The<unk>  arises from the branches from lateral and<unk>  cords of the brachial plexus, courses through the anterior part of arm, forearm, and hand, and terminates by supplying the muscles of the hand. Arm After receiving inputs from both the lateral and<unk>  cords of the brachial plexus, the<unk>  enters the arm from the axilla at the inferior margin of the teres major muscle. It then passes vertically down and courses lateral to the brachial artery between biceps brachii (above) and brachialis (below). At first, it is lateral to the artery and lies anterior to the shoulder joint; it then crosses anteriorly to run<unk>  to the artery in the distal arm and into the cubital fossa. Inside the cubital fossa, the<unk>  passes<unk>  to the brachial artery. The<unk>  gives off an articular branch to the elbow joint. A branch to pronator teres muscle arise from the<unk>  immediately above the elbow joint. Forearm The<unk>  continues in the cubital fossa<unk>  to the brachial artery and passes between the two heads of the pronator teres, deep to the bicipital aponeurosis (aponeurosis of biceps) and superficial the brachialis muscle. It crosses the ulnar artery (branch of brachial artery) while being separated by the deep head of the pronator teres. It then travels between the flexor digitorum superficialis (above) and flexor digitorum profundus (below). The<unk>  is accompanied by the<unk>  artery (a branch of anterior interosseous artery) during this course. Then, about 5 cm above the flexor retinaculum (wrist), it emerges between the flexor digitorum superficialis <unk> ly) and the flexor carpi radialis (laterally) into the hand. The main trunk of the<unk>  innervates the superficial and deep groups of the muscles in the anterior compartment of the forearm with the exception of flexor carpi ulnaris. The<unk>  does this by giving off two branches as it courses through the forearm: *Muscular branches are given off in the cubital fossa to supply flexor carpi radialis, palmaris longus, and flexor digitorum superficialis. *The anterior interosseous branch is given off in the upper part of the forearm, courses with the anterior interosseous artery and innervates flexor pollicis longus and the lateral half of flexor digitorum profundus (the ulnar half is supplied by ulnar nerve, as is the flexor carpi ulnaris muscle). It ends with its innervation of pronator quadratus. In addition to its supply to muscles, this nerve also supplies the distal radioulnar joint and wrist joint. The<unk>  also gives off sensory and other branches in the forearm. The palmar cutaneous branch of the<unk>  arises at the distal part of the forearm. It supplies sensory innervation to the thenar eminence of the palm and the central palm. Articular branches are given to the elbow joint and proximal radioulnar joint. Vascular branches supply the radial and ulnar arteries. Meanwhile, a communicating branch is given to the ulnar nerve. Hand The<unk>  enters the hand through the carpal tunnel, deep to the flexor retinaculum along with the tendons of flexor digitorum superficialis, flexor digitorum profundus, and flexor pollicis longus. From there, it is divided into recurrent muscular branch and digital cutaneous branch: * The muscular branch (also known as recurrent branch) supplies the thenar muscles (opponens pollicis, abductor pollicis brevis, and superficial part of flexor pollicis brevis) *Digital cutaneous to the proper palmar digital branch and the common palmar digital branch: The proper palmar digital branch gives out three digital branches to the lateral one and a half digits (two digital branches to the thumb, one digital branch to the lateral side of the index finger). The digital branch to the index finger also supplies the first lumbrical. The common palmar digital branch divides further into two branches. Both the<unk>  and lateral branches supply the second and third interdigital clefts with adjoining index, middle, and lateral half of ring finger. The lateral branch also supplies the second lumbrical. Variation The naturally occurring anomalies of the<unk>  are: * Bifurcation of the<unk>  typically occurs after the nerve exits the carpal tunnel; however, in a small percentage (5-10%) of individuals, the<unk>  bifurcates more proximal in the carpal tunnel, wrist, or forearm. * During gestation, a<unk>  artery that serves the hand retracts. However, in some individuals, the<unk>  artery does not retract and follows the course next to the<unk>  into the hand. * Martin-Gruber anastomoses can occur when branches of the<unk>  cross-over in the forearm and merge with the ulnar nerve to innervate portions of the forehand. * Riche-Cannieu anastomosis can occur when a connection exists between recurrent branch of the<unk>  and deep branch of the ulnar nerve of the hand.
Median nerve
Anterior interosseous nerve
Nerve fascicle
Long thoracic nerve
Sensory nerve
Nerve plexus
Accelerator nerve
Achilles tendon