Although "congenital" muscular torticollis is encountered frequently by pediatricians and orthopedic surgeons, there is no uniformity of thought as to its etiology or therapy. There is much confusion as to diagnosis. The numerous factors which may contribute to the development of a torticollis (wry neck) deformity are found in the accompanying classification.
Congenital muscular torticollis is a distinct entity, the primary pathologic picture being limited to the sternocleidomastoid muscle. Associated deformities of the face, head, ear and cervical spine are secondary in character, resulting from an abnormal position of the head both prior and subsequent to birth.
Muscular torticollis may be present at birth or may manifest itself first on about the tenth to the fourteenth day, at which time the appearance of a hard, immobile, fusiform swelling (fig. 1) is noticed in the sternocleidomastoid muscle. The delivery is usually difficult or abnormal, most often breech. The swelling or "tumor,"
CHANDLER FA, ALTENBERG A. "CONGENITAL" MUSCULAR TORTICOLLIS. JAMA. 1944;125(7):476-483. doi:10.1001/jama.1944.02850250016006