Teres minor is a narrow muscle located at the (back) posterior of the shoulder, (below) distal to the infraspinatus. It is one of the four muscles of the rotator cuff and helps with external rotation of the shoulder. Related Definitions Infraspinatus Rotator Cuff Rotator Cuff Tear Subscapularis Supraspinatus Editor’s Top Picks Rotator Cuff Injuries How Do Rotator Cuff Injuries Occur? Rotator Cuff Injuries: Symptoms Rotator Cuff Injuries: Causes and Risk Factors Rotator Cuff Injuries: Diagnosis Rotator Cuff Injuries: Initial Treatment