Cervical rib.

ABSTRACT

Cervical rib is a supernumerary rib. It is one of the deformities of the musculoskeletal system. According to Terves and Keith, there is always a rudiment of a cervical rib in the fetus which usually disappears but in 1-2 %, it persists throughout life. Only a part of this percentage has symptoms. Genetic Factors may play a role. Clinical important It causes pressure on brachial-plexus or subclavian artery. These structures are entrapped between the cervical rib and scaleneus muscle. There is positive Adson’s sign i.e. radial pulse is lost in the arm during abduction and external rotation of the shoulder. There is compression of brachial plexus which causes weakness of muscles of the hand near base of the thumb. This is known as THORACIC OULET SYNDROME. A supernumerary rib develops from anterior tubercle of cervical vertebra- like Meckel’s Diverticulum. Incidence 5 – 6 % .Mostly an incidental finding: