DEFORMITIES OF THE THORAX The chicken- or keel-shaped chest (pectus carinatum) is a not infre quent result of rachitis. A superficial examination gives an impression as if the thorax were pressen together with the hands from opposite sides. The transverse thoracic diameter is, therefore, diminished, while the sterno-vertebral diameter is increased. The projection of the sternum, after which the deformity is named, is most conspicuous.
On both sides of the sternum there is often found a flat cavity in the anterior thoracic wall extending from the second to the eighth rib. Many theories as to the development of pigeon-breast have been advanced, but a satisfactory explanation for all the changes which pro duce a pigeon-breast is still lacking.
It is certain that abnormal softness of the bones, which is a product of rachitis, is a preliminary cause of the development of pigeon-breast, but it is not sufficiently clear what other forces contribute to the develop ment of this deformity. Clinical experience teaches us that contractions of the diaphragm are involved in it.
Very frequently pigeon-breast is observed. in rachitic children suf fering from whooping-eough which is associated with very violent spasmodic contractions of the diaphragm. Furthermore, the greatest depression along the front part of the thorax corresponds to the point of insertion of the diaphragm. But how this action of the diaphragm in particular brings about a deformity of the thorax and why the sternum alone is pushed forward as a result of these contractions while the ribs in the immediate vicinity are drawn inward, is still a conundrum.
As a rule a pigeon-breast represents only an :esthetic defect. We have never had occasion to observe that during the growing period the deformity showed any inclination to become worse. On the con trary, lighter degrees of pigeon-breast disappear without any treatment whatever. Marked deformities of the thorax, however, if unattended remain stationary and show even in later life the rachitic symptoms of infancy.
Treatment of pigeon-breast is gratifying if started when the ribs and sternum are still soft. In a case of light incipient deformity we order the patient to assume a recumbent position upon a hard mattress. The mother places her hand upon the child's sternum and presses upon the thorax while the child takes deep inspirations and expirations. The child is also told to perform the various gymnastic exercises recom mended in the treatment of round shoulders.
Should the parents be dissatisfied with the improvement, an ortho pedic apparatus must be employed. Hoffa recommended a spring, similar to one used in trusses, which encircles t he thorax and terminates at each end with a pad. This approximates the sternum and spine by means of elastic pressure. We have personally experienced good results early with orthopaedic corsets to which a cushion was attached to exert pressure upon the sternum from before backward.