€PAVIN. 
535 
this state the foot comes in contact with the ground, in order 
that the animal may propel himself onwards, and in doing which 
the tarsus is forced inwards. To contend with this, we have liga¬ 
ments sufficient in a well-formed limb to sustain the weight. 
The first I shall name are the lateral ligaments on the inside of 
the hock ; they are four in number, each of them taking its own 
peculiar direction, while on the outside there are only two. 
The first ligament we meet with on the internal part arises 
from the tibia; a portion of it is inserted into the lower part of 
the astragalus, and the remainder passes in a fan-like form over 
the inner part of the cuneiform bones, and attaches itself to the 
head of the metatarsus. I believe that it is owing to this liga¬ 
ment that horses affected with spavin flex the leg so quickly, 
because it is then thrown out of action ; while, on the contrary, 
it is in use in the extended position. Besides the alorementioned 
ligament connected with spavin, there are underneath it, and 
expanding in front of the articulation, ligaments joining the 
cuneiform bones, astragalus and metatarsal bones together, and 
in which the disease named bone spavin seems to exist. Why 
this should be most frequently found on the superior and inner 
part of the metatarsal and cuneiform bones evidently depends 
upon the action of these bones, and on their being thrown in¬ 
wards, as both anatomy and physiology cleanly dictate. 
Certain forms of hocks favour this kind of action, and there¬ 
fore are more liable to bone spavin than others are. I need not 
here bring forward each description of hock that is subject to 
this disease, because I am fully aware that I could not, in a 
written essay, satisfactorily explain the forms and connexions of 
these bones. 
The hocks most subject to spavin are those that approach each 
other, called cow hocks . Next are those that are narrow at the 
inferior part of the tarsus, and which are named curly hocks , and 
of this kind those where the os calcis inclines backwards. 
The first stage of spavin is inflammation of the ligament that 
unites the small bones together; and this is succeeded by partial 
ossification of the ligament, and is frequently accompanied by 
exostosis. At this period we have generally lameness, and par¬ 
ticularly if there is any motion remaining among the bones. If 
the inflammation continues for any considerable time, there may 
be ulceration of the articular cartilage, and the lameness will be 
severe. 
This ulceration is invariably at the anterior part of the articu¬ 
lation formed between the astragalus and cuneiforme magnum, 
and also in the two inferior bones; the weight being more directed 
to these parts in the act of progression. 
