The course of the axillary nerve among adult Kenyan cadavers

Background: The axillary nerve is one of the terminal branches from the posterior cord of the brachial plexus and is closely related to the surgical neck of the humerus where it may be injured. Objective: This study set out to describe the course of the anterior and posterior branches of the axillary nerve in an adult Kenyan population. Methods: This was a cross-sectional study conducted at the Department of Human Anatomy Laboratory, Moi University. Dissections were done on 51 formalin prefixed left adult upper limbs. Results: The nerve originated from the posterior cord of the brachial plexus and divided within the quadrangular space into anterior and posterior branches. The main trunk supplied teres minor (35.3%), teres major (15.7%) and subscapularis (3.9%) muscles. The anterior branch supplied the anterior (100%) and middle (92.1%) parts of the deltoid. The posterior branch innervated the posterior part of deltoid in all specimens. The middle part of deltoid received dual innervation in 7.8%. The shoulder joint was innervated by both the main trunk (80.4%) and anterior branch (19.6%). The upper lateral cutaneous nerve of the arm arose from the posterior branch in all specimens. Conclusions: The nerve has an anterior branch distributed over and consistently innervates the anterior and middle parts of deltoid muscle, while the posterior branch supplies the posterior part.