Supinator muscle Anatomy

Table of Contents

Supinator is a spiral muscle contained in the posterior compartment of the forearm, along with the brachioradialis, and the superficial and deep forearm extensors. It curls around the proximal part of radius, connecting it with the ulna. In doing so, the muscle crosses the sagittal axis of the forearm causing the supination movement of the hand.

Origin :

It originates from the lateral epicondyle of humerus, annualar ligament, radial collateral ligament and supinator crest of the ulna.

Insertion :

It inserts into the lateral, posterior and anterior surface of the proximal third of the ulna

Nerve supply :

The posterior interosseous nerve supplies the muscle.

Blood supply :

The radial recurrent artery, posterior interosseous artery, and posterior recurrent interosseous artery supply the muscle.

Action :

It acts as the supinator of the elbow when the elbow is in extension.

Function :

Supinator muscle rotates the radius laterally at the proximal radioulnar joint. This action puts the radius parallel to the ulna, therefore bringing the hand into the supine position (facing anteriorly, palm up, like holding a bowl of soup).

Strengthening Exercises :

1. Wrist Twist :

For this exercise, you‘ll need to be seated and you‘ll need a dumbbell.
Rest the elbow of your right arm on your knee while seated. Hold the dumbbell in your right hand at its end.
Beginning with the dumbbell in a vertical position, twist your hand to the side so the dumbbell is then at a 90-degree angle horizontally.
Hold the position for a moment and then move it back up to its original vertical position.
Repeat the movement 10 times in the span of 3 sets

2. Hammer Rotations :

Standing or sitting in a chair, keep the hand on the table in a comfortable position and feet equally apart as shown in the figure.
Your hand and wrist should both be hanging off the table while holding the hammer.
Hold the hammer in such a way that it is pointed outside of your body.
When you’re ready, turn the hammer to the inside of your body like a windshield wiper. Do this for 3 sets of 10 reps (5 each side).

Stretching exercise :

Forearm pronation and supination: Bend the elbow of your injured arm 90 degrees, keeping your elbow at your side. Turn your palm up and hold for 5 seconds. Then slowly turn your palm down and hold for 5 seconds. Make sure you keep your elbow at your side and bent 90 degrees while you do the exercise.

Related pathology

The radial nerve divides into deep and sensory superficial branches just proximal to the supinator muscle. This can lead to entrapment and compression of the deep branch and could potentially result in selective paralysis of the muscles served by this nerve. Many possible causes are known for this nerve syndrome (known as supinator entrapment syndrome) including compression by various soft-tissued masses surrounding the nerve, and stress caused by repetitive supination and pronation.

Supinator Muscle