A Case report: Unilateral synostosis of first sternocostal joint.

Synostosisis an immobile joint formed when the gap between two bones ossifies and become a single bone. Bony joints can be formed by ossification of fibrous or cartilaginous joints. The first sternocostal joint is an unusual variety of synarthrosis, inaccurately called as synchondrosis. The attachment of the first rib to the sternum also becomes a synostosis with age. This rare synostosis of sternocostal joint was found incidentally during routine osteology classes at Department of Anatomy, BJMC, Ahmedabad, Gujarat, India. This specimen showed rare unilateral synostosis of first rib with sternum on left side. This synostosis can lead to restricted chest wall movements and compression of neurovascular bundle causing thoracic outlet syndrome (TOS). Knowledge of such rare synostosis is of utmost importance to anatomists, thoracic surgeons, orthopedicians, radiologists, dermatologists.