CLEIDOMASTOID 11USCLE Dieffenbach first described this condition in 1S30 and also first brought out its causal relation with congenital wry neck.
Symptoms. —Soon after birth, or a few days later, a tumor, of a hard, cartilage-like consistency, is found in the sternocleidomastoid muscle and moreover usually in its sternal portion; the tumor varies in size from that of a hazel-nut to that of a pigeon egg and over it the skin is usually unchanged although at times cedematous. When the muscles are relaxed the tumor is easily movable with the sternomas toid; it is not painful, although at times fender on pressure. In some instances the chin is pointed toward the healthy side, in some toward the diseased side and in others the positon of the head is normal. The general health is not disturbed.
Nature and Pathological this condition we have to deal with a tearing of the fibres of the stcrnomastoid with a conse quent bleeding. The blood flows under the muscle-sheath and between the torn fibres; in cases of considerable duration it is possible to demon strate, microscopically, the partial disappearance of the muscle fibres and proliferation of young connective tissue.
Occurrence and disease, in the majority of instances, occurs in children delivered without the aid of instruments.
The right side is more often affected than the left, in rare instances both sternomastoids are affected. The disease occurs most often with
breech presentations, less often with vertex presentations. In cases of unassisted labor the occurrence of the hipmatoma must be attributed to an extreme traction on the sternomastoid; this traction can take place only from an excessive rotation of the head (KiIstner) and more over the sternomastoid which remains inactive during the act of rota tion is subjected to the greater traction; therefore the muscle affected corresponds to the side towards which the head is rotated. In assisted labor also, rotation of the head is responsible for the tearing of the muscle although pressure of the forceps, of the fingers of the accoucheur or of the cord wound round the neck are said to be able to produce this lesion.
The prognosis is good. The tumor usually disappears spontaneously within a few (-I -S) Proof is wanting that a permanent wry neck ever develops from this condition.
The treatment consists in massage of the diseased muscle, carried out very gently, for several minutes daily. In case the disease has existed for some time and wry neck has developed, it is recommended to employ passive movements of the head, in the sense of rotation away from the affected side.