Ulnar Nerve Entrapment 

What is ulnar nerve entrapment?

Ulnar nerve entrapment is a condition that occurs when the ulnar nerve, which runs from your neck to your hand, becomes compressed or irritated. This nerve is responsible for providing sensation to your pinky and ring fingers and controlling some of the hand's small muscles that allow you to perform fine motor tasks. Ulnar nerve entrapment can happen at various points along the nerve’s path, but it most commonly occurs at the elbow or wrist.

What is the ulnar nerve?

The ulnar nerve is part of the peripheral nervous system, which connects the brain and spinal cord to the rest of the body. It runs down the arm, passing through the cubital tunnel at the elbow and the Guyon’s canal at the wrist. This nerve is crucial for the function and sensation of the hand, especially the pinky and ring fingers.

Types of ulnar nerve entrapment

There are two main types of ulnar nerve entrapment:

• Cubital tunnel syndrome: This occurs when the ulnar nerve is compressed at the elbow.
• Guyon’s canal syndrome: This occurs when the ulnar nerve is compressed at the wrist.

Symptoms and Causes

What causes ulnar nerve entrapment?

Ulnar nerve entrapment can be caused by a variety of factors, including:

• Overuse injuries: Repetitive motions that involve bending the elbow or wrist can stretch or irritate the ulnar nerve.
• Trauma: A direct blow to the elbow or wrist can damage the ulnar nerve.
• Cysts or tumors: Growths in the arm can compress the ulnar nerve.
• Arthritis: Inflammatory conditions can cause swelling around the nerve.
• Prolonged pressure: Resting your elbows on a hard surface for extended periods can compress the nerve.

Risk factors

Certain activities and conditions increase the risk of ulnar nerve entrapment, including:

• Sports: Baseball, tennis, and golf can involve repetitive arm movements that irritate the ulnar nerve.
• Occupations: Jobs that require frequent elbow bending or leaning on the elbows, such as typing or assembly line work, can lead to nerve compression.
• Medical conditions: Diabetes and arthritis can increase the likelihood of nerve entrapment.

Symptoms

Symptoms of ulnar nerve entrapment typically develop gradually and may worsen over time. Common symptoms include:

• Numbness and tingling: This usually occurs in the pinky and ring fingers and can extend up the arm.
• Hand weakness: Difficulty gripping objects or performing tasks like writing or buttoning clothes.
• Pain: Discomfort or pain in the elbow or wrist, which may worsen at night.
• Claw hand: Severe cases may result in the pinky and ring fingers curling into a claw-like position.

Diagnosis and Tests

Physical examination

During a physical exam, your healthcare provider may perform specific tests to diagnose ulnar nerve entrapment:

• Froment’s test: This involves holding a piece of paper between the thumb and index finger. Difficulty doing so may indicate ulnar nerve dysfunction.
• Tinel’s test: Tapping the area over the ulnar nerve at the elbow or wrist can produce a tingling sensation if the nerve is irritated.
• Wartenberg’s sign: Difficulty bringing the pinky finger in line with the other fingers while the hand is flat on a surface may indicate nerve problems.

Diagnostic tests

If physical tests suggest ulnar nerve entrapment, additional tests may be ordered to confirm the diagnosis:

• Electromyography (EMG): Measures the electrical activity of muscles to assess nerve function.
• Nerve conduction studies: Evaluate how well electrical signals travel along the nerve.
• Imaging tests: MRI, neuromuscular ultrasound, or X-rays can help identify the location and cause of nerve compression.

Management and Treatment

Nonsurgical treatments

Many cases of ulnar nerve entrapment can be managed without surgery. Treatments include:

• Nonsteroidal anti-inflammatory drugs (NSAIDs): These medications can reduce pain and inflammation.
• Physical therapy: Exercises can improve flexibility and strength, reducing pressure on the ulnar nerve.
• Splints or braces: Wearing a splint at night or during activities can prevent the elbow or wrist from bending and worsening the condition.

Surgical treatments

If nonsurgical treatments are ineffective, surgery may be necessary. Surgical options include:

• Nerve decompression: Relieves pressure on the ulnar nerve by removing or reshaping structures that compress it.
• Nerve transposition: The nerve is moved to a different location to prevent compression.
• Cyst or tumor removal: If a growth is compressing the nerve, it can be surgically removed.

Prevention

Preventive measures

To reduce the risk of developing ulnar nerve entrapment or to prevent the condition from worsening, consider the following:

• Avoid prolonged elbow flexion: Try to keep your elbows straight, especially during sleep.
• Use proper ergonomics: Adjust your workstation to reduce strain on your elbows and wrists.
• Stretch regularly: Regularly stretching the arms can help keep the ulnar nerve from becoming compressed.

Outlook / Prognosis

Complications

If left untreated, ulnar nerve entrapment can lead to permanent nerve damage and muscle wasting in the hand. Early intervention is key to preventing serious complications.

Prognosis

With appropriate treatment, many people with ulnar nerve entrapment experience significant improvement. Nonsurgical treatments are often effective, but in some cases, surgery may be required. While most people recover fully, some may have lingering symptoms or require additional treatment.

Living With

When to seek medical attention

Contact your healthcare provider if you experience any of the following:

• Persistent numbness or tingling: Particularly if it affects your ability to perform daily activities.
• Weakness in the hand: Difficulty gripping or holding objects.
• Pain that does not improve: Especially if it interferes with sleep or daily tasks.

Sources

1. American Academy of Orthopaedic Surgeons (AAOS). "Ulnar Nerve Entrapment at the Elbow (Cubital Tunnel Syndrome)." OrthoInfo, 2024.
2. Mayo Clinic. "Ulnar Nerve Entrapment." Mayo Clinic, 2024.
3. National Institute of Neurological Disorders and Stroke (NINDS). "Ulnar Neuropathy Fact Sheet." NINDS, 2024.