In the cases where weight is not supported without the affected leg being passively placed in position, it is necessary to provide for the subject’s comfort in several ways.

Mechanical appliances such as braces of some kind in order to keep the affected leg in a position of carpal extension, constitute the essential part of treatment.  The leg is supported in such a manner that flexion of the carpus is impossible.  Due regard is given to prevent chafing or pressure necrosis by contact of the skin with the braces—­this may be done by bandaging with cotton.  The supportive appliance is kept in position for ten days or two weeks.  At the end of this time the brace may be removed and the subject given a chance to walk, and improvement, if any exists, will be evident.  When there is manifested an amelioration of the condition, moderate daily exercise and massage of the affected parts are helpful.

Should the subject be seriously inconvenienced by the application of a brace or other supportive appliances, it is necessary to employ slings.  Further, if weight is supported entirely by the unaffected member, laminitis may supervene if a sling is not used.

Thrombosis of the Brachial Artery.

Thrombosis of the brachial artery or of its principal branches is of very rare occurrence in horses.

Etiology.—­Partial or complete obstruction of arteries (brachial or others) occurs as the result of direct injury to the vessel wall from compression and tension of muscles and resultant arteritis; lodging of emboli; and parasitic invasion of vessel walls causing internal arteritis.

Symptomatology.—­If sufficient collateral circulation exists to supply the parts with blood, no inconvenience is manifested while the subject is at rest.  Where the lumen of the affected vessel is not completely occluded, there may be no manifestation of lameness when the ailing animal is moderately exercised.  Consequently, the degree of lameness depends upon the extent of the obstruction to circulation; and, likewise, the course and prognosis depend upon the character and extent of such obstruction.

In severe cases, lameness is markedly increased by causing the animal to travel at a fast pace for only a short distance.  There are evinced symptoms of pain, muscular tremors and sudation, but the affected member remains dry and there is a marked difference of temperature between the normal areas and the cool anemic parts.  When the subject is allowed to rest, circulation is not taxed, and there is a return to the original and apparently normal condition, only to recur again with exertion.  This condition characterizes thrombosis.

Treatment.—­In these cases, little if any good directly results from any sort of treatment in the way of medication.  Absolute rest is thought to be helpful.  Potassium iodid, alkaline agents such as ammonium carbonate and potassium carbonate, have been administered.  Circulatory stimulants also have been given, but it is doubtful if any good has come from medication.