What is ulnar nerve entrapment?

Ulnar nerve entrapment, also known as a pinched ulnar nerve, is when your ulnar nerve is squeezed or irritated. This can cause pain, numbness or weakness in your arm and hand.

Your ulnar nerve is a peripheral nerve that travels down the inside of your arm and into your hand.

Read more on peripheral nerve disorders.

You can develop ulnar nerve entrapment in different parts of your arm, including your:

• elbow — called cubital tunnel syndrome
• forearm
• wrist — called Guyon's canal syndrome

Ulnar nerve entrapment in your wrist is not common.

Ulnar nerve entrapment usually affects adults. It is rare among children or adolescents. There are different types of nerve entrapment disorders. Sometimes you can have more than one at the same time.

What are the symptoms of ulnar nerve entrapment?

If you have ulnar nerve entrapment, your first symptom will usually be numbness in your ring finger and little finger. As your condition gets worse, you may notice:

• reduced sensation in your arm that gradually gets worse
• muscle weakness and reduced strength in your hand
• trouble using your hand and arm
• discomfort when you touch the skin over your nerve
• positive Tinel's sign — a tingling feeling when your doctor taps your affected nerve

What causes ulnar nerve entrapment?

Ulnar nerve entrapment can develop when:

• something presses directly on your nerve
• there are problems with the blood flow to your nerve
• your nerve passes through a narrow space, causing it to be stretched or squeezed when you move

Often it is not known why you develop ulnar nerve entrapment. Some conditions can increase your risk of developing ulnar nerve entrapment, including:

• living with obesity
• smoking
• diabetes, high cholesterol levels
• injury or trauma to your elbow, including fractures
• joint conditions — rheumatoid arthritis, osteoarthritis or cysts in your joint

How you use your elbow can also increase your risk, for example:

• having a job or hobby that involves you repeatedly opening and closing your elbow
• sleeping with your arm flexed (closed)

When should I see my doctor?

You should see your doctor if you:

• think you have symptoms of ulnar nerve entrapment
• are having treatment for ulnar nerve entrapment and your symptoms are not improving

How is ulnar nerve entrapment diagnosed?

Your doctor can diagnose ulnar nerve entrapment by:

• asking questions about your symptoms, especially your pain and medical history
• examining your arm — your muscle strength, feeling in your arm and how you move your elbow, arm and fingers. These tests can help diagnose ulnar nerve entrapment and rule out other conditions.
• referring you for tests — MRI (magnetic resonance imaging), CT (computed tomography) scans and other tests.

Your doctor will also try to find out what caused your ulnar nerve entrapment.

It can be hard to diagnose ulnar nerve entrapment because your symptoms can be general. Other medical conditions you are living with can make it harder to diagnose.

Often when you are diagnosed with ulnar nerve entrapment, you will also be diagnosed with carpal tunnel syndrome at the same time. Carpal tunnel syndrome happens when the median nerve comes under pressure in your wrist.

How is ulnar nerve entrapment treated?

Your doctor will recommend treatment for ulnar nerve entrapment that focuses on managing your symptoms. The type of treatment will vary based on how severe your symptoms are. You may need one or more types of treatment.

If you have mild symptoms that come and go, your doctor may recommend you try these treatments for at least 3 months:

• Physiotherapy — ask your doctor to recommend a physiotherapist near you.
• Ergonomic support — this involves adjusting your posture and how you use your arm, especially when you work and sleep.
• Wearing an orthosis at night — this is a splint to prevent you from completely bending your elbow.
• Steroid injections — this is a type of anti-inflammatory treatment.

If your symptoms are severe, your doctor may recommend surgery. There are different types of surgery your doctor may consider. Your doctor will refer you to a surgeon if you need one. Together, you and your doctor will discuss which surgery is right for you.

Recovery after surgery can take time. Usually, you will be able to start using your arm fully 4 to 6 weeks after surgery. Depending on the type of work you do, you will most likely be able to return to work after 6 weeks.

What are the complications of ulnar nerve entrapment?

If you have severe ulnar nerve entrapment, you are at risk of developing significant weakness in your arm and hand as your muscles deteriorate. This can affect your ability to do your everyday tasks and may also impact your quality of life.

If you need surgery to treat ulnar nerve entrapment, there are other risks of complications, including:

• worsening of your symptoms
• damage to your nerve that can cause you to lose sensation around your elbow and parts of your arm
• infection

Your doctor will discuss the best way to reduce your risk of complications.

Can ulnar nerve entrapment be prevented?

You cannot always prevent ulnar nerve entrapment, because the cause is often not known. You can control some factors that increase your risk of developing ulnar nerve entrapment, such as:

• quit smoking
• manage your diabetes
• make sure your workplace and home setup doesn't increase your risk of ulnar nerve entrapment
• adopt a healthy lifestyle

Resources and support

• Read more about your ulnar nerve on the Queensland Health website.
• Learn about how good ergonomics can look after your health and wellbeing with the Australian Government Comcare factsheet.

You can call the healthdirect helpline on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available 24 hours a day, 7 days a week.