What Causes Pectus Excavatum?
The precise physiological causes of Pectus Excavatum are not completely understood. However, most researchers agree that the condition could be caused by excessive growth of the costal connective tissue/cartilage that binds the ribs to the breast bone/sternum. Pectus Excavatum occurs at the junction of the ribs and sternum where the costal cartilage is located. Overgrowth of the cartilage causes the ribs and cartilages to buckle and pushes the sternum inwards, resulting in the Pectus Excavatum condition. Similarly, it is equally possible for the sternum to be pushed outwards, leading to the less common Pectus Carinatum deformity.
Some researchers have also postulated that a abnormality in the diaphragm can cause increased traction on the sternum and result in the condition. More specifically, a shortened central tendon within the diaphragm and/or a shortened muscular partition between the chest and the abdominal cavity can place excess stress on the sternum and cause it to cave inwards.
The underlying factors behind these causes are again not precisely understood, though many hypothesis that the deformity is a genetic defect, since many individuals with the condition have a first degree family member with the condition.
While the vast majority of Pectus Excavatum cases are not associated with any other condition, some disorders are associated with the sunken chest feature of the Pectus Excavatum anomaly:
- Scoliosis, where the spine curves and causes the rib cage to twist and become deformed.
- Marfan?s syndrome, an inherited connective tissue disorder which causes skeletal defects such as long limbs, chest abnormalities, curvature of the spine and certain facial features including a highly arched palate, and crowded teeth.
- A deficiency disease occurring primarily in children, resulting from a lack of vitamin D or calcium and insufficient exposure to sunlight, which disturbs normal bone growth.
- Poland?s syndrome, a rare inherited condition which involves the absence or underdevelopment of the chest muscles on one side of the body.
- Many individuals with spinal muscular atrophy develop Pectus Excavatum due to the diaphragmatic breathing that is associated with the disease.
- Pectus excavatum also occurs in about 1% of those diagnosed with Celiac disease, for reasons which are currently unknown.
The condition can develop at any point during an individuals natural growth cycle. However, it commonly occurs at birth but becomes more obvious during early adolescence/puberty when growth is more rapid. Once the growth cycle is complete the anomaly remains the same unless corrected with cosmetic surgery or non-surgical alternatives.