Tennis elbow is a condition that causes pain around the outside of the elbow. It’s clinically known as lateral epicondylitis. It often occurs after strenuous overuse of the muscles and tendons of the forearm, near the elbow joint. You may notice pain: on the outside of your upper forearm, just below the bend of your elbow when lifting or bending your arm when gripping small objects, such as a pen when twisting your forearm, such as turning a door handle or opening a jar. The elbow joint is surrounded by muscles that move your elbow, wrist and fingers. The tendons in your elbow join the bones and muscles together, and control the muscles of your forearm. Tennis elbow is usually caused by overusing the muscles attached to your elbow and used to straighten your wrist. If the muscles and tendons are strained, tiny tears and inflammation can develop near the bony lump (the lateral epicondyle) on the outside of your elbow. As the name suggests, tennis elbow is sometimes caused by playing tennis. However, it is often caused by other activities that place repeated stress on the elbow joint, such as decorating or playing the violin. Pain that occurs on the inner side of the elbow is often known as golfer’s elbow.