THE TREATMENT OF SPAVIN. 73; 



porosis and rarefying ostitis, in the great majority of cases affecting the 

 cuneiform bones and the metatarsus. This rarefying ostitis is soon 

 succeeded by condensing arthritis. At the same time the corre- 

 sponding articular cartilages become the seat of chondritis, with pro- 

 liferation of cartilage cells and degeneration of the fundamental 

 substance, resulting sooner or later in anchylosis of the joints in 

 question. Often, though not invariably, inflammation extends to the 

 joint, or, possibly, directly from the bone to the periosteum of the 

 small tarsal bones, and there produces an ossifying periostitis, accom- 

 panied by exostoses on the inner surface of the lower line of bones of 

 the hock. The lesions seen in the tissues surrounding the joint are 

 secondary. 



M. Joly considers that what is called spavin, and treated under 

 that name, is a complex pathological process, the stages of which are 

 as follows : — (i) Dry arthritis of the lower tarsal joints ; this is spavin 

 arthritis. (2) Anchylosis of the inflamed joints — spavin anchylosis. 



(3) Exostosis, localised, in consequence of the anatomical formation of 

 the hock, at the infero-internal surface of the joint — spavin exostosis. 



(4) Extension of the disease to the lower tarsal joints, and invasion of 

 the tarso-metatarsal joints and superior tarsal joints — circular spavin. 



The author states that these four phases of the disease do not 

 succeed in regular order throughout the entire extent of the hock. On 

 the contrar}', the\' extend by zones, gradually invading wider areas, 

 one zone having terminated its second or third cycle when the next is 

 only in the primary stages. 



M. Barrier considers that spavin consists essentially in a dry chronic 

 arthritis, usually leading to anchylosis and deformity. It starts in the 

 joints at the infero-internal surface of the hock, and tends to travel 

 from below upwards, and from within outwards. 



The evolution of the morbid process which ends in spavin forma- 

 tion may be summarised as follows : — (i) Strain of the ligamentous 

 structures, either at the surface or in the depths of the small tarsal 

 joints. (2) Ostitis and osteo-periostitis, at first of a rarefying, then of 

 a condensing character, of the osseous structures affected, or of neigh- 

 bouring parts, under the influence of concussion. (3) Peripheral 

 anchylosis, sometimes without deformity, but usually with new growths 

 of bone, which later tend to envelop the joint. (4) Dry arthritis,, 

 ending either in central, very firm anchylosis, or in progressive 

 osteoporotic deformation, or in eburnation of the diseased articular 

 surfaces. 



