Pectus anomaly describes a deformity with the sternum (breastbone). The condition is the most common congenital wall deformity.

There are two main types of anomaly:

• Pectus excavatum (also known as “funnel chest”/”sunken chest”) in which the sternum is sunken inwards and the chest looks hollow
• Pectus carinatum (also known as “pigeon chest”) in which the sternum is raised and the chest pushed out. There may sometimes be a depression (dip) on one side and a protrusion (bulge) on the other.
• There is also a rare third type of anomaly called pectus arcuatum. This is where there is a ridge high across the upper part of the sternum and so the rest of the chest falls away to a flatter shape.

Pectus anomalies occur in around four people in every 1,000 and are more common in men. Anomalies vary from mild to very marked.

What causes pectus excavatum / carinatum?

Pectus anomalies are thought to be caused by poorly coordinated and possibly excessive growth of the costal (rib) cartilages. The anomaly occurs between the ribs and sternum (breastbone) before a child is born and can be excessive.

As the cartilagea grow longer, they “buckle” and push the sternum either inwards (pectus excavatum) or outwards (pectus carinatum).

Certain conditions are associated with pectus anomaly, such as:

• scoliosis – where the spine curves and becomes deformed
• Marfan’s syndrome – an inherited disorder of the connective tissue 
• Poland’s syndrome – a rare inherited condition which involves the absence or underdevelopment of the chest muscles on one side of the body

A pectus anomaly is often seen at birth but usually becomes more obvious during early adolescence when growth is rapid. Once growth is complete the anomaly remains the same.

What are the effects of pectus anomaly?

Many people with pectus anomaly accept and live happily with the shape of their chest. However, some people experience physical problems, such as reduced stamina, frequent respiratory infections and chest pain.

There may also be psychological problems such as negative self-image and low self-confidence. The most common concern for those with pectus anomaly is being seen without their chest covered.