Nerve
Axillary nerve
Supplies the deltoid
High-yield
Injured in surgical neck fractures and anterior shoulder dislocation → weak abduction and 'regimental badge' sensory loss.
Overview
A terminal branch of the posterior cord that passes through the quadrangular space to supply the deltoid and teres minor.
Reference facts
- Roots
C5, C6 (posterior cord)
- Course
Passes through the quadrangular space with the posterior circumflex humeral artery, winding around the surgical neck of the humerus
- Motor
Deltoid and teres minor
- Sensory
Skin over the inferior deltoid ('regimental badge' area) via the superior lateral cutaneous nerve of the arm
Clinical correlation
Deltoid paralysis and loss of the rounded shoulder contour after surgical neck fracture.