Which muscles are innervated by the upper and lower subscapular nerves?

The upper and lower subscapular nerves primarily innervate the subscapularis and teres major muscles. The upper subscapular nerve targets the upper portion of the subscapularis muscle, while the lower subscapular nerve innervates both the lower part of the subscapularis and the teres major muscle.

These muscles play significant roles in shoulder movements. The subscapularis, located on the anterior surface of the scapula, is a key player in internal rotation of the arm and stabilization of the shoulder joint. The teres major assists in similar functions, contributing to shoulder adduction and internal rotation as well.

Other options provided do not align with the innervation pattern of the upper and lower subscapular nerves. For instance, the serratus anterior and pectoralis major are innervated by different nerves, specifically the long thoracic nerve and the lateral and medial pectoral nerves, respectively. The flexor carpi ulnaris and hypothenar muscles are innervated by the ulnar nerve, while the supraspinatus and infraspinatus muscles are innervated by the suprascapular nerve. Understanding these innervation patterns is