Congenital absence of the pectoralis major muscle of right side. (Richardson.)
The most common cause of thoracic asymmetry or deformity is rickets, which may be an early or a late manifestation. By the ordinary changes permitted in the epiphyses and along the costochondral junctions is produced the peculiar appearance known as “rickety rosary.” In these cases the effect of the weight of the upper part of the body upon the soft and changeable structures of the osseous and cartilaginous ribs, as well as the vertebræ and the sternum, are to be noted. Pronounced types of deformity result from such changes, producing extreme cases of pigeon-breast, or of hollowing in front known as birds’ nest deformity, while alterations occur in the vertebræ, producing various expressions of kyphosis and scoliosis. (See [Fig. 504].)
These deformities of the back thus produced require to be differentiated from those produced by Pott’s disease, the former being unaccompanied by symptoms and occurring slowly, while the latter are usually accompanied by pain and are progressive in character, as well as more or less disabling. With a softened skeleton in a rapidly growing child such trifling influences as the position assumed in the nurse’s or mother’s arm, or that habitually taken in sleep, may affect and modify symmetrical growth. Rickety deformities of the spine and thorax, if not too far advanced, permit of being checked and much improved by braces, along with the measures indicated in rachitis. Without the latter, however, the former would be almost ineffectual.
Fig. 503
Malformation of chest following empyema. (Sayre.)
Fig. 504
Deformity of the thorax, the result of rickets. (Gibney.)