ABSTRACT
Pectus excavatum is the most common of chest wall deformities in infants, children, and adolescents. Its incidence is estimated at between 1 and 400 live births and 7.9 per 1000 births and it has a male-to-female ratio of 3:1. The exact etiology of pectus excavatum is unknown. It clearly has a genetic predisposition, with patients having a family history of chest wall deformities in 37 percent of cases. What is remarkable is that patients may have a family history of a carinatum or protrusion deformity as well as of a depression deformity. The pectus excavatum depression is created by two components. First is a posterior angulation of the sternum, generally at the level of the insertion of the second or third costal cartilages. Second is the posterior angulation of the costal cartilages to meet the sternum. In older teenagers, there may be posterior angulation of the most medial part of the osseous rib as well as the cartilaginous component. The pectus excavatum depression may be symmetric or asymmetric. In the asymmetric deformities, the more acute and severe depression is primarily on the right side. The rarest configuration of pectus excavatum is a combination of ipsilateral depression and a contralateral carinate protrusion. In approximately 90 percent of cases, the excavatum deformity is noted within the first year of life. This is in marked contrast to a carinatum deformity, where almost half of the patients have the protrusion noted after they enter the pubertal growth spurt.
