Ulnar nerve

The ulnar nerve (n. Ulnaris) departs from the medial bundle of the brachial plexus. It consists of the fibers of the anterior branches of the eighth cervical - the first thoracic (СVIII-ThI) spinal nerves. Initially, the ulnar nerve is located next to the median nerve and slightly medial to the brachial artery. In the middle third of the shoulder, the nerve deviates into the medial side, then perforates the medial intermuscular septum of the shoulder and goes down to the posterior surface of the medial epicondyle of the humerus. On the shoulder, the elbow nerve does not give branches. Next, the ulnar nerve gradually shifts to the front surface of the forearm, where it first passes between the muscular tufts of the initial part of the elbow flexor of the wrist. Below the nerve is located between the ulnar flexor of the wrist medially and the superficial flexor of the fingers laterally. At the level of the lower third of the forearm, he goes to the elbow groove of the forearm near and medial to the same arteries and veins. Closer to the head of the ulna from the ulnar nerve is its posterior branch (r. Dorsalis), which on the rear of the hand goes between this bone and the tendon of the ulnar flexor of the wrist. On the forearm, the muscular branches of the nerve innervate the elbow flexor of the wrist and the medial part of the deep flexor of the fingers.

The back branch of the ulnar nerve on the back of the hand is divided into five back finger branches. These nerves innervate the skin of the rear of the hand from the ulnar side, the skin of the proximal phalanges IV, V and the ulnar side of the third finger.

The palmar branch (r. Palmaris) of the ulnar nerve, along with the ulnar artery, passes into the palm through the gap in the medial part of the flexor retainer, on the lateral side of the pea-bones. Near the hook-shaped process of the hook-shaped bone, the palm branch is divided into a superficial and a deep branch. The superficial branch (r. Superficialis) is located under the palmar aponeurosis. From it the branch to the short palmar muscle first departs. Then it is divided into a common palmar finger nerve (n. Digitalis palmaris communis) and its own palmar nerve. The common palmar finger nerve passes under the palmar aponeurosis and is divided into two palmal fingertips in the middle of the palm. They innervate the skin of the facing sides of the IV and V fingers, as well as the skin of their back surfaces in the area of the middle and distal phalanx. The palmar finger nerve itself (n. Digitalis palmaris proprius) innervates the skin of the elbow side of the little finger.

The deep branch (r. Profundus) of the ulnar nerve first accompanies the deep branch of the ulnar artery. This branch passes between the muscle that removes the little finger, the medial and short flexor of the little finger laterally. Then the deep branch deviates to the side, it goes obliquely between the bundles of the muscle that removes the little finger, under the distal sections of the flexor tendons of the fingers, located on the interosseous palmar muscles. The deep branch of the ulnar nerve innervates all the muscles of the little finger's elevation (the short flexor of the little finger, which removes and contrasts the little finger of the muscle), the back and palmar interosseous muscles, and the leading thumb muscle of the hand and the deep head of the short flexor of the thumb of the hand, 3rd and 4th vermiform muscles, bones, joints and ligaments of the hand. The deep palmar branch is connected by connecting branches with the branches of the median nerve.