ABOUT THE CHEST (THORAX)

The chest or thorax is a part of the body located between the neck and the abdomen, specifically thoracic diaphragm. It is encased by the ribs and spine. The chest wall consists of the spine, the sternum, and ribs. A part of the rib depicted in the yellow is made not of bone but of much softer cartilage. The cartilage part of the rib is loosely attached to its bony part. It is cartilages and the sternum that are depressed in pectus excavatum.
The incidence of pectus excavatum is 1 in 300 boys, and is much rarer in girls. It is hardly ever diagnosed in African-American and Latino children.
The aetiology of pectus deformities remains unknown but in 40% patients there is a family background. In some patients there is a genetic error in cartilage development, and multiple genetic factors may play a role.
Chest deformities may become detected as early as in infancy but appear more prominent in adolescence.
The rigidity of the chest wall increasing with age together with reduced lung compartment may result in poorer sport performance.

3D tomography scan shows intact bony ribs. Not visible cartilages are depressed.
Considerable scoliosis of the spine is apparent.

The same patient as above. The lines depict the maximum width and height at the level of the depressed sternum. The Haller index (ratio of width to height) of 3.86 is well above normal 2.5.
The heart became shifted to the left.