Epicondylitis of the humerus is commonplace, and yet often misdiagnosed and subsequently mistreated. On this premise, the following study of 391 patients with this condition has been undertaken. Actually, the cause of this pathology is unknown, although direct trauma, repeated shearing movements of the upper extremity, etc., are often described as etiological factors. By way of contrast, the lateral epicondyle is involved in the vast majority of cases, and the medial epicondyle is only occasionally involved as the site of this malady.
Tennis elbow, which is a rather hackneyed phrase, actually can be one of two types of pathology. The commoner type involves the common extensor tendon of the forearm at its origin on the lateral epicondyle of the humerus. This entity may be referred to by various titles, such as lateral epicondylitis, epicondylitis externa, and epicondylalgia (external). The more infrequent lesion involves structures with a synovial lining. There are