The Teres Minor origin is Scapula (Lateral) and its insertion is the lower shoulder joint capsule (inferior aspect greater tuberosity of the humerus)
The test is the same as the infraspinatus muscle. Abduct the arms and bend the elbows bent at 90 degrees. Place your hands on the outside of their arms. Encourage gentle force that opens their arms and externally rotates them.
The occurrences of rotator cuff damage increases with age commonly due to degeneration and general weakening of the tendon.
This lying spinal twist uses the teres minor muscle along with the infraspinatus and other muscles to bring the shoulder down. (The shoulder on the arm that the gaze is towards.)