[Skeletal muscle involvement in enthesopathy of the lateral epicondyle of the humerus (so-called tennis elbow)].

Muscle specimens from the origin of the m. extensor carpi radialis brevis, were obtained from 53 patients suffering from chronic enthesopathy of the lateral epicondyle of humerus (EELH). Frank neurogenic atrophy as well as disuse atrophy were caused by radicular irritation due to the cervicobrachial syndrome. The borderline and/or reinnervation patterns of the muscle lesion may be due to the compression neuropathy of the peripheral branches of the radial nerve or may reflect adaptation of the muscle to the chronic nociceptive stimulation in sense of chronic reflex atrophy of the muscle. The elbow joint, and especially the humeroradial joint in cases of EELH represents a functional unit. Any damage to any part leads to secondary reparative and adaptive changes in other structures including the muscle.