface of
the brain, ending in the optic ehiasma.
(m) On the ventral surface, the optic chlanaa (ehiasma opticum)
forms a conspicuous elevation, the posterior portion of which
IS traceable into the optic tracts, the anterior portion into
the basi's of the Mcond cranial, or optic Mrref.
(n) The hypoph^tii, or pitulUry body, lies immediately behind
the optic ehiasma.

On luc.mnt ,,t h, ,ncli«urr liv the wall. „f the hv,K.i,hv«inl (ona
an,l al.„ ,1, ,l,;(ht uttiuhment t,. tfie l.niin. the hMK.phv.iJ i»c„mm™|y
clet:Khed m removing the hruin frum the sktilf. ',„' which c»« " iVit-
ex°>o.S '"'■ "■''"■"'"""" "" ^■'""■''' vriim c.f the third ventricle i>
(o) The tubar cinereum is a small elevation of grev matter
appiarinK on the ventral surface after the removal of the
hvi)ophysis. It is the bast of attachment of the infundi-
bulum, the latter heinj; the slender e.\tension of the brain
downward toward the hypophysis.
(p) The mammiUary body (corpus mammillarc) forms a con-
spicuous rounded dc.ation, lying at the posterior end of the
tuber cinereum Tl c structure is single, but there is an
indication of lateral obes.
l.v THK Mi:si:.\ci:pil.\i.()\-;

(a) The dorsal surface is marked by four elevations, the corpora
quadngemina. The anterior pair, distinguished as the
colhcuh superiores, are much larger than the posterior pair
the coUiculi mferiores. '

(b) The ventral surface is occupied bv a pair of divergent cords
the cerebral peduncles (pedunculi cerebri), separated bv a
faint median depression, the interpeduncular fossa (fossa
mtcrpcduncularis).

(c) The tliird cranial, or oculomotor nerve (n. oculomotorius)
arises from the ventral surface of the cerebral peduncle.

IN THi: rhombi:nci:ph.\i.ox:

(a) The cerebeUum forms an arch over the posterior portion of
the brain, and is supported by stout pillars from its sides
In addition to the ridges of its surface the whole structure is
divided into several lobes, including the median portinn or
vermis, the lateral hemispheres, and the stalked bodies or
floccuh, arising from the hemispheres. '

(b) The anterior meduUary velum (velum n.cdullare anterius) is
the thin membrane unlcrlying the anterior portion of the
cerebellum and connecting the latter with the inferior
colhcuh. It lornis a small anterior portion of the roof of the
fourth ventricle.

Ti« Ckntbal \krvols System.

, s:rx:^'" '■* '-■•'' '--.'^i.i^rsr. ;/;;;:

..r'"' '"'"'' '•"'••"'linK Iran,.
\crMh across ih,- brain and

du dfd ,n.„ „v„ p^r.s hv a
median dtpr.ssicn, inc .ulcM

basilar arliTV.
(f) The anurior' median fissure of
he spinal cord ends at the
wsterior margin „f (he ,«„s
ma faint depression, the (o«

cord IS largely replaced forwards
h> the pyramid (pvrami,r a

«ne to ,h/"''. "' ""^ "■'•'.lie
ime^ojhe postenor margin of

(h) The trapezoid body (corou.

form H r""" "" '" «he angle '-fr rfc' ,

DC. rpB.^ — I . _ ;="ure' 1'.. [wmi;
(mejtenctp-

nf .k ""^ lateral margir

°' .the p>ramid with the i»,

net^eT t'"'^'"'' "<««°^1 fS?^™-i.,}S:i%a""- '^■

190

Anatomy of fuE Rabbit.

(j) The lixth crani*!, or abducent nerve (n. abducens), is a slender
cord arising at tlie anterior end of the pyramid.

(k) The seventh cranial, or facial nerve (n. facUlis), and the
eighth, or acotiitic nerve (n. acusticus), arise from the lateral
margin of the trapezoid body.

The two nerves are closely associated, the former being slightly
anterior in position. Its chief portion « •hf.'""'"'™'; '""X °o"r
the nerve receives a sensory filament, the portlo Intermedia or
intermediate nerve.

(1) The glossopharyngeus, vagus, and accesaorius arise by several
roots arranged in a linear series along the lateral margin of
the medulla. The trunk of the accessorius -extends back-
ward on the spinal cord, its roots, about ten in number,
arising as far back as the fifth cervical spinal nerve.

(m) The twelfth cranUl, or hypoglossal nerve (n. hypoglossus),

arises by several roots from the ventral surface of the medulla

and at the lateral margin of the pyramid, its point of origin

corresponding to that of the ventral root of a spmal nerve.

4. The arteries of the brain may be traced n its ventral surface as

follows: ,. , , J

(a) The basilar artery (a. basilaris) is a median trunk formed on
the ventral surface of the medulla oblongata by the union of
the vertebral arteries, the latter here represented by their
cut ends.

(b) The inferior cerebeUar artery (a. cerebelli inferior) is the
largest of several transverse vessels arising from the basilar
and passing laterad to the cerebellum.

(c) The posterior cerebral artery (a. cerebri posterior) is formed
on either side at the level of the anterior margin of the pons
by the division of the basilar. It passes to the posterior
portion of the cerebral hemisphere.

(d) The superior cerebellar artery (a. cerebelli superior) is a
branch of the posterior cerebral, passing to the anterior
portion of the cerebellum.

(e) The cut end of the ittemal carotid artery lies on either side
of the tuber cenereum. It is connected backwards with the
posterior cerebral.

(f) The middle cerebral artery (a. cerebri media) is given off
from the internal carotid, passing to the middle portion ot
the hemispheres.

(g) The anterior cerebral artery (a. cerebri anterior), the con-
tinuation of the carotid, passes to the anterior portion of
the ventral surface and the olfactory bulb. The anterior
cerebral is connected with that of the other side, a complete
anastomotic loop being formed around the hypothalamus by
combined branches of the vertebral and carotid arteries.
This is the circle of Willis.

The Centrai. Nekvous Svstem. iqj

(a) The fourth venWcle (ventriculus quartus) is the extensive

o^ardstifh th*" "-e rhombence'phalon/ It is «™ec :d
orwards with the cerebral aqueduct and backwards with

pnncipal y by the anterior and posterior medullary vela the

»"ratXrd:s i° '"^ "^'^'^""■" ^'- "> "- ---e-

(b) The rhomboid fossa (fossa
rhomboidea) is the shallow de-
pression enclosed by the thick
lateral and anterior walls and
floor of the ventricle. The
middle line shows a shallow
depression, the posterior me-
dian Assure (fissura mediana
posterior), on either side of
which the floor is raised into a
low ridge, described as the
medial eminence (eminentia
mediahs). The posterior end
of the fossa forms with the
enclosing wall the somewhat
triangular figure described as
the calamus scriptorius.

(c^ The lateral supports of the
cerebellum, now represented bv
their cut ends, are formed by
fibre-bands passing into the

cerebellum from adjacent ven-
tral portions of the brain. In

each a middle band, the

brachium pontis, enters the

pons : an anterior band, the

brachium conjunctivum, enters

the mesencephalon, while a

k». ij

fr. p.

Dorea] view, after removal of the
tTv'^^. v)' \'^- Pr^^'^'U'" conjunc-
tivum. b.p.. brachium lonliN' cl
clava: cl.i.. inferior colliculiis" (me-
sencephalon) ; c,r., restiform Ixxiv;
e.m., media] eminence; f.c. taicicnlus
cuneatuB; f.R., tascicnluB Rracilifi
i.m.p posterior median fissure of
the rhomboid fossa; f.r., 'rhomlioid
-, , ...,.,v a fSa, s.m.p,, posterior median .sulcus

llshed with the medulla through ™<i"n"v vei™. " •"'"'"

the restiform body.

*■" L''rvous"^'i.,7" "' ""^ f"'^ ■' '"■•■"'^•i ''V a thick ridge of
nervous matter, convex on its medial side, the restSorm

s^Je/'TT ■•""'o™'') I's anterior portion bears aT^
spherical elevation overlying the origin of the acoustic nerv?"

192

Anatomy of the Rabbit.

(e) The posterior funiculus, in passing forward from the cord,
is divided into medial and lateral portions. The medial
portion, the fasciculus gracilis, forms a narrow band ter-
minating forwards in a club-shaped expansion, the clava.
The lateral portion, the fasciculus cuneatus, passes into the
restiform body.

6. The brain may be divided by a median vertical section, and one-
half examined from the medial surface (Fig. 56). In addition to many
of the features already made out on the surface the following may be
noted :

(a) The deep but extremely narrow cavity formed by the third
ventricle is the first space appearing in the brain from the
anterior end. the first two (paired) ventricles lying laterally
in the hemispheres. They are connected with the third
ventricle by a narrow transverse canal, the interventricular
foramen (foramen interventriculare).

Fig. S8. The brain in median section: a., anterior commiasure; a.c, cerebral aque-
duct; b.o, olfactory bulb; cb.. cerebellum; c.cl., corpus callosum; c.f.. body of the
fornix; cl.i., interior coUiculus; d.s,. superior coUiculua; cm., mammillary body;
CO., optic chiasma: c.p,, pineal body; (i.e., cervical lli-xurc; h.. habenular commissure;
h.c. cerebral hemisphere; hp. hippocampus; inf., infundibulum; l,t., laminal tcrminalis;
m.o., medulla oblongata; p.. posterior commissure; p.c. chorioid plexus of the third
ventricle; pd.c, cerebral peduncle; pn.,pons; sp., iplenium; b. pi., septum pellucidum;
t.c, tuber cinereum; th., thalamus, maua intermedia; v.m.a., anterior medullary
velum; v.m.p,, poiiterior medullary velum; v.q., fourth ventricle; v.t., third ventricle.
I, olfactory nerve (oridin); 11, optic nerve,

(b) The anterior boundary of the third ventricle is formed
ventrally by the narrow partition separating the two hemi-
spheres, in the dorsal portion of which is the small anterior
commissure (commissura anterior). The ventral portion of
the ventricle is projected toward the optic chiasma forming
the recessus opticus, and into the infundibulum, forming the
recessus infundibuli.

(c) The mesencephalon contains no ventricular expansion, its
substance being perforated only by a narrow tube, the cere-

The Cenikai, Nervous SysiEM.

193

'«^t!,Xtu'?tfet.e'"""''"^' ^"'^^ "-cts the third

^'^'pfartC„dtT^„i;,:^?:rj" -^^ ^-'°^'.v it

reality is extended as TThin sheef "^^ fi?*"'?" ' ''"' '"
toward the lamina terminalis Posteriorly t h-n^f /°''""""''*
forming the ipleniiun the l-.tf, k ■ • "™"<ls downward,
of the fornix, 'whTc™WbeW^[ ^'"^ »«^<^hed to the bod.;

'omii (corpus tomicis). They V^iJ T,l^ "npa.r^d body of the
Pn f^"f"r''r'> as the columSiofX fornix maramillary body, a"d
in the Wy of the fornix aSd ofte™ -JS i^ (columnae fomicis). meet

corpus callosum is a thTn area o? til n"'l™'' P°"'™ °' 'he
7 Thener'''^'"""™'^'*^'^-'"-'-'^

fro.^o?e^™LrrstLiXTur:r-^->•^
spte''S;d°r'th':™hSXr:'r;^' '^ "- -'™--

mto the olfactory-bulb andZekward in „ T'""' ''"'^"^
end of the heinisphere oas^^nn ° ■'> P"'"^™"- free

. ,,,^f-''theopening^ofth;iKtere«„4urt;ame'n' ''^'""^'^

penpheral grey cortex detSart'L-^^S "^^'"^ "' '"^

form of two convex ridges One of ,h ™'"'^'' '" '^e
medial in position, is the hILZl ^"^^ Posterior and
smaller, anterior and lateral in n'^^P™-. '^'"^ °'her is
striatum. Between the two bodfeT i™' ^""^ '' '^^ "T"*

Seo-uV^ choHoid P.-Co'-fir^iitr/^s/^'b:
Xidur'™ °' '■'^ -". '-i^ed^'^^^^^^^^

may^I-TrrerdTtl^frttVa^^^^^^^^^ ^""""r'- ^^'-s
toward the cribriform plate, or the r^ah^^I f- ""'^'-^ downward
taining the nasal region still i^Lctmlv bed ^* n"™ °' ""^ ^"""'l con-
extended examination of the nas^ f"ssae ^ Th f r"'"^''"^ ''"• ^ ™°re
are largely those described in connlctrwith^';L'X'i:Sn'%*";.°.t92r

APPENDIX.
THE PRESERVATION OF MATERIAL*

The method commonly used in the preparation of material for
dissecting purposes consists in first embalming the body with suitable
preserving fluids; afterwards filling the arteries with a colored injection
mass, so that they are more easily traced. The objects served by
embalming are: (1) preserving the body from decomposition for a
sufficient length of dme to complete the dissection; (2) keeping the
body as nearly intact as possible; and (3) having the organs in good
condition for study. The point last -mentioned is an important one,
since much depends on having the parts f the animal in such condition
that they are easily and comfortably handled, and also easily observed.
The desired results are accomplished, first, by introducing the preserving
fluid through the bloodvessels, instead of by immersing the animal, as
was formerly the practice; secondly, by using in the preserving fluid
such materials as will leave the organs in a condition as near the natural
one as possible and at the same time keep them moist and flexible
throughout dissection.

A suitable fluid for the purpose is that recommended by Keillert for
the preservation of human subjects. The formula is as follows:

Formalin 1 .5 parts

Carbolic Acid 2 5 *'

Glycerin 10.0 "

Water 86.0 "

IPO.O

A convenient method of making up the fluid, especially when em-
balming the animals in numbers, is to prepare the mixture of formalin,
carbolic acid and glvcerin as a stock-solution, to be diluted for use by
adding to each part of stock 6 parts of water. The amount required
varies according to the size of the animal, the flow of the fluid in the
vessel he length of time during which the animal is left under the action

♦The methods here given appl>^ onlv to the preservation of specimens for
or.linarv dissettion, either singly, or in numbers for a laboratory course, with a few
observations on the difficulties which are likely to be experienced. Especially in
the matter of injections, the student who has acquired some knowledge of the
vascular system will be able to make complete injections of the portal system and
also satisfactory injections of the systemic veins, though the latter are somewhat
more difficult on account of the presence of valves in the vessels. Finer vascular
injections and injections of the lymphatic system according to the directions given
in the anatomical textbooks may also be suggested.

tKeiller, W. "On the Preservation of Subjects, etc." (American Journal of
Anaiomy), Vol. 11.. lfl02-3.

The Preskrvation of Materjal.

195
Not less than

:^C^c'^^i,5t:ll^JS^:ti^— eo,„™„.

fluij;';r^ei?ed':' trarexirprrii,;"''''''^KL^ ^^^--^ '- «■«

tached; about 6 feet of rabber tuhi„? ^ * ""bb^r tube may be at-
table: several three wav^reees to d"^ide ^h^:," "'"' """ "^'^''"l^

.ubln,. and, «„all. ^^n^^^^^J^^^^^^^^'^ ^^T fto^a!

ordS'a^r? ^ra"s:tbi™'o^!^^ IZ ZZTZCln^r """' "^ "-""^
desired thinness. The tubin/ul^d far th^t •^'^Y''"?'^ <»" '<> the

6 mm. outside diameter Thfc«,nn„i« V ^''^f ''"'"''' ** "' ^b""'

7 cm. long: and Ts narrow end .h l^ I" «""P'^"^<i should be about
l.i;-2mm.forabout2cm aTthetiD Th ^^^\^ "/."'l"™ '''^"'^•" "'
in the flame in order toround the marl^nh''/''""''' ''t'™<'hed lightly
damage the wall of the ves«l ^ '''' '"^'°"' "'herwise it might

shouw'b^onhitsTqualtvT^r' lH: """J"" ^''^ ">^ ■»-" '"be
diameterof 4mm. le ^of^roner sT/e t'„",^?"' ''"^/'■"uld have an inside

•""f^' J-s^'^"'" ^ 1°'? ™ '^e '^"er'°un1e7irrat pr^s^uT''' '''''''

irrig^a'l^r^S; aS";„^tKntr tT"! f '" -'p -P'-'or or
may have a capacity of^one or iw^' P*"^'*""- J"- ordmary funnel. It
immaterial, so long as °he oU™,„^, f" '^ '/'^*"'>' b^ever. is

bavfbrtm^^X-r^HS"— ^^^

J^^^^ft;^^sl«lEi3^-"-t^-^

the operation. If at anv time tLr ' be mam amed throughout
sufficiently to admit VorarwIa^Wn"!;^ '!i"f '" "'^ "PParatus
the cannula, there is almost ce^t^n to be t- b*^ "*•" •"' "'""'^''
specimen under treatment hntoL.u '™"ble, not only with the
«Jumn of fluid is Wd back un. 1 1 '■"■"^."bich come after. The
the rubber tubing ^^ P™P^' ""« by a clamp placed on

is pS:dt7s' Llt't'h^ tate'-^hTefad " "'7'""'^ ^^ "

maf be tor^ b"a1lc;r'a;d"r^rdX''rn"trS'middV","^'°"' '^ '^i^
same time the superficial enii,»«ri^ , ^'^"'™' .n"?*"^ '"ne, and at the

^ll'^^utaneo.t^ssue^t?^^^^^^^^^

structures of the cervical region ^^'K' ='"™ '° "^ous important

196

Anatomy of the Rabbit.

the inner surface of the thigh and of the abdominal wall w.11 be expo«d^
The white «.rd representing the "«""»! «8amentl.es m the bottom
of the iniuinal furrow. Appearing from beneath the ligament m this
So^ttonTnd passing to the Wace of the thigh are the femoral yerve,
«te V kndvdn covered by an exceedingly thin layer of n."«;le be-
roneing to the irtorius. The three structures may be separated from
one'another and the muscle pulled away at the same '™'. ^y J"^-^
lengthwise along the structures with the fine forceps. The "'"V """

and bv its white coloration. The vein will be found greatly O'stenoea
whh blood. The nerve lies in front and partly on the lateral side of the

"' w'hen the femoral arterv has been fully exposed, a ligature of coarse
thread previouslv moistened, may be passed around its base, close t„

well down into it beyond the inguinal I'Sament^ P' d t£ knot

tightened bv a gentle even pull on the ends of the thread. The knot

should never be pulled very tight or doub ed. , , . „^ ;„,_ ,),»

At the moment when the cannula is securely fastened into he

s;::s^w^:^seS'':^^t^i^t£'S^^ S

a stout flexible iire. passing around the back of the animal. The body
should be turned slightly to the operator s left.

""'since small difficulties f-quentlv occur in the process es^e^^^^^^^

The PKgSERVATION OF MaTEKIAI.. 197

The abdomen become7'gteX disfe„ded"'fh' "^'^''' '" '"^ "'"'>■
swollen, the eves protrude and ih^ri!',, ^^ subcutaneous tissue

nasal cavity bv t*ing the noswis "' '° ""''"' ""^ ""'O '° '"e

.he^:ruttheL1."aiPn"S%a''rtfX''rn T' ''i!'—'^'' front
set aside for twentvfour hours in „„„--^.P''''''^- ■ The animal is then
readv for injection ■ *" "P"*"" P"^"'""- '^f" this it is

watlr" to'X'rnsSce™;^ t'inTrtL''' r'"Vj''"''>' ^"'-'' -"
coloring material, such as verm'i;ro„T"ver'??m:iltfnUtv"„1- ■'"""''
There is some advantage in usinc » ^r- f" i- l"^"'".^ "• carn.me.
in making up this mass the artlrLh '■ '""J"'''" '"s'<''"l °f water alone
ance, which is doubOe's due parUvtrhef,^"'™"'''^ ''"«'■'" ^^
the fixing of the starch in th'?vess^?s Th' P^'-*''™''™ a-d Partly to
strained before use, in order to avo^^th. I *'' """I ^ Ihoroughlv
are too large to go through tht ■ P'^'^^f"" m it of particles which

a syringe, tL lattfr bebgfrov 'ded^rtta nih '"/1^"T 'i^ ^"'^ "'"'
as that used in the embalming process Th •"'"' °'.""' "^'""^ ^'"^

a gentle, even pressure a"d 1*^5 s^metime^ Z^^ '", "''"' '" ''>' ^PP'>'"8
■nection to run backward and orwa^drth.fh^^^T^ '° ''"°"- ""^
a little more pressure When ,Z\ . i u 'l''^' """^ '""« applying
the tube is clam%d BvdrawW Zn^' ^^"'^ "j^u ^'""^ '" this wav
is loosened suffidentlv o S? " ?h ™"' "f ""^ ''S^'"<' '^e knot
finger pressed on the end ^7 the '?ess^'''^,H'?rn'f ' """.^^^ l^^PJ-^ '^
tight without loss of injection ""'>' ""*" ""^ ''rawn

bec^mrclog^S^Xr %KeXd'","-' r^-""-' "-a. the cannula
Inthiscaseifmarbeeari V" 'h ,"^^^^^ "J"' ""Sulated blood,
cannula should alwavs be uLd ° ' "P'^"''- ^""^ ^"^

indetuelv! prnv^fJel how:ve"^h°.t'"' ""''''""' «'^™ =""'™ ""' ""P

tamination from the surfrc, tV P"^*^*""""^ ^"= '"ken to avoid con

the thick coating of hairs it U "1, "T^^^^y necessarv in view of

animal with a preserving fluid w^hiT F,'""' """<'"<^' to spoi.ge the

diatelv, or if manv swdmen^L h ^ ''"' P^"f' r="<^ 'he coat imme-

animal for a moment A suitable Zri^'f"'"'!''' '" '""""* '"' ""ole

alcohol, made bv add ng t/"' "f^'l,^;/'' /"^ ""is purpose is formalin-

ordinarv spirit and wLti The l^h^l " ""^'"'^ °' "'I""' P^^'^ <><

and assists^he formato „ pSrvaTion 'xh^fl '""'^'i'^'^Penetration

out of the coat as much as wssible Th "''T''' ^' ^fl-^^'^d

quantitv is not harmful unres^aftl Vh ^ P^^^nce of a considerable

should gain access to tt tissues and d!,fr'*';!,'™ 5"' ^«""' '"e fluid

of the embalrain.. fluid '™>' ""^ ^^'^'^t of the glycerin

198

Anatomy « :a* Rabbit.

For the storage of material either before or during dissection no pre-
caution is necessary except that of protecting the body from undue
exposure to evaporation. A convenient plan for handling the material,
however-one that is in use at the present time in the laboratories of the
Universitv of Toronto— is that of providing for each specimen a iinc-
lined copper box. with sliding top, and of dimensions ample lor the
largest specimens- -namely, 6 x 6 x 20 inches. This type of storage box
was designed several vears ago by Professor Ramsay Wright for the
purpose, but is one which has proved useful for stormg purposes in many
other ways.

it

INDEX

Abdofnrn, 111
Abdiiminal aorta, 133
cavity, 60, us
wall, muiclet of, II3
Abduction in Itmbi, 32
'^"•»°'^?. f "piraiory tract., 43
Acinuua flandi, 11

Acoirttic mcatun, txtrnal. 77, 88. SB 111
inlrrnal, 81, 8» ' ' **

Adaptation, 6
Adduction in limbi, 32
A<li[>iae tisi'ie, 13
AHcri;iit norves, 22
Alliinr«in, 14
Alveolar flandi, 11
Anal apcriurr, 111
^ flands, li, 130
Analogy, 5

AnaMomosi;. of intestinal vcisel., 116
Anatomy ilclmcd, a
Ankle, iwn.j. of. J08

joint, 1S8
Aorta, Kc Artcriei.
Aortic archts. branchial. 44
Aperture, ana>, 111

ot autlilory tube. 185
of larynx. 1B3
Of mouth, llo
of nosf. external. Ill
. mt.Tnal, 82, ig5
piriform. S3, !I4

of thorax, inferior, luperior, 74
urinoginital. Ill •->■"'.«»

of uterine tube, internal, 131
ot uterus, exiirnal, 132
Aponeuroses, 13
Appendicular ikcleton, U, 98
Arachnoidca. 184
Arch of aorta. 173
Arches, branchial aortic 44

visceral, 28, 31
Arrectnrc* pilorum. 10
Arterial lisament, 44 ITfi
Arteries, chief

aorta, abdominal, 133

coeltac. 117, 118
■Iiac, 133

intercortal. 133, 178
himbar. 133
mesenteric, inferior, 126

superior, 1]?, 125
pulmonary. 44, i7g
renal. 127

Sl-ermatie, internal. ]£9, 131
subclavian. 173
See ninodvessels
Arthrodia. 19

Articulations, naturt of 17
of ankle. 156
of hip. knee, 105
Asymmetry, 24

in digestive tube. 40
in vascular systtm. 24, 45
Atria of heart, 43. 176
Auditory epithelium, 12
ossiclcB, 77. 90
. tube, 79, 89. 185
Axial skeleton. 30, 68

in chordates, 8

Axis, basicranial. 31 77

ba-ifacial, 31

Axiup f(,iifm«(*j.

longitudinal, of body, 23, 30

poMhon of orsan tyatem* with rvtpect to.
Aaillary fos<iB, 111

lymph nodes of. 138

Vessels and nerves of. 137

Hall and socket joints. 18
llaxicranium. .11. 77
iticeim muscles, 2(1
l-i aieral symmetry. 23
Ilile duct. 121
Biology. 3

Itipennate muscles. 20
Illaddcr. urinary. 128
Uloodvesdels. general structure of. 21
lining membranes of. 12

I °„'t'hS,r',v^ •■"•'"■■"■"•

I of hmbs. anterior. 137, 142

I iK>*.lcrior. 149. 1B3

of neck, 160, 162

of orbit. 16S

of pelvis. 133

See Arteries, Veins.
Body, diviii ns of, 110

posture jf, 23, 24

pituitary. 35, 188
Boms structure, development, types of. 14

i-.'airi. general divis'ions, 34
I dissection. 186

Hexures of. 38
olfactory, 34, 186
J'ranchiomerism, 27 '8
lironchi. 177
i jjulb. olfactory. 34. 186
( Itulbourethral gland. 131, 132

Caecum, 42, 123
Capillary vessels, blood. 43
I lymphatic, 46

I Capsules of joinis. 18 ■
of Sense organs, 31
Carpus, bones of. 102
Cartilage, structure of. 14
bones. 15; of .kull, 31
(aitdal vertebr*. 73
Cflval veins, inferior. 117, 134. 176
I superior. 174, 176

Cavity, abdominal. 50. Ilfi

of central nervous system. 34
of larynx. 166
of inoutb. 42, 164
°' !"*;«^.„i3. 82. 92. 193
orbital, 7!>
pericardial, 49, 175
l>eritoneal, 60. 116
pleural. 49. 177
fcrouH, 49
of skull. 79
of thorax. 74
tympanic. 89 flO, 171
tell. Mructure of, 8
Central nervous system, general divisions, 34

jptnai cord. 184
terebral cranium, 31

hemispheres. 34. 186

nerves, see Xervous System.
Cerebellum. 36. 188
terebrum, 36
Cervical vcrttbra, 70
rh3rar!,F- vf animals, 5
Chondrocranium, 31

200

Indicx.

Chofdatci, cHarMlcra of, t
ChorioicI utrxui. Mruclurr of, It

of I- :>ral vrnirklei, Itl

of in. • vcnincic, 1S7
ClrcuUliuii, oriniin of, 31

Sec VaacuUr and Lymphatic Sjritenis.

pulmonary, 43

portal. 4&

•yi>lrmic, 43
ClaMification, purpoae ci, t

of organ ayitcma, 26
Clavicle, 100
Cliiorii, 111,

■tructurc of, 132
Cloaca in lower vcrtcbratci, it
Cocti' 171
Cr' a. 4», 118
Culon. 41, 124
Coloration of Kkin, He, 13
Column, vcrttbral. G8
Comparative anatomy defined, S

method of, 4
Conjugation in Protoioa, t

Convergence, fi
Condyle* of fcmiif, lOfl

oi-cinital, 76, 85

of tibia, 107
Curd. *permatic. 129

spinni, n4, 184

voca), 16«
Corpora miadrigcmina, 18S
Corptm cstlnfuni, 186, 193
Cuxal bone, 103
Cranial cavity, 79

ne^vc^ fee Nervotn System.
Craniota, character! of, 8
Cranium, cerebral, viweral, 31

See Skiltton.

Deferent ducts 129
l>riiial formula, 4L'
Dentition, in rabbit, 42

in rodents, 7
Descent of te.Mi*. 48
Descriptive anatomy, 3

term?!, 23
Diaphragm. 179
Diarthrosis, 18

IHgcKtive tube, wall of, 10, 21. 119
Digestive system, 40

glands of, 11; anal, 130; oral, infraorbj-
ml. 167: parotid. 157i submaxillary,

liver,' 120: |>ancrea«, 118, 122

intestine*, smalt, 122; large, 123

mouth. 42. 164

pharynx, 43, 164

orsophaRHs. 41. 164, 178; connection with
Momach, 1 16

Momach. 41. 116
Digits, anterior limb, 103, 112

posterior Hmh, 109. 112
Dissection, method of, 3

of rabbit, lie
Ducts, of liver. 121

nasopalatine, 165

of oral glands, infraorbital, 167

parotid. 157: submaxillary, 1S9

of pancreas, 132

of prostate. 159

thoracic, 46

urinogenital, 46, 127, 129, 131
Ductus arteriosus. 44

deferens. 139
Duodenum. 41, 122
Duplicidentata, 7
Dura mater. 184

Ear. external. Ill

middle, hii, 90, 171
internal, 171; capsule of, 31

Afferent nvrvet, tt

V.n, fertliUed. «

Kgg-laylng niaminalB, T

Rlaalic fibres of connective tissue, IX

Klbow, poBJllDn of, ta, 111

Rmbryo, ornn systcma in, 29

Fmbryonic Udney, 47

I''narthrosiB, IS

Kncephalcn, see Brain.

endothelia, 12

Knvironment, relations of animals to, S

Kplcardlum, I7fi

ICpicondyles, of femur, IOC

of humerus, 100
Kpideriiiis, 10
Kpididymis. 129
FlpiglotliK, 165
Kpiphyses of bones, IT
Fpiitropheus, 70
Kpilhclial, tissues, 9
Krect posture in man, 24
Fusiachian, tube, sec .\udilory Tube.
Extension in limbs, 32
h'ye. til; dissection. 166
Kydids, 111

rttbri, 70, 71

Facets, articular, of «

Fascia. 13

Fat. 13

Femur. 105

Fertilised egg, »

Fibres, of ccnncctive tissue, 12

muscle, 19

nerve. 32
Fibrocartilage, 14
Fibrous connective l'.'^..ue, 12
Fibula. 107
Flexion In limba, 33
Flexures of brain, 38
FJoeculus of cerebellum. 188
Follicles, of hairs, 10, 113

lymphatic. 45; of intestine. 123; of tonsil,

ik

nvarian, 131
Fool, 112

slteleton of, 108

See Hand,
.'oramina of skull, chief, 78
Forearm. Ill

mui-cles of, 140

nerves and vessels of, 142

skeleton of, 101
Fore brain, 34. 186
Formula, dental, 42
Function, relation of structure to, 4
Functional organs, 5

Can bladder, 120
Ganglia

spinal, 38, 184
sympathclic, of head, 170 ^
prevertebral; csliac, 11 1

inferior mesenteric. 126; superior
mcsenti-ric. 117
of trunks, cervical. 164. 175

thoracic. 178; lumbar, sacral,
caudal, 134
Gastric glands, 11
r.eneral anatomy, 3
Genital organs, external. Ill
female. 131
male. 138
Giniitymus. 18
Girdle, pectoral, 98

pelvic, 103
Glands,

of digestive system, 11

anat. 130; gastric 11; nral. l^i, 153.
167; liver, 120, pancreas, 118, 122

Indcx,

cirilbclial, 10

»' Irmvhillc wnum, 11

;! sH''"'""'"^ '""-"■ '"

thymua. jtj
layrtoid, KO
of urinoieniul •yitem,

Clidin, JoS^Yb""'' »""•""■ "»
Oonad*, 48

&.■;■„':;„•:'; s' ""•"• •'•""•• «

Cutwrnoculum, |8, 12§

Cuauioiy cpilhelium, 12; orf.ni, 185

|liir«. Mructure of, 10
Hand, 111

jiplHon of, ]f)2
H«rd p«rate, 42. 165
Harpi and rabbin. diMinciion of 6
lead, diMrction of, ID?

ikcleion of. 76
J["rt. 43, 176
Hfmipphcrc. of brain, 34. ISC

of ccrebrrium. 188
Hepatic portal •jnlfm. 46

See Portal Vein.
llprr'lttj', 6
Hinrl hrnin, 3<
HmK jointa, 1«
Hjl' oint, 163
Ijisi.ilogy. 3
llomoftny, S
Ilomoplaijr, S
Ilumrrui, 100
Hyoid apparatus, 97

«rch. 28
Hypophysis. 36. 188

Ileum. 123
Ilium, 104
Inciior* in rod*nt«, 7

""■aTsr"'^ "■"""■ ""-"«'.'"

Insertion of muRcIeR, 20
Integument, ace Skin.
Interartieiiiar cartilage*. 14
intercenuJar substance, 12
Interpretation of structure 4
Intcsimes. 40, 41

divisions of. 122

large, 123

lymphatics of. 11 «, 123

muscle layers of, 21

serojis coal of. 118

small. 122
Involuntary muscles. 19, 20
Ischium, 105 • ". -"

Jfjunum. 123

Joints, structure of, 18

ankle. 156; hip. knee. 1R5
Jugular veins, external, 1G8; mternal, lUfl '

Kidney. 127 '

embryonic. 47
position of, 48
Knee joint, 18 J.-JS (

position of. 33 I

Labyrinth of tar. 171

(■thmoidal, 92
Lacrimal apparatus,

Harderian and lacrimal glands 167
nasolacrimal rangl. 82 94- H,lt l«
Lacteal ves^ls, nO ' ^^^

Larynx, 165

201

Lrg, 113

muMlea of. Ifio
nerves and yfiMJa of, 1S3
skricion of, 107
f-eporid», cbaracirrt of. «
Lrpus. genus defined, «
Ligaments. 11

Limbs, gtncrtl poailioo of, 32
■nicrior, divisions. 111
dissection of, 136
■kelelon. 98
posterior, divisions, 112
dissection of, 144
skeleton, nrf

Lips, no

Liver, 11, 120
Long axis of body. 33, SO
I Lumbar verlebrtr, 71

Lumbosacral plrxus, 144. 1S4
Luitgs. 43, 177
Lymph, 9
Lymuhalfe system, ih

follicles of Mcculiis rotundus, 123

'Tn"r'n.,'i2."""'""' "'■ ~""
vessels of mesentery, 118
thoracic duct, 46
Mammalia, chsraclera of, T
Mammary glands. 7. 11, 1I|
^, ninpfes of. 111
Mandible, 84, 98
Mandibular arch. 28
Marsupial mammalia. 7
Meatus, acoustic, external. 77, S8, 89, 111

internal. 81, 89
Medulla oblongata. 37
Membrane bone, 15; of skull, 31
mucous, in
tympanic. 171
Meninges of <■■ -iiral nervous system, 184
Meaencephalo. . 36, 188 -

Mesenchyme, 12

Mesenterial small intestine. 41. 123
Mesentery, 116, 123
structure of, SO
Mesoderm, 27
Metacarpus, 103
Metatarsus, 109
Microscopic anatomy, 3
Midbrain, 36, 188
Middle ear. see Kar.

Monotremata, 7
Morphology. 3

Morphological aspect of structure, 4
Motor nerves, 22
: Mouth, cavity of. 42, 164
; glands of. see Digestive System.

Mucous membrane, 10
■ »» 1 *-'"',V^ ."' •'om^h. 119; of intestine, 10
Multicellular organisms. 9
Muscles, iitructure and types of, 19
of abdominal wall. 113
i of face. 158

I of limbs, anterior. 135; posterior, 144

of mastication. 141
of reek, 159. see vt^rtebral
occipital. 182
( of skin. 113. 136. J57

I of tongue. 162

vertebral. 180

Nasal cavity. 43. 83. 92, 193
Nasopalatine ducts, 185
Nasopharynx, 164
Neck, dissection of. IKR
jVrrves, structure and types of. 22
Nervous system, general divisions, 34
central, brain. 186; spinal cord, 184

202

Indrx.

Nrrvoua •yw •m—ronlimmtxL
pcHphrtal.

crmnisl nrrvn, St

I. utfKiorr, IHt
II. »Mic. I«7, IN*
III. ocuUimulor, lO, ID*

III. in,HI«inu>"r, ivvi •"•

IV. trochlear. I«», ll»
V. irlitminal, iii, !••, I7D,
IHH
VI. Bbilucrnt, IS», isn
VII. facUI. 167. 170. IVO
VIII. Moifik, ItO

XI.

1"

Ml. hy|H>B)..<>.ji, .tiU, 113. ISI,
1»»
■pinal nerves. compcwilJoii of, 8R
crrvkal, I3S. 131
lumbar, aarral, 144, 164
thoracic. 178
nIrxuM* of, brachial, cervical,
13tt: luinb<>i>acral, 114, 104
■ympalhi-tic ■yntrm, 311

riiialia. civtiac, IIT; mcientrrlc.
inferior. 12%: ■uperlor. 117l ul
h('B<l. I7<), «rr trunk*.
pleRU«eii. alxioniinal, 118, 1Z<

cardiac. 17fi
trunko. rervical. I«0, 1«4: lumbar,
oacral. 134; thoracic, 178
Nervou* tiMiicx, :;i

Noar. apcrKireii of, cKli-rnal, 111: piriform.
83. ft4
internal, 83. IS4
cavity of. 4.1, K3. 92. 183
NolDchtiTil. in chorilaleit, 8; in rabbit. 29, 30

(Vh<i<)onti<U, 7
Oeaophaim. 41, t«4. ITK
Olfactory hrain, 34, 186

epithelium, 11
Omenta, irratcr, leuer. 117
Ontogeny, 4
OrhJcular muncles, 20
Orbit, 7G; Mrucluie- .if. 188
Organx. rfefinilion of, 8

relative divclopmenl of. u

vltceral. 49
Organ lyitems. *m' System*.
Origin of n-u»U.>. 2ll
OaBlclei of ear. 77, 90
Oateocranium, 31
Oateclogy of rabbit. 68
Ovary, ini; position of, 49
Oviduct. 47, UI
Ovum. 9

Palate. 42, ISri
Pancreas, 11, 118. 122
Parotid glanr). 11. 167
Pectrral ([irdle. 98
Pelvir girdle. 103
Penis. Ill; structure of, 129
Pericardium, 49, 175
Perichondrium, 16

Per --

Peritoneal cavity. liO. llC .

Peritoneum, general relations nf. GO; parietal.
HE; visceral, 116

of libddir. 128

of intestine!., 116. 122. 123, 124, 125

of kidney. 127

of liv

. 120

of ovary, 131
of stomach. 117

of testis, J29 , ,

rttaliugvs, (tigiiai. of hand, 103, 11:'; -1 f'>vt.
109. 112

Fhyslulogical aapeci ef atruciure, 4

I'hyslolugy. i

t ia mairr, 181

Pigmrniatlon of skin, etc., II

Pineal butly. 3«, 116

Pituitary body. », 181

Pl-icrnta, 7

Plarenial mammals, 7

Planes of h>»iy, 113

Ptaiiiigradt: foot. 7. 33

PKura. pleural cavity. ". "' . „.

Plexuses, of spinal nerves, brachial, ISt

cervical 138; lumlxisacral. 144, 1B4

of •ympathetic nerves, abdominal aortic.

126; cardiac, 175, c.aliac, 118, hypogaa-

trie. 128; mesenteric. Inferior. li«;

supe'ior. 118; renal, sinrmalic, 12*

Pons, 38. INt

Popliteal finsa, 112 „ , ., ,

Portal syslvm, he|tallc, 45. see Portal Vein.
renal. 45

portal vein. 119, 121

Posture uf body, in man. 34
in i|uadru|irds. 23, 24

Prevertebral ganglia. 38

Pionation. 33

Prone iiositlon of body, 21:

Prosencephalon. 34, 186

Prostate, 131

Prnlnma. cell* of, 9

Pubis, lo:. , , .

Pulmonari artery, 178 : circulation, 43

UuBdrice[ia musclci, 20

RaWiit, races of, 6
Radius, 101 ....

Rami cnmmunicantr*. 38, 184
Recapitulation, law of, 4
Rectum, 123
Reduced organi, 5
Regional sections. 51
Renal portal system, 45
Replacing bones. 15
Reproduction in Protoaoa, 9
Reproductive organi, 46

female, 131

male, 128
Respiration, branchial, pulmonary. 44

relation of ribs to, 14; diaphragm, 179
Reipiratory system. 43

accessory respiratory tracta, aee Rose.

'""■."■ "' . . ,«ft 177
respiratory tracta, low, m

Retrogressive organs. 6 -

Rhombencephalon, 34, 36, 188

Rib., 73

Rodents, characters of, 7

Roots ot spinal nerves. 38. 184

Sacculus rotundu*, 122

Sacral v.rtcbr«. 72

Sacrum, 72

Scapula, 98

Scrotum. 111. 128

Sebaceous glands. It

Sections regional. 51

Segmentatmn of body. 27

Seminal vesicle. 130

Sense organs, Hpecial. capsules ol, ai

.pilhelium of, 11

See Kar. Eye, Nose.
Sensory epitheUa, 11

hairs. 10, 110

nerves, 22
SrtJtijin of nose. 83

of thoran. 175

Indcx.

n of. ai;

Scroui cavlik*. 4t

mrmhranw, 12, if

tunic nr lnl»Hne, 111
Sr»m»itr hontm, lA

«!-. 1i.,''i"''^' •"'"***'* '•'; potlerior, lOf
»|nip)i(ia(-nutB, 7 r— . ivp

Hkt-[i't«| irticm, 10

Itbrlcton, a|>rrnillcular, 3>, <)|
<>( interior limb, »H
■>» poatrrlur Hmb. 103
Mi*I. ao, 11

■fcull. 75; primary cnmpuiilii

banc! of, IS
vi-rhbral column, Id
Sfcln Mruciur, p(. 10. 13, 113
llanrf* of. It

SL ir*"*'".."'! '"• '55. 1(17

Khii)). ifc iikcictnn,

smnuth muKlt'. 1», 31

Soft luUlr. IIG

numaric nrrvr*. 22

hprcial anaiomy, 3

SlHrmalk ctird. tn

Simincrcr mu*cln«, 30

npinal cnlumn, .10, |8
eon). 34. I8(

SpI«"Yl7 ■"■' ''*'•■"*"'" SyMcm.

Sternum, 74

Mninach, 41, 111; utructurt- c>f wall. Ill

Suhcutanrou* iis«up, 13, ii3

Sulifittiiiioiial orgoni. fi

huhlinfiial iland. tl

Suhma«illary sir ..|. 11, ISI

Su.lnn(«r.„„ gljr U, 11

Supination. 33

SMiirar.nal ■ lot ... 117

S«.«t Klan<r«, 11

Symmtlry. Mlatcral. SI

hympathMic ncrvoui nyrtem. tee Nervom

Symphy.il., 18: of mandtblr, 84
^ of pelvia. 103
Synartlinii-i,. 18
SytichondTcin. 18
SyMcmn, ofEan, dcfinrH. 8, 2«

cl^nvihcalion of, 21

jltnt-ral arranfement. 27

in embryo, 29

•liffstivr. 40

lymphatic, 4S

ticrvom. 34

rr«niratory, 43

okclt-lal. 30

urini-Brniial. 4<
, vBMuTar. 43
SyMcmic circiilation. 43

Tamus. hone* of, 108
Taste bu<U of tonfuc. 165

ftnt.'lti'ri*^'"'^''''*"'''^
T<-ntorium crrchelli. So
IcrmmoIojT''. 23
r.Tr.»iriaI virrtcbratrii, 8

Thigh. 113; muBcIPft of. 144

ntrvcs and vcmcIs of, 14»
Thoracic aorta, 178

cavity, 74

'tiicl. 48

vcrtchrie. 71
rhoia-c. Iumy, 74

.lissittion of, 172
rhymu!. Blanii. 173
Thvrcoi.l glatid. 180
Tihia, lOT

20:

TiaauM, ilrllnrit. ■

claail heat ion uf. f

conncclivc. 13

riilthrhal. I

muMTular. IK

nrrvouk, 31

•kclrtat, 13. 14
T'lniuf. M3, 18(

rrK^hea. 43. 110. 177

T;ke'^ m,:&:r7« ^' »"'^'—l' Syttm.
Trunk, divioioni of, m

•fcclrton. IN
Trunk., lymphatic. 4|

neural. 34

ulerim-. 131
Tunic, of diii.iive tube, mucou. lo

muMUlar. 31 '

.fri>u., Ml

"I .lomach, 111
rurhinatetl bom-, un, »3
rym|«nic cavity, Ss. »«, 171

memfaraiii-, 171

. I»t

t nic'llular fbnd., 11

"rianinma, y
I nip«'nnate muitcir*, 30

tCh^'a.'JJS^r''''^ '"•'''""'•'■ «
Trinary organs. 48, 127
i-rinogenilal aperture. Ill

,. ly.tem, 41, 127

J tennc tube, 131

I tcrus. 131; lypfi of, 18

J>fina, 132
Vascular sy.iem, 43

a.ymmitry in, 34, 4G

See ArteriM. Hloodvc*iwU. Veini.
V-n.. trunk, cava), inferior, 117, 134 17|
■Hpenor, 174, "■« * *'*

hypotaalrii, "iJi'i
jugular, •

. 131

fnal, 127
spermatic, 129. 131

.™l,"r°! i'j"",;?*' ■*'■ '"• '"
Vermiform proci-.H. 133
* eruhraJ column. S8
\ crlehrate*. cbaractcra of, 8
l-rr.-«|ria1, 8
organ .ystcm. in, 27
%eiic.e seminal, 130
I \t»tihulum 48, 133
I ^ Itceral arches. 28, 31
I ncrvec. 22

cranium, 31
Tgan., 49

peritor ""

V.oral fnldi
\*oluritary
Vulva. Ill

1ti6

I WhI k? "' •connective tissue. 12
M'^j'^ -iibMance of nirv.us syitcri- -^l

I Wild rabbits. spectM of. « '^ ""■ "**
Wrist, bonea of, 102

Vtllow fibres of connective tissue, 12

/oologira! jv^,t;„n ^f rabbit, C