There is an indentation on the front side of the chest. The deepest area lies at the level of the distal part of sternum and the xiphoid process (Fig. 1.3). The abnormality is usually present at birth, but can also develop later. A funnel chest seldom causes physical complaints, the issue tends to be only cosmetic. The abnormality is common in Marfan syndrome.

Partial fusion disorders of the cranial area are the most common. In the distal area they are very rare. It is also possible that the sternum is split along the entire length (total sternal fissure). This abnormality is accompanied by cardiac anomalies and/or defects in the diaphragm.

In this abnormality several ribs are usually absent on one side of the chest wall. There may also be sternal and vertebral abnormalities such as hemivertebrae and block vertebrae. As a result there is a flail thorax, which can lead to a shortness of breath.

In Poland syndrome¹ there is a unilateral absence of the pectoralis minor muscle and the sternal part of the pectoralis major muscle (Fig. 1.4). Males are affected in 70 % of cases. It is generally combined with abnormalities of the hand on the same side, such as small hands (hypoplasia) with absent fingers, webbed fingers (syndactyly) and/or shortened fingers (brachydactyly). The combination of hypoplasia of the hand, syndactyly and brachydactyly is sometimes called symbrachydactyly. There may also be absence of the forearm flexor muscles and the entire arm may be under-developed. Associated anomalies may be the Klippel-Feil syndrome1(short neck), Möbius syndrome1 (paralysis of the facial muscles), a Sprengel deformity (elevated shoulder blade) and pectus excavatum.