Quadrilateral Space Syndrome
A clinical syndrome resulting from compression of the axillary nerve and posterior circumflex artery in the quadrilateral space. The quadrilateral space is the anatomic space in the upper arm bounded by the long head of the triceps, the teres minor and teres major muscles, and the cortex of the humerus. |
Venous Thoracic Outlet Syndrome
Results from compression and eventual thrombosis of the subclavian vein, which occurs inside of a triangle bordered by the first rib, clavicle and the subclavius muscle/costoclavicular ligament. |
Arterial Thoracic Outlet Syndrome
Arterial TOS occurs because the subclavian artery is repeatedly compressed in the scalene triangle at the level of the first rib and in the costoclavicular space, damaging its wall. |
Axillary Artery Aneurysm
The mechanism of injury to the axillary vessel is unclear, but there may be damage from the pectoralis minor muscle during repetitive hyperabduction, extension and external rotation of the shoulder. |