Medial epicondylitis is less common than lateral epicondylitis and results from injury to the muscles and tendons on the inside (medial aspect) of the elbow. Injury is most often caused by overuse of the flexor tendons of the forearm, particularly the pronator teres and flexor carpi radialis tendons. Commonly occurs secondary to chronic overuse in sports such as baseball, golf, swimming, or from occupations that require a strong handgrip and excessive pronation of the forearm.