THORACIC OUTLET SYNDROME
Thoracic outlet syndrome can present with diffuse arm symptoms, including numbness and tingling. Often the person will describe a path down the inside of his/her arm to the little and ring fingers. This is often made worse by overhead activities.
The brachial plexus and/or subclavian/axillary arteries can be compressed at various sites as they travel downward into the arm. Several common sites are possible, including an elongated C7 transverse process (cervical rib), the scalene muscles, the costoclavicular area, and the subcoracoid area (between the coracoid and the pectoralis minor). Muscular compression at the scalenes or with the pectoralis minor is believed to be due to tight muscles and/or posturally induced (forward head and rounded shoulder habit). Some research reports that 40% of cases there is a report of inciting trauma. It is important to recognize that only 1% of the population has cervical ribs, and only 10% of those individuals have symptoms. A fibrous band connecting the cervical rib to the first rib also may be the culprit in some cases.