Pectus excavatum is a congenital abnormality characterized by depression of the sternum (usually above the xiphisternal junction) and symmetric or asymmetric prominence of the ribs on either side. Its origin is unknown; however, it is thought that excessive diaphragmatic traction on the lower sternum or displacement of the heart into the left hemithorax is largely responsible. Family history of some type of anterior thoracic deformity is present in 37% of patients. If uncorrected, the disease usually worsens at adolescence. Self-limiting deformities are either gone or vastly improved by the age of 3 years.
Clinically, the majority of patients are asymptomatic unless pectus excavatum is extreme. Patients with pectus excavatum have reduced chest cavities and TLC. Pulmonary function often is normal except in severe cases, in which VC, TLC, and maximum breathing capacity may be diminished.