The thoracic outlet space is created by the clavicle, first rib, subclavius muscle, costoclavicular ligament, and anterior scalene muscle. It most often affects subclavian artery, vein, and the lower trunk (C8 & T1) of the brachial plexus. The neurological exam may reveal sensory changes in the ring and little finger and intrinsic weakness. Radiographs here show cervical ribs, but could also show a Pancoast tumor or even be normal.
Leffert reviewed thoracic outlet syndrome and cautioned that surgery be reserved for intolerable symptoms as surgical complications can be significant.
Thompson provides a concise review stating that Thoracic outlet syndrome (TOS) represents a group of heterogeneous and potentially disabling upper-extremity disorders that are caused by extrinsic compression of neurovascular structures between the first rib and clavicle. There are 3 distinct types of TOS, which are classified according to the principal anatomic structures involved and the clinical syndromes that result: neurogenic TOS, venous
TOS, and arterial TOS.