The healthy chest is gently rounded all over, its contour being more rounded in women by the breast tissue. In cross-section it is oval-shaped with a longer dimension from side to side than from back to front.
Barrel chest is found in long-standing ASTHMA or chronic BRONCHITIS and EMPHYSEMA, when the lungs are chronically enlarged. The anterio-posterior dimension of the chest is increased and the ribs are near horizontal. In this position they can produce little further expansion of the chest, and breathing often relies on accessory muscles in the neck lifting up the whole thoracic cage on inspiration.
Pigeon chest is one in which the cross-section of the chest becomes triangular with the sternum forming a sort of keel in front. It may be related to breathing problems in early life.
Rickety chest is uncommon now and is caused by RICKETS in early life. There is a hollow down each side caused by the pull of muscles on the softer ribs in childhood. The line of knobs produced on each side where the ribs join their costal cartilages is known as the rickety rosary.
Pectus excavatum, or funnel chest, is quite a common abnormality where the central tendon of the diaphragm seems to be too short so that the lower part of the sternum is displaced inwards and the lower ribs are prominent. When severe, it may displace the heart further to the left side.
Local abnormalities in the shape of the chest occur when there is a deformity in the spine such as scoliosis which alters the angles of the ribs. The chest wall may be locally ﬂattened when the underlying lung is reduced in size locally over a prolonged period. (See SPINE AND SPINAL CORD, DISEASES AND INJURIES OF.) This may be seen over a scarred area of lung such as that observed in pulmonary TUBERCULOSIS.