Ribs: A set of twelve curved bones which connect to the vertebral column posteriorly, and terminate anteriorly as costal cartilage. Together, they form a protective cage around the internal thoracic organs.Rib FracturesCervical Rib: A supernumerary rib developing from an abnormal enlargement of the costal element of the C7 vertebra. This anomaly is found in 1-2% of the population and can put pressure on adjacent structures causing CERVICAL RIB SYNDROME; THORACIC OUTLET SYNDROME; or other conditions.Cervical Rib Syndrome: A condition associated with compression of the BRACHIAL PLEXUS; SUBCLAVIAN ARTERY; and SUBCLAVIAN VEIN at the thoracic outlet and caused by a complete or incomplete anomalous CERVICAL RIB or fascial band connecting the tip of a cervical rib with the first thoracic rib. Clinical manifestations may include pain in the neck and shoulder which radiates into the upper extremity, PARESIS or PARALYSIS of brachial plexus innervated muscles; sensory loss; PARESTHESIAS; ISCHEMIA; and EDEMA. (Adams et al., Principles of Neurology, 6th ed, p214)Intercostal Muscles: Respiratory muscles that arise from the lower border of one rib and insert into the upper border of the adjoining rib, and contract during inspiration or respiration. (From Stedman, 25th ed)Thoracic Wall: The outer margins of the thorax containing SKIN, deep FASCIA; THORACIC VERTEBRAE; RIBS; STERNUM; and MUSCLES.Thoracic Outlet Syndrome: A neurovascular syndrome associated with compression of the BRACHIAL PLEXUS; SUBCLAVIAN ARTERY; and SUBCLAVIAN VEIN at the superior thoracic outlet. This may result from a variety of anomalies such as a CERVICAL RIB, anomalous fascial bands, and abnormalities of the origin or insertion of the anterior or medial scalene muscles. Clinical features may include pain in the shoulder and neck region which radiates into the arm, PARESIS or PARALYSIS of brachial plexus innervated muscles, PARESTHESIA, loss of sensation, reduction of arterial pulses in the affected extremity, ISCHEMIA, and EDEMA. (Adams et al., Principles of Neurology, 6th ed, pp214-5).Sternum: A long, narrow, and flat bone commonly known as BREASTBONE occurring in the midsection of the anterior thoracic segment or chest region, which stabilizes the rib cage and serves as the point of origin for several muscles that move the arms, head, and neck.