306 CHAPTER 38. 



portion, or in other words the consolidated part, of the bony deposit will 

 not yield to any treatment. 



611. Unnerving. 



Division of the nerve has been recommended for lameness arising from 

 spavin with the view of destroying sensation. The operation, however, 

 is useless, because the nerA-e, which supplies the anterior portion of the 

 hock, is so situated that it cannot be reached and divided. It may per- 

 haps be said that the nerve might be cut higher up ; but at that point 

 it is too near the muscle which works the tendon. 



In the fore-leg, where the operation of unnerving is often beneficially 

 appbed in navicular disease, the position of the nerve and muscle is 

 different. 



612. Examination of the hock. 



In the examination of a hock for spavin, it is necessary in the first 

 place to compare the two hocks together. Any difference in size is vei-y 

 suspicious, especially in the adult horse. A hock, however, which may 

 at first si^ht appear large on the inside, may on closer examination prove 

 to be exactly similar to the other ; and if so, the formation must be re- 

 garded as natural, and generally as sound. It is true that there may be 

 spavins in both hocks ; but it is very rarely, if ever found, that the two 

 abnormal gro\vths are exactly similar. In long, coarse-coated horses, the 

 hocks should be damped before examination, so as to make the hair lie 

 smooth. 



Allowance must be made in certain horses for the shape and pro- 

 minences of the bones at the inner and posterior part of the hock, — - 

 which may be due to the line of incidence to the ground. In sickle- 

 hocked horses, for instance, there is often an apparent, but natural en- 

 largement of the bones at the inner and posterior part of the hock, which 

 is oft€n mistaken for spavin. In other horses there may be an abnormal 

 prominence of particular bones in both hocks, which, if exactly similar, 

 must be regarded as natural. 



Ridges in the centre of the middle aud lower tiers of the bones, and 

 a similar development at the head of the inner splint bone, are also some- 

 times mistaken for spavin. These ridges are in reality eminences for 

 the attachment of the ligaments. They are most fully developed in well- 

 bred horses, whose ligaments are strong and therefore require powerful 

 attachments. They are easily distinguished from spavins by the fact of 

 both hocks being similarly formed ; and again by their being in the 

 centre, and not on the edges of the bones as would be the case in a dis- 

 eased growth ; and further by the existence of a similar development in 

 the bones of the knee. Such ridges, far from being a sign of disease, are 

 an indication of strength. 



Besides the general examination of both hocks required to ascertain 

 that they are exactly pairs, it is necessary to inspect minutely the inner 

 front and inside of each hock separately from several points of view, in 



