Posterior Axillary Nerve Branch to Teres Minor

ramus posterior nervi axillaris ad teretis minorem

The posterior branch of the axillary nerve supplies the teres minor before turning forward to supply the overlying posterior deltoid. The teres minor branch is the most posterior motor supply in the shoulder and may be selectively affected by quadrilateral space syndrome.

Region: Shoulder

Clinical Relevance

Clinical Notes

Selective teres minor denervation from posterior axillary nerve branch compression in the quadrilateral space syndrome produces teres minor atrophy visible on MRI as fatty infiltration of the teres minor with preserved posterior deltoid function. The quadrilateral space is bounded by the teres major, teres minor, humerus, and long head triceps. Dynamic compression of the posterior circumflex humeral artery and posterior axillary nerve branch occurs during overhead arm activity.

Pathology

Common Injuries & Conditions

Quadrilateral Space Syndrome with Teres Minor Denervation

Posterior axillary nerve branch compression in the quadrilateral space producing teres minor-specific MRI fatty infiltration and posterior shoulder pain with overhead activity, managed by arthroscopic or open quadrilateral space decompression.