A system of practical medicine. By American authors. Vol. 4

by Unknown

FIG. 33.

Showing Atrophy of the Right Deltoid and Arm, and the Left Arm.

FIG. 34.

Showing Atrophy of the Deltoid, posterior aspect, and the Scapular Muscles.

Beginning most frequently in the right, both upper extremities become sooner or later involved.

In other instances in which the upper extremities are previously involved the atrophy begins in the shoulder, in the deltoid—here again the right first. Succeeding the deltoid, the scapular and trapezius muscles may be involved in any order, while a grotesqueness of effect is often produced by reason of certain adjacent muscles retaining their natural size or even being hypertrophied. This is particularly the case with the anterior part of the trapezius, which is almost never involved. With the shoulders first affected, the arm and forearm may retain their usefulness and strength; but the power of lifting the arm from the side, and especially of raising it above the head, is lost. And if the patient wishes to lay hold of anything, he must swing his arm forward with a jerk until it is brought in reach of his fingers, and then it must often be caught up by the pathologically hooked terminations of these.

The muscles of the trunk do, however, become at times involved—the pectorales, the latissimi, serrati, and intercostales, and even the diaphragm and abdominal and lumbar muscles. Life is seriously jeopardized when the intercostals and diaphragm are affected, in consequence of interference with respiration. If the intercostals cease to contract, the upper part of the thorax ceases to move, and if the diaphragm is involved, the epigastric and hypogastric regions are drawn in during inspiration, and talking and singing are interfered with. Even a mild bronchitis is apt to be fatal in consequence of the difficulty in expelling the secretions.

The muscular atrophy thus produced is generally accompanied by a corresponding wasting and retraction of the skin, so that this continues applied to the muscles in the usual manner. In some instances, however, this is not the case, and in these a baggy condition of the skin is added, which gives its subject an appearance which has more than once rendered him valuable to the showman as the elastic-skin man, etc. It sometimes happens, on the other hand, that the atrophy is obscured by an accumulation between the muscle and skin of adipose tissue, and an appearance of hypertrophy rather than atrophy may be produced in consequence, analogous to the same state of affairs in pseudo-hypertrophic paralysis, the relations of which disease to progressive muscular atrophy will be considered under the head of Diagnosis.

At almost any stage the disease may come to a standstill, and may continue thus for many years. The time required to attain its various degrees also varies greatly, but the spread is usually slow, requiring, as a rule, years for its completion. A general involvement of the voluntary muscles of the entire body is exceedingly rare.

As stated, the disease may begin in the lower extremity, but much more rarely. It is very seldom that the same order of invasion pursued in the upper extremity is followed in the lower—that is, beginning with the interossei. It may begin in the thigh and involve it alone, or extend to both thighs, or both legs as well. Under these circumstances weakness of the legs is a striking symptom, the patient being unable to stand, often falling down or requiring a cane or crutches to assist him. In illustration of this mode of invasion may be related one of Roberts's cases, that of an adult woman thirty-eight years old, a domestic servant, in whom at thirty-six was perceived a weakness in the right thigh. She first noticed that it grew tired sooner than the left. This gradually increased, until she was compelled to sit much of the day, then to use a stick, and finally crutches. This was accompanied by a gradual wasting of the thigh-muscles. Even in this case the loss of power was greater than would have been expected from the degree of atrophy, the loss of bulk incident to which Roberts believed to have been in part replaced by fat. In other instances, however, the extremest degree of atrophy has been noted where the disease has commenced in the lower extremities.

The deformity produced by the wasting muscle is sometimes further increased—more frequently in the earlier stages—by a painful swelling of the joints, first mentioned by Remak, called by him neuro-paralytic inflammation, and referred to the sympathetic. This may affect the small (phalangeal) as well as the larger joints (shoulder and elbow).