PLATE II. 



SPAVIN DISSECTED. 



Plate II, represents the near hock of a thorough-bred horse, purchased by Cross, 

 knacker, Camden Town, for slaughter, being rendered useless by excessive 

 lameness arising from a spavin of unusually large size upon it, and more pro- 

 minent and better defined than such tumours in general are. The animal had 

 worked in a street- cab as long as he was able ; and was suffering so much pain 

 in the hock at the time of purchase that Cross had him killed the moment he 

 reached the slaughter-house. The magnitude of the tumour, as well as the 

 form of it, with the skin on, was that of the section of a middle-sized orange, 

 spread abroad at its basis, so that it occupied pretty well the whole of the 

 inner surface of the hock. Denuded of its skin and dissected, it appeared as 

 is represented in the annexed Plate. 



a, The os calcis. 



h, The large metatarsal or cannon bone. 



c, The small metatarsal or splent bone. 



d, The astragalus. 



e, g, The limits, superiorly and inferiorly, of the spavin tumour ; whose surface 

 exhibits a knobby irregularity, and whose substance is osseo-cartilaginous, 

 incapable of being penetrated to any depth by the point of the scalpel, and yet 

 in places soft enough to admit of having holes cut or dug into it. Throughout, 

 it exhibits the same inflammatory vascularity (patchy redness) which its internal 

 surface displays. 



/", Part of the periosteal membrane, in which the tumour is encased, dissected off. 



■p, A piece of whalebone inserted into the joint between the two flat cuneiform 

 bones, at the only place where the joint proved penetrable. The red part imme- 

 diately above the whalebone represents the groove made by the inner division of 

 the tendon of the flexor metatarsi. 



/, hy 0, A line drawn from / to h, representing the basis of a triangle whose apex 

 is at 0, will include the osseo-cartilaginous deposit, spreading from the spavin 

 tumour at the side, upon the fore part of the cannon bone, where it is partly 

 covered by the tendon of the flexor metatarsi, which is seen (at k) detached and 

 turned down. 



r The inner division of the biceps tendon of the flexor metatarsi, divided and 

 dissected, in its course to be inserted into the head of the inner small meta- 

 tarsal bone, which is buried deep in the substance of the tumour. 



I The slender tendon of the flexor accessorius, hanging down out of its sheath. 



m, The tendon of the flexor pedis. 



n. The tendon of the flexor suffraginis. 



