The
pronator teres is a
muscle of the
human body (located mainly in the
forearm) that, along with the
pronator quadratus muscle, serves to pronate the forearm (turning it so that the palm faces posteriorly).
Structure
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 below 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
The pronator teres is innervated by the
median nerve.
Action
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...
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