Superficial head of pronator teres

At a glance

English

Superficial head of pronator teres

Latin (TA2)

Caput superficiale pronatoris teretis

System

Muscle

Region

Upper limb

Side

Paired, left and right

About the superficial head of pronator teres

Pronator teres is the rounded muscle that crosses the upper front of the forearm obliquely, from the inner side of the elbow to the middle of the radius. It forms the medial border of the cubital fossa. It has two heads. The superficial, or humeral, head is the larger and provides most of the bulk; the small deep, or ulnar, head lies beneath it.

The superficial head springs from the lowest part of the medial supracondylar ridge, just above the epicondyle, and also from the tendon common to the whole superficial flexor group. The deep head comes from the medial side of the coronoid process of the ulna. The two join, and the muscle passes down and laterally under brachioradialis to a flat tendon that attaches to a rough area at the middle of the lateral surface of the radius, at the point where the bone is most curved.

Pronator teres turns the palm downward, rolling the radius over the ulna, and it is the faster and more forceful of the two pronators. It also helps flex the elbow. Its pull on the curved middle of the radius gives it good leverage. The median nerve supplies it, and its blood comes from the anterior ulnar recurrent artery and from muscular branches of the radial and ulnar arteries.

The median nerve leaves the cubital fossa by passing between the two heads, and the ulnar artery passes deep to the deep head. Thickening of the superficial head, or a fibrous band between the heads, can squeeze the nerve, a problem called pronator syndrome, with aching in the forearm and tingling in the thumb and fingers on repeated pronation.

Attachments, action and supply

Origin

Medial supracondylar ridge just above the medial epicondyle, and the common flexor tendon.

Insertion

With the deep head, the middle of the lateral surface of the radius.

Action

Pronates the forearm; assists elbow flexion.

Nerve supply

Median nerve (C6, C7).

Blood supply

Anterior ulnar recurrent artery and muscular branches of the radial and ulnar arteries.