HealthInfo Canterbury
Overview of ulnar nerve compression
Tirohanga whānui ki te kōpeketanga akaaka kōwhiti
Ulnar nerve compression is a common condition affecting a nerve that travels down the inside of your arm, around the inside of your elbow and finishes on the little-finger side of your hand. This is called the ulnar nerve.
Ulnar nerve compression is also called ulnar neuropathy and sometimes cubital tunnel syndrome.
When your ulnar nerve is damaged or compressed, it affects the strength and feeling you have in your hand and sometimes your arm.
Exactly what symptoms you get depend on where the nerve is affected, but it's likely you'll have tingling or numbness in your little and ring fingers and pain or aching on the inside of your elbow or forearm. At night this may be bad enough to wake you.
In serious cases of ulnar nerve compression, your ring and little fingers may become weak so your fingers bend creating a "clawed hand".
The symptoms of ulnar nerve compression often get worse when you bend your elbow for a long time (for example, when you're talking on the phone or while sleeping), lean on your elbow or use a tool that you have to grip strongly.
Ulnar nerve compression affects men more often than women and is more common in older people.
Causes of ulnar nerve compression
Ulnar nerve compression is often caused by the nerve on the inside of your elbow (commonly known as the funny bone) being squashed (compressed) or stretched. Behind your elbow crease, the nerve is close to your skin and is relatively easily irritated.
Sometimes it happens because of a broken bone (fractured humerus) or another injury to your arm. Other times it's caused by something simple, such as leaning on your elbow, pulling your arm or sleeping with a bent elbow.
It can also happen if your nerve is compressed at your wrist, although this is less common. This can happen because of a broken bone in your wrist or an injury on your wrist below your little finger.
It can happen from repeatedly using your hand in a certain way, such as using heavy hand tools for a long time, pushing someone in a wheelchair or grasping handlebars for a long time while riding a bike.
Occasionally, your ulnar nerve can be compressed in your armpit area, for example if you hang your arm over a chair or use crutches. Other less common causes include infection, inflamed blood vessels and a lump in your armpit.
Diagnosing ulnar nerve compression
Your GP is likely to diagnose ulnar nerve compression after talking to you and examining your arm.
Investigations such as blood tests and X-rays aren't usually helpful, although your doctor may ask for these if they're trying to rule out something else that may be causing your symptoms.
You may be referred to a specialist for what are called nerve conduction studies. These measure how well and how quickly your ulnar nerve conducts electrical signals. A specialist may also arrange for you to have an MRI.
On the next page: Treating ulnar nerve compression
Written by HealthInfo clinical advisers. Last reviewed June 2022.
SourcesReview key: HIWAH-240323
