The anatomic course of 40 long thoracic nerves was studied in relation to a
natomic landmarks and reference lines, that is, the axillary lines and firs
t 2 ribs. After its supraclavicular course, the nerve passes beneath the cl
avicle within the axillary sheath and then emerges from the axillary sheath
. As it passes inferiorly and posteriorly from the point of emergence to th
e posterior angle of the second rib (that is, the attachments of serratus a
nterior 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 d
escend inferiorly between the middle and posterior axillary lines. When he
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.