Muscle · Elbow

Extensor carpi radialis brevis

Musculus extensor carpi radialis brevis

The tennis elbow muscle. It is the shorter of the two radial wrist extensors and it arises directly from the common extensor tendon on the outer point of the elbow, which places its origin at the exact spot that hurts in lateral elbow pain. The reason it takes the punishment is mechanical: every time the hand grips, this muscle has to contract hard just to stop the wrist collapsing, so a small patch of bone at the elbow absorbs the cost of work being done in the hand. Most people who get tennis elbow have never played tennis. And the reason the hand is gripping that hard is usually not in the arm at all: Momentum's clinical model reads elbow pain as a force-transfer failure from the trunk and shoulder — excessive gripping without shoulder support. The elbow pays for what the shoulder will not do, and this muscle is where the bill arrives.