![]() Pronator teres syndrome is one cause of wrist pain. It also weakly flexes the elbow, or assists in flexion at the elbow when there is strong resistance. It is assisted in this action by pronator quadratus. If the elbow is flexed to a right angle, then pronator teres will turn the hand so that the palm faces inferiorly. Pronator teres pronates the forearm, turning the hand posteriorly. Also, additional slips from the medial intermuscular septum, from the biceps brachii, and from the brachialis occasionally occur. Next, the signal goes down the median nerve branch of the brachial plexus and stimulates the pronator teres to contract causing the hand to pronate. The signal then goes through the ventral rami and down the root ganglions of C5, C6, C7, C8, and T1 (which together form the brachial plexus). Once at the pyramids, the corticospinal tracts decussate and the signal goes down the lateral corticospinal tract until it reaches the ventral horns of C5, C6, C7, C8, and T1. It continues down the corticospinal tracts through the capsule, midbrain, and pons where it arrives at the medullar pyramids. To stimulate the pronator teres, a signal begins in the precentral gyrus in the brain and goes down through the internal capsule. ![]() The pronator teres is innervated by the median nerve and nerve roots C6 and C7. 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. ![]() 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 median nerve enters the forearm between the two heads of the muscle, and is separated from the ulnar artery by the ulnar head. The ulnar head (or ulnar tuberosity) 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 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 pronator teres has two heads-humeral and ulnar. It has two attachments, to the medial humeral supracondylar ridge and the ulnar tuberosity, and inserts near the middle of the radius. The pronator teres is a muscle (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). ![]()
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