Other agents, such as tincture of iodin, solutions of silver nitrate, saline solutions and various more or less irritating preparations have been employed; but in the use of these preparations one may either fail to stimulate sufficient inflammation to cause regeneration to take place, or infection is apt to occur. Where suppuration results, surgical evacuation of pus must be promptly effected else large suppurating cavities form. The employment of setons constitutes a dependable method of treatment of shoulder atrophy, but because of the attendant suppurative process which inevitably results, this method is not popular with modern surgeons and is a last resort procedure. After-care.--Regular exercise such as the horse usually takes when at pasture, is very helpful in treating atrophy, and in some cases it has been found that no reasonable amount of irritation would stimulate muscular regeneration; but by later allowing patients to exercise at will, recovery took place in a satisfactory manner. No special attention is ordinarily necessary. Paralysis of the Suprascapular Nerve. Anatomy.--The suprascapular (anterior scapular) nerve, a small branch of the brachial plexus, is given off from the anterior portion of this plexus. The nerve rounds the anterior border of the neck of the scapula, passing upward and backward under the supraspinatus (antea-spinatus) muscle and terminating in the infraspinatus (postea-spinatus) muscle. Etiology and Occurrence.--As the result of direct injury to this nerve by contusion such as may be received in runaway accidents, collar bruises, especially collar bruises in young horses that are not accustomed to pulling and that walk in a manner to cause side draft, injury to the nerve occurs, and partial or complete paralysis supervenes. Some writers state that it may be produced by confining an animal in recumbency, with the casting harness. The common cause of paralysis or paresis of this nerve in cases such as one observes in country practice, is bruises from the collar in colts that are put to heavy farm work or where ill fitting collars are used. Symptomatology.--With partial or complete suspension of function of the suprascapular nerve there results enervation of the supraspinatus and infraspinatus muscles. Since these muscles act as external lateral ligaments of the scapulohumeral joint, when they are incapacitated, there naturally follows more or less abduction of the shoulder when weight is borne. In extreme cases, as soon as the ailing animal is caused to support weight with the affected member, the joint is suddenly thrown outward in a manner that the average layman at once concludes that there must be scapulohumeral luxation, and the veterinarian receives a call to see a case wherein the "shoulder is out of place." There exists, however, no luxation in such cases.