Vulnerability of long thoracic nerve: an anatomic study.

The anatomic course of 40 long thoracic nerves was studied in relation to anatomic landmarks and reference lines, that is, the axillary lines and first 2 ribs. After its supraclavicular course, the nerve passes beneath the clavicle within the axillary sheath and then emerges from the axillary sheath. As it passes inferiorly and posteriorly from the point of emergence to the posterior angle of the second rib (that is, the attachments of serratus anterior muscle), it makes a posterior angle of 30.7 degrees +/- 4.3 degrees on average, relative to the anterior axillary line. It then continues to descend inferiorly between the middle and posterior axillary lines. When the arm is raised, the axillary neurovascular bundle moves superiorly with the movements of the arm. The long thoracic nerve is angulated and stretched at the point it passes out of the axillary sheath.