Lateral epicondylitis, often referred to as Tennis or Golfer's Elbow, is a condition affecting the tendons that attach on the lateral side (outside) of the elbow (lateral epicondyle). These tendons, which connect muscle to bone, manipulate the forearm in an upward motion as well as extension of the wrist and hand. Damage to these tendons, often tears or inflammation, can result in pain in the elbow or that radiates down the forearm.

The condition occurs most often due to severe overuse. While playing tennis and golf are possible causes, any activities requiring repetitive motion of the wrist or forearm can result in the condition.

Further Reading:

American Academy of Orthopaedic Surgeons: Tennis Elbow (Lateral Epicondylitis)