360 THE HOCK. 



In the cut of the inside of the thigh, page 355, p represents the course of the 

 principal artery ; at q are blood-vessels belonging to the groin ; at r is the large 

 cutaneous vein, or the vein immediately under the skin. The principal nerves 

 on the fore part of the inside of the thigh pursue their course at , in the direc- 

 tion of the subcutaneous vein ; and those of the posterior part are seen at *, 

 while at u are those important ligamentous bands at the bending of the hock 

 which confine the tendons. 



In the cut of the outside of the thigh, page 356, p will give the course of 

 the anterior arteries and veins ; q that of the principal nerves, and coining 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. 330, 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 sub- 

 cutaneous vein of the side of the chest. 



In the cut of the inside of the arm, p. 331, the lines above represent, in the 

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

 and arm ; and, on the muscles, A; represents 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 have sometimes been sprained. This may be detected by diffused heat, 

 or heat on the inside of the thigh above the stifle. Rest, fomentations, bleeding, 

 and physic, will be the proper means of cure. 



THOROUGH-PIN. 



Mention has been made of wind-galls and their treatment. A similar enlarge- 

 ment is found above the hock, between the tendons of the flexor of the foot and 

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

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

 pin, a, p. 357. It is an indication of considerable work, but is rarely attended 

 by lameness. The mode of treatment must resemble that for wind-galls. 

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

 Behoves the buyer to examine well a horse that is disfigured by it, and to ascer- 

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



THE HOCK. 



This is a most important joint, occasionally the evident, and much oftener the 

 unsuspected seat of lameness, and the proper formation of which is essentially 

 connected with the value of the horse. It answers to the ancle in the human being. 



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

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

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

 shaped bone, b, the astragalus, which has two circular risings or projections, 

 and, with a depression between them, answering exactly to the irregularities of 

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

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

 bone, and with which it is united by very strong ligaments. This bone, c, is 

 called the os calcis, or bone of the heel, and it projects upwards, flattened at 

 its sides, and receives, strongly implanted into it, the tendons of powerful 

 muscles. These bones rest on two others, the os cuboides, d (cube-formed), 

 behind, and the larger cuneiform or wedge-shaped bone e, in front. The larger 

 wedge-shaped bone is supported by two smaller ones, /, and these two smaller 



