Shoulder pain and an isolated teres minor nerve lesion.

The finding of isolated teres minor denervation during examination of the shoulders using MRI occurs in 3% to 5.5% of examinations. We describe eight patients with shoulder pain, in whom electromyography revealed an isolated lesion in the motor branch of the axillary nerve to the teres minor muscle. This nerve lesion is clinically impossible to diagnose, the lack of a clear diagnosis often resulting in inappropriate treatment and therefore potentially prolonged disability. Hence, when encountering shoulder problems, neurophysiologists should examine the teres minor muscle as a matter of routine. In the MRI and ultrasound examinations of patients with shoulder problems, therefore, not only routine tendon and joint structure but also muscles should be evaluated.