Teres Major and Subscapularis
Muscle Function of Teres Major: Medially rotates, adducts, and extends the shoulder joint.
Muscle Function of Subscapularis: Medially rotates the shoulder joint, and stabilizes the head of the humerus.
Palpation: Inferior lateral aspect of the scapula in between where the teres major originates from the inferior angle of the scapula and inserts into the lesser tubercle of the humerus. The subscapularis is not palpable due to being located on the ventral surface of the scapula.
Strength Testing: Position ““ subject is prone with ipsilateral hand resting on ipsilateral posterior hip. Stabilization ““ none usually required. Resist ““ against extension and adduction of the humerus. Pressure is applied to examinee”™s arm just above elbow in the direction of humeral abduction and flexion.
Possible Substitutions: The latissimus dorsi and pectoralis major also contribute to medial shoulder rotation.
Origin: Dorsal surfaces of the inferior angle and lower 1/3 of the lateral border of the scapula.
Insertion: Crest of the lesser tubercle of the humerus.
Origin: Subscapular fossa of the scapula.
Insertion: Lesser tubercle of the humerus and shoulder capsule.