Overview

The upper and lower subscapular nerves are small motor branches from the posterior cord of the brachial plexus. Both supply subscapularis; the lower nerve also supplies teres major.

Origin and Course

They usually carry fibres from C5 and C6. Their short paths run from the posterior cord directly toward the deep muscles on the front of the scapula.

Function

They activate subscapularis, an important internal rotator and rotator cuff stabilizer. The lower nerve also activates teres major.

Common Injuries

Isolated injury is unusual. These nerves are more likely to be affected as part of a posterior cord, brachial plexus or surgical injury.

Pain and Weakness Patterns

Weakness may reduce internal rotation strength. Because several muscles perform this action, subtle deficits can be difficult to isolate.

Clinical Relevance

Their proximity to the posterior shoulder matters during surgery. Examination focuses on the broader pattern of muscle weakness rather than expecting a distinct sensory loss.

References

Standring S, ed. Gray's Anatomy. 42nd ed. Elsevier; 2020.
Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy. 9th ed. Wolters Kluwer; 2023.

Upper and Lower Subscapular Nerves