Elbow Joint Muscles
The elbow joint is a simple hinge joint but most movements involving the elbow joint also involve the radioulna joint where the forearm bones (radius and ulna) join at the elbow joint. Muscles producing movements at the elbow and forearm are the triceps brachii, brachioradialis, brachialis, biceps brachii and the anconeus.
Pronator Teres works the hardest when the elbow is flexing the hand simultaneously pronating.
The Triceps Brachii also assists Latissimus Dorsi in extending the shoulder joint. It contracts strongly during the up phase of a push up, to straighten the arm.
The Brachioradialis muscle acts to supinate the forearm from a pronated position, when it flexes the elbow. When starting in a supinated position, it acts to pronate the hand as it flexes the elbow.
The Brachialis acts to flex the elbow whether in pronation or supination, along with Biceps Brachii. As Brachialis is attached to the Ulna, which cannot rotate, it is the only true flexor of the elbow.
The Biceps brachii crosses both the elbow and shoulder joints. Its action on the shoulder joint is very weak flexion.
The Anconeus works alongside Triceps Brachii in extending the elbow. It also acts to pull the synovial membrane out of the way of the olecranon process when the elbow is extending.