[1] The primary function of the teres minor is to modulate the action of the deltoid, preventing the humeral head from sliding upward as the arm is abducted.

This might include throwing a powerful pitch, holding a fast moving rope during water sports, falling over onto an outstretched hand at speed, or making a sudden thrust with the paddle in kayaking.

People affected note shoulder pain and paresthesia down the arm first and foremost in abduction, extension, external rotation and overhead activity.

Selective atrophy of the teres minor muscle has been seen and pulled together directly with compression of the corresponding axillary nerve branch or posterior humeral circumflex artery.

Fibrous bands, cysts of the glenoid labrum, lipoma or dilated veins can occupy the quadrilateral space pathologically.

Similar symptoms are common with anterior shoulder dislocation, humeral neck fracture, brachial plexus injury and thoracic outlet and inlet syndrome.

Posterior humeral circumflex artery compression and reduced blood flow in stressful arm positions and or maneuvers can be diagnosed by a Doppler ultrasonography.

Additional electromyography is helpful to reveal any decelerated nerve conduction velocity, and thus denervation of the concerned muscle.