Lateral epicondylitis, also known as "Tennis Elbow", is the most common overuse syndrome in the elbow. It is a tendinopathy injury involving the extensor muscles of the forearm. These muscles originate on the lateral epicondylar region of the distal humerus. Lateral epicondylitis most often occurs related to overuse. Any activity that over stresses the involved tendon, the extensor carpi radialis brevis, can cause the disorder. These activities include repetitive work, gardening, tennis, and golf.