Ulnar nerve dysfunction
Key points
- Ulnar nerve dysfunction involves impaired movement or sensation in the wrist and hand caused by damage to the ulnar nerve.
- Ulnar nerve dysfunction is a common form of peripheral neuropathy.
- Pain or numbness may awaken the patient from sleep.
- Neuromuscular examination of the hand and wrist indicates ulnar nerve dysfunction.
Alternative names
Neuropathy - ulnar nerve; Ulnar nerve palsy
Definition
Ulnar nerve dysfunction involves impaired movement or sensation in the wrist and hand caused by damage to the ulnar nerve.
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, supplying flexion (bending movement) to the wrist and aiding movement and sensation of the wrist and hand.
Dysfunction of a single nerve group (such as the ulnar nerve) is classed as mononeuropathy. Mononeuropathy implies a local cause of the nerve damage, although systemic disorders may occasionally cause isolated nerve damage such as occurs with mononeuritis multiplex.
The usual causes are direct trauma, 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 damage involves destruction of the myelin sheath of the nerve, or destruction of part of the nerve cell (the axon). This damage slows or prevents conduction of impulses through the nerve.
The ulnar nerve is commonly injured at the elbow because of elbow fracture or dislocation. The ulnar nerve is near the surface of the body where it crosses the elbow, so prolonged pressure on the elbow or entrapment of the nerve may cause damage.
Prolonged pressure on the base of the palm may also cause damage to part of the ulnar nerve, resulting in symptoms that are localized to the small hand muscles. In some cases, no detectable cause can be identified.
The mechanical factors may be complicated by ischemia (lack of oxygen related to decreased blood flow) in the area.
Symptoms
- Sensation changes
o Of the 4th or 5th fingers
o Of the hand below the 4th and 5th fingers
o Numbness, decreased sensation
o Tingling, burning sensation
o Pain
o Abnormal sensations - Weakness of the hand
Pain or numbness may awaken the patient from sleep. The dysfunction is aggravated by activities such as tennis or golf.
Signs and tests
Neuromuscular examination of the hand and wrist indicates ulnar nerve dysfunction. There may be weakness of wrist and hand flexion 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.
Frequently asked questions
What is ulnar nerve dysfunction?
Ulnar nerve dysfunction involves impaired movement or sensation in the wrist and hand caused by damage to the ulnar nerve.
What are the risk factors for ulnar nerve dysfunction?
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, supplying flexion (bending movement) to the wrist and aiding movement and sensation of the wrist and hand. Dysfunction of a single nerve group (such as the ulnar nerve) is classed as mononeuropathy. Mononeuropathy implies a local cause of the nerve damage, although systemic disorders may occasionally cause isolated nerve damage such as occurs with mononeuritis multiplex. The usual causes are direct trauma, prolonged external pressure on the nerve, or compression of the nerve caused by swelling or injury of nearby body structures.
What are the symptoms of ulnar nerve dysfunction?
- Sensation changes o Of the 4th or 5th fingers o Of the hand below the 4th and 5th fingers o Numbness, decreased sensation o Tingling, burning sensation o Pain o Abnormal sensations
- Weakness of the hand Pain or numbness may awaken the patient from sleep. The dysfunction is aggravated by activities such as tennis or golf.
How is ulnar nerve dysfunction treated?
Written and revised by
Gerald Hurowitz, M.D.
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