THOROUGH-PIN— THE HOCK. 265 



principal nerves on the fore-part of the inside of the thigh pursue their 

 course at t, in the direction of the cutaneous vein ; and those of the pos- 

 terior part are seen at s, and at u are those important ligamentous bands at 

 the bending of the hock which confine the tendon. 



In the cut of the outside of the thigh, page 260, p will give the course 

 of the anterior arteries and veins; q the course of the principal nerves, 

 and coming into sight below ; and r the bands described in the former 

 plate. 



Also, in the cut of the outside of the shoulder and arm, p. 233, the figures 

 1, 2, and 3, designate the places of the principal artery, nerve and vein of 

 the leg ; 4 gives the subcutaneous vein running within the arm ; and 5, the 

 subcutaneous vein of the side of the chest. 



In the cut of the inside of the arm, p. 235, the lines above represent, in 

 the order from the front, the principal nerves, the arteries, and veins of the 

 shoulder and arm, and, on the muscles, k gives the principal subcutaneous 

 vein of the inside of the arm, and i the artery by which it is accompanied. 



The stifle-joint is not often subject to sprain. The heat and tenderness 

 will guide to the seat of injury. Occasionally, dislocation of the patella 

 has occurred, and the horse drags the injured limb after him, or rests 

 it on the fetlock ; the aid of a veterinary surgeon is here requisite. The 

 muscles of the inside of the thigh, generally, have been sometimes sprained : 

 this may be detected by diffused heat, or heat on the inside of the thigh 

 above the stifle ; rest, fomentations, bleeding, ^d physic will be the proper 

 means of cure. 



THOROUGH-PIN. 



We have observed that there are placed in the neighbourhood of joints, 

 certain bags, containing a mucou^ fluid for the purpose of lubricating the 

 parts, and that these sometimes become inflamed and enlarged. We have 

 spoken of wind-galls and their treatment. A similar enlargement is found 

 above the hock, between the tendons of the flexor of the foot and tlie 

 extensor of the hock. As from its situation it must necessarily project cm 

 both sides of the hock, in the form of a round' swelling, it is called a 

 thorough-pin, a, p. 262. It is an indication of considerable work, but, 

 except it be of a very great size, it is rarely attended by lameness. The 

 mode of treatment must resemble that recommended for wind-galls. 

 Although thorough-pin cannot be pronounced to be unsoundness, yet it 

 behooves the buyer to examine well a horse with thorough-pin, and to ascer- 

 lain whether undue work may not have injured him in other respects. 



THE HOCK. 



We now arrive at a very important joint, often the evident, and much 

 oftener the unsuspected seat of lameness, and the proper formation of which 

 is essentially connected with the excellence and value of the horse. We 

 shall describe it at length. 



The inferior head of the tibials formed into two deep grooves, with three 

 sharpened ridges, one separating the grooves, and the other two forming the 

 sides of them. It is seen at a in the following cut. It rests upon a very 

 singular bone, h, called the astragalus (shaped like the die or dice used by 

 the ancients), which has two circular risings or projections, and with a 

 depression between them, answering exactly to the irregularities of the 

 tibia, and these are received and morticed into each other. At the posterior 

 part its convex surface is received into a concavity near the base ot another 

 S 



