Tennis elbow (lateral epicondylitis)
What it is
Pain on the outside of the elbow where the tendons that straighten the wrist and fingers attach to the bone. The tendons wear down or develop tiny tears, and the pain starts mild and builds over weeks.
Why it happens
Repeating the same gripping or wrist movement many times, in racket sports, weight training, gaming, or playing an instrument. It is most common in adults between 30 and 50, but teenagers get it from the same repeated movements.
Little League elbow (medial apophysitis)
What it is
Pain on the inside of the elbow in young throwers, where the growth plate is irritated by the repeated pull of the forearm muscles. It only happens while the growth plates are still open.
Why it happens
Throwing too much, too hard, or with poor technique before the elbow has finished growing, most often in baseball pitchers, but also in cricket, javelin and tennis serving.
Wrist sprain
What it is
A stretch or tear of the ligaments that connect the bones of the wrist, causing pain, swelling and bruising, and sometimes a popping feeling at the time of injury.
Why it happens
A fall onto an outstretched hand, common in skateboarding, snowboarding, basketball, gymnastics and simply tripping.