What is pectus excavatum?
Pectus excavatum, also known as 'funnel chest', 'sunken chest' or 'Cobbler's chest', is a congenital chest wall deformity. It is the most common chest abnormality present at birth, appearing in about one in every 300-500 live births.   In a person with pectus excavatum, the connective tissue that connects the breastbone (sternum) to the ribs grows too much. As a result, the middle of the chest appears sunken.
Mild pectus excavatum usually does not have any further effects on the body. However, the abnormal appearance it gives the chest can cause body image issues for the person. In severe cases of pectus excavatum, where the sunken area is deep, the lungs and the heart may be affected.
Causes and risk factors
It is not known what causes pectus excavatum. It is due to abnormal growth of cartilage connecting the breastbone and the ribs. Pectus excavatum is about four times more common in boys than in girls. Of all people with pectus excavatum, 15-40% have a close relative with the condition,   suggesting it has some genetic basis.
- Marfan syndrome - a genetic disorder of connective tissue. Pectus excavatum is a symptom of Marfan's syndrome;
- Noonan syndrome - a genetic condition that typically affects the heart, musculoskeletal system, facial features, kidneys, spleen and liver;
- Poland syndrome - a disorder affecting chest muscles;
- Ehlers-Danlos syndrome - a group of genetic disorders affecting the collagen protein in connective tissues, causing hypermobile joints and fragile, easily-stretched skin;
- Osteogenesis imperfecta - a genetic disorder that causes bones to be brittle and easily breakable;
- Scoliosis - an abnormally curved spine;
- Spinal muscular atrophy - a genetic disorder of spinal nerve cells that affects muscle control;
- Congenital heart disease; 
- King-Denborough syndrome - a rare genetic disorder affecting the muscles and facial features, and;
- Sprengel's deformity - a problem with the shoulder blade due to a scapula bone that is too high.
Signs and symptoms
Many people with pectus excavatum have no symptoms and lead a normal life. Symptoms of pectus excavatum can include:
- A sunken area in the middle of the chest, which is present at birth, but may not be recognised until an older age;
- A displaced breastbone (sternum), usually to the right;
- Scoliosis - an abnormal curvature of the spine;
- Chest pain, and;
- A characteristic slouching posture.
- In more severe cases, pain and difficulty with physical exertion and exercise, since the lungs and the heart cannot expand normally, and;
- Irregularities in heartbeat (arrhythmias and heart palpitations). 
- Some older children and adults can be bothered by the appearance of their chests, which may affect their body image and lead them to be embarrassed with their appearance.
Methods for diagnosis
Pectus excavatum is diagnosed by the appearance of the chest. Further tests can evaluate how each person with pectus excavatum is affected by the condition, if at all. These tests can include:
Types of treatment
Pectus excavatum often does not require treatment at all; many people live completely healthy, normal lives. For those who do need (or want) treatment, there are several options:
There are numerous surgical procedures that can repair pectus excavatum. Whether or not to undergo chest 'reconstruction' to repair pectus excavatum depends on the individual case. The timing of surgery is also important; experts currently recommend delaying surgery until after puberty. Nowadays, the Nuss method is preferred over the earlier, more invasive Ravich method, especially for children.    It involves inserting a curved metal bar into the chest to remove the central sunken area in the chest.
The 'vacuum bell' is a recent non-surgical treatment method.   It involves attaching a large bell-shaped suction cup to the chest and using vacuum to lift the sternum. Repeated treatments show an improvement in pectus excavatum symptoms, but it is not yet clear what the long-term benefits may be.