Radial nerve
Last reviewed: 23.04.2024
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Radial nerve (n. Radialis) is an extension of the posterior fasciculus of the brachial plexus. It consists of the fibers of the anterior branches of the fifth cervical - the first thoracic (CV-ThI) spinal nerves. The thickness of the radial nerve is the largest branch of the brachial plexus. It begins at the level of the lower edge of the small pectoral muscle. Initially, the nerve goes behind the axillary artery, then between the lateral and medial heads of the triceps arm muscle passes into the shoulder (spiral) canal. Before the entrance to this channel from the radial nerve, the posterior cutaneous nerve of the shoulder (n. Cutaneus brachii posterior), which goes back, perforates the long head of the triceps brachium muscle and the fascia of the shoulder next to the tendon of the deltoid muscle. The nerve innervates the skin of the posterolateral surface of the shoulder.
In the arm muscular canal from the radial nerve, the posterior cutaneous nerve of the forearm (n. Cutaneus antebrachii posterior) departs. This nerve initially goes along with the radial nerve, then passes between the lateral and medial heads of the triceps muscle of the shoulder. The nerve emerges on the back of the forearm and innervates the skin of its posterior side to the level of the wrist joint. On the shoulder, the radial nerve innervates the triceps muscle of the shoulder and the ulnar muscle.
Coming out of the shoulder cannula, the radial nerve perforates the lateral intermuscular septum of the shoulder and descends between the brachial and the beginning of the brachial muscle. At the level of the elbow joint, the radial nerve is divided into a superficial and a deep branch. The superficial branch (r. Superficialis) of the radial nerve is thinner and longer than the deep branch of this nerve. Initially, the superficial branch goes down under the brachial muscle, then between the brachial muscle and the long radial extensor of the wrist. In the lower third of the forearm, the superficial branch is located subcutaneously, gradually deviates laterally, then passes to the rear of the forearm between the radial bone and the tendon of the brachial muscle. At a distance of 4-5 cm above the level of the styloid process of the radius, this branch gives branches to the skin of the dorsal and lateral sides of the base of the thumb and is divided into five dorsal nerve nerves (nn. Digitales dorsales). Two of these nerves are directed to the radial and ulnar sides of the thumb, innervating his skin from the back. The remaining three finger dorsal nerves branch out in the skin of the 2nd finger and the radial side of the third finger at the level of their proximal phalanx. The skin of the middle and distal phalanges of the 2nd and 3rd fingers innervate the palmar nerves of the median nerve. The deep branch (r. Profundus) of the radial nerve perforates the supine muscle, gives the muscle branches to it and to the short radial extensor of the wrist. Near the radius of the radial bone, the deep branch passes to the back of the forearm, where it gives the muscle branches to the other muscles of the rear of the forearm. The longest of these branches is the posterior interosseous nerve (n. Interosseus posterior). It passes between the superficial and deep layers of muscles on the rear of the forearm, innervates the interosseous membrane and adjacent muscles.
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