Other types of chest wall deformities: Jeune's Syndrome: is a form of congenital dwarfism that leads to a chest wall deformity. In Jeune’s syndrome the chest is extremely small. The ribs are often abnormal, broad, short and irregularly joined to the costal cartilages and sternum. This produces a small bell-shaped, inflexible chest cavity which doesn't grow well and makes breathing difficult. -Poland Syndrome consists of a spectrum of abnormalities of one side of the chest including the absence of the pectoralis muscle(s), under development of breast tissue and areola, rib abnormalities and, in some cases, inadequate development of the arm, hand, and fingers of the same side.