The forearm
The forearm holds 20 muscles, most of them long and thin. The wrist flexors lie on the palm side and start together on the medial epicondyle, the bump on the inner side of the elbow. With the finger flexors beneath them they bend the wrist and fingers, and one of them, the pronator teres, turns the palm down.
Superficial muscles on the front of the left forearm, among them the pronator teres, the flexor carpi radialis, the palmaris longus, the flexor carpi ulnaris and the brachioradialis, Gray's Anatomy, 1918, figure 414Wikimedia Commons, Henry Vandyke Carter, Public domain (Gray414.png)
The wrist extensors and the finger extensors lie on the back and start on the lateral epicondyle, on the outer side of the elbow. They straighten the wrist and fingers. Overuse of their common tendon in gripping causes tennis elbow, a pain over that bump.
Superficial muscles on the back of the forearm, the wrist and finger extensors with their tendons running into the hand, Gray's Anatomy, 1918, figure 418Wikimedia Commons, Henry Vandyke Carter, Public domain (Gray418.png)
The brachioradialis runs from the lower humerus to the end of the radius at the wrist. It bends the elbow and is strongest with the thumb pointing up, as when lifting a glass.
Sources
- Susan Standring (ed.), Gray's Anatomy, 42nd ed. (2020), chapter on the elbow and forearm.
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