466 
W. J. MARTIN. 
being- the slightest constructed bone in the joint, naturally is 
the first to become the seat of inflammation from the unequal 
distribution of weight. 
The divergent views held by some of the most eminent 
members of the profession in regard to the pathology of spavin, 
renders the subject a most difficult one for the general prac¬ 
titioner to approach, or even to venture an opinion on. Some 
hold that it is the ligaments of the joint in every case that are 
first to become the seat of the inflammatory action, and from 
them it next extends to the substance of the bones. Others 
claim that the disease invariably originates in a strain of the 
inner tendon of the flexor metatarsi muscle ; while others claim, 
among them being the distinguished Dieckerhoff, that the in¬ 
flammation is first set up in the sheath of the tendon of the 
flexor metatarsi muscle, though why inflammation of this 
sheath should cause spavin, when it rarely causes even slight 
lameness, appears strange to me. Our own opinion is that 
spavin is nothing more nor less than an ostitis of the bones of 
the hock joint; the ostitis may originate within the cancellated 
structure of the bone (endositis) or on the external surface of 
the bone (periostitis). Endositis is the form present in idio 
pathic spavin, while the periostitic form is due to traumatic 
causes, as strain of the ligamentous structure of the joint, from 
concussion, etc. 
In endositic inflammation of the bones of the tarsus the del¬ 
icate membrane lining the Haversian canals becomes highly 
congested and inflamed ; this inflammation in time spreads from 
within outwards, and affects the space between the compact 
bones and the periosteum. As the articular cartilage of a joint 
may, for all practical purposes, be considered a continuation of 
the periosteum, it can be readily seen how endositis may rapidly 
spread throughout an articulation. One important fact in 
connection with the pathology of spavin or other forms of bone 
disease should be borne in mind, and that is, “ that it is in 
the soft parts of bone, the periosteum, the medullary mem¬ 
branes, and the delicate connective tissues which pervade the 
