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Cubital Tunnel Syndrome
Numbness or tingling in your little and ring fingers, or a weakening grip? Cubital tunnel syndrome, caused by pressure on the ulnar nerve at the elbow, is a common reason. This page explains what it is, why it happens, how it’s diagnosed and the options for managing it.
At a glance
What is it?
Pressure on the ulnar nerve as it passes behind the elbow, causing inadequate blood supply to the nerve
Common symptoms
Numbness and tingling in the ring and little fingers, often worse with the elbow bent
Who it affects
More common in people who lean on their elbow often, or who have had a previous elbow injury or arthritis
Is it serious?
Not sinister, but ongoing pressure can lead to lasting numbness, weakness and hand muscle wasting
Treatment options
Activity changes, elbow padding, night splinting, or surgery
First step
A consultation to confirm the diagnosis and consideration of nerve conduction studies to assess the severity of nerve compression
What is it?
Cubital tunnel syndrome happens when the ulnar nerve, which runs down the inside of the arm and behind the elbow, becomes squeezed or irritated at the elbow. This is the nerve you feel when you knock your “funny bone”. Pressure here causes numbness, tingling and sometimes weakness in the hand, particularly the ring and little fingers. It is the second most common nerve compression in the arm after carpal tunnel syndrome.
Causes and risk factors
- Regularly bending the elbow for long periods, such as when sleeping, working or on the phone
- Leaning on the elbow, for example at a desk
- A previous elbow fracture or dislocation
- Arthritis or bone spurs around the elbow
- Swelling or a cyst pressing on the nerve
- Diabetes, which can make nerves more sensitive to pressure
The ulnar nerve is more exposed to pressure at the elbow than most other nerves in the body, which is why everyday habits like resting on the elbow or sleeping with it tightly bent can bring on or worsen symptoms.
Symptoms and how it presents
The main symptoms are numbness, tingling or a pins-and-needles feeling in the ring and little fingers. Symptoms are often worse when the elbow is bent for a long time, such as while sleeping, driving or holding a phone to your ear.
As the compression becomes more significant, grip and pinch strength can weaken, and fine movements such as doing up buttons can become clumsy. In more severe or longstanding cases, the small muscles of the hand can visibly waste and the ring and little fingers may develop a clawed appearance.
How is it diagnosed?
Cubital tunnel syndrome is usually diagnosed from your history and an examination of the elbow and hand, including checking sensation and muscle strength.
A nerve conduction study is often used to confirm the diagnosis and show how severe the compression is. An x-ray may be helpful if a previous injury, arthritis or bone spur is suspected as a contributing cause.
Treatment options
Treatment depends on how severe your symptoms are.
Mild symptoms are often helped by simple changes, such as avoiding leaning on the elbow, padding the elbow, and keeping the arm straighter at night, sometimes with a light splint to stop the elbow bending fully during sleep. A hand therapist guides you in these treatments.
If symptoms are more severe, do not improve with these measures, or there is weakness or muscle wasting in the hand, surgery to release the pressure on the ulnar nerve at the elbow is usually recommended. In more severe cases the nerve is also moved to a new position (transposition) to keep it from being stretched or compressed with elbow movement.
When to see a hand surgeon
It is worth seeing a hand surgeon if you have ongoing numbness or tingling in your ring and little fingers, if you notice your grip weakening or your hand becoming clumsy, or if simple measures such as avoiding pressure on the elbow have not helped. Earlier assessment gives more treatment options and helps prevent lasting nerve or muscle damage.
What to expect at your appointment
At your first appointment, Dr Tomlinson will take a history of your symptoms and examine your elbow and hand, including your sensation, muscle strength and any wasting. She may arrange a nerve conduction study or x-ray if needed. Together you will discuss the diagnosis and the treatment options that suit your situation.
Frequently Asked Questions
What is cubital tunnel syndrome?
Pressure or irritation of the ulnar nerve where it passes behind the elbow (the funny bone nerve), causing numbness, tingling and sometimes weakness in the hand, particularly the ring and little fingers.
What causes it?
Often related to everyday postures that put pressure on the nerve, such as bending the elbow for long periods when sleeping, working or on the phone, or leaning on the elbow. A previous elbow fracture or dislocation, arthritis or bone spurs, a cyst pressing on the nerve, and diabetes can also contribute.
What can I do myself?
Avoiding leaning on the elbow, padding the elbow, and keeping the arm straighter at night, sometimes with a light splint to stop the elbow bending fully during sleep, can help mild symptoms. It’s worth being assessed if numbness or tingling persists or your grip is weakening.
What can a hand therapist do?
Guide you through activity changes and night splinting for mild symptoms, and support your recovery with therapy if you have surgery.
What can a hand surgeon do?
Confirm the diagnosis and refer you for a nerve conduction study (if needed) to show how severe the compression is. If symptoms are more severe, not improving with simple measures, or there is weakness or muscle wasting, surgery to release the pressure on the ulnar nerve at the elbow is usually recommended, sometimes with the nerve moved to a new position.
What can I expect from treatment?
Mild symptoms often improve with activity changes and night splinting. Surgery is a well-established procedure aimed at relieving pressure on the nerve. How much sensation and strength recovers depends on how severe and how long-standing the compression was before treatment.
What happens if it's left untreated?
Ongoing pressure on the nerve can lead to lasting numbness, weakness and muscle wasting in the hand. Earlier assessment gives more treatment options and helps prevent lasting nerve or muscle damage.
Related conditions and treatments
Cubital tunnel syndrome is one of several nerve compression conditions affecting the arm and hand. If your numbness or tingling involves the thumb, index and middle fingers rather than the ring and little fingers, you may be experiencing carpal tunnel syndrome, which involves the median nerve at the wrist instead. The ulnar nerve can also be compressed further down, at the wrist, where the condition is called ulnar nerve compression at the wrist (Guyon’s canal). It is possible to have more than one nerve compression at the same time.