External epicondylitis of the humerus is also known as “bursitis of the brachioradialis joint” and “tennis elbow”. It is a chronic injury disease caused by the repeated stimulation of the starting point of the wrist extensor muscle group of the forearm. The clinical manifestations are slow in onset, with occasional pain on the lateral side of the elbow after exertion, aggravated over time, such as lifting, twisting towels, even sweeping and wringing clothes, with pain and soreness, sometimes the pain can be radiated to the extensor side of the forearm, radial side, wrist, upper arm and shoulder. Some people have increased pain at night. Local pressure pain, mostly at the attachment of the extensor digitorum generalis tendon and at the brachioradialis joint, and resistance pain. The pain may be associated with semi-clenched fist, flexion of the elbow, ulnar deviation of the wrist joint, or elbow extension pain in the forearm rotated forward position. The radial extensor carpi radialis longus, shortus, extensor digiti minimi, ulnar extensor carpi radialis and brachioradialis all start at the external epicondyle of the humerus. Overstretching of this muscle group, such as bruising, strong elbow rotation, repeatedly exerting too much force on the wrist, too long or prolonged lifting and throwing heavy objects, can cause inflammatory lesions in the external epicondyle of the humerus. The radial extensor muscle at the epicondylar attachment is mainly strained, causing joint stiffness, pain and dysfunction. The disease occurs in carpenters, masons, tennis and table tennis players and housewives.