LIGAMENTS. 33 



of the bones which form them are, in both cases, held together by strong 

 inelastic ligaments, of which there are various kinds. Capsiclar ligaments, 

 for instance, loosely encircle their joints in order to protect the apparatus 

 which lubricates the ends of the bones. Lateral ligaments are placed on 

 each side of the joint, and, being attached both above and below it, keep 

 the bones together, while admitting often of considerable play. Anmilar 

 ligaments form protecting sheaths for the passage of tendons ; and interosseous 

 ligaments bind bones closely together. Besides these, we have suspensory 

 and check ligaments, which, as far as we are at present concerned, are 

 respectively represented by the structures, bearing these names, which are 

 found in the legs, below the knees and hocks. 



The ligaments to which I have referred are, like tendons, composed of 

 white fibrous tissue (a variety of connective tissue, see p. 14), which is 

 hard, strong and inelastic. Yellow ligaments are, without going into minute 

 differences, to be distinguished by the fact of their yellow colour, and by the 

 possession of considerable elasticity, which enables them to passively bear 

 weights which would otherwise fall on the muscles. A familiar instance of 

 the manner in which elastic ligaments mechanically save the expenditure of 

 muscular force, is afforded by the arrangement which keeps the claws of a 

 cat retracted without entailing exertion on the animal ; for each claw is kept 

 back by a small elastic ligament, which becomes stretched when the digits 

 of the paw are extended by their muscles. As soon as these muscles 

 cease to act, the ligaments, by their power of contraction, regain their 

 natural length and retract the claws. An enormously powerful elastic liga- 

 ment is attached to the withers, and goes straight from them, in the form 

 of a.cord, to the top of the head (the bony prominence between the ears), to 

 which it is inserted. At about a third of the distance from the head to the 

 withers, a broad sheet of elastic tissue is given off from the corded portion, 

 and is united to all the spines of the neck vertebrae, except the first. This 

 sheet accordingly acts as a partition between the muscles on the respective 

 sides of the upper part of the neck. The entire ligament, therefore, by its 

 strength and elasticity greatly aids the muscles in supporting the weight of 

 the head and neck. The amount of stretching which it can undergo in 

 ordinary circumstances may be approximately estimated by comparing the 

 length of the neck, when the head is held up in its usual position, to that 

 when it is lowered to allow the animal to feed off the ground. In the first 

 case, with a horse 15.3 high, it will probably not exceed 28 inches in 

 length ; but in the latter it must be over a yard long, supposing that 

 the animal does not unduly bend his knees. Any depression or elevation 



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