This section is from the book "The Stable Book: Being A Treatise On The Management Of Horses", by John Stewart. Also available from Amazon: The Stable Book.
This is the most dangerous accident to which the stabled horse is liable. The horse often scratches his neck, ears, or some part of his head, with a hind-foot. In doing that, or rather in drawing back the foot after that is done, the pastern is sometimes caught by the halter-rein. In a moment the horse is thrown upon his broadside, while his head and the entangled foot are drawn together. The neck is bent at an acute angle, the head lying upon the shoulder, and in this position it is retained by the hind-foot. The injury which the horse receives varies according to the violence of his struggles, and to the time which he lies in this painful situation. The pastern, or some part of the leg, often the thigh, is sometimes deeply cut; but this is not the worst part of the accident. Frequently the neck is bent so much to one side, and so severely twisted, that weeks must elapse before the horse is able to move it freely, and sometimes it remains permanently distorted, the head being carried awry. The neck has been completely broken in this way, and after the horse was liberated, it was discovered that he could not move a limb, nor make the least motion of any kind, with the exception of breathing, swallowing, and a few movements of the ears, eyes, and mouth.
The remainder of the body was quite powerless, and the horse died through the course of the day This fatal result is not common.
When the horse lies long he is always a good deal bruised and very stiff, unable to get up without assistance. Sometimes the back is injured so as to produce partial palsy of the hind-legs. When the horse happens to fall upon the leg that is drawn up, his head is below him, and if not immediately relieved, he is soon suffocated.
In the most of cases this accident may be prevented. All that is necessary is to keep the halter-rein clear of the feet. It should not be needlessly long; it should always be loaded with a sinker, and the ring, through which it runs should be at the proper height. Two reins prevent the horse from getting his head too far round on either side. As greater security, the rein may be made to pass behind the manger, and in that case one rein is sufficient. (See Fig. 2, page 26.) When the manger is low and the rack high, the rein must be long, and can not be kept tense, for the sinker can not descend far enough. The manger should be raised, or the reinring placed higher, by some other contrivance.
 
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