Teres Minor Muscle A key member of the rotator cuff, teres minor plays an essential role in shoulder stability and controlled movement. Origin: Upper 2/3 of the lateral border of the scapula Insertion: Inferior facet of the greater tubercle of the humerus Nerve supply: Axillary nerve (C5–C6) Function: • External (lateral) rotation of the arm • Assists adduction • Stabilizes the humeral head in the glenoid cavity Clinical insight: Weakness in external rotation with an intact deltoid may suggest t