Pronator teres muscle

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Pronator teres muscle
Pronator-teres.png
Anterior view of the left forearm. Superficial muscles. (Pronator teres colored at center.)
LatinMusculus pronator teres
Gray'sp.446
humeral head: medial epicondyle of humerus (common flexor tendon)
ulnar head: coronoid process of ulna
Middle of the lateral surface of the body of the radius
ulnar artery and radial artery
median nerve
Actionspronation of forearm, flexes elbow
Supinator muscle
TAA04.6.02.025
FMAFMA:38450
Anatomical terms of muscle
 
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Pronator teres muscle
Pronator-teres.png
Anterior view of the left forearm. Superficial muscles. (Pronator teres colored at center.)
LatinMusculus pronator teres
Gray'sp.446
humeral head: medial epicondyle of humerus (common flexor tendon)
ulnar head: coronoid process of ulna
Middle of the lateral surface of the body of the radius
ulnar artery and radial artery
median nerve
Actionspronation of forearm, flexes elbow
Supinator muscle
TAA04.6.02.025
FMAFMA:38450
Anatomical terms of muscle

The pronator teres is a muscle of the human body (located mainly in the forearm) that, along with the Pronator quadratus, serves to pronate the forearm (turning it so that the palm faces posteriorly when from the anatomical position).

Etymology[edit]

The word pronator comes from the Latin pronus, which means “inclined forward or lying face downward”, and has to do with the muscle's action being pronation of the forearm. The Latin term teres, which means "round or cylindrical shaped" or "long and round", refers to the shape of the muscle.[1][2] The indirect English translation of pronator teres is therefore: cylindrical muscle that pronates (the forearm).

Structure[edit]

The pronator teres has two heads—humeral and ulnar.

The humeral head, the larger and more superficial, arises from the medial supracondylar ridge immediately superior to the medial epicondyle of the humerus, and from the common flexor tendon (which arises from the medial epicondyle).

The ulnar head is a thin fasciculus, which arises from the medial side of the coronoid process of the ulna, and joins the preceding at an acute angle.

The median nerve enters the forearm between the two heads of the muscle, and is separated from the ulnar artery by the ulnar head.

The muscle passes obliquely across the forearm, and ends in a flat tendon, which is inserted into a rough impression at the middle of the lateral surface of the body of the radius, just distal to the insertion of the supinator.

The lateral border of the muscle forms the medial boundary of the triangular hollow known as the cubital fossa, which is situated anterior to the elbow.

Innervation[edit]

The pronator teres is innervated by the median nerve.

Action[edit]

Pronator teres pronates the forearm, turning the hand posteriorly. If the elbow is flexed to a right angle, then pronator teres will turn the hand so that the palm faces inferiorly. It is assisted in this action by pronator quadratus.

It also weakly flexes the elbow, or assists in flexion at the elbow when there is strong resistance.

Variations[edit]

Occasionally, the ulnar head is absent. Also, additional slips from the medial intermuscular septum, from the biceps brachii, and from the brachialis occasionally occur.

Clinical aspects[edit]

Pronator teres syndrome is one cause of wrist pain. It is a type of neurogenic pain.

Additional images[edit]

References[edit]

External links[edit]

This article incorporates text from a public domain edition of Gray's Anatomy.