Which nerves innervate the subscapularis?

The subscapularis muscle is primarily innervated by the upper and lower subscapular nerves, which branch from the posterior cord of the brachial plexus. The upper subscapular nerve specifically innervates the upper portion of the muscle, while the lower subscapular nerve innervates the lower portion. This dual innervation is essential for the muscle's function, particularly in movements involving internal rotation of the arm and stabilization of the shoulder joint.

The significance of these nerves lies in their targeted approach to the muscle, ensuring that it receives adequate neural input to perform its specific functions effectively. Distinguishing the subscapular nerves from other nerves like the thoracodorsal or axillary nerves helps in understanding muscle control and the overall anatomy of the shoulder region, which is critical for both diagnostic and therapeutic applications in muscle injuries and rehabilitation.