What is forearm supination?

The neutral position for pronation and supination of the forearm is when making a fist with the palm facing up (holding a pen), the pronation position is with the palm facing down, and the supination position is with the palm facing upward. 80-90 degrees.

The muscles that pronute the forearm are the pronator teres and pronator quadratus; the muscles that pronate the forearm are the supinator and biceps brachii.

The forearm has connective tissue, nerve tissue, and muscle tissue. The skin on the front area of ??the forearm is thin and mobile. On the ulnar side of the superficial fascia, there are important veins and their branches, as well as the medial cutaneous nerve of the forearm; on the radial side, there are the cephalic vein and its branches, and the lateral cutaneous nerve of the forearm; the palmar branches of the median nerve and ulnar nerve are supported by the flexor muscles. Bring out the deep fascia proximally.

The deep fascia in the forearm area is thin and tough, and is strengthened by the biceps aponeurosis near the elbow; the distal part is thickened at the front of the wrist, forming a thick and tough flat band, called the flexor muscle Support belt. The deep fascia of the forearm area sends out intermuscular septa to the deep part, between the flexor and extensor muscles, and is connected to the ulna and radius respectively; it, together with the two bones and the interosseous membrane of the forearm, forms the anterior forearm fascial sheath .

There are 9 muscles in the forearm anterior muscle group, which are divided into 3 layers: Superficial layer: from the radial side to the ulnar side are the brachioradialis, pronator teres, flexor carpi radialis, Palmaris longus, and flexor carpi ulnaris; middle layer: only the flexor digitorum superficialis; deep layer: the flexor digitorum longus on the radial side, the flexor digitorum profundus on the ulnar side, and the pronator quadratus on the deep side of the two muscles. Pronator teres: Its two heads originate from the medial epicondyle of the humerus and the coronoid process of the ulna respectively. The median nerve passes between them, and the ulnar artery passes through the deep surface of the ulnar head.

The muscle fibers run obliquely downward and outward, ending on the outer and back sides of the middle 1/3 of the radius. The proximal end is attached to the supinator muscle, and the distal end is attached to the pronator quadratus muscle. When the radius is fractured, the fracture line is above or below the insertion point of the pronator teres muscle, and the dislocation results are different. Palmaris longus: The muscle belly is very short and the tendon is slender. It can flex the wrist and tighten the palmar aponeurosis. Clinically, the tendon can be used for tendon transplantation.

Reference: Baidu Encyclopedia-Elbow Dislocation