Carpal tunnel or cubital tunnel: which nerve is it?

In short

Carpal tunnel syndrome compresses the median nerve at the wrist, and cubital tunnel syndrome compresses the ulnar nerve at the elbow. The pattern of numbness separates them. Numbness in the thumb, index and middle fingers points to the wrist. Numbness in the ring and little fingers points to the elbow.

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 each tunnel is

Let's take a look at the two places a nerve can get squeezed on its way to your fingers, because they sit at opposite ends of the same arm. The first is a tight space in the front of your wrist, or what we call the carpal tunnel, and the nerve travelling through it is the median nerve, which carries feeling to the thumb, the index and middle fingers and the thumb side of the ring finger.¹ The second sits on the inside of your elbow, behind the bump most people know as the funny bone, or what we call the cubital tunnel, and the nerve travelling through that one is the ulnar nerve, which carries feeling to the little finger and the other half of the ring finger and drives the small muscles that pinch, grip and button a shirt.²

Which fingers go numb, and what does that tell you?

Map the numbness on your own hand before you do anything else, because that map is the most useful thing you can bring to a visit. Draw an imaginary line straight down the middle of your ring finger. If the numbness sits on the thumb side of that line, the tunnel under suspicion is the one at your wrist. If it sits on the little-finger side, it is the one at your elbow. There is a second clue in how you sleep. A wrist curled under you at night raises the pressure inside the carpal tunnel, and an elbow bent for hours, on the phone or folded under a pillow, pulls the ulnar nerve tight behind the funny bone.² Both can happen in the same arm, and a nerve pinched up in the neck can imitate either one, so the finger map narrows the question rather than settling it. This page is information. It is not a diagnosis, and the exam is what makes the diagnosis.

Treatment options depend on the diagnosis

Dr. Knight does not use injections for cubital tunnel syndrome.

Treatment options depend on the diagnosis and severity of the symptoms.

• Change what is provoking the nerve: keyboard and mouse position, the phone held up to the ear, the elbow parked on a hard armrest.
• Wear a brace at night. A wrist brace holds the wrist straight, and an elbow brace keeps the elbow from folding while you sleep.¹²
• Add an anti-inflammatory such as ibuprofen to settle the swelling inside that tight space.
• For the wrist, a cortisone injection into the carpal tunnel may be considered when bracing and activity changes are not enough.¹
• Surgery may be needed if conservative treatment fails or the symptoms are advanced.

Where the diagnosis is not clear from the exam, Dr. Knight will arrange nerve testing and tell you where it is done.

When to call us

• The numbness has stopped coming and going, and is now there when you wake and through the day.
• You are dropping things, or you cannot pinch a key, turn a lid or button a shirt.
• The muscle at the base of your thumb, or the web between thumb and index finger, looks flatter than on the other hand.
• Several weeks of a night brace and changed habits have not moved the symptoms at all.
• The numbness started after a fall or a direct blow to the wrist or the elbow.
• Weakness or numbness spreads through the whole arm, or arrives with face or speech trouble. That is a call to 911, not to us.