Pronator teres

The pronator teres (Latin: musculus pronator teres) is a fusiform-shaped muscle of the upper limb that extends between the humerus, radius and ulna. It belongs to the anterior muscles of the forearm and is classified as one of the forearm flexors. The pronator teres lies in the first, most superficial layer of the anterior compartment. This muscle is composed of two heads - humeral (superficial) and ulnar (deep).

Origin

The humeral head of the pronator teres muscle originates superior to the medial epicondyle of the humerus - from the medial supracondylar ridge. In contrast, the ulnar head arises from the coronoid process of the ulna.

Insertion

The pronator teres extends in an oblique manner to the radial side of the forearm and forms a flat tendon that inserts on the middle aspect of the lateral surface of the radius.

Action

The pronator teres muscle provides the flexion and pronation of the forearm at the elbow and proximal radioulnar joints, respectively.

Innervation

The pronator teres is innervated by the median nerve (C6, C7) - a branch of the brachial plexus.

Blood supply

The pronator teres muscle receives arterial blood supply from the branches of the radial, brachial and ulnar arteries.