The horse : with a treatise on draught and a copious index by Youatt William 1776-1847

Author:Youatt, William, 1776-1847
Language: eng
Format: epub, pdf
Tags: Horses, Horses -- Diseases
Publisher: London : Baldwin and Cradock
Published: 1831-03-25T05:00:00+00:00

ill velocity. The product of the power, and the space passed over by the arm of the lever to which it is attached, must always be equal to the product of the weight, and of the space passed over by the arm that supports it; and if a power, equal to thirty times the weio-ht, is oblio-ed to be exerted at the upper part of the bone of the arm, the centre of that bone, which may be considered as the centre of the weight, will pass over thirty times the space, and the extremity of the limb will pass over sixty times the space. The muscle will contract with a great deal of rapidity, but the foot will move with sixty times that rapidity, in order to pass over sixty times the space in the same time. This is precisely what we want. Extensive and rapid motion are the excellences of the horse. He is valuable in proportion as he has them, combined with stoutness; and by this conformation of the limb alone could he obtain them. Therefore the tendon is at first unusually strong; it plays through the natural but perfect pulley of the bone of the arm without friction; the body of the muscle is mixed with tendinous fibres, and the insertion into the fore-arm is very extensive, lest the application of such immense force should tear it from its adhesions. There is sufficient strength in the apparatus ; the power may be safely applied at this mechanical disadvantage; and it is applied close to tlie joint to give an extent and rapidity of motion which could not otherwise have been obtained, and without which the horse would have been comparatively useless.

At the back of the arm are other flexor muscles of great power, to bend the lower portions of the limb. We have described two of them belonging to the arm and the leg, and we must not pass over the vei^y peculiar ones acting on the feet. Only a small portion of one of them can be seen in our cut, page 233, at 1.

The first is the perforated flexor muscle : the reason of the name will presently appear. It arises from the lower and back part of the inner head of the lower bone of the shoulder, and intermixed with, or rather between the origins of the muscle next to be described, and called the perforating muscle. As it descends along the bone of the arm, it becomes tendinous; and, approaching the knee, it is bound down by arches or bands of ligament, that it may not start in sudden and violent action. Proceeding from the knee, it widens, and partly wraps round the tendon of the perforating muscle, and they run down together in contact, yet not adhering; freely playing over each other, and mucous fluid obviating all friction. Both of them are inclosed in a sheath of dense cellular substance, attached to them by numerous fibrils ; and they are likewise supported by various ligamentous expansions.

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