The Heart in Sternal Depression.

The place where the apex beat appears on the chest wall depends as much on the symmetry of the thorax as on the size of the heart. A change in the alignment of the spine, the posterior fulcrum of the thoracic cage, in the form of scoliosis, alters the position of the beat. Local deformity of the ribs which form the walls of the cage will do the same thing. Deformity of the sternum, the anterior fulcrum of the thorax, as a cause of displacement of the apex beat has received less attention. The effects of depression of the sternum (pectus excavatum) on the shape and position of the heart have been studied in sixteen adults examined during the past year.