The supinator runs between the bones the radius and ulna in the forearm. It supinates your forearm, turning it palm up. The opposite of this pattern is pronation, rotating the forearm so that your palm faces downward. The causes, pain patterns, corrective actions, and self-care are similar to brachioradialis. Supinator dysfunction is at the root of most cases of lateral epicondylitis, sometimes called “tennis elbow”.

Pain from supinator trigger points often originates on the outside of the forearm, near the elbow. It may also progress down the arm toward the base and web of the thumb.

The primary cause of supinator trigger points is stress overload. This can happen with any activity that involves repeated rotation of your forearm, flexing the wrist, deviating the wrist toward the pinky side, or loading the forearms incorrectly when carrying boxes or packages. The classic example is playing tennis, mis-hitting the ball, off-center, with the arm fully extended, twisting the forearm, and requiring a strong effort to keep the racquet straight.

Less frequent forceful pronation of your wrist (the opposite of supination) can also activate supinator trigger points. For instance, carrying a backpack to work and flipping it onto the desk, palm side down and arm extended, is forceful pronation of your forearm.

When your elbow is flexed, the biceps is the most powerful supinator of the forearm, the supinator merely assists, and injuries are less frequent. When your arm is extended, the much stronger biceps is unable to assist and your supinator becomes the prime mover.

Supinator trigger points do not usually happen in isolation and are part of a pattern that often includes the brachioradialis, brachialis, triceps, wrist, and finger extensors.

Corrective actions include trigger point pressure release, stretching, and avoiding activities that overload the muscle.