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LIBRARY
NEW YORK STATE VETERINARY COLLEGE
ITHACA, N.Y.

This Volume is the Gift of

Dr. S. Weissman

mine sPavin group of lameness

DATE DUE

es i a

GAYLORD

Sou aaoiay

Library

The original of this book is in
the Cornell University Library.

There are no known copyright restrictions in
the United States on the use of the text.

http://www.archive.org/details/cu31924000963854

The Spayin Group of
Lamenesses

W. L. WILLIAMS, Ithaca, N. Y., CARL W. FISHER, San
Mateo, California, and D. H. UDALL,
Ohio State University

LIBRARY
NEW YORK STATE VETERINARY COLLEGE
ITHACA, N.Y.

This Volume is the Gift of

Dr. S. Weissman

DATE DUE

GAYLORD

PRINTED IN U.S.A,

The Spavin Group of
Lamenesses

e

W. L. WILLIAMS, Ithaca, N. Y.. CARL W. FISHER, San
Mateo, California, and D. H. UDALL,
Ohio State University

Reprinted from 42d Annual Proceedings of A.V. M.A.

HARTFORD, CONN.
Press of the Case, Lockwood & Brainard Company

1906

The Spavin Group of Lamenesses.

W. L. Wittiams, Irwaca,'N. Y., Cart W. Fisoer, SAN Mateo, CAtt-
FORNIA, AND D, H. Upati, Onto State Universiry.

Historically, spavin is perhaps the oldest lameness of the
horse. Standing in the foremost rank economically, it has
received at least as much, if not more study than any other.
Grouped about this malady and certainly allied, if not identical,
to it, in cause and pathology, is a long'list of separately de-
scribed affections, some of which may well challenge the suprem-
acy of spavin itself in their frequency and power of diminishing
or destroying the usefulness of the horse. We have, therefore,
elected to give spavin the title réle, rather from convenience
than from an inherent right of this one affection to dominate the
nomenclature of this extensive group. Among the most com-
mon and important members of the group, in their approximate
order of frequency and economic importance, we would mention
spavin, navicular disease, ringbone, sidebone, sesamoiditis,
spinitis, gonitis, carpitis, humero-radial arthritis, scapulo-humeral
arthritis, etc. In the observations of Dr. Fisher spavin should
occupy third or fourth place in frequency. ‘

Taken asa group, they constitute by far the most important
lamenesses and, in the destruction of the value of the horse, take
high rank among all diseases to which this animal is liable.

Under the title of arthritis sicca or arthritis deformans,
numerous writers on general veterinary pathology group these
affections together without definitely assigning them to a com-
mon cause or suggesting, as a rule, any close relationship beyond
the evident similarity of tissue changes, indeed most writers
on regional surgery ignore generic identity and treat each as
an isolated disease. Without desiring to detract in the. least.
from the excellency of the very extensive literature upon these
as separate diseases, we desire to present the entire category
as one group of closely allied affections, or, rather, as a malady
expressing itself by common phenomena in various parts of the
skeletal tissues and in other parts of the integument.

The senior author first had his attention attracted to the
group, as such, through observations made as a result of a

Williams, Fisher, and Udall: The Spavin Group.

professional residence of some duration in the Rocky Moun-
tains, the Mississippi Valley, and in the eastern United States
extending altogether over a quarter of a century, in which
it was seen that the malady, almost unknown in one region,
became a scourge in another part of the country, and between
the two extremes offered every possible variation; peculiarities
which called for some deeper and more satisfying explanation
than accident or traumatism.

Later he enlisted the collaboration of C. W. Fisher, D. V. M.,
of San Mateo, California, and Professor D. H. Udall, D. V.M.,
of the Veterinary Department of the Ohio State University, -
who selected this topic for their joint thesis for graduation at
the New York State Veterinary College, and who, during the
years from 1899 to 1901, conducted a series of original and
highly instructive investigations in relation to its pathology,
in which work they were ably advised by Dr. V. A. Moore.

Since the presentation of their thesis, Drs. Fisher and Udall
have had opportunities for further valuable observations. The
wide geographical separation of the contributors permits the
presentation of views based upon data obtained in numerous
locations reaching across the continent from the Atlantic to
the Pacific, and the subject to be viewed from the standpoint
of student, practitioner, and teacher.

The conclusions submitted constitute in general the joint
views of the three authors. The major part of the thesis of
Drs. Fisher and Udall is presented as such without essential
change, for which they assume full responsibility. The respon-
sibility for other portions is accepted by the senior author.

The very instructive, though all too few, urinalyses herein
quoted are the work of Dr. George W. Cavanaugh, Professor
of Agricultural Chemistry, Cornell University, the samples and
clinical data having been supplied by the senior author.

PATHOLOGY.

This affection or group of affections having been generally
viewed as the result of a traumatism, the pathology has been
chiefly studied in the light of separate localized maladies, con-
sequently each has had its morbid anatomy investigated and
described separately, each description being a repetition of the
other varying only in the predominance of this lesion in one,

=

Williams, Fisher, -and Udall: The Spavin Group. 5

of that in another. True, here and there an author has vaguely
hinted at the systemic etiology of one or another member of
the group, as has Dieckerhoff (Der Spat des Pferdes) in rec-
ognizing brustseuche as an essential cause of some cases of
spavin.

During the period of our study and subsequent to the prep-
aration of the thesis mentioned, Messrs. Vivien and Augustin,
in the Revue Generale de Leclainche for July, 1904 (Am. Vet.
Review, Nov., 1904, page 712), came forward with a thesis
ascribing this group essentially to systemic disturbances and
assigning to trauma a secondary rdle so that, working without
knowledge of the trend of each other’s investigations, the gen-
eral conclusions have proven parallel in some of their leading
features.

In dealing with the pathological anatomy, it is not essential
for us to enter into it in detail, since the data published by
any one of several authors would necessarily be repeated, and
if included as related by any one of them regarding one of the
group of maladies, would serve for a description of the lesions
of any other one or all of them almost indifferently. Were
we to take the descriptions of the lesions of spavin by Percivall,
Dieckerhoff or Eberlein, they would, in a large measure, corre-
spond, varying somewhat because of the bias of each as to
the etiology of this affection, and if we set aside the influence
of this belief, then each description would serve equally well for
ringbone, navicular disease or other member of the group. If
we select from the most extensive and recent investigations in
the histology of these affections, we would mention Eberlein
(Monatshefte fur Praktische Thierheilkunde, Vol. IX, pp. I-49)
as to spavin, and Karnbach (Monatshefte fur Praktische Thier-
heilkunde, Vol. XI, page 516), and Udriski (Ibid, page 337) on
ringbones.

The initial point of the disease process is variously held by
different authors, in harmony with their views as to the cause.
If the systemic hypothesis of Vivien and Augustin and that of
ourselves be accepted, the pathologic orgin is general, and the
controversy has been waged over the first region of visible
intensity, which may vary in different cases. The disease,
according to our observations, affects the entire skeletal system,
involving primarily the ‘general system and causing constitu-
tional disturbances, of which the arthritis becomes the local

6 Williams, Fisher, and Udall: The Spavin Group.

manifestation. With such a view, it follows that no articular
tissue occupies a first place in the history, but any one of the
tissues concerned may be the first to become visibly affected.

Bone AND ARTICULAR CaRTILAGE. The short bones, composed
of cancellated tissue and having an abundance of red marrow,
take a prominent, if not the chief part in the known pathologic
changes, and, according to many recent investigators, is the
tissue in which the first visible lesions of the disease appear.

These lesions are first discoverable chiefly in the subchondral
layer, and may be seen by the naked eye in -early stages as
variable sized, dark reddish-blue spots through the compara-
tively transparent articulat cartilage, as is shown at I, 2, 4; 5,
6, 7 in Fig. I and at B in Figs. II and JIT. These areas are
irregularly circular in form and tend to occur simultaneously at
corresponding points on the ends of the two bones concurring
in the articulation.

‘Histologically examined, the Haversian canals widen greatly,
assuming sac-- or ampulla-like enlargements designated How-
echip’s lacunee. The bone cells decrease in size, their prolonga-
tions disappear and their outline becomes more regular. The
canaliculi vanish in the severely affected parts. The bone matrix
liquefies, forming cavities of considerable size, and, by exten-
sion toward the articular cartilage, finally reaches it, and the
granulation tissue interrupting the nutrition to the superposed
cartilage, it, too, becomes involved. The disease of the cartilage
generally begins in the deepest layers, bordering the subchon-
dral excavations in the osseous tissue, the superficial cartilagi-
nous layers remaining for a time intact. The disease processes
within the cartilage are analogous to those taking place in the
bone. The cartilage cells multiply, enlarge, lose their normal
character, and assume the appearance of giant cells or osteo-
clasts. The chondral matrix softens, becomes fibrillated and
destroyed. When the superficial layer of cartilage is finally
dissolved or thoroughly undermined by the erosive process tak-
ing place in the subchondral bone; it breaks and falls into the
excavation beneath, forming deep pit-like cavities, opening upon
the articular surface by a mouth usually much smaller in diam-
eter than the excavation beneath, producing the macroscopic
‘appearances shown in Figs. II IV.

These pits appear to be always the seat of active inflam-
mation, are occupied in part by tissue débris which has become

Fic. 1.— Symmetrical sesamoiditis. A, Metacarpus; B, Suffraginis; C, Sesamoids.
I. x, 2, 4, Erosions of articular cartilage, with darkened background. 3, Repaired fissure of

the head of rst phalanx.
II. 5, 5, Erosions apparently from friction. 6, 7, Erosions with dark background. 8, 8, Ex-

ostoses on sesamoid bone.

‘yuawe3T] repnsdeo pauexory3 A[snoursous ay Ul peppequit sliqep jo sesseur SN01ID9N ‘G ‘= “SHqep oMoroau
yy peyy sud ay ‘sjyutof jo aouerayuinoio ye auoq pue aSv[niies Jo suoisorg ‘D ‘D ‘av0g jo seo1e powmeyur Yiep uodn Ajayerpeuw: Sunset ssepyszes aepnoiiy ‘g ‘gq
raSepied ae[nonie yewsou Ayeyeurxoiddy ty ‘y ‘3y8H ey] Je sniduny tyyey ye eppdvog = ‘wauroeds jam ulosy UMeIp ‘sIyYyIe TeauInYy-ojndess —"]] ‘DIF

Fic, III. — Longitudinal Section of humerus, shown in Fig, I}.
A. Approximately normal articular cartilage.
B. Darkened area in bone, due to intense inflammation, corresponding to the dark areas in Fig. II.

C, C. Erosions at margin of articular cartilage.

Fic. 1V.—Spavin. Section through the lower tarsal row and metatarsus showing condensing
ostitis, with marked osteo-sclerosis in tarsal bones.

Williams, Fisher, and Udall : The Spavin Group. 7

- necrotic and fallen into the cavity, or the red marrow may
proliferate, and a mass consisting of connective tissue, vessels,
and lymphoid marrow cells completely occupy the cavity if the
superficial layer of cartilage remains intact. The amount of
necrotic tissue débris is unusually abundant in Figs. II and III
at C.

If the superficial cartilaginous layer has broken down com-
pletely and the excavation has acquired an opening into the
articular cavity, the granulation or marrow tissue may grow
up into the joint cavity, and, meeting there with prolongations
from corresponding erosions in the opposing bone, the two may
fuse, producing fibrous anchylosis which constitutes in a measure
a reparative process.

The reparation of the affected parts is largely a reversal of
the processes just outlined. The bone cells, lymphoid marrow
cells or osteoblasts resume their normal properties, the osteo-
clasts largely disappearing, new osseous lamella form about the
Haversian canals, new lacune and canaliculi appear, and instead
of rarefying ostitis, we observe an ostitis condensans, which
generally more than replaces the prior bony lamella, producing
an osteo-sclerosis as shown in Fig. IV, in which the former
porotic bone has become exceedingly dense, almost like ivory.
‘This represents the recovery of the osseous lesions in the most
complete form we are able to recognize.

If the marrow cavities which we have described push their
way near to or upon the surface of the joint and ossification of
these prolongations take place, they cause hard, rough, pointed
elevations or calciffed points, readily felt in some, cases upon
the joint surface, and capable of causing friction erosions on
the opposing articular surfaces.

Following the fibrous anchylosis, the prolongations tend to
become ossified, producing an osseous anchylosis of varying
degrees of completeness. Rarely the entire joint surface be-
comes denuded of articular cartilage and the anchylosis may
then become complete, but generally there are islets of articular
cartilage of varying sizes, which leave the anchylosis incomplete,
and according to incompleteness, insecure, exposing it to inter-
ruption or fracture resulting in a renewal of pain and lameness.

In other cases the prolongations of red marrow with their
vessels and connective tissue fibers fail to fuse with those from
the opposite joint surface, but push against them and into any
depressions or cavities in the opposing surface, the prolongations

8 Williams, Fisher, and Udall: The Spavin Group.

being irregularly conical, the projections from the two opposing
surfaces alternating and interlocking in a way. to produce 4
false anchylosis competent to fix the joint to a limited degree
without giving the security of a true and complete fusion.

PERIOSTITIS AND ExostosEs. As we have already ‘suggested,
the ostitis is general, with here and there points of special
virulence which determine gross lesions. These areas of inten-
sity are not always subchondral, but are possibly even more
frequently subperiosteal, leading to the formation of exostoses,
which constitute the most universally visible lesions of the
malady.

In many cases the subchondral and subperiosteal lesions
are simultaneous, as is shown in Fig. V, where the destruction
of the articular cartilage and the exostoses are equally prominent.
In other cases, as seen in many peri-articular ringbones (Fig.
VI), the areas of intensity are chiefly subperiosteal and the
articular cartilage largely escapes destruction. When the in-
flammation involves the periosteum, it is generally in the
immediate vicinity of the attachments of the capsular ligaments.

Instead of the destructive processes, we have outlined in
the osseous tissue, the periosteum, when the seat of the disease,
tends to a productive inflammation. The deeper osteogenetic
layer assumes increased activity, the osteoblasts multiply, and
new osseous tissue is rapidly formed. The Haversian canals
extend outward from the normal into the new formed bone.
The new osseous tissue possesses all the essential characters
of normal bone, but the regularity is disturbed in various ways.
The Haversian canals are larger and more irregular in arrange-
ment, the new bone is softer and more fragile. Its outline dur-
ing life appears somewhat smooth and regular, but when the
affected bones are macerated and the connective tissue removed,
the surface is found to be very irregular with many deep inden-
tations passing into the exostoses, dividing them up into irreg-
ular adherent bony masses. The new formed bone tends finally
to undergo osteo-sclerosis when the active stage of the disease
has passed, and may in time atrophy.

SyNovitis. Synovitis is a well-nigh constant condition in

this affection, and while it apparently bears a close relation in-

many cases to the usury of the articular cartilage, this does
not seem to be constant, nor can synovitis be recognized in all
cases, either inira vitam or post mortem.

Fic. V.— Humero-radial and femoro-tibial articulations, showing extensive disease, with deep
erosions and abundant marginal exostoses. The specific gravity of these bones is greatly decreased.

Fic. VI.—A series of ringbones, showing in the two upper rows the interphalangeal articular
surface, with erosions ; and in the lower rows the same specimens showing the exostoses.

Fic. VII. —A series of navicular bones, showing variations in erosions, pit-like excavations
and exostoses.

Fic. VILI.— Femoro-patellar articulation (gonitis), from Case IV. S. M., Synovial membrane,
thickened and tufted. N, Calcified nodule in the walls of the articular capsule, from which sus-
pended by a narrow neck, 1s a second nodule, N’, which might readily become a floating body. E.
C, Diminutive and flattened external femoral condyle, between which and the enlarged internal
condyle, I. C., the trochlear groove is practically wanting. P, Patella, showing at E, an extensive
erosion, caused by friction in passing out and in over E. C, at E’, the result of ‘‘ floating disloca-
tion of the patella.”’

|

Fic. IX. — Gonitis and floating luxation of the patella in eighteen-months colt. .
I. Normal femur. II. Diseased femur from Case IV, showing another view of the femur ir
Fig. VIII.

A, External condyle. B, Internal condyle. ai

In I, the external condyle is sharply defined and well elevated above the sulcus, while in II the
condyle is rotund, flattened with almost no depression or groove between it and the internal condyle.
The differences between the two internal condyles is very much greater. The normal (I) is well-
defined and sharp, while the diseased (II) is greatly enlarged, puffed up, and undulating at its
upper part. There is in JI no trochlear groove in which the patella may glide, and no external
trochlear ridge to guide it; hence patella slipped out and in position at each step.

Williams, Fisher, and Udall: The Spavin Group. 9

It is most apparent when the intense areas of the disease

involve an important articulation. The character of this synovitis
has been in controversy. Many of the older authors speak of
this affection in a general way as arthritis sicca or dry arthritis,
but, when they do so, they have in mind, apparently, only those
joints of limited motion and scant synovia. It is essential for
repair in cases of developed spavin or ringbone that eventually
synovia should cease to be secreted in order that contact’ of
the denuded bones may occur and permit anchylosis. In these
articulation there are only very limited synovial sacs incapable
of distension, and severe inflammation apparently quickly des-
troys, or diminishes, their secretory power. In the larger artic-
ulations with extensive synovial sacs, the secretion -becomes
very greatly increased. In many cases of spavin, presumably
without erosion of the cartilage of the tibio-astragaloid articu-
lation, the synovial sac of this joint is greatly distended, con-
stituting what we may well term a false bog spavin in contra-
distinction to the generally greater distension of the joint, some-
times unaccompanied by lameness, or, so far as we know, by
any osseous disease, to which we ordinarily apply the term of
bog spavin. Ths distension serves to cover and disguise the
exostosis of spavin and in this way tends to lead to error in
diagnosis. It is a part of the one affection, the synovitis of ordi-
nary spavin having the same etiology and prognosis.
+ Still more pronounced, and quite characteristic of the malady,
is the synovitis in gonitis. There the distension of the femoro-
patellar bursa is, next to the lameness, the most prominent
sign of the malady and, moreover, its results are serious for
the integrity of the articulation. When occurring in young
animals, the extreme distension of this sac lifts the patella
upwards and forwards, until it is above the external trochlear
ridge, inducing a floating dislocation of the patella, as seen in
Figs. VIII and IX. The floating patella is drawn outwards
over the external ridge by the biceps femoris and other muscles
during flexion, and inwards again during extension, the result-
ing attrition wearing away the cartilage and bone from the
summit of the external trochlear ridge and from the median
ridge of the patella, as shown at E and E* in Fig. VII.

The increased pressure upon the summit of the ridge, the
disuse of the trochlear groove and the internal ridge, along
with the disease processes, taking place within the articular

2

10 Williams, Fisher, and Udall: The Spavin Group.

end of the bone, bring about serious deformities in the joint.
The external ridge loses its cleanness of outline, flattens down
and becomes practically level with the bottom of the sulcus,
while the internal trochlear ridge puffs up, enlarges in every
direction, is rounded and obtuse everywhere; the trochlea has
lost its function as a conduit for the patella and the efficiency
of the joint is permanently and incurably destroyed. Compare
Figs. VIII and IX. If we examine one of these articular cav-
ities, it is found filled with an excessive amount of transparent
or semi-transparent, faintly reddish or yellowish, thin synovia.

The synovial papille are hypertrophied, greatly thickened and
elongated, as shown at SM in Fig. VIII, and’ some of the more
prominent are calcified at their free extremities, as shown at
N, while another nodule, N+, is attached to it by a narrow neck,
which time or accident may cause to part, and a free body in
the joint result.

In many cases the articular capsule is thickened and indu-
rated, sometimes becoming enormously so to the extent of one-
half to one inch of dense fibrous tissue, and, rarely, within
this dense mass may be found large masses of necrotic tissue
debris, as shown in Fig. IT at D D.

The following portions, to and including page 208, is an ab-
stract of the thesis already referred to. The outline of the work
was planned by Professor W. L. Williams, and the microscopical
technique largely under the supervision of Professor: V. A.
Moore.

MatertaL AND Meruops or Invesrication: — In the investi-
gation of this disease we have had recourse to the clinical cases
of the New York State Veterinary College. The material for
both clinical and post mortem examination has been more than
sufficient to occupy the available time devoted to the work. In
some cases the history of the patient has been somewhat deficient,
yet enough has been given with the majority of them to trace
the origin and character of the clinical symptoms.

The following scheme has been employed as a working basis,
but the amount of time required for carrying out the experiments
has of necessity confined us to a limited portion of the original
outline.

Williams, Fisher, and Udall: The Spavin Group. 11

I. Gross examination.
A. Physical.
(a) History of animal.
(b) Character of lameness (local, general).
(c) General condition of the patient.
B, Anatomical examination of joints and extremities,
(a) Amount and character of synovial fluid.
(b) Character of synovial membranes and capsular ligaments.
(c) Condition of articular cartilage.
(d) Character of deformity.
II. Urine analysis.
(a) Determination of reaction.
(b) Amount of phosophates and other solids.
III. Pathological examination of the tissues.
A. Bone (macroscopic and microscopic changes).

Preparations of bone for microscopic examination were made
in the following manner: Small pieces of fresh tissue were fixed
in an alcoholic-sublimate solution, or in picric alcohol; these
were hardened in ethyl alcohol by placing them first in that of
fifty per cent. strength, then removed to that of sixty-seven per
cent., eighty-two per cent., and ninety-five per cent. respectively ;
the hardening process being complete in from three to five days.
Specimens that were fixed in the alcoholic solution of corrosive
sublimate and hardened in alcohol were employed for filed prepa-
rations, which were excellent for demonstrating the inorganic
structure of the bone. To bring out the structure of both the
organic and inorganic tissue it is necessary to decalcify. The
following fluid was used for this purpose: sixty-seven per cent.
alcohol, ninety-seven parts; concentrated nitric acid, three parts.
The methods of technique may be found in “Normal Histol-
ogy,” Piersol. The sections were stained in hematoxylin and
picro-fuchsin and mounted in Canada balsam. Several other
stains were used, but the above were the only ones that gave

satisfaction.
EXAMINATION OF SUBJECTS.

Case 1.—A bay mare fifteen years of age, brought to the clinic in
the spring of 1900 to be treated for lameness in the right hind limb.

Symptoms; anemia; slight ventral hernia; lameness very marked,
especially in the hind limbs; well developed gonitis on the right side;
upon urging the animal to trot she appeared to be lame in every joint.

Autopsy:— Left anterior extremity: scapulo-humeral articulation; the
articular cartilage was roughened on the head of the humerus; the syno-
vial membrane discolored.. Elbow joint: the cartilage on the trochlea of

12 Williams, Fisher, and Udall: The Spavin Group.

the humerus contained an ulcerlike depression, one-half by five-eighths
of an inch in size; a similar roughness was present on the articular
surface of the ulna. Carpus: cartilage slightly eroded between the
articular surfaces of the os magnum and radius, and between the small
carpal and metacarpal bones; on microscopic examination the cartilage
was found torn, villous, and fibrous; the cartilage cells proliferated and
enclosed in mother capsules. The osseous tissue of the os magnum was
abnormally hard and many of the marrow cavities were empty, while others
were completely filled with marrow cells; the canaliculi of the lacunz had
undergone marked atrophy, this was also true of the protoplasmic ex-
tensions of the bone corpuscles; many of the bone corpuscles (cells)
within the lacune assumed a roundish form. :

Right posterior extremity: femoro-patellar articulation: the synovial
fluid had increased in amount; the articular cartilage presented extensive
erosion on the inferior surface of the patella; the entire surface of the
fibro-cartilaginous process eroded; the corresponding surface of the
femur had undergone similar changes but not discolored. Femoro-tibial
articulation: cartilage extensively eroded, in places the atrophy was com-
plete. One of these areas presented a polished surface one and one-fourth
inches by three-fourths of an inch in diameter, portions of the cartilage in
places had undergone osseous degeneration. The histological changes
identical with those of the carpus; metaplasia of the cartilage matrix and
arrangement of the proliferated cartilage cells in mother capsules. Tarsus:
cartilage absent over a small triangular area on the distal extremity of the
tibia; bony exostosis in the form of a spavin. Fetlock: discoloration and
roughness on the internal condyle of the first phalanx.

Left posterior extremity: femoro-tibial articulation: cartilage rough-
ened; synovial membrane discolored; capsular ligament thickened; the
histological changes were the same as previously described. Tarsus: tibio-
astragaloid articulation: normal. Astragalo-scaphoid articulation: car-
tilage atrophied in the form of erosion-like ulcers that reach to the bone;
bursa of cunean tendon normal. Fetlock: cartilage and bone normal:
tendon sheaths discolored.

Conclusions; An examination of the bones of this animal suggested
that the diseased processes were well advanced. Exostoses and pro-
liferative changes in general seem to have reached a termination; the
solidity of the bone itself and appearance in the marrow cavities indicated
a condensing stage of the disease. Although a few of the marrow cavities,
were entirely filled with cells the greater number were comparatively
empty so that large open spaces were visible. (Figs. X and XI.)

Case II.—A small bay mare, advanced in age, brought to the clinic
to be destroyed because of chronic navicular disease. Clinical examination
revealed no exostoses.

Autopsy:— Right anterior limb: bursa podotrochlearis: cartilage and
tendon roughened, the bone was also affected. Suffragino-coronal articu-
Jation: the proximal extremity of the second phalanx presented areas of
discoloration near the center, upon removal of the apparently normal car-
tilage these punctiform areas were seen to be present in the bone.

Left anterior limb: articulations apparently normal. Bursa podotro-

Fic.X. —Section through cuneiform magnum and medium, demonstrating osteo-sclerosis and 9
anchylosis. a, Marrow cavities containing relatively few marrow cells. B, C, Articular cartilage,
D, Lacunz, many of which contain no bone cells. x, Norma bone cells x, 50. Case No.l. =

Fic. XI. — Section through cuneiform magnum and medium, demonstrating osteo-sclerosis and
anchylosis. x, 450. A, Marrow cavity containing relatively few marrow cells. B, Articular car-
tilage. D, Lacune containing no bone cells. x, Lacunz containing bone cells; atrophy of the
cells and canaliculi are common. Case No. I.

Williams, Fisher, and Udall: The Spavin Group. 13

chlearis: the tendon over the navicular bone was extensively roughened.

Posterior limbs: small nodular exostoses were found in the region
of the tarsal joints; firm anchylosis of the cuneiform magnum and medium,
the latter also anchylosed with the metatarsi. Cunean bursz obliterated,
there being a firm union between the tendons and the bone.

Case III.—A thirteen year old mare. Eight years ago she suffered
from lameness of the anterior limbs, and although vigorous, stumbled
frequently when driven. This condition was present up to the time
of death. Disease of the hind limbs was not diagnosed during life.

Autopsy; —Right anterior limb: scapulo-humeral articulation: car-
tilage slightly roughened over the head of the humerus, it appeared to be
roughened and thinner than normal. Carpus: cartilage covered with
ulcer-like depressions between the upper row of bones and radius, small
pieces of fibrous tissue floated in the depressions; slight lesions present on
the distal end of the metacarpus.

Right hind limb: femoro-tibial articulation: articular cartilage almost
completely atrophied over the median trochlea of the femur; the latter
bone was very porous at its distal end, the handle of a bistuory could
easily be pushed into the osseous tissue for a distance of one and one-
half inches.

Left hind limb: femoro-tibial articulation: lesions allied to those
found in the corresponding limb, the trochlea of the femur was less
porous.

Case IV.— Patient presented at the clinic April 3, 1900, when the
following notes were made: age one year, diet four quarts of oats and
ten pounds of hay daily. Patient to be treated for gonitis first noticed
about April second, and from which the animal appeared to be very
lame. Clinical examination’ revealed one gonitis, two spavins, and four
ringbones. This animal was killed in December of the same year
because of a chronic luxation of the patella.

Autopsy: —Left hind limb: femoro-patellar articulation: synovial
membrane distended with a large amount of fluid; extensive thickening of
the capsular ligament; erosion of the external trochlea of the femur and
roughness of the internal condyle. The external trochlea very compact,
the inner soft and porous. Femoro-tibial articulation: the changes were
similar to those in the preceding. Free bodies were found in the joint
composed of bone, cartilage, and connective tissue. Histological examina-
tion; the trabecule and osseous portions of the marrow cavities well
marked, the latter containing many giant and lymphoid marrow cells.
The giant cells were not all in direct contact with the trabeculz, some were
situated in the middle of the marrow cavity. Tarsus: bones apparently
normal; the cartilage exhibited small, punctiform, reddish-blue spots
about two millimeters from the external margin of the articular
surface. These correspond to those mentioned by other investiga-
tors (“points of contact” of Eberlin). Upon a histological examin-
ation of a section made through one of these points the following
conditions were noted: the cartilage cells grouped in an irregula man-
ner, their form more rounded and somewhat larger than in a like section
of normal bone. An empty cavity was noted between the cartilage and

14 Williams, Fisher, and Udall: The Spavin Group.

bone (Fig. XII), which may be due to mechanical manipulation of the
tissue. The following changes were noted in the bone: the canaliculi of
the lacune entirely atrophied in the region of the empty space (Z), the
lacune roundish in form, the marrow cavities completely filled with cells
and capillaries (Fig. XII, D1). The bone apparently in a condition of
active hyperemia; obviously a case of osteo-porosis in the early stages.

Case V.—A bay gelding draft horse twenty years old, bred and
raised upon the University farm. The diet consisted of hay with five
pounds of corn and oats mixed night and morning, and five pounds of
oats at noon. The animal had always been vigorous and in excellent
health. April seventeenth, nineteen hundred, he was presented to the
clinic to be treated for lameness in the hind limbs, which had come on
gradually, and at times was not noticeable. Diagnosed as gonitis. The
following October the animal was returned to the clinic without improve-
ment and owing to his age and severe lameness was left for disposal.

Autopsy: — Pronounced changes were found on the proximal extremi-
ties of both tibial bones; articular cartilage entirely absent from median
side of left tibia, around this area the cartilage was very much thickened.
Exostoses in the form of nodules were abundant around the articular sur-
faces, some were firmly attached while others were held in place by
fibrous tissue. The articular cartilage of the condyles of the femur
presented a rough appearance; slight abrasions were found in some of
the other joints. Histological examination, thin sections from the
proximal extremity of the tibia presented bone and cartilage undergoing
rapid and complete degeneration (Fig. XIII); the solid bone matrix:
(trabecule) had lost nearly all of its characteristic structure; the lacune
were.entirely absent over a great extent of the sections examined. Just
beneath the abraded cartilage (Fig. XIII, A) the changes were very
marked, only an occasional round space indicated the presence of a
former lacune. The marrow cavities visibly enlarged and entirely filled
with marrow cells, among which were many giant cells (Fig. XIII, D);

‘Howschip’s lacune were abundant.

Examination of this bone with a microscope that magnified fifty
diameters revealed many places where the marrow cavities and trabecule
had a very similar appearance; the cavities were so completely filled with
cells and capillaries, and the bone had lost so many of its typical features
that a higher magnification was necessary to determine the exact location
of the boundary line. In certain of the marrow cavities reparative pro-
cesses were beginning to take place. Marrow cells that had the appearance
of osteoblasts in developing bone of young animals were arranged around
the periphery of the cavity in contact with the bone trabecule. Blood
vessels and connective tissue were present as in the reticular tissue of
normal bone marrow, the amount of such connective tissue, was, however,
abnormally small. The areas in which reparative processes were taking
place were very small in comparison with the whole amount of diseased
tissue; they were very suggestive, however, of the method by which
such osteoporotic bone may become hard again, and finally pass to
osteo-schlerosis.

num ofa yearling

porosis in the early stages from the os mag

Fic. XII.— Demonstrating osteo-

colt. X,50. Case No. IV.
A, Cartilage cells, round in form and irregularly grouped.

B, Cartilage.

D, Bone.
D/, Marrow cavities, completely filled with cells and capillaries.

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Fic. XIII.
Howship’s lacune. These ar

cells and vascular structures
of the articular cartilage.

Fic. XIV.— Proximal extremity of the tibia, showing extensive osteo-porosis. A, Marrow
cells. B, Osteoclasts (giant cells). C, Bone matrix. D, Lacune, in which canaliculi are absent,
bone cell having undergone almost complete atrophy. F, Howship’s lacune. This drawing is
made from the same section as Fig. XIII, Case V. X, 450.

the tibia, showing extensive osteo porosis. A, Lacunz,

C, Bone cell. D, Bone matrix (trabeculz). E, Line of

Fic. XV. — Proximal extremity of
B, Canaliculi extensively atrophied.
contact between bone and marrow.
and F. X, goo.

F, Marrow cells. X, Marrow cavity; note similarity of C

fay

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years. A, Cartilage cells. C, Boundary
D, Marrow. E, Tella ossea. X, 50.

Fic. XVI.— Healthy scaphoid of horse ; age 12
between articular cartilage and bone.

Williams, Fisher, and Udall: The Spavin Group. 15

A glance at the cartilage of this tibial bone shows that it was
extensively diseased (Fig. XIII). The cells are arranged in
mother capsules and variable in size; near the free surface of the
cartilage they are greatly modified in structure and arrangement.
In certain areas the cells are larger (Fig. XIII, E'). The con-
_ nective tissue between the cells is -increased in amount and
_ fibrous in character, while normal articular cartilage is of the
hyaline variety. In places we find a metaplasia of the cartilage
with splitting of its fibers, in other places the cartilage has en-
tirely atrophied, bringing the abraded articular surfaces of the
bones in direct contact.

The condition and appearance of the bone and marrow in this
section offers a suggestion to the influence exerted by the giant
cells (osteoclasts) upon bone resorption. This is the only case
in which we have been able to demonstrate the presence of such
cells in large numbers, only a few being observed in case IV.
In case V, however, they were very abundant both in Howschip’s
lacunz and in the center of the marrow cavities. Certain parts
of the sections examined presented areas where no giant cells
were visible, the marrow cavities were rich in a cellular structure,
and the bone matrix presented marked indications of resorption.
The lacunz were misshapen or rounded, some were very much
enlarged with ‘irregular and poorly defined outlines, others ab-
normally small: The bone cells in such lacunze were hypertro-
phied, atrophied, or absent. In the majority of cases noted they
were present, enlarged, and granular in appearance, their posi-~
tion in the bone matrix alone, distinguishing them from neigh-
boring marrow cells (Fig. XIV).

While it is generally believed that the osteoclasts exert a
certain influence in bone resorption we have a case where it
would seem that resorption was rapidly progressing in their
absence (Fig XIV). It is difficult to understand just how the
osteoclasts can bring about such marked changes in the bone
cells that are deeply situated in the bone matrix; the idea
suggests itself that the primary change begins in the individual
cells themselves, those of the trabeculz, as well as in those of
the Haversian canals. As the bone tissue atrophies it is perfectly
logical that the Haversian canals should become enlarged. Sup-
pose in Fig. XIV, for example, that three or four of the bone
corpuscles continue increasing in size until they occupy a common
space, and that at the same time this. breaks through into the

16 Williams, Fisher, and Udall: The Spavin Group.

neighboring marrow cavity; such changes would result in the
formation of a Howschip’s lacuna.

Summary. — This group of: diseases is characterized by an
inflammation of the bone, cartilage, and capsular ligament. The
following changes are noted in the bone: hypertrophy of the
marrow cavities, and atrophy of the osseous matrix. The mar-
row cells are greatly increased in numbers. The bone cells
(corpuscles) become granular in appearance and smaller in size.
The lacune are enlarged, and at the same time may lose their
typical form. The canaliculi undergo partial or complete atrophy.
The disease process seems to be operative throughout the whole
’ extent of the affected -area at the same time; that is, bone
resorption is not confined to those portions of the osseous matrix
with which the marrow cavities are in direct contact (osteo-
myolitis), but progresses just as rapidly within the interior of
the compact bone (ostitis). These changes are found in the
bone during the earlier and more active stages of the disease
(osteo-porosis). They are demonstrated in figures XI, XII, XIII,
and XIV. During this stage the bone is abnormally soft, porous,
and light (osteo-porosis), later becoming more compact and
heavier (osteo-sclerosis). The histological characteristics of
osteo-sclerosis (condensing ostitis) are atrophy of the marrow
cavities and hypertrophy of the bone matrix; the-cellular struc-
ture of the marrow cavities becomes greatly increased in amount
(Figs. XI and XIII). There is a cessation of the inflammatory
process; and resorption of bone is replaced by a regeneration of
the osseous structure. Many of the lacunz, however, fail to
regain their lost bone cells (Fig. X, d). The disease of the bone
has been accurately termed: ‘“‘ Osteo-porosis succeeded by os-
teo-sclerosis’’ (Gotti, Bayer, Frohner, Eberlein, etc.).

The characteristic changes in the cartilage are: fibrillation of
the superficial layers, extending in some cases to the osseous
tissue; hypertrophy of the intercellular matrix, as well as hyper-
trophy and proliferation of the cartilage cells; partial or com-
plete atrophy of certain portions of the articular cartilage charac-
terized in some cases by the formation of ulcer-like depressions
(Figs. XII and XIII).

The capsular ligament presents the most pronounced changes
in those articulations of which the knee joint is a type. In cer-
tain cases, especially in the earlier stages of the inflammation
caused by this disease, the capsular ligament is distended with an

6

Williams, Fisher, and Udall: The Spavin Group. 17

abundant serous exudate (serous arthritis) ; bluish-red discolor-
ations of the serous membrane are observed. As the disease ad-
vances one finds connective tissue proliferations and osseous
degeneration of the ligament (arthritis deformans). In many
cases these degenerative proliferations become constricted at
their points of attachment to the capsular ligament and drop
into the articular cavity where they are found as free joint bodies
(Case No. V, femoro-tibial articulation).

It will be seen that this disease has many lesions in common
with arthritis deformans as described by Fréhner: “In human
surgery deforming inflammation of the joints is a chronic,
aseptic, senile arthritis (malum senale) which leads to severe
and permanent changes in the entire joint. It is not character-
ized by suppuration; it may have a spontaneous or traumatic
origin; is either mono- or polyarticular; its favorite seat is in
the joints of the knee, hip, shoulder, and elbow, on the fingers,
and in the vertebral column. It is a non-febrile arthritis that is
ushered in with stiffness, crackling, and slight pain in the in-
volved joint; usually continuing during the life of the indi-
vidual, and finally leads to deformity of the entire joint.
Anatomically it consists of degeneration and new formation
processes of the cartilage, bone, and joint capsule.

““(a) In the articular cartilage one finds changes character-
istic of arthritis ulcerosa-sicca chronica; namely, fibrillation of
the superficial layers, focus-like areas of fibrillation and soften-
ing of the deeper layers, ulceration, and even complete atrophy
of the cartilage with the formation of smooth, polished surfacés.
One also finds active proliferation of the cartilage in the form of
nodular processes.

“(b) In the bone there exists a subchondral inflammatory
osteo-porosis with atrophy of the lacune in addition to bony new
formation.

““(¢) The joint capsule shows proliferation, thickening, and
wrinkling. One occasionally observes the formation of free joint
bodies.” (Bayer-Fréhner “ Tierarztliche Chirurgie und Geburts-
hilfe Allgemeine Chirurgie,” 1905.) —

While this group of diseases, of which spavin is a type, bears
a very close resemblance to arthritis chronica deformans, there
are certain features that are not characteristic of the latter affec-
tion; namely, in the spavin group the changes in the first stages
of the disease are confined largely to the bone (Fig. XII). In

18 Williams, Fisher, and Udall: The Spavin Group.

arthritis deformans the cartilage is the primary seat of the prin-
cipal changes. In view of these facts Professor Fréhner defines
spavin as follows: “Spavin is principally an ostitis of the os
magnum-and medium as well as the metatarsus, from which there
afterwards secondarily develops a deforming inflammation of the
tarsal joint. It is more correct, therefore, to define spavin as an
osteo-arthritis chronica deformans.” (‘ Allgemeine Chirurgie,”
1905.) The same term is applied by this author to the changes
which, occur in ringbone, gonitis, omarthritis, etc. It is obvious
that the lesions found in the preceding five cases are in accord-
ance with Professor Frohner’s interpretation of the disease. It
is further noted that, similar to arthritis chronica deformans in
man: “it may have a spontaneous or traumatic origin.” Further
investigations may reveal that the influence of traumata, as direct
causes of the disease, has been somewhat over-rated. In cases.
III and IV the existence of a spontaneous (pathological), in-
direct etiological factor seems to be fairly well demonstrated,
being present in both a young and an old animal; many careful
and widely distributed examinations are necessary to determine
the extent of this influence.

The causes of “ osteo-arthritis chronica deformans,”’ when
of “pathological” origin, lack complete and unobjectionable
demonstration. Rachitis and rheumatism are doubtless operative
in many cases of the disease when occurring: in young animals;
the latter may be a more important factor than is generally al-
leged (“‘ Monatshefte fiir praktische Thierheilkunde,” Vol. XV,
page 211: “ Rachitische Schale und rachitischer Stelzfuss beim
Pferde:” Frohner).

This pathological condition is not confined to young animals.
The visible lesions may be confined to one or two bones and
articulations, or be well distributed through those of the extremi-
ties.

Clinical examination may lead to diagnosis of lameness in the
anterior limbs when a post-mortem examination of the same

animal shows that the disease is more pronounced in the posterior
limbs (Case IIT).

URINALYSIS.

The composition of the urine during this affection has not
been fully investigated, nor have definite observations been made

Williams, Fisher, and Udall: The Spavin Group. 19

regarding the volume or density of that excretion. We became
interested in relation to the amount of phosphates occurring in
the urine of animals affected with this disease as compared with
those in apparent health, but failed to carry these investigations
to a conclusive stage. The few data are highly suggestive, how-
ever, and should stimulate further study. The following table
exhibits graphically the results of the few analyses made by
Prof. Geo. W. Cavanaugh relative to the phosphoric acid (P20s)
in the urine.

Laboratory Phosphoric Acid
Number of Condition of Animal per Liter of
Analysis Urine
2,672 Slight double navicular disease traces
2,673 Non-diagnosable shifting lameness (Rheumatism ?) -| no trace
2,674 Healthy farm horse......ecesseeeeeeeececeesescce ++| no trace
2,675 Healthy farm horse .+.+eseeesse sence sence eeeceee «| no trace
2,676 Weanling colt with four active ringboneS.-....-+eeeeeeeeeseeeceeers 4-55 grammes
2,677 Same patient after an interval of eleven days..-...++e+sseereereeeeee 3.70 grammes
2,678 Second sample from 2,673 (was being fed phosphates in large’ quan-
tities)sc cs cercceenncecne wens ce cccntecsasenessansanstesnaesnaeenes -09 grammes
2,679 Second sample from 2,674 (was being fed phosphates in large quan-
HHHIES) 0 nce niecncenein oecleveinee sian esceic ieeneuteeersesnece seenewe trace

These fragmentary records serve to indicate that during the
active stages of ringbone. and navicular disease an excess of
phosphorus, presumably in the form of calcium phosphate, is
present in the urine. It occurs only in traces in 2,672, the mare
at that time having been under the best possible hygienic condi-
tions as understood by us, and the presence of the malady barely
recognizable in a short gait without limping.

In 2,676 and 2,677 the amounts of phosphates become very
marked and stand out as distinctly pathological when compared
with the other analyses. The case, a weanling filly, was suffering
acutely with four active ringbones from which she recovered her
general condition and now, after eight years observation, is
working sound, the large ringbones being quiescent.

In sharp contrast to these are samples 2,673, 2,674, and 2,675,
the first of which had a peculiar, intermittent lameness for a
year or more, shifting from region to region without apparent
* cause, or without inducing any recognizable lesions in any part
and ended by apparent recovery which has remained constant
for eight years. Nos. 2,674 and 2,675 were healthy farm animals
employed at regular farm work.

An interesting query is here raised upon which chemists seem
to be at variance, some claiming that phosphates are not normally

20 Williams, Fisher, and Udall: The Spavin Group.

excreted in the urine of the horse while others are insistent that
it is so excreted in measureable quantity. It would appear that
one of the great difficulties in the analysis of the urine of the
horse is an attempt to apply the methods used in examining the
urine of man, especially quick, approximate methods which yield
reasonably accurate results, or rather estimates in human urine,
and which may be in part or wholly invalidated by the widely -
dissimilar character of equine urine. Have the different. investi-
gators dealt with urine of essentially different composition? Was
that urine which contained phosphates normal? In the fore-
going we find in acute ringbone a maximum of 4.55 grammes of
phosphoric acid (P205) equivalent to 10.18 grammes of calcium
phosphate (Ca3(-PO4)2) and then meet with complete negation
in normal work animals.

Another interesting feature is the effect of the feeding of
large quantities of phosphates upon their excretion by the kid-
neys. After the animals from which samples 2,673 and 2,674
were taken had later been given two to three ounces daily of
sodium phosphate in their food, the former showed .og grammes
of P205 per liter of urine or .02 of the quantity observed in
2,676, while the later, 2,674, showed only traces of phosphates.
This would appear to suggest that the ingestion of an unusual
amount of phosphates tends to establish or increase their presence _
in the urine, but only very slightly as related to the amount in-
gested, most of it evidently being excreted by the intestinal tract’:
or other avenues of egress.

Urinalysis appears to be a most inviting field for the further
study of this malady.

ETIOLOGY.

As most authors consider the entire group to be so many
distinct affections, they attempt to elucidate separate causes in
each instance, and in so doing have invoked for each, almost
every conceivable form of mechanical insult and other injuries.

Confessing the identity of the lesions, wherever they may |
occur, we should admit a cosmopolitan reason for their existence, _
which would serve equally to explain spavin, navicular disease, °
fracture of the ribs, anchylosis of the vertebrz, or any other
member of the group. As an illustration we might take the
horse .from which Figures XVII and XVIII are taken. Here

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Fic. XVIII. — Sections of foot from the same case as Fig. XVII.

II.

Cross section of os suffraginis near its superior end.

O.S., Os suffraginis.

Ex., Exostosis on os suffraginis (ringbone), tending to envelop the three flexor tendons.
F.C., Flexor of the corone. F.P., Flexor of the os pedis. F.S., Flexor of the suffra-
ginis (suspensory ligament).

Longitudinal section of the left half of fore foot. O.S., Os suffraginis. R.B., Ring-
bone on os suffraginis. O.C., Os corona. S.B., Sidebone. Ex.N., Exostosis on
navicular bone. O,N., Navicular bone. O. N. C., Articular cartilage of navicular
bone. O.P., Os pedis. A. and B., Arteries.

1

Williams, Fisher, and Udall: The Spavin Group. 21

we have shown ringbone, sidebones, navicular disease, sesamoi-
ditis, vertebral anchylosis, and thirteen broken ribs. Although
no detailed autopsy was made and the diseased parts noted were
only incidentally discovered while examining for tendonitis and
tendo-vaginitis, it is fair to assume that other parts of the skele-
ton were similarly involved. It would be absurd in this case
to refer the sidebones to concussion from the shoe heels, the
navicular disease to shoeing with too low a heel, the ringbones
to strain of the lateral ligaments, the sesamoiditis to concussion,
the tendonitis to strain, the spinal anchylosis to unobserved slip-
ping in the stall and the thirteen fractures of ribs to as many
blows from a rough groom or horseshoer. Coming simultane-
ously as these did, and maturing within a few weeks without the
action of any of the foregoing causes, so far as can be deter-
mined, we are forced to look for a cause which will afford as
good an explanation for the broken ribs as for the navicular
disease.

The alleged causes of the different members of this group of
affections are so numerous and varied that we cannot fully con-
sider each in its relation to the etiology of others, but must rather
content ourselves with a brief study of the relation of those
factors indicated as the essential element in the etiology of one
member of the group to the causation of the others; that is,
we desire to study the etiology of the group as a group and not
become misled by what may appear as essential causes in one
member which could not have any influence upon another.

The principal cause assigned by veterinarians for this affec-
tion is traumatism, rarely some constitutional disease of the bony
skeleton or of the general system, and occasionally heredity is
charged with a very important rdle.

Strain. Among the trauma, strain holds perhaps the first
place as an alleged cause of this disease, and this form of trau-
matism being generally considered so common and _ universal
renders it a very convenient and ever-present means of explana-
tion.

In order to fully consider this allegation, we need first to
study the mechanism of the limbs of the horse, the parts most
frequently and most evidently affected, and learn how. far the
ligaments of these articulations are subject to injury as a result
of over extension in the direction of their fibers; and secondly,
to inquire what actual evidence can be adduced as to the fre~

22 Williams, Fisher, and Udall: The Spavin Group.

quency and extent of these injuries. Were the question pro-
pounded, in what two animals are strains most common; doubt-
less the uniform answer would be, man and horse, some placing
the one, some the other, first. Carefully examined comparatively,
they represent the extremes in anatomical structure and attitude
among the higher mammalia.

Comparing the thoracic limbs of the two, we find in man
a member adapted for the prehension and holding of objects, for
climbing and for more or less suspending the body; while in
the horse it is used essentially for weight bearing, supporting
fifty-five per cent. of the body weight, and plays a fundamental
part in the process of locomotion. In man it is rigidly attached
to the thorax by means of the clavicle, while its sole attachment
in the horse is by means of powerful and elastic muscles, with the
heavy skin covering, which permits extensive movements of the
member upon the chest.

The scapulo-humeral articulation of man, with the support
of the clavicle, stands out prominently from the thorax with
the humerus free and the joint so formed that a very extensive
area of motion, representing a hemisphere, is permitted. In the
horse, on the other hand, the extensive flattened contour of the
scapulo-humeral region with the angle existing between the two
bones closely applied against the chest walls, prohibits in a large
degree rotation, adduction, and abduction, and limits its move-
ments in health chiefly to antero-posterior flexion and extension,
so that direct strain upon the ligaments, originating in the
humerus itself, is practically prohibited, while strain upon the
joint transmitted through the radius is usually nullified by the
free movement of the shoulder on the chest wall or by closure
of the scapulo-humeral angle, each of which safeguards are denied
to man.

As a result of the formation of the shoulder man suffers
rather frequently from severe strain or dislocation of that joint
or fracture of the clavicle from violent impact on the humerus,
while in the horse these accidents are rarely diagnosable, the dis-
location of the scapulo-humeral articulation occurring so rarely
that few practitioners see cases. Since dislocation must always
constitute the finality of the strain of articular ligaments, its
frequency serves as an index of the occurrence of the latter.

Examining the limb as a whole, we find that in man it is
capable of extension in a straight line from end to end, resulting

Williams, Fisher, and Udall: The Spavin Group. 23

in defective elasticity unless specially posed, while in the horse
the long axis of the limb describes great alternating angles, the
scapulo-humeral opening backwards, the humero-radial forwards,
and the phalanges extending obliquely downwards and forwards
from the metacarpus. When a horse places its weight upon the

end of the last phalanx, the smallest base of support seen in any

mammal, the very narrowness of that support, combined with the
angles in the limb and especially the obliquity of the pastern,
serves to almost entirely prohibit lateral impact, and any violence
- tends rather to decrease the angles and shorten the limb. As
a result dislocation and strain are well-nigh unknown, and the
lateral articular ligaments in the horse are comparatively small
except in the scapulo-humeral articulation, where passive liga-
ments are replaced by powerful muscles which permit of a con-
siderable normal displacement of the articulation without injury.
It thus occurs that lateral or median luxation in its ordinary
meaning almost never takes place anywhere in the anterior limb
of the horse whereas it is comparatively frequent in the arm of
man, not an articulation escaping.

The mechanism to prevent antero-posterior luxation in the
horse is highly developed, the powerful biceps assumes the role
of a great musculo-tendinous band to retain the scapulo-humeral
articulation in front while the anconean group of muscles pre-
vents the sufficient opening of the angle behind to admit of
posterior luxation and at the same time the two muscles guard,
in a reverse manner, the humero-radical articulation. Beyond
these, the great flexor muscles and their powerful tendons serve
as elastic supports upon which the articulations rest securely
behind with little need for posterior ligaments and with the
weight ever inclining backwards upon these tendons to such a
degree that almost no provision is required against anterior dis-
placement, or anterior strain. ,

In man, on the other hand, the great freedom of movement
in every direction, including rotation, submits each and every
joint to overtension of its ligaments. They may become strained
or may rupture and luxation follow, or the ligaments may prove
too resistant and the bones become fractured. Anatomically
strains and luxauons and fractures resulting therefrom should
be common in man and very rare in the horse. Clinically we
observe these quite commonly in the thoracic limb of man and
abundant strains which do not end in luxation or fracture, but are

'

24 Williams, Fisher, and Udall: The Spavin Group.

clearly diagnosable as strain by immediate pain in the part fol-
lowed by rapid inflammation, which tends finally to subside after
rest, with thickening and weakening of the ligaments, and with-
out exostosis or ostitis.

In the anterior limb of the horse, the guardianship of the
great flexor tendons over the articulations is well shown by the
frequent strain or rupture of these structures, whereas in man,
ithe feebly developed corresponding parts rarely suffer injury,
which is instead borne by the bones and articulations.

Upon examining the pelvic limb we observe an equally pro-
nounced contrast in anatomical arrangement as related to strain
so far as it is borne by the joints and bones or by the great
musculo-tendonous apparatus. -

In man the femur continues the spinal column in an approx-
imately direct line, while in the horse it is directed abruptly
forwards upon a horizontal spinal column, forming an angle
opening forward, at once reversed at the knee where the femur
and tibia are on a direct line in man. The great angle of the
tarsus opening forward in the horse is highly efficient in ward-
ing off lateral strain, while in man it is lost by the tarsus coming
in contact with the ground. The entire limb of man is practically
direct from the hip to the ground, and supports above the up-
right spinal column, so that any violence of movement falls
directly upon an unyielding, erect column, the bones and liga-
ments of which must suffer, while in the horse the great angles.
of the limb effectively ward off strain and throw it from the
bony column upon the powerful musculo-tendonous apparatus
which receives the shock and records the consequences in strains
and ruptures of the great flexor tendons. (In this comparison
we view as a tendon the so-called suspensory ligament of the
fetlock, which contains muscle fibers, represents an active muscle
in man, and is described as a muscle in the horse by various
anatomists, especially the Germans, and properly belongs with
the great flexor tendons whose functions and injuries it shares.)

We must therefore conclude that both anatomically and clinic-
ally man is preéminently disposed to strains and their finality,.
luxations, or fractures, while in the horse the impact of trans-
mitted violence falls upon the musculo-tendonous apparatus.

We rarely see a luxation or dislocation from a strain in the
limb of a horse except the foot becomes caught in a tramway
or similarly firm place. Without anatomical evidence of liability

Williams, Fisher, and Udall: The Spavin Group. 25

of strain or clinical proof of its frequent occurrence, we are com-
pelled to conclude that strain bears but a secondary part in the
etiology of this group of affections.

Concussion. Concussion is so closely related to strain, it is
the sudden impact of one body against another in a manner
which tends to crush the weaker of the opposing bodies, rather
than to divide it by fracture or rupture, that we might define it

as the same force acting in a different direction. The effect of —

concussion depends largely upon the resiliency of the surface of
contact and the facility by which it may glide away from the
concussing force. The articular ends of the long bones and the
entire short bones are cancellated and elastic and the angular

direction at which the bones of the extremities meet in a horse, —

as already described, admit of their ready recoil in obedience to
concussion.

The disease does not most frequently attack those bones most
subject to concussion, nor at the points where concussion is
apparently the greatest. We observe the navicular bone swing-
ing in the hammock-like tendon more frequently seriously at-
tacked than the adjoining pedal bone, which certainly receives by
far the greater concussion; but more interesting is the fact
that the plantar surface of the navicular bone is universally the
portion most obviously affected, whereas if concussion caused it,
the chief pathologic changes should be found on the dorsal sur-
face which, so far as we know, always escapes. In ringbone con-
cussion plays no very evident part. In horses with exceedingly
oblique pasterns, the disease is probably as common as in those
with upright pasterns and certainly more recalcitrant to all at-
tempts at cure, yet the obliquity of the pastern obviates concus-
sion and supplants it with strain on the tendons.

In spavin it is difficult to see how there can be greater con-
cussion between the lesser bones of the tarsus and the metatarsus
than between the astragalus and tibia, yet the former constantly
suffers and the latter only very rarely.

Some have suggested that the anchylosis of spavin is a pro-
cess of evolution tending ultimately to efface the latter joints, but
the tendency is seen only in diseased animals which, if the con-
, tention were true, would tend to show that it is a pathologic
evolution.

Gonitis can ‘scarcely be regarded as the result of concussion
as the parts usually affected are those most widely propped apart

3

‘

26 Williams, Fisher, and Udall: The Spavin Group.

by means of the fibro-cartilaginous discs. Throughout the entire
group, it cannot be well charged that concussion plays a funda-
mentally essential réle in the causation of the malady.

It is instructive also to study the frequency of this group of
affections in those animals where concussion and strain are most
common and violent compared with those whose environment
protects them most completely from these injuries.

Were we to single out the horse amongst all others which is
most subject to strain and concussion, we would probably select
the fire department animal, whose work is on a hard pavement,
before a heavy load, starting suddenly at a run under the whip
and continuing at high speed until reaching the destination, or
stopping from exhaustion. This horse may split the hoofs, rup-
ture the tendons, or break the bones, but is probably about the-
freest horse iri existence from ringbone, spavin, and navicular
disease.

Or let us take the cow horse of the west, bearing a saddle
of seventy-five pounds and a rider of two hundred pounds during
a long and trying day, a large part of the time at a brisk gallop,
over bank and coulee, badger holes and prairie dog towns, over
stones and through morass, dodging an enraged animal, darting
here and there in pursuit of fleeing stock and, when the lariat
is thrown, the horse must suddenly stop to bring his quarry to
the ground and then be keenly alert to hold it.

Such animals break their legs or necks, but rarely suffer from
ringbone, spavin, or navicular disease. We might enlarge further
and it would be found that those animals put to hard, trying
work, constant in character, are not the ones to suffer from these
affections, though admittedly suffering much from strain and
concussion. On the other hand, we have seen foals less than six
months old which had been born in a box stall and had never
been allowed the pleasure of a frolic, to show four large ring-
bones and two well-marked spavins.

It is a well-known fact that horses used intermittently, or
horses doing light delivery work, but kept all day long in the
harness standing tied to a post, like peddler’s horses and delivery
horses belonging to small concerns, suffer very seriously, as do
also the cheaper class of private horses and children’s ponies,
which are only occasionally used as opportunity or caprice of the
owner may dictate. It is very common also in those pet horses
which are driven very sparingly and infrequently or rarely.

Again it is to be noted that horses suffering from severe

Williams, Fisher, and Udall: The Spavin Group. 27

strain or violence to a limb do not as a rule develop this affection
in the injured member, but while standing upon the other legs,
develops the disease in them, or, perhaps more closely felated to
this group than we have yet admitted, the well foot suffers in
time from sinking of the os pedis, which Dollar translates in
his version of Mdller as “ standing laminitis.”

Regardless of the contention that the strain causes the ring-
bone, navicular disease, spavin, or other similar ailment on the
supporting limb, it certainly should be more likely to occur in
the injured member as the result of the greater strain which
caused the original disaster.

FauLty SHorinc. Improper shoeing has been blamed for
well-nigh all the ills to which horse is heir and has fairly won
enough opprobrium.

Its effect in inducing this malady should be viewed carefully.
We all fully realize that careful shoeing, pathological shoeing as
we sometimes term it, definitely alleviates some cases of ring-
bone, spavin, or navicular disease, and we may well deduce
therefrom that improper shoeing has a definite relation to the
cause, but whether its influence is fundamental or contributory,
perhaps we will not all agree. Since all stabled horses are shod
and most horses affected with this disease are stabled, it is very
easy to blame the shoeing, and since the feeling existing between
the average practitioner and shoer is frequently not very cordial,
it is easy to place the blame on the latter.

We have no data to show that barefooted horses, when kept
under the same conditions, suffer any less than those which are
shod. We would not have it understood that we think shoeing
exerts no influence, but that the relation is contributory or sec-
ondary and we shall recur to this influence later.

CoMPRESSION FROM TENDONS. The idea of Dieckerhoff that
spavin is due to a tendo-vaginitis of the cunean division of the
flexor metatarsi tendon is supported by the curative results fre-
quently obtained by cunean tenotomy, but the deduction cannot
be extended to most other members of the group. The argument
is perhaps equally good in reference to navicular disease. But
the influence of the compression of tendons is so limited in its
scope that it cannot be relied upon as an essential etiological
factor. We believe, however, and to that extent agree with
Dieckerhoff, that it does play a very important secondary role
in the two affections noted, and shall deal further with this

question below. \

28 Williams, Fisher, and Udall: The Spavin Group.

CoNTRACTION OF THE Hoor. The contraction of the hoof has
only been alleged to act in relation to one or, perhaps, two
of the maladies, navicular disease and sidebones, and hence
loses much of its interest to us in considering the etiology of
the group.

Even in the specified maladies the question is one of ani-
mated’ controversy, some urging its causative importance, others
denying it wholly and assigning it a position of effect instead.
Certain it is that chronic navicular lameness is accompanied
by contraction, but it is difficult to show that it causes the
affection, if we look upon navicular disease as a separate malady.
When considering navicular disease as one member of a great
group, contraction and dryness of the hoof must be reckoned
as a contributory or modifying cause rather than essential.

Lavor. CONFINEMENT. The character of the labor or degree
of confinement apparently exerts a profound influence upon the
development of the affection. We have already referred to this
in considering the influence of strain and concussion. In gen-
eral, it may be stated as a rule that those animals are most free
“9m these affections which are either regularly worked, whether
moderately or severely, or enjoy the constant freedom of the
open range or pasture, and that those are most vulnerable which
are closely confined and kept in enforced idleness, worked inter-
mittently, or put at work where they are driven but a brief time
each day and kept standing hitched in a vehicle during long
hours.

In the free clinic of the New York State Veterinary Col-
lege, where many of these observations have been made, it
is found that numerous cases occur during April, May, and
June. The farm animals in this community have little or no
work during the winter months, and are generally kept closely
stabled without exercise, on a limited diet of oats and hay, and,
soon after being put to work in the spring, develop lameness,
due to some member or members of this group. How con-
finement may act prejudicially we do not know, but the clinical
evidence of its influence is strong. The horse is preéminently
an animal of action, and any severe restriction tends to lower
his power of resistance to disease. This group of affections
is generally considered the special heritage of city horses, which
are constantly subjected to stabling, shoeing, and working on
hard streets

Williams, Fisher, and Udall: The Spavin Group. 29

We have already pointed: out that shoeing cannot influence
the whole group, but only a few members, and paved streets
can scarcely occupy an essential place, or the disease could
not be abundant in country places. In the vicinity of the New
York State Veterinary College the disease among farm horses
is so prevalent as to givé it the proportions of an enzodtic of
serious import, but there are no paved roads to act as a causative
factor.

Ciimate. The effect of climate has not been well studied,
but it is known that this group of affections have rather inter-
esting geographical limitations, but whether this is due directly
to the effect of the climate upon the horse, or whether it is
rather indirect through the food and the necessity for stabling
has not been definitely ascertained; but, so far as observed,
its influence is indirect. The affection is most common in the
eastern United States, and in the great cities of the middle states ;
it is comparatively rare in the agricultural districts of the Mis-
sissippi valley, and becomes more rare as the Rocky Mountains
are approached, where over large areas it is practically unknown,
to become more common again on the Pacific slope.

Various explanations may be offered. The horse normally
belongs to high, arid or semi-arid plateaus with dry soil and
not very abundant vegetation of a high nutritive value and free
from fungi, which conditions are attained in those regions where
the disease is most rare. We must at the same time note that
in these regions the horse enjoys the greatest liberty and is
little confined in stables; it is, moreover, the newest part of
our country. The senior contributor has noted an apparent
increase of this malady in central Illinois as the country be-
comes older and the soil and crops have undergone changes
as the outcome of continued cultivation.

Foop. A restricted diet constituting an unbalanced food
ratio induces serious perversions of nutrition, among which
we meet with experimental rhachitis, wherein a condition of.
the bony skeleton is induced which is not distinguishable from
the changes taking place in this group of lamenesses. Pigs fed
upon an exclusive diet of corn meal and confined closely so
as to limit them strictly to the diet given, soon succumb to
tickets. A similar condition is seen in horses fed exclusively
on bran. Hinebauch presented a highly interesting paper at
our thirtieth annual meeting (Proceedings of U. S. V. M. A,,

30 Williams, Fisher, and Udall: The Spavin Group.

1893, p. 103) under the title of “Millet Disease in Horses,” in
which, by feeding millet to horses in North Dakota, mostly
in close confinement, serious losses were induced, with symp-
toms and pathologic conditions not separable from rhachitis.

Food must, in our judgment} be regarded as playing a highly
essential réle, though in just what manner we cannot assert,
nor can we wholly separate the question of food from that ‘of
climate and housing.

At times it appears that the food acts directly and consti-
tutes in itself a sufficient cause. We (W.) saw, in Montana,
in one case some twenty-five or more foals, all showing signs
of rhachitic affection in the form of spavins, ringbones, etc.
They were confined on a marshy, alkaline “bottom” pasture,
where the grass was of a coarse variety. The following year
the next foal crop, from the same parents, were pastured on
high foot-hills, and the disease did not recur.

Herepitry. The spavin group of lamenesses are generally
said to be hereditary. Sires and dams so affected, whether
lame or not, and regardless as to whether they ever have been
lame or not, are excluded from the show ring as breeding stock
on the ground of hereditary unsoundness.

Under the head of climate we have already roughly out-
lined the geographical distribution of the malady, it being prac-
tically enzodtie in one section and well-nigh unknown in another, :
though the ancestry of the animals in the two localities is as
nearly identical as can well be. This speaks strongly against
heredity. On the other hand, in those parts of the country
‘ where the affection is common, a diseased mare may raise a
series of colts, all affected and for generation after generation
the disease may continue in a given line and on a given farm,
but we should remember two possibilities, the breeding and the
farm. If given environments on a breeding farm can cause
spavin in a mare, there is no known reason why the same con-
ditions should not produce the same state in her progeny and
in theirs, generation after generation. When discussing the
question of food, we related the case of one ranch where this
affection prevailed when foals were confined in a given pasture,
but disappeared when the mares were moved to a different char-
acter of grazing land. Among the foals of a previous season
from this same farm, was a vigorous, highly bred stallion with
two enormous spavins on otherwise excellent legs. This animal

Williams, Fisher, and Udall: The Spavin Group. 31

was used for stud purposes on a near-by farm on an excellent
band of roadster mares, where for years he bred choice stock,
none of which, we are assured, showed any tendency to spavin
or other affection of the group. Dr. Fisher contributes an
observation on a California breeding ranch where a number
of foals were confined in paddocks and highly fed. Osteo-poro-
sis became general, some perished, the remainder were then
removed to a hillside pasture one-half mile distant, where they
promptly recovered.

The only clinical evidence of heredity which we have been
able to observe is the occurrences of the disease among offspring
under the same conditions as those which produced it in the
affected parent, while affected animals removed from the sur-
roundings in which they acquired the malady do not transmit
it to their offspring. We hold that a hereditary disease is
cosmopolitan, knows no geographical limitations, and is not
overcome by such environments as climate, food, or housing,
and, taking this view, we cannot admit heredity as a cause of
spavin or its allies. . 2

We believe, however, that hereditary peculiarities in con-
formation may tend to predetermine, in case the disease does
arise, whether it shall appear in the form of spavin, ringbone,
or other affection.

RHEUMATISM. It is exceedingly difficult to arrive at any
definite conclusion as to the réle played in the causation of
this group of affections’ by the oft alleged rheumatism. The
fundamental difficulty in arriving at a conclusion is the inse-
curity of our definition of the term, we having as yet determined
no rheumatism lesion which can serve to clearly distinguish that
affection, whether in man or animals, while in the disease under
consideration we have lesions of quite a definite character, not
capable of differentiation among possibly two or three different
maladies, it is true, but by no means suggestive of rheumatism
as described in man.

If we attempt to draw our conclusions from the disease
known as rheumatism in man, the symptomatology is very un-
like. We have occasional shifting of lameness in a few cases,
it is true, but, as a rule, it is in a way permanent in the affected
part, and, while rheumatism in man is ordinarily sudden in its
onset, spavin and its allies generally come on insidiously, and
only rarely appear suddenly. It seems to us that we are not

32 Williams, Fisher, and Udall: The Spavin Group.

warranted at present in arriving at the conclusion that rheu-
matism plays any important part etiologically.

Conractous Pneumonia (Brustseuche). Dieckerhoff has
observed the frequent occurrence of spavin following conva-
lescence after contagious pneumonia. This is a common obser-
vation and applies quite as fully to other members of the group.
As already related, the horse from which Figs. XVII, XVIII,
VIII, and IX were taken, after having apparently become
convalescent from contagious pneumonia, quickly developed
tendonitis and tendo-vaginitis, on which account he was des-
troyed, when beneath these swellings were found ringbone, side-
bones, navicular disease, and sesamoiditis, and, upon opening
the chest, thirteen fractured ribs and anchylosis of the vertebrz
were revealed. Probably other contagious fevers of the horse
tend to usher in this group of lamenesses, and certainly we know
that any injury which may confine a horse in the stable for a
long period, especially if the general system is markedly de-
pressed, is very liable to finally end in an attack of this malady.

So far as we know, the contagious pneumonia or other
affection has no immediate relation or, rather, it does not con-
stitute an expression of the former, but by its debilitating influ-
ence prepares the way for spavin and its allies.

RHACHITIS, OSTEO-POROSIS, OSTEO-MALACIE. In the affection
or affections variously described as osteo-porosis, osteo-malacie,
and rickets, we meet frequently with spavins, ringbones, gonitis,
etc., which are not distinguishable during life from the ordinary
affection ascribed to other causes. In our paper presented to this
association (“ Rhachitis.” Proceedings of U.S.V.M.A., 18g1,
page 113), we cited cases in which enormous spavins developed
during a well-marked attack of osteo-porosis, that in the same
stable nearly all weanlings died from typical rhachitis, some
of them suffering from spontaneous fracture of the spinal col-
umn, while some older colts suffered from lordosis, kyphosis,
or skoliosis. When spavin and its allies occur during rickets,
osteo-porosis, or osteo-malacie, it appears to be an essential part
of the malady itself, not a result of it. Our knowledge of the
relationship existing between osteo-malacie, osteo-porosis, and
thachitis has not been determined; some believe they are iden-
tical, others consider them different, but fail to fix the boundaries
between them or establish definite rules for differentiation.
Prominent members of this society have time and again urged

Williams, Fisher, and Udall: The Spavin Group. 33

the special study of osteo-porosis, but to no avail. If that one
malady, if it be separable from the others, could be definitely
described and differentiated from other diseases, it would be
a great help. In the present state of our knowledge, we can
only say that spavin and its allies appears frequently as a mani-
festation of this disease or group of diseases.

A Rareryine Ostitis, Nor AT Present IDENTIFIABLE WITH
EITHER OF THE PrEcEDING. We regret possibly adding to the
confusion by calling special attention to a form of disease ex-
Pressing itself preéminently as spavin or its allies.

It occurs in the form of a rarefying ostitis affecting most,
visibly the short bones like the phalanges, navicular and sesa-
moids, and the lesser bones of the tarsus and carpus, producing
the characteristic lesions already described. The indefiniteness
‘of the preceding affections renders it difficult to place this one.
It presumably belongs among the three, but whether to call
it osteo-malacie, rhachitis, or osteo-porosis, we are at a loss
to state. Either name might well be applied etymologically,
since it affects the spinal column, and hence may be called
thachitis; the bone is softened, rendering the term osteo-
malacie appropriate, and the bone is abnormally porous, which
permits the designation of osteo-porosis. In the area of our
chief observations of this disease, the neighborhood of Ithaca,.
New York, the affection is very common, has no limitations
as to age, sex, or breed. It appears frequently in the form
of ringbones and spavins in foals of three or four months, and
is very common during the first winter of the foal’s life. It is
not at all rare to see such a foal with two spavins and four
ringbones ; with adult horses, on the other hand, the exostoses
are usually not so symmetrical and universal. In some cases
there is but one discoverable exostosis during life, and between
this and cases where a sound joint does not seem to exist, but
where the lesions are only discoverable upon post-mortem
examination after cleaning the bones, there is every gradation.

In severe cases there are constitutional disturbances of a
marked character expressed by a general appearance of bad
health, and, among other things, an excess of phosphates in
the urine?

In the region mentioned, typical osteo-porosis, with the
enormous bulging of the facial and cranial bones, is wholly

unknown. In nine years there has not been a case typical of

34 Williams, Fisher, and Udall: The Spavin Group.

osteo-porosis presented at the clinic of the New York State
Veterinary College, while spavin and its allies easily takes first
place numerically among all diseases -of the horse, whether
medical or surgical, contagious or sporadic, but those animals
presented because of this malady by no means represents the
sum total of animals presented with it for other ailments. Nor-
mally, only those cases which are lame are presented because
of the affection, but probably not more than twenty per cent. of
the affected are lame, a large proportion of them apparently
escaping lameness throughout their lives. We must leave the
identification of this malady for further study, with the hope
that the important group of diseases, expressed chiefly by a
rarefying ostitis or porous and softened condition of the bones,
possibly accompanied in all forms by phosphaturia, either be
definitely identified as a single disorder or ‘clearly separated
from each other in a manner as to permit of a safe differential
diagnosis.

InFecTION. Over and above all causes suggested stands
the question of infection, one which is quite unanswerable from
the data at hand.

Clinically such an explanation is not rendered impossible,
and some investigators claim an infection as the fundamental
cause.

FACTORS IN THE LOCALIZATION OF THE LESIONS.

If the disease, as we have already ventured to say, is funda-
mentally a constitutional and not a local one, it remains for
us to consider the causes for the concentration in oné or more
small areas of the visible indications of the malady as expressed
in exostosis, lameness, or other abnormality.

In discussing the causes of the malady, we have. taken

_ occasion to state that in our opinion many of the alleged chief
causes were contributory or modifying rather than, essential,
since in our view they tend to determine the location of the
pronounced symptoms of the disease, after the essential consti-
tutional disturbances have become established either visibly or
invisibly. We believe also that mechanical insult, either direct
or indirect, may act as the sole means of developing the visible
signs of the disease, which might otherwise disappear by reso-
lution. We are not in a position to deny the possibility of

Williams, Fisher, and Udall: The Spavin Group. 35

inducing the local lesions as a definite and essential result of
a traumatic injury, but cannot admit that a mechanical insult
at one point can induce general histologic lesions throughout
the bony skeleton and induce serious pathologic changes in_
the prinary secretions. It has not yet been determined if a
spavin, ringbone, or other local lesion ever exists in the active
or formative stage without a generalized pathologic condition
of the skeleton and changes in the urine. Granting the exist-
ence of constitutional disease, the factors which determine the
localization appear to be largely capable of explanation.
Referring to the preceding chapter on pathology, it appears
that the bones most affected are those which we commonly know
as “short,” and that the chief destruction takes place within
the lacunze and red marrow, which forms so large a portion of
these and of the articular ends of the long bones. Thus we
find the chief expression of the malady in the digits, navicular
bone, the lesser carpal and tarsal bones, the spinal column, and
the ribs. But we would not be understood that compact bony
tissue does not undergo equally important changes in propor-
tion to its comparative amount of active elements, as is shown
by theit decreased specific gravity and by their fragility as seen
in fractures in these cases. The short, spongy bones become
the chief points of attack because the contain a preponderance
of the tissues in which the disease works its greatest havoc..
We may consider the varieties of mechanical insult under |
three heads: compression, strain, and concussion, and believe |
we have related them in approximately their order of impor-~
tance. The horse is preéminently an animal of motion, but
when not in locomotion maintains the standing position rather
than recumbency in a very remarkable degree in comparison
with other mammals. Some horses habitually stand while
sleeping and do not lie down during long periods of time, while
many horses which are kept in the harness long hours daily
are compelled to stand a large part of the time, closely tied
in an uncomfortable position between the thills of a wagon,
where little opportunity for restful changes of attitude is allowed,
even the head being fixed by tight reining. This brings con-
stant pressure to bear upon certain articulations and the bones
concerned. If we study the anatomical arrangement of the
navicular bone, we find it being constantly compressed, when-
ever weight is borne upon the limb, between the unyielding

36 Williams, Fisher, and Udall. The Spavin Group.

second and third phalanges above and in front, and the tightly
stretched flexor pedis tendon behind and below. The com-
pression may be varied somewhat on the superior surface and
shifted from one articular facet to the other by changing the
relation of the coronal and pedal bones, but, so long as weight
is borne, the pressure on the inferior or tendonous surface is
constant and unchangeable. The superior surface of the bone
remains apparently normal as a rule, while the inferior face
undergoes serious changes -in which the tendon also shares.
The anatomical relation of the navicular bone is alike in front
and behind, but a horse bears approximately fifty-five per cent.
of his weight upon his anterior limbs, and the burden is so great
that normally both feet share it constantly in the same degree,
while in the hind feet the weight-bearing demand, when stand-
ing, is unimportant and the limbs are alternately rested. The
anterior navicular bones suffer often and severely, those of the
posterior limbs almus. never. Some say that strain or concus-
sion plays the greater rdle here, but the strain is certainly
greater during locomotion in the hind than the fore foot, and
the concussion is far less in the navicular than in other neigh-
boring bones.

In ringbone the occurrence of the affection most frequently
in front is again quite as suggestive of compression as of con-
cussion or strain, though admittedly the two latter play a far
greater role here than in navicular disease.

In spavin we find the disease affecting with greatest fre-
quency those bones which are under the most constant com-
pression. The tendo-achilles behind, the flexor metatarsi in
front, by their tension when the foot is at rest permit little
relief from the compression of the cuneiform bones between
the head of the metatarsus and the astragalus. When weight.
is placed upon the limb, the compression of these bones con-
tinues. To add to this, acute pressure is brought to bear upon
the seat of spavin by the crossing over it of the tightly stretched
cunean tendon. The theory of Dieckerhoff, allotting to this
stretched tendon an important réle in the causation of spavin,
though we regard it as secondary, is in our judgment thoroughly
justified, and the relief from spavin lameness secured by cunean
tenotomy adds weight to the theory.

The belief in the importance of compression is further sup-
ported by the alleviation of spavin, ringbone, and especially

Williams, Fisher, and Udall: The Spavin Group. 37

navicular disease by so shoeing the animal as to relieve the
painfully affected parts from compression. One of our most
useful diagnostic agents in spavin, the spavin test, consists of
exalted pain brought about by unusual compression. We prob-
ably all recognize the evil influence of the low heel and long toe
in determining navicular disease, and regard neglect in the
changing of shoes and proper shortening of the toes as a highly
important factor, and its significance. to us is found in the
increased compression of the navicular bone by the vicious posi-
tion of the foot. In the same way we regard unnatural dryness
of the hoof as acting injuriously through the compression of
the bony structures included within it. We meet with strong
proof of the importance of pressure as a causative force, when,
after netirotomy, the natural protection of the diseased parts
through the agency of pain is destroyed, the consequent pres-
sure resulting often in increased virulence of the rarefying osti-
tis, leading to destruction of the integrity of the bones, ending
in “breaking down.” Compression probably acts chiefly by
disturbing the circulation and causing congestion, and accelerat-
ing in this way the pathological changes occurring, especially
necrosis and atrophy of the tissues.

Strain appears to play an important part in localization. We-
have noted, in several cases, especially in old-standing, quiescent
spavins, a sudden eruption of lameness dating from becoming
cast in the stall or from overexertion in drawing a heavy load.
Perhaps this was due to a fracture or interruption between two
more or less anchylosed bones. In other instances the exostoses
have not been observed until shortly after a severe strain, but
these cases with a definite history of strain constitute the excep-
tion and not the rule. Probably the great influence of strain
in localization is due to overtension of a degree which would
be counted normal under proper conditions, and acquire impor-
tance only because the tissues are weakened by disease. We
‘might say it is the result of an attempt of a part to perform
its normal function when unfitted by existing disease.

The same may be said of concussion. In some cases we
meet with concussion fractures, inducing sudden and extreme
lameness as in fracture of the navicular bone where it has been
weakened, as shown in Fig. I, or splitting of the first or second
phalanx, injuries which may occur as the result of extreme
violence, but most generally seen in animals suffering from
some osseous disease.

38 Williams, Fisher, and Udall: The Spavin Group.

The part, consequently, which concussion plays in the locali-
zation of the disease, is probably considerable and of the same
general character as the influence of strain; that is, the part
is damaged by the concussion, not because the latter is extraor-
dinary, but as a result of decreased power of resistance in the
bone as a result of disease.

The breed of the animal fixes in a measure the character of
the labor and the two factors acting through the preceding causes,
apparently influence the localization. Draft breeds are rarely
kept confined in the standing position so long as smaller horses,
nor are they kept confined in stables for so long periods, their
work being more constant. They do not suffer so much from
navicular disease, probably because this bone is not subjected
to so much abnormal, continued compression. But here we
are frequently deceived by navicular disease being hidden be-
neath ringbone or sidebones, so that it is not diagnosed. Per-
haps another reason acts in these cases. Draft horses have flat
feet, and if the navicular bones become painful from disease
and the horse attempts to relieve the compression, the pedal.
bone may move backward and downward and sinking of the.
os pedis result instead of, or along with the navicular disease.

On the other hand, strain and concussion play a more
important part in the draft horse, and we see comparatively
more frequently those forms of the disease most readily charge-
able to these factors. -

The conformation of the limb by which the compression,
strain, or concussion is modified in a given part influences the
localization of the disease. If a hock be faulty and other articu-
lations good, we should expect that fact to tend to determine
the disease assuming the character of spavin in preference to
other forms.

THE CAUSES OF LAMENESS.

This group of diseases is so often accompanied by lameness
and so frequently not that it is desirable to know upon what
conditions it depends, since upon our judgment in this matter
rests the value of our opinion as to the prognosis and the prob-
able usefulness of the patient.

So far as we know, when the subchondral bone has been
removed and the articular cartilage has dropped into the cavity,
causing the familiar erosions, the animal can never again go

Williams, Fisher, and Udall: The Spavin Group. 39

sound unless the articulation or bursa has become obliterated
through anchylosis or the sensation has been surgically de-
stroyed. But this lesion is not essential to the production of
lameness. In some cases we have all the cardinal symptoms of
navicular disease or spavin without externally visible changes
in structure, such as exostosis, synovitis, or periostitis, and their
prompt recovery forces us to conclude either that an error in
diagnosis has been made or that the pathologic condition was
such as to admit of prompt resolution. We do not believe that
a prompt recovery from what appears as typical navicular lame-
ness is conclusive evidence of diagnostic error, but hold it not
only to be possible, but of not very infrequent occurrence. So
with other forms of the disease, and we must find other explana-
tion for the pain. We have observed well-marked cases of
general soreness with typical symptoms of navicular disease
or other member of the group which responded quickly to treat-
ment, and in which neither erosions, exostoses, periostitis, nor
synovitis could be recognized or their presence in a serious.
degree suspected, and we were forced to the conclusion that
the intra-osseous pain resulting from the pathologic changes
going on is responsible for the lameness. In one case of very
severe lameness, a careful autopsy failed to reveal superficial
lesions in keeping with the pain, and it could only be attributed
to intra-osseous pain resulting from the ostitis. In Figs. II and
III at B the inflammation would seem sufficient to induce lame-
ness without the lesions at C.

In many cases, especially in ringbone, there is severe lame-
. ness without good proof of erosions, and the exostoses are so
situated as to not interfere materially with the movements of
the articulation. It is impossible to determine here whether the
pain is caused by the exostoses or by the intrasosseous changes;
probably it should be referred to both, but after the subsidence
of the active inflammation, we observe repeatedly that exostosis
does not cause pain. Whether within the original bone, within
the new formed bone, or in the periosteum, the lameness must
be due to inflammatory processes still at work.

The synovitis in itself probably causes lameness sometimes,
though we do not find cases, except perhaps in navicular disease,
where manipulation can induce pain. With the common ten-—
dency toward anchylosis, we must anticipate frequent interrup-
tions in the process; two bones will become partially anchy-

40 Williams, Fisher, and Udall: The Spavin Group.

losed, and the destruction of motion be sufficiently effective to.

cause a cessation of pain, but an accident or hard work may
interrupt the anchylosing process and suddenly cause more or
less severe lameness.

In other cases, not very rare, the lameness, when appearing

suddenly, can only be attributed to fracture, the bones having
become so weakened that they break from ordinary use, as is
seen in split phalanges and as might readily occur in the navic-
ular bone in a case like Fig. XIX. In yet other cases, the
lameness is due to the tearing away of the tendons from the
softened bone. Finally there is a tendency in some of the larger
joints, as at N?, Fig. VIII, to the calcification of the synovial
fringes and their ultimate detachment and escape into the syno-
vial cavity, where, floating freely, they may become engaged
between the ends of the bones, causing sudden and extreme
lameness until such time as the floating body may become dis-
lodged.

SYMPTOMS.

The symptoms of this group of lamenesses are exceedingly
varied and complicated. The advent of the affection is usually
_ slow and insidious, but it may appear suddenly and pursue a

rapid and violent course. In many cases ringbone and spavins
[ appear in young animals so insidiously that even with two
spavins and four well developed ringbones, there may be no
lameness or stiffness to attract the attention of the owner, the
animal may be thrifty, in good flesh and growing well, the
exostoses attain their growth and become wholly quiescent and
remain so, the animal performing ordinary work during its life-
time without apparent difficulty of any kind, the exostoses hav-
ing the simple value of blemishes. As a rule, it may be said
that the younger the animal the less serious the exostoses and
other lesions of which this may be the chief expression. In
these cases where the owner observes no symptoms of lameness

or difficulty of locomotion, it is not unlikely that the trained’

eye would note a peculiar stiffness of gait, a disinclination to
run and play, a caution in locomotion, a “tied in” gait. Certain
it is that in numerous cases of a very insidious type, in young
and old animals alike, there is no distinct lameness, but for
weeks or months, exceptionally for years, there is an ill defined
soreness in the gait, not amounting to lameness, but abbreviating

NOY AN,

Tlic. X1X.— Two navicular bones, seriously excavated by disease, illustrating how fracture
of that bone may occur. Upper row, Inferior surface of navicular bones. Lower row, The same
bones cut transversely and showing extensive excavation in the interior, largely destroying the

strength of the bone.

Fic. XX.— “ Breaking down’”’ after neurotomy for navicular disease.

F. C.. Flexor conona tendon.

F. P., Flexor pedis tendon.

O. N., Navicular bone. ’

In the left-hand specimen the flexor pedis tendon has torn away from the pedal bone, the torn
end resting at postero-superior portion of os corona, while other posterior ligaments have given

wa ermitting great displacement of phalanges. } i j
ae the Rene aaa figure the navicular bone has been displaced along with the flexor pedis ten-
don. In neither case is the tendon ruptured, but torn away from the bone.

Fic. XXI.—A fore foot showing extensive dissemination of the disease in mild form, there

being evidences of carpitis, sesamoiditis, ringbone, sidebones, and navicular disease.

Williams, Fisher, and Udall: The Spavin Group. 41

the stride. Generally the undefined stiffness develops more or
less rapidly into distinct lameness of varying severity, which
is frequently masked in a measure by its symmetrical character,
the two limbs becoming simultaneously affected in the corre-
sponding joint. The lameness generally tends to decrease. dur-
ing moderate exercise, and in spavin especially may wholly dis-)
appear. Severe work, either at a rapid pace or heavy draft,|
increases the lameness, and this becomes still further accentu-
ated if after a period of hard labor the animal is kept closely
confined for some hours. ;

In severe cases the lameness increases more or less rapidly
in intensity, the number of joints involved tend to increase, the
spinal column becomes rigid, and the animal has difficulty in
getting up when down, or, after experiencing difficulty, avoids
lying down and sleeps in the standing posture.

At times the lameness is very sudden. Perhaps a ringbone
or spavin has long existed without lameness, when suddenly,,
with or without known accident, the animal becomes severely,
lame, perhaps as the result of a fracture between two imper-
fectly anchylosed bones, or, as in a case observed by us (W.),

what appeared to be a fracture of the navicular bone, like in *

Fig. XIX, occurred during a journey, the animal starting appar-
ently sound, returning later severely lame in one foot from
navicular disease, lameness quickly following in the other foot
and continuing in both until neurotomy became necessary.
In ‘other cases one of the phalanges becomes cracked without
adequate reasons aside from the diseased condition, as shown at
3 in Fig. I, As a general rule, there is no history of trau-
matism, and in many cases where mechanical injury is alleged
-the evidence is by no means convincing.

The local manifestation of disease may precede, accompany,

er follow the advent of lameness. These consist of the cardinal 4

symptoms of inflammation, any one of which may be wanting.
In extensive joints with large synovial sacs, there is usually
an increase of synovial fluid:::. This is notable in gonitis, and
constitutes the chief visible change in the joint. In sesamoi-
ditis it is well marked, and in navicular disease the bursa is
sometimes so distended as to show in the heel. . In spavin, the
tibio-astragaloid bursa is frequently distended, serving as a mask
for the more definite exostoses of the lesser bones. While
authors describe this group as dry arthritis, it seems to us that
4

|

!

42 Williams, Fisher, and Udall: The Spavin Group.

, the designation is wholly inappropriate, and that as a rule there

is increased synovial accumulation.
Exostosis constitutes perhaps the most constant change. It

‘ occurs early in the disease and may be of every conceivable

degrge, from minute elevations of bone, undistinguishable dur-
ing life, to enormous enlargements sometimes developing chiefly
on one side of the joint, tending to throw the bones out of their
normal direction, causing great deformity. The exostoses are
nearly always symmetrical, which may lead to confusion, two
spavins of equal size being frequently regarded as ‘“‘ rough”
hocks. ‘
Heat is rarely recognized as a symptom, but may be present
in very active disease of such a joint as the hock or stifle.
Pain is chiefly expressed as a resuit of locomotion or the

bearing of the animal’s weight upon the affected part. It can-

not generally be induced by ordinary digital compression or
manipulation. In navicular disease, pain is evinced sometimes
by striking the sole or frog with a hammer, by pressing over
the bursa with hoof testers, and by compressing the bursa from
the heel with the thumb. Compression of the navicular bone
by causing the animal to bear its weight on a wedge, with its
base directed forward also causes an expression of pain.

In spavin, the flexing of the hock (spavin test) by* compress-
ing the small bones of the tarsus causes pain which finds expres-
sion in increased limping when the foot is released.

The constitutional symptoms are of every grade. In a large
proportion of cases they are absent or too inconspicuous to at-
tract attention. In severe cases there are general symptoms of
ill health, in numerous cases the patient is listless, very disinclined
to move, there are digestive derangements, with marked loss of
flesh.

As already related under pathology, the urine appears to
contain an excess of phosphates. This symptom has not yet
been sufficiently studied to make it reliable and available, but we
have strong hopes that in the near future urinalysis may become
a valuable guide in diagnosing the malady.’

DIFFERENTIAL DIAGNOSIS.

We need to differentiate this group of affections from other
maladies and also to distinguish between the individual members
of the group.

Williams, Fisher, and Udall: The. Spavin Group. 43

As a group one of the important characteristics is the ab- ~
sence of traumatism. Admittedly traumatism at times occtirs
and modifies the localization and intensity of the visible disease
process, but these cases are so: exceptional and stand out so
boldly as to rather emphasize the rule.

Another important factor in differentiation is the well- -nigh
constant multiplicity of lesions. They are largely symmetrical, i
if one hock has a spavin, so has the other, if there is one ring-
bone there are probably others, if navicular disease exists in one
fore foot it is well-nigh sure to co-exist in the other. Ifa spavin
is present, a search will probably reveal slight ringbones, if
gonitis appear, there can probably be found a spavin or ringbone.
Most practitioners do not search for these and many fail to
recognize their diagnostic value, which is their sole importance.
as a rule, because the smaller of these exostoses are not un-
sightly and have little danger for the usefulness of the patient.

The character of the lameness is quite unlike traumatisrn
whether infected or aseptic. In the former of these two there
is a tendency to suppuration or erysipelatous inflammation, in
the latter, like strains, etc., there is sudden lameness quickly
reaching a crisis and gradually receding. In this group the
lameness is insidious and persistent, with the few exceptions
we have noted.

The local manifestations possess a high value, the exostoses
are characteristic and we rarely meet with bony enlargements
likely to be mistaken for these. It is true that the exostoses may
be of so small size that different examiners will hold different
opinions and admittedly they exist in imperceptible gradations
and finally reach a point where their presence or absence cannot
be decided during the life of the patient.

We have already referred to the subject of urinalysis under
the heads of pathology and symptoms.

The differentiation between the lamenesses arising from the
various members of the group is frequently difficult and not
rarely impossible. It is not always essential that the differentia-
tion should be clear, yet is nearly always advantageous.

If a horse, lame in a hind leg, presents an evident spavin
and at the same time shows gonitis with the rigid stifle and
distension of the femoro-patellar capsule, we may rest assured
in the present state of our knowledge, that he is lame in the
stifle, but may not be able to exclude the hock. We might find |

44 Williams, Fisher, and Udall: The Spavin Group.

a modification of the lameness by inducing local anesthesia of
the hock and thus exclude the spavin.

- Spavin and ringbone exostoses frequently occur together and
are difficult to differentiate. The spavin test is uncertain as the
flexion usually involves violence to both parts, though the com-
pression on the ringbone may be reduced to a minimum by
exerting the force upon the metatarsus instead of the toe.

If one of the exostoses is old and the other recent, the lame-
ness may be fairly attributed to the latter:

The best method of differentiation is local anzesthetization
of the plantar nerves.

In the fore foot we find difficulty in differentiating between
ringbone, sidebone, and navicular disease, and in some cases we
meet with compound lameness, all three being present, as is
shown in Figs. XVIII and XXI. The presence of ringbone pro-
hibits, especially if it is low, the detection of navicular lameness, as
any test which we may be able to apply to the one will act very
similarly on the other. The sidebones frequently extend up so
high as to cover over or become continuous with ringbones in
which case we are powerless during the life of the animal to
differentiate. The common presence of sidebones and ring-
bones in draft horses with navicular disease prevents the diag-
nosis of the latter and leads to the opinion that it does not occur
in draft animals. When but one form of exostosis is present and
we'can detect no navicular disease, we may assume its absence,
but it is not safe to base a prognosis upon such assumption.

In the absence of exostosis, navicular disease is fairly easily
diagnosed.’ It must always be remembered in differential diag-
nosis that a horse limping to-day from a slight ringbone may be
lame to-morrow from navicular disease, conditions which give
abundant room for professional friction when different veteri-
narians examining a horse at close intervals clash in diagnosis.
Each may be correct.

COURSE AND TERMINATION.

As in other diseases resolution may, and frequently does occur.
When recognized early in its course ere irrecoverable lesions
have occurred, the causes removed and prompt measures taken
to correct the local and general disturbances, recovery may be
complete and permanent. | ;

Williams, Fisher, and Udall: The Spavin Group. 45

In other cases the constitutional changes are so rapid and
severe that the animal quickly loses condition, is listless, disin-
clined to move, becomes greatly emaciated, spontaneous frac-
tures occur or the case otherwise becomes hopeless and the animal
is destroyed.

The vast majority of cases pursue courses between these
extremes. Many young animals develop multiple exostoses with-
out notable lameness, anchyloses occur in some of the smaller
joints, the patient recovers its general vigor and goes through
life doing satisfactory labor without lameness.

Many other cases, especially in young animals, are lame for
a time, but if the joint be of limited motion, anchylosis may
occur after some months or even years and the lameness dis-
appear. Subsequent to anchylosis the lameness may recur in
the affected joint at any time during the patient’s life, due
either to a return of the disease process or to an accidental dis-
turbance of an imperfect anchylosis. Sixty to seventy-five per
cent. of spavin and ringbone lameness in young animals end in
recovery by anchylosis if early attention be given.

In the residue of these cases and in sixty to seventy-five per
cent: of aged horses that become affected, the disease in these
joints resists treatment and remains permanent, seriously dimin-
ishing and frequently destroying the value of the animal. The
character of the articulation modifies greatly the prognosis.
When the disease affects the stifle (gonitis), a colt may recover,
but the collection of synovia in the femoro-patellar capsule usually
floats the patella outward, causing it to pass over the external
femoral condyle producing “floating” luxation, ending in a
failure of the external condyle to develop, thus destroying the
trochlea and even if the disease processes abate, the patella slips
out and in at each step and the animal is worthless. This result
is well shown in Figs. VIII and IX. Anchylosis being barred
in such articulations, when important changes have occurred in
the joint, the lameness becomes permanent and disabling.

In some cases of chronic navicular disease, it is believed that
the flexor tendon and bone become anchylosed and alleviate or
stop the lameness. In one very lame dissecting subject, we found
firm anchylosis between the bone and tendon.

Anchylosis cannot well occur in important joints, and when
it does, that in itself renders the animal useless. Anchyloses of
the vertebrz, especially in the lumbar region, are not rare; when

46 Williams, Fisher, and Udall: The Spavin Group.

limited they may not interfere greatly with the animal’s move-
ments, but when extensive, render its movements stiff and inter-
fere with lying down and getting up.

Fractures may occur either in what we may term a spon-
taneous manner, that is, in the course of ordinary movement, or
function, or accidentally from some extra insult.

We have already referred to the thirteen broken ribs shown
in Fig. XVII, in which the fractures were scattered irregularly
over both sides of the chest and had apparently occurred singly
and without any violence. The spine is liable to become so
fragile as to fracture spontaneously in getting up, and the
pasterns and navicular bones occasionally give way in a similar
manner without adequate violence; the admirably protected
pedal bone may give way on its plantar surface, permitting the
tendon of the flexor pedis to pull out, carrying a portion of the
bone with it. While this may occur in any case, it is, especially
prone to follow neurotomy with the. consequent weight put
upon the pedal bone which in its pathologic state it is unable to
bear.

The “accidental” fractures occur variously, by falls or
blows like other fractures, only more certainly induced usder
slight provocation.

Of greatest interest to us are the fractures from casting for
operation. A large proportion of animals suffering from frac-
tures during casting accompany confinement for some surgical
operation for spavin, ringbone, navicular disease, or some other
member of the group. The fact is significant and we habitually
decline to cast a colt for castration except definitely at the owner’s
risk when the presence of exostoses referable to this group are
evident. We regard the casting of these animals as a constant
danger quite out of proportion to ordinary casting risks and
when necessary to confine such a patient for any reason, are
careful to stipulate that it is done specifically at the owner’s risk
after he has been fully advised of the dangers.

PROGNOSIS.

The prognosis of the disease has been largely covered inci-
dentally in the preceding section.

The probability of life is excellent, the fatalities occurring
almost only in severe cases of the maladies or forms known as
osteo-porosis and rickets.

Williams, Fisher, and Udall: The Spavin Group, 47

The prospect of resolution without visible traces of the
malady are remote, only those few cases which we are able to
diagnose prior to the establishment of extensive lesions or which
without recognition undergo some change in environment or
care offering hope for complete recovery.

A large proportion recover their usefulness through a restora-
tion of any lost vigor, repair of the affected bone and other
tissues, or the anchylosis of joints of limited motion. In other
cases, changes in shoeing and other forms of handling alleviate
the pain and render the animal capable of doing. certain kinds
of labor in comparative comfort, especially slow work on soft
ground. .

A’ goodly part of the total, perhaps twenty-five to thirty per
cent., remain permanently lame and essentially worthless.

TREATMENT.

The handling of this group of affections may be undertaken
with a variety of objects in view, according to conditions. We
may aim at the attainment of resolution, the repair of the af-
fected parts with permanent blemish, the production of anchylosis,
the alleviation of pain, or the production of anzesthesia.

Any attempt to induce resolution necessarily demands our
attention to the care of the animal, especially in relation to the —
character of food, housing, and exercise. In discussing the
causes, we have necessarily indicated indirectly that in order to
abort the affection in its early stages, we would do well to
allow a variety of food: of good quality, and preferably the
freedom of the pasture. If the exigencies of weather or sur-
roundings demand housing, we would desire the ordinary hy-
gienic conditions, including regular daily exercise of a moderate
kind. These conditions are also advisable as contributory to
other methods of treatment at.any stage of the affection.

Internal medication has not been placed on a secure experi-
mental basis. While some writers, in cases of rickets or other
disease involving increased excretion of phosphates in the urine,
advise the internal administration of these, claiming good results,
although advising with it other medication and care which
would probably favorably affect the course of the disease, others.
have found no benefit from the administration of phosphorus.

Although we can readily comprehend the reason for admin-
istering phosphates as an alterative and thereby hope to secure

48 Williams, Fisher, and Udall: The Spavin Group.

good results, we fail wholly to see why, when the system is
wasting phosphates, we should supply more to be added to those
already being excreted. There are enough phosphates in the
food and perhaps in the body, but the organism is repelling the
element and discarding it from the system. We consequently
incline rather to attempt in some. way to cause the system to
assimilate and conserve the phosphorus on hand. Without know-
ing the exact nature of the disease, it is difficult to formulate a
system of medication.

Were we to assume that the disease is an infection or intoxi-
cation, we would turn to those substances which, when given
internally, may be believed to exert a bactericidal power -or
cause the elimination or destruction of their products. -

In the cases termed millet disease by Hinebauch, he secured
apparently good results by the administration of salicylate of soda
and nitrate of potash. Berns has reported good results in the
treatment of osteo-porosis with the salicylate. Possibly bitter
tonics would act similarly.

We have had some apparently excellent and specific results
from the administration of potassium iodide in daily doses of
one-half to one ounce or more, especially in acute cases of recent
origin, accompanied by general soreness of the skeleton where the
patient was, so to speak, “lame in all four legs and stiff in the
back.” The recovery in several cases, where double navicular
disease seemed clearly present, along with general symptoms
mentioned, has been prompt and enduring. We have usually
combined the iodide with nux vomica.

We may further favor resolution by relieving the most vul-
nerable parts in which the disease threatens to localize by dimin-
ishing the labor or stress demanded of the part. The same
processes tend to alleviate the diseasé when once established, and
increase the usefulness of the horse. A good example is the
high-neeled, or the roller motion shoe which relieves the tension
on the flexor pedis tendon and thereby alleviates navicular dis-
ease and sometimes ringbone or spavin. The same is true of the
elastic padded shoes which relieve the concussion. Partly in
the same manner relief is sometimes had from pain due to those
members of the group having their location within the hoof, by
relieving the encased parts from the pressure of hard, @ry hoofs
by mechanical expanders or expanding them by maceration.

Williams, Fisher, and Udall: The Spavin Group. 49

Of distinct use, both as a curative agency in the earlier stages
and as an alleviating remedy in confirmed lameness, is the appli-
cation of cold water. The continuous irrigation probably serves
the best purpose and there are numerous methods for applying
this, but we question if any equals in efficacy the standing of the
horse in a cold, running stream where such a method is avail-
able. The highest efficiency of this treatment is attained by. con-
tinuing it for four or five hours-daily over a long period of time.

The application of warm or hot water or packs is counselled
by some and possibly has a value approximating that of cold.

In attempting to alleviate pain and restore usefulness through
the medium of anchylosis, various means are used, having gener-
ally a tendency to excite a more acute and reparative inflam-
mation. Mildest among these are stimulating liniments and
vesicants, and for these purposes anything and everything which
will irritate has been used and recommended. In former days
the aromatic oils like origanum, spike, and others were in high
repute and perhaps justly so. They are still used, as is also to
a large extent camphor and turpentine. Jodine and mercury
have a prominent part in veterinarian’s prescriptions and patent
nostrums and possess reasonable efficiency. None of them are
reliable and are generally considered inferior to more radical
measures.

- Subcutaneous injections over. the affected part of oil of mus-
tard, turpentine, concentrated salt solution, and other substances
have been advised and cures reported.

Setons were formerly in vogue with many, especially in
spavin and navicular disease, and apparently exercised a benef-
icent tenidency, but they have been largely discarded.

Cautery has long been in high favor and is perhaps the most
universally applied of any form of treatment in these affections.
It is applied in the two forms of line and puncture firing with
endless deviation in extent, intensity, and plan. The method is
largely a question of choice, though we believe the present
tendency is rather towards multiple deep punctures. The instru-
ment for the firing is purely a matter of choice, most veteri-
narians now using the thermo-cautery as being more convenient
and neater. An old form of treatment for ringbone and spavin
was the now obsolete spavin punch, in which a group of sharp
steel spikes were driven into the exostosis of spavin or ringbone.
We know little of its efficacy.

50 Williams,Fisher, and Udall :. The Spavin Group.5

Dieckerhoff introduced and recommended the tenotomy and
tendo-vaginotomy for the relief of spavin, an operation not.
applicable to other members of the group, but having distinct
merit in the one disease. ee

Periosteotomy has been repeatedly used and commended in
such exostoses as ringbone and spavin and has proven effective
in many cases. Peters introduced a combination of tenotomy and
periosteotomy for the cure of ‘spavin which bears his name.

We and others have resorted to fixation in some cases, espe-
cially in spavin, with good results. The effect has been highly
favorable in very severe spavins with intense inflammation and
swelling and such excessive lameness that the animal declined
to bear any weight upon the affected limb. In such patients the
encasement of the affected member in a firm plaster of Paris
cast gave prompt and grateful relief with rapid abatement of the
swelling and inflammation and early recovery of ability to work.
Fixation has not been sufficiently tried in the more common
type of cases.

When the foregoing means have failed to cure or ameliorate
the disease, there remains as a final resort, the destruction of the
power of feeling either temporarily or permanently. Temporarily,
by local anesthesia, the chief legitimate motive is the use of
cocaine or other like drug for diagnostic purposes. A recent
writer has stated that in one case the injection of cocaine and
adrenaline gave permanent cessation of lameness. The propo-
sition needs further proof.

Generally we aim to produce permanent anesthesia of the
part by neurotomy. Much discussion has been had as to where
we should operate for a given case of disease. Generally speak-
ing, the best place to operate is the nearest point on the proximal
side of the affected part where the sensory nerve supplying that
region can be readily reached. The larger the nerve trunk, the
more permanent the interruption of sensation. In case of the
digital nerve, — low neurotomy, — the innervation of the part is
frequently restored after six to twelve months. Neurotomy is
properly only a final resort and is not otherwise justifiable because
of the dangers involved. The chief and ever-present danger
from the operation is the placing upon the weakened bones of
the foot of an increased amount of weight which, in their dis-
eased condition, they cannot bear; this apparently intensifies the
rarefying ostitis within the bones and corresponding degenerative

Williams, Fisher, and Udall: The Spavin Group. 51

processes in the tendons and other parts. The bones become
more porous and their power of resistance decreases until they
crush under pressure, or yield to tension of their tendons or liga-
ments, the ends of the latter tearing away accompanied by frag-
ments of the degenerate bone. Or the tendon may so far
degenerate as to part transversely.

It is not always the part which was considered chiefly dis-
eased before operating that gives way after neurotomy, but may
be| some other bone or tissue. For example, after neurotomy
for navicular disease, the navicular bone is fairly protected, and
may escape serious injury while the disease processes in the pedal
bone, previously ignored, become intensified and the flexor
tendon tears away from its semilunar crest carrying portions of
bone with it. Following double neurotomy for spavin the break-
ing down may occur in the tarsal bones, the sesamoids, the os
pedis, or the flexor tendons.

Neurotomy has the futher danger that in the absence of
sensation, any injury to the part is unheeded, and the highly
protective office of pain is wanting so that the patient continues
to use the injured part with disastrous results, preventing the
healing of the injury, causing it to extend and finally destroying
the foot. (Fig. XX.)

The selection of cases for neurotomy requires a high degree
of judgment. After excluding all badly formed feet and all
which are suffering from or tending to infections, we still need
to determine which will bear the new strain put upon them when
the pain is removed.

The general rule is that we should not unnerve an animal
which is acutely or extremely lame, in bad general condition, or
in a recent case. This rule is in full harmony with our view
of the constitutional character of the disease and would warrant
our stating the above rule in a new garb — do not perform neu-
rotomy so long as the general disease is active, but wait until
the systemic disturbance has passed and the question has resolved
itself into a painful, incurable local lesion, the parts retaining
sufficient vitality to safely resume their normal function when the
sense of pain is destroyed.

Opinions of neurotomy will always vary because in different
localities and among different classes of horses the seriousness
of the systemic disease will differ. In those areas where the
disease is generally mild and the active systemic disturbance

52 Williams, Fisher, and Udall: The Spavin Group.

promptly passes, leaving only a local permanent one, the operation
proves comparatively safe, while in those regions where the
disease is usually severe, with long continued and serious sys-
temic disturbance, it becomes highly dangerous. Veterinarians
operating on the two different classes will have opposite views
as to its safety. We have seen cases of plantar neurotomy for
navicular disease go down in thirty days, and under different
conditions another work perfectly for ten or more years.

The ethics of neurotomy is an embarrassing question for the
practitioner. No more humane or economic operation is known
to the veterinarian in properly selected cases, relieving constant
suffering of a severe type and restoring to usefulness an animal
otherwise no longer fit for work.

But probably eighty per cent. of unnerved horses are ille-
gitimately or surreptitiously sold to an innocent purchaser, and
the important question arising is the moral responsibility of the
operator. Plainly the veterinarian has for a money consideration
disguised a serious unsoundness in an animal and has thereby _
aided the vendor in imposing upon an innocent purchaser.
Where an owner submits an animal for the operation with a
clear intent to use the horse legitimately whether at work or in
sale, the freedom of the veterinarian is evident, but when he
clearly desires the operator to aid him in making a dishonest sale,
it seems to us that he becomes a party to the fraud. Between
these two extremes the question of propriety on the part of the
veterinarian vacillates.

A recent German writer proposes that in performing neu-
rotomy care should be taken to leave an unsightly and telltale
scar to warn the unwary purchaser, but this device would only
warn the wary buyer, and no scar, soever large, would protect
the uninformed. Neither would most of us agree to perform
an operation in such a bungling and unsurgical manner as to
insure a scar where it can be generally avoided.

Strict laws with severe penalties or selling unnerved horses
without the knowledge of the purchaser might be made to check.
the evil.

EXAMINATIONS FOR SOUNDNESS AND SALE.

In the examination of horses offered for sale, the search
for the spavin group of lameness constitutes an important
part, largely because they may be disguised. Their bilateral

Williams, Fisher, and Udall: The Spavin Group. 53

symmetry frequently gives the animal a short gait, which it is
difficult to identify as lameness., The lameness in some members
of the group disappears with exercise as is specially observed
in spavin. The symmetrical exostoses on both legs confuses
the inexperienced and’ at times leads the experienced astray.
‘The application of local anesthesia effectively masks the disease
temporarily, or the animal may have been unnerved.

It becomes necessary, therefore, to eliminate every possi-
bility of fraud by delaying examination until the effects of
exercise or cocaine shall have vanished and careful search made
for neurotomy. In addition to these precautions, a rigid search
for the lesions of the disease is assumed. When evidences of
the malady are discovered, the examiner needs place some value
upon it.

Some say that a horse with spavin, ringbone, etc., is unsound
and that condemnation is mandatory. A buyer does not care,
if intelligent, if a horse is sound’ or unsound. We would not
attempt to say that a horse was sound or unsound, but would
give him a conscientious examination, record our findings, and
interpret them as well as our judgment would permit.

An animal with quiescent lesions, like ringbone or spavin,
which are not interfering with locomotion and in which all
systemic disturbances have passed by, will probably work or
breed indefinitely without disadvantage. Admittedly lameness
may and does recur in these animals, ‘but*we have no data to
show that a larger per cent. become lame than of horses not
previously affected. The blemish resulting from the exostosis
has a varying value according to size and the class of horse.
In common work animals the blemish is of little consequence,
but in horses of special value the blemish may be exceedingly
serious.

Our views of the breeding value of animals affected with
a member of this group have already been suggested when dis-
cussing heredity as a cause. If not a hereditary affection, and
we believe it is not, then it cannot be objectionable from a
breeder’s standpoint. If an animal has a badly formed hock,
he is clearly rejectable on that ground whether spavined or not,
but if a foal is kept under improper environment, and thereby
acquires a spavin on an otherwise excellent tarsus, we see no
more reason for excluding him from the breeding stud than
though he had a callous from a broken leg.

54 Williams, Fisher, and Udall: The Spavin Group.

When active lesions are present the horse is unfitted for
either work or breeding according to intensity.

OTHER MALADIES POSSIBLY ALLIED TO THIS
GROUP OF AFFECTIONS.

In this great group of diseases it is not easy to definitely
limit it in its scope. If, as alleged in this discourse, the disease
is systemic in character, any tissue may stuffer. In the one
case related and shown in Figs. XVII and XVIII, we stated
that the various affections belonging to this group were revealed
as a consequence of the presence of tendonitis and tendo-vagi-
nitis. These affections seemed to be the initial appearances of
interruption of the convalescence from contagious pneumonia.

This tendonitis and tendo-vaginitis is a common complica-
tion of contagious pneumonia, and closely associated with the
appearance of the spavin group of lesions. Clinically they are
closely related and seem to be due to the same causes. It is a
common assertion, moreover, that in this group of lamenesses,
the flexor tendons occasionally part, though in reality they
generally merely pull away from the bone, carrying parts of
osseous tissue along.

Another interesting malady which appears in the region

of Ithaca, New York, quite abundantly consists in the gradual . . «.

sinking of the os pedis without history, of laminitis or other
disease. It seems identical with what Moeller describes as
sinking of the os pedis, and which is rendered by Dollar in his
translation as standing laminitis.

In cases which we have met, navicular disease is present,
and it seems possible that in flat-footed horses, in attempting
to throw the weight on the toe of the hoof, the os pedis slips
backwards and then downwards, carrying the sole with it
Moeller attributes it to standing on one foot while the corre-
sponding member is disabled. As we have seen it here, both
pedal bones sink simultaneously and insidiously without- dis-
cernible cause, under the same conditions most common in
the spavin group. .

These addenda are only suggestions as to a possible rela-
tionship which may yet prove of interest.

Ves
eh
itansnectys Wa
ratach ah eet
inlghn Sait ea

att
etnias
uaa ek Fab teeth
tate tia