Movements of the forearm

The elbow joint is a modified hinge joint resulting in a wide range of movements of the forearm.

Forearm flexion

Forearm flexion is rotation in the anatomic plane such that the radius and ulna move anteriorly. It occurs primarily in the articulation between the humerus and ulna and can achieve approximately 150° of movement. It is the opposite of forearm extension.

• brachialis (primary)
• biceps brachii (primary)
• brachioradialis
• pronator teres

Forearm extension

Forearm extension is opposite of forearm flexion, that is the straightening of the radius and elbow back to the anatomic position (to 0°). Gravity also assists extending the elbow. It is the opposite of forearm flexion.

• triceps brachii (primary)
• anconeus

Forearm supination

Forearm supination is rotation of the radius so the palm faces posteriorly (back to the anatomical position). It occurs primarily at the proximal radioulnar joint by rotation of the radial head against the radial notch of the proximal ulna, held in by the annular ligament. It is the opposite of forearm pronation.

• supinator (when slow and unrestricted)
• biceps brachii (when fast and restricted)

Forearm pronation

Forearm pronation is rotation of the radius so the palm faces anteriorly (away from the anatomical position). It occurs primarily at the proximal radioulnar joint. Gravity also assists pronating the elbow. It is the opposite of forearm supination.

• pronator quadratus (primary)
• pronator teres