Three potential compression sites responsible for thoracic outlet syndrome include:Physical exam: the lost art of medicine.
1. Interscalene triangle - borders include anterior and medial scalene muscles and the first rib.
2. Costoclavicular space - between clavicle and first rib.
3. Pectoralis minor tunnel - space between pectoralis minor tendon anteriorly and coracoid process of scapula.
The majority of patients have one of the following congenital or acquired conditions in one or more of the potential compression sites:
Congenital lesion include cervical ribs, scalenus minimus muscle, wide insertion or hypertrophy of anterior scalene muscle, anomalous first rib, slender body habitus with a long thin neck. Acquired lesions include extreme muscular build, fractures to clavicle or first thoracic rib with nonanatomic alignment or exuberant callus formation, supraclavicular tumors or lymphadenopathy.
Effort thrombosis is a form of post-traumatic thrombosis of the axillary vein, usually observed in younger individuals following exercise or occupational activity. The etiology is compression of the axillary vein by either subclavian muscle or costocoracoid ligament during forced abduction. This is known as Paget-von Schrötter syndrome.