Symptomatology.—Lameness is the first manifestation of shoulder atrophy, and in many cases where lameness is slight, the veterinarian may fail to discover the exact nature of the trouble if he is not very proficient as a diagnostician of lameness or if he is careless in taking into consideration obtainable history, age of the subject, etc. Because of the fact that the average layman believes that practically every case of fore-leg lameness wherein it is not obvious that the cause is elsewhere, is due to a shoulder affection of some kind, we may be too hasty in giving the client assurance that no “sweeny” exists. In some of these cases where a diagnosis of “shoulder lameness” has been made and the client has been assured that no sweeny exists, the patient is returned in about a week and there is then marked atrophy of one or both of the spinatus muscles.
A mixed type of lameness characterizes this affection, and in the average case there exists little evidence of local pain. The salient points in recognizing the condition are a consideration of history if obtainable; age of the subject; finding slight local soreness, by carefully manipulating the muscles which are usually involved; noting the character of the lameness if any is present; and where atrophy is evident, of course, the true condition is obvious.
Treatment.—Subcutaneous injections of equal parts of refined oil of turpentine and alcohol, with a suitable hypodermic syringe, is a practical and ordinarily effective treatment. From five to fifteen cubic centimeters (the quantity varies with the size of the animal), of this mixture is injected into the atrophied parts at different points, taking care to introduce only about one to two cubic centimeters at each point of injection. The syringe should be sterile and, needless to say, the site of injections must be surgically clean.
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.