Anatomy of the axillary nerve and its relation to inferior capsular shift.

Axillary nerve injury is a recognized complication of the capsular slide procedure for multidirectional instability of the shoulder. Axillary nerve dissection followed by an anterior or posterior capsular shift procedure was carried out on 12 autopsy subjects to observe: (1) the normal relationships of the nerve; (2) its proximity to structures dissected in the procedure; and (3) the effects upon it of both anterior and posterior capsular shift procedures. The axillary nerve arises immediately posterior to the coracoid process and conjoint tendon. It crosses the inferolateral border of the subscapularis 3 to 5 mm medial to its musculotendinous junction, and it lies in intimate contact with the inferior capsule as it passes through the quadrilateral space. The nerve should be visualized prior to transecting the subscapularis tendon. During detachment of the inferior capsule from the humeral neck, the humerus should be gradually externally rotated, and the nerve should be gently retracted with a small flat instrument. Sutures reattaching the flap should be carefully placed to avoid injuring the nerve. The tendinous insertion of the teres minor is preserved from a posterior approach. The nerve can be visualized and protected during capsular detachment.