Surgical anatomy of the thoracic outlet syndrome.

Operative and cadaver dissections have shown that neurovascular compression in the thoracocervicoaxillary region occurs most frequently at the following three levels: the superior thoracic outlet, the costoscalenic hiatus and the costoclavicular passage. At each, a fibromuscular and osseous frame surrounds and fits the neurovascular bundle rather snugly. Pathologic conditions and some normal anatomic variants of the frame or of its contents could lead to contents-container space incompatibility, thus producing symptoms of neurovascular compression. Evaluation of the rigid frame of the region has shown that the first thoracic rib is its key element at all three possible levels of compression. Review of the many possible anatomic variants of osseous, fibromuscular and neurovascular components of the passage illustrates the necessary complexity of any operative attempt intended to detect and treat all possible anatomic causes of compression. Removal of the first thoracic rib, regardless of most other anatomic causes for thoracic outlet syndrome, provides a simple alternative by creating a patulous thoroughfare which eliminates all three possible levels of compression, even when other undetected predisposing anatomic structures are not removed.