Where the inflammation becomes infective, surgical interference is necessary. The prompt evacuation of pus, with adequate provision for wound discharge, should be attended to before extensive destruction of tissue takes place. Resolution is prompt as a rule in such cases because of the vascularity of the structures and the ease with which proper drainage may be effected. No special after-care is necessary if drainage is perfect, except that one should avoid injecting the wound cavity with aqueous solutions unless it be absolutely necessary to cleanse such cavity, and then it is best to swab the wound rather than to irrigate it freely.
No satisfactory consideration of the pathogeny of this condition is recorded, but practitioners have long distinguished between muscular atrophies which are apparently caused without doing serious injury to nerves and muscular atrophy which seems to be due to nerve affection. In the first instance, recovery when proper attention is given, is prompt; whereas, in the latter, regeneration of the wasted tissues requires months in spite of the best sort of treatment.
The parts more frequently affected are the supra- and infrascapularis (antea- and posteaspinatus) muscles. But in some cases the triceps group is involved; however, this occurs in unusual and chronic affections. No doubt, these chronic cases are due to suspended innervation and are not to be classed with the ordinary case of atrophy of the abductor muscles of the humerus (supra- and infraspinatus) as in the usual case of “sweeny.”
Occurrence.—Shoulder atrophy such as the general practitioner commonly meets with, is an affection, more often seen in young animals and it seems to be due to injuries of various kinds which contuse the muscles of the shoulder. Ill-fitting collars and pulling in a manner that there occurs side draft with unusual strain on the muscles of one side of the neck and shoulder, seem to be the more frequent causes of this trouble. Blows such as are occasioned by kicks and falls frequently result in atrophy of shoulder muscles.
Course.—In some cases a rapidly progressive atrophy characterizes the case and lameness and atrophy appear at about the same time. The affection in such instances does not recover spontaneously but constitutes a condition which requires prompt and rational treatment so that function may be fully restored to the parts involved.
Occasionally one may observe cases where there is but slight atrophy; where the disease progresses slowly and atrophy is not extensive or marked. In vigorous young animals that are left to run at pasture when so mildly affected, spontaneous recovery occurs.