Chest wall deformities

Pectus excavatum, also known as sunken, funnel or caved-in chest, is the most common congenital disorder (present at birth) of the front (anterior) chest wall. It is the result of abnormal growth of the cartilages between the ribs and the breastbone (sternum). The abnormal growth causes the breastbone to move inward or rotate to one side. Pectus excavatum usually involves the middle lower portion of the breastbone and may worsen with age. The abnormality may be unequal, or asymmetrical, between the right and left sides.  

Pectus carinatum, or pigeon chest, is much less common than pectus excavatum but arises from the same abnormality of the breastbone and rib cartilages. In this case the breastbone protrudes out, usually asymmetrically.