Ulnar nerve dysfunction Health Article

Definition

Ulnar nerve dysfunction is a problem with the nerve that travels from the wrist to the shoulder. The condition causes movement or sensation problems in the wrist and hand.

Alternative Names

Neuropathy - ulnar nerve; Ulnar nerve palsy

Causes, incidence, and risk factors

Ulnar nerve dysfunction is a common form of peripheral neuropathy. It occurs when there is damage to the ulnar nerve, which travels down the arm. The ulnar nerve is near the surface of the body where it crosses the elbow, so prolonged pressure on the elbow may cause damage. The damage involves the destruction of the covering of the nerve ( myelin sheath) or part of the nerve (axon). This damage slows or prevents nerve signaling.

A problem with one single nerve group (such as the ulnar nerve) is called mononeuropathy. The usual causes are direct injury, prolonged external pressure on the nerve, or compression of the nerve caused by swelling or injury of nearby body structures. Entrapment involves pressure on the nerve where it passes through a narrow structure.

The ulnar nerve is commonly injured at the elbow because of elbow fracture or dislocation. Prolonged pressure on the base of the palm may also cause damage to part of the ulnar nerve. In some cases, no detectable cause can be identified.

Symptoms

• Abnormal sensations in the 4th or 5th fingers

• Numbness, decreased sensation

• Tingling, burning sensation

• Pain

• Weakness of the hand

Pain or numbness may awaken the patient from sleep. The condition is made worse by activities such as tennis or golf.

Signs and tests

An exam of the hand and wrist can reveal ulnar nerve dysfunction. There may be weakness of wrist and hand bending and difficulty moving the fingers. Severe cases may display wasting of the hand muscles or a characteristic "claw-like" deformity. A detailed history may be needed to determine the possible cause of the neuropathy.

Tests that reveal ulnar nerve dysfunction may include an EMG (a recording of electrical activity in muscles) and nerve conduction tests. Other tests may include blood tests, x-rays, and imaging scans.