What is cubital tunnel syndrome?

In short

Cubital tunnel syndrome is compression of the ulnar nerve where it passes behind the bony bump on the inside of your elbow, the one people call the funny bone. It causes numbness and tingling in the little and ring fingers, aching along the inside of the elbow, and in time a loss of pinch and grip strength.

Written for patients by The Hand and Wrist Institute. Prepared for review by John T. Knight, MD. Last updated September 5, 2026How we write and review

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What cubital tunnel syndrome is

Let's take a look at the inside of your own elbow. Find the bony bump there, the funny bone, and understand that the zing you feel when you knock it is not the bone at all, it is a nerve running in a shallow groove just behind it. That groove and the band of tissue roofing it make a tight passage, or what we call the cubital tunnel, and the ulnar nerve travels through it before diving between two muscles in the forearm. Every time you bend the elbow the nerve is stretched and pressed against that hard edge, so hours of a bent elbow, day after day, is what irritates it.¹ The culprits are ordinary: a phone held to the ear, an elbow on a hard armrest, long keyboard stretches.

That nerve does two jobs, and the second one surprises people. It carries feeling to the little finger and half the ring finger, and it runs the small muscles inside your hand that let you pinch a key, pick up a coin and button a shirt. That is why weakness and clumsiness, not just numbness, are part of the picture.

Cubital tunnel syndrome or golfer's elbow?

Both hurt on the inside of the elbow, so here is the test you can apply. Cubital tunnel syndrome is a nerve problem and the symptom travels: tingling and numbness run down into the little and ring fingers, worse at night or after the elbow has been bent a while. Golfer's elbow, or what we call medial epicondylitis, is a tendon problem and the symptom stays put: it hurts at the bump when you grip hard, twist a lid or bend the wrist against resistance, and it does not make your fingers go numb.² Numb fingers means think nerve. Pain only when you grip means think tendon. Both can be present at once, which is why the exam decides it and this page does not.

Treatment options depend on the diagnosis

Treatment depends on the severity of the symptoms. Dr. Knight does not use injections for cubital tunnel syndrome.

• Rest the elbow and change what is loading it: off hard armrests, a headset instead of the phone, less repetitive hand and wrist work.
• Add an anti-inflammatory such as ibuprofen to reduce swelling inside that tight space.
• Wear a brace at night that keeps the elbow from folding.¹
• If the exam leaves the diagnosis unclear, Dr. Knight will arrange nerve testing and tell you where it is done.
• Surgery may be needed if conservative treatment fails or the symptoms are advanced. It means opening the tunnel and then either moving the nerve to the front of the elbow or shaving part of that bony bump so the nerve no longer climbs over it.

The diagnosis is made by examining you. The nerve test is an adjunct that shows how severe the compression has become, and it is read alongside the exam rather than instead of it.

When to call us

• The numbness in the little and ring fingers is there all the time rather than coming and going.
• Your hand is getting clumsy: dropped coins, a weak pinch, trouble with buttons or keys.
• The web between your thumb and index finger looks hollow next to the other hand.
• Weeks of a night brace and changed elbow habits have made no difference, or the symptoms began after a fall onto the elbow.
• You have been putting this off for months. Nerves recover more slowly the longer they have been compressed, so the visit is worth making now rather than later.