ABSTRACT
Thoracic outlet syndrome (TOS) is defined as a set of symptoms caused by the compression of the brachial plexus and subclavian vessels in the thoracic outlet region. Anomalies in musculoskeletal structures may be responsible for TOS, including prolonged transverse process of the seventh cervical vertebra, cervical rib, and first anomalous rib and clavicle fractures. The authors describe a case of a young woman with pain in the left forearm, accompanied by intermittent claudication, weigh loss, myalgias and ischemic lesions in the fingers, with no pulses and no measurable blood pressure in the left arm, who was initially diagnosed as Takayasu arteritis. The chest radiography showed accessory cervical ribs and the dynamic vascular image tests (Doppler ultra-sound and angiography) showed bilateral compression of the subclavian artery, confirming the diagnosis of TOS.