In the wrist, the ulnar nerve is susceptible to cut injuries. In the fingers and palm, the finger nerve is susceptible to lacerations or contusions. The deep branch of the ulnar nerve is a motor branch and can sometimes be injured by stabbing or penetrating injuries. In the elbow, the ulnar nerve is often injured by direct trauma or combined with fracture and dislocation. The ulnar nerve injury caused by severe elbow valgus deformity and ulnar nerve slippage is also called elbow canal syndrome or chronic ulnar neuritis. If the hand is not protected during general anesthesia and left dangling over the edge of the operating table, paralysis may result from prolonged compression. In cervical-rib or anterior oblique syndrome, the ulnar nerve is most often damaged.
Overview Applied anatomy The ulnar nerve originates from the medial bundle of the brachial plexus and is composed of C7, 8 and T1 nerve fibers.
2. The deep branch is the motor branch. It passes through the short flexor of the little finger, the abductor of the little finger and the opposite palmar muscle of the little finger, turns laterally along the hook bone groove, and accompanies the deep palmar arch, along which it gives off branches to innervate all the interosseous muscles, the third four earth muscles, the thumb adductor and the deep head of the thumb short flexor.
Clinical manifestations and diagnosis 1. When the nerve is injured on the elbow, the ulnar carpal flexor and deep finger flexor tendons of the forearm are semi-paralyzed and atrophied on the ulnar side, unable to flex the wrist to the ulnar side and flex the distal interphalangeal joint of the ring little finger. The intrinsic muscles of the hand were extensively paralyzed, and the small interphalangeal muscle was atrophied, with obvious depression between the metacarpals. The ring little finger has a claw-like deformity. The claw deformity is mild in the upper part of the elbow, but in the distal part of the deep finger flexor muscle branch, the claw deformity is obvious because there is no counteraction of the finger flexor and finger extension by the intrinsic hand muscles, i.e., the ring little finger is hyperextended at the metacarpophalangeal joint and flexed at the interphalangeal joint. Because of the antagonistic effect of the first two earthworms, the middle finger is not obviously claw deformed. Each finger cannot be abducted internally. Because of the paralysis of the thumb adductor muscle, the paper grip test between the thumb and the thumb showed no strength, and because of the paralysis of the intrinsic hand muscle, the grip strength of the hand was reduced by about 50% and the hand lost flexibility.
2. Sensation Loss of sensation on the ulnar side of the palm, all of the little finger, and the ulnar half of the ring finger.
Principles of treatment Do release, decompression or repair surgery according to the injury.