Why Is My Pinky Finger Numb? A Hand Surgeon Explains

A pinky finger that goes numb has a way of announcing itself at odd moments — halfway through a phone call, an hour into a drive, or in the middle of the night when the ring finger has gone quiet along with it. Most people's first guess is carpal tunnel syndrome, because that is the hand condition everyone has heard of. It is usually the wrong guess.

Carpal tunnel syndrome affects the thumb side of the hand. The pinky and the outer half of the ring finger belong to a different nerve entirely — the ulnar nerve — and when those fingers go numb, the question is where along that nerve's path the pressure is sitting. The answer is most often the elbow, not the wrist.

Robert Wysocki, MD, a hand, wrist and elbow surgeon at Midwest Orthopaedics at Rush, explains why the pinky and ring fingers go numb, what tends to set it off, what people commonly try first, and the signs that mean it is time to have a hand and wrist specialist take a look.

The Nerve Behind a Numb Pinky Finger

Three nerves share the work of feeling and moving the hand, and each one owns a territory. The median nerve supplies the thumb, index and middle fingers and the thumb side of the ring finger. The ulnar nerve supplies the small finger and the other half of the ring finger, on both the palm side and the back of the hand. The radial nerve covers the back of the thumb and the back of the hand.

That map is the reason a numb pinky is such a useful symptom. Numbness confined to the small finger and the outer edge of the ring finger points squarely at the ulnar nerve. Numbness that also involves the thumb, index or middle fingers — or that spreads up the forearm — points somewhere else, and a specialist reads that pattern before anything else.

The ulnar nerve starts in the neck, travels down the inside of the upper arm, passes through a shallow groove on the inside of the elbow — the spot most people know as the "funny bone" — runs down the forearm, and enters the hand through a small tunnel at the wrist. It can be pinched at any of those points, but one of them accounts for the large majority of cases.

Where the Ulnar Nerve Gets Pinched

At the elbow: cubital tunnel syndrome

At the elbow the ulnar nerve sits just under the skin with very little padding, which is why a knock there sends a jolt to the pinky. When the nerve is compressed or stretched in that groove over time, the result is cubital tunnel syndrome — the elbow being the most common place the ulnar nerve is compressed, and cubital tunnel syndrome the usual reason a pinky finger goes numb.

Two everyday mechanics do most of the damage. Bending the elbow stretches the ulnar nerve around the bone and tightens the space it runs through; hold that position long enough and the nerve's blood supply drops and the fingers go numb. Holding a phone to the ear, reading in bed, driving with the elbow flexed on the door, and — above all — sleeping with the arms bent and hands tucked under the pillow are the classic triggers. Leaning on the elbow presses the nerve directly against the bone: armrests, desks, car doors, a habit of propping the chin on a hand.

Some people are simply built for it: the nerve slips in and out of its groove as the elbow bends, irritating it with every repetition. Thickened tissue over the nerve, an extra muscle, a ganglion cyst in the groove, bone spurs from elbow arthritis, or an old fracture or dislocation can all narrow the space. Throwing athletes put unusual stress on the same spot.

At the wrist: Guyon's canal

Less often, the ulnar nerve is compressed where it enters the hand, in a passage called Guyon's canal. Ulnar tunnel syndrome of the wrist tends to come from pressure on the heel of the hand — long hours on bicycle handlebars (it is sometimes called "handlebar palsy") or vibrating power tools — or from a ganglion cyst pressing on the nerve. The fingers affected are the same, which is why the two conditions are easy to confuse from the outside; the difference is that wrist-level compression typically spares the back of the hand and comes without the inner-elbow ache, and a specialist's exam usually separates them.

When the ulnar nerve is not the problem: the neck and the rest of the body

Occasionally the ulnar nerve is fine and the problem is upstream. A pinched nerve root in the neck — most often from a herniated disc in the cervical spine at the lowest levels — can produce numbness in the small finger, both sides of the ring finger and the inside of the forearm, frequently with neck or shoulder-blade pain. Diabetes is a common companion to ulnar nerve compression and can also cause its own nerve damage in a broader, stocking-and-glove pattern. Thyroid disease, vitamin B12 deficiency and heavy alcohol use can do the same. Numbness in both hands at once, in more than one nerve's territory, or alongside symptoms in the feet is a signal to look beyond the elbow.

Pinky Numbness vs. Carpal Tunnel: How to Tell

Because the two conditions get confused so often — people searching for carpal tunnel information regularly land on it while describing a numb pinky — it helps to lay them side by side.

The two can coexist, and some people have both a wrist and an elbow problem. That is common enough that a specialist examines the whole arm rather than stopping at the first tender spot, because the treatment for pressure at the elbow is different from the treatment for pressure at the wrist. Sleeping with the wrists curled does to the median nerve what bent elbows do to the ulnar nerve, which is why hands that go numb during sleep can come from either end of the arm.

What Cubital Tunnel Syndrome Feels Like Over Time

Early on, the symptoms are usually intermittent — tingling or a dull, dead feeling in the pinky and ring fingers that comes with a bent elbow and fades when the arm straightens. Many people first notice it on the phone, on a long drive, or on waking. Some are woken by it. An ache along the inside of the elbow or a burning feeling down the inner forearm often travels with it, and a knock to the elbow can send what patients describe as an electric shock down the arm into the fingers.

If the pressure continues, the nerve's motor fibers begin to suffer. Grip weakens. Fine tasks — buttoning a shirt, typing, turning a key — become clumsy, partly from lost sensation and partly from weakness in the small muscles of the hand that the ulnar nerve controls. Spreading the fingers apart or pinching the thumb against the index finger becomes harder. In advanced cases those muscles visibly waste, the hand loses bulk between the thumb and index finger, and the ring and small fingers begin to curl into a claw-like posture. Muscle that has been lost to long-standing compression does not reliably come back, which is the practical reason not to let a numb pinky drift on for months.

What People Commonly Try First

For mild, on-and-off symptoms, the measures a hand surgeon usually suggests first are simple, and they follow directly from the mechanics above.

• Keep the elbow straighter, especially at night. Sleeping with the elbow bent is the single most common aggravator. A towel wrapped loosely around the elbow, or a soft elbow pad, discourages the arm from folding up during sleep. A specialist may recommend a night splint for the same purpose.
• Stop leaning on it. Padding the armrest, moving the elbow off the desk edge and off the car door, and breaking the chin-in-hand habit take pressure off the nerve at its most exposed point.
• Change the posture, not just the activity. A headset or speakerphone instead of a phone held to the ear; a book propped rather than held; the elbow relaxed rather than flexed on a long drive.
• Anti-inflammatory medication. Over-the-counter options such as ibuprofen or naproxen are sometimes used for the elbow ache; whether they are appropriate depends on your health history, so ask before starting them.

Hand therapists also use nerve-gliding techniques that encourage the ulnar nerve to slide freely through the elbow and wrist. These are effective for some people, and they are better learned from a therapist than from a video — the same movements done aggressively can irritate a nerve that is already inflamed.

These steps are most effective in mild to moderate cases. If numbness keeps returning despite them, or if weakness has already appeared, self-management has run its course.

When to See a Hand and Wrist Specialist

Pinky numbness that appears once after a long drive and clears within minutes is rarely a medical problem. The following patterns deserve one:

• Numbness or tingling in the pinky and ring fingers that keeps returning for more than a few weeks, regardless of changing how you sleep or sit
• Numbness that has become constant rather than intermittent
• Weakness — a weaker grip, trouble spreading the fingers, difficulty with buttons, keys or typing
• Dropping things or noticeable clumsiness in the hand
• Visible thinning of the hand muscles, or the ring and small fingers beginning to curl
• Numbness that involves the thumb, index or middle fingers too, or that runs up the forearm — a sign the problem may not be the ulnar nerve at all
• Numbness in both hands, or in the hands and feet together
• Numbness with neck pain, pain radiating from the shoulder, or after an injury to the elbow or wrist

Weakness and muscle wasting are the changes a surgeon most wants to see early, because they mark the point at which the nerve is losing function rather than just complaining about it.

How a Specialist Finds the Cause

A hand and wrist specialist starts with the story — when the numbness happens, which fingers exactly, what the elbow was doing at the time — and an examination of the whole arm, not just the hand. The exam typically maps sensation finger by finger and on the front and back of the hand, tests the strength of the small hand muscles and the finger flexors, and checks the way the thumb and index finger pinch. Two office tests are standard: tapping over the ulnar nerve at the elbow to see whether it reproduces tingling in the fingers, and holding the elbow fully bent for a short time to see whether the numbness appears. The neck and the wrist are examined as well, because both can mimic the elbow.

Where the diagnosis is unclear, where symptoms are severe, or where surgery is being considered, nerve conduction studies and electromyography (EMG) measure how well the ulnar nerve is carrying signals and can pinpoint where along its path it is being compressed — elbow, wrist or neck. X-rays may be ordered to look for bone spurs or arthritis at the elbow, and ultrasound or MRI occasionally to look for a cyst or other structure pressing on the nerve.

Treatment follows from that picture. Most people with mild or moderate cubital tunnel syndrome improve with activity changes, protection of the elbow and night splinting. When symptoms persist despite those measures, when weakness or muscle loss is present, or when nerve studies show significant compression, treatment for cubital tunnel syndrome may include surgery to give the nerve room — either releasing the tissue that forms the roof of the tunnel or moving the nerve to a new position in front of the elbow so that bending no longer stretches it. Compression at Guyon's canal is treated at the wrist, sometimes by removing a cyst; a neck source is treated as a spine problem. Which approach fits, and whether surgery is warranted at all, is a decision made with the surgeon after the examination and any nerve testing.

Frequently Asked Questions

Does carpal tunnel syndrome make your pinky finger numb?

No. Carpal tunnel syndrome compresses the median nerve at the wrist, which supplies the thumb, index and middle fingers and half of the ring finger. The pinky is supplied by the ulnar nerve. Pinky numbness points to the ulnar nerve, usually at the elbow. Some people have both conditions, which is one reason a specialist examines the whole arm.

Why does my pinky finger go numb when I sleep?

Most people sleep with their elbows bent, often with the hands tucked under the pillow or the arms folded. Hours in that position stretch the ulnar nerve around the inside of the elbow and reduce its blood supply, so the ring and small fingers go numb by morning. Keeping the elbow straighter at night — a towel wrap, an elbow pad or a night splint — often reduces it. If it continues, an evaluation is worthwhile.

Why is only my left pinky (or right pinky) numb?

Nerve compression is usually one-sided, and it tends to affect the arm that does the leaning, the phone-holding or the driving. Numbness in one pinky is typical of cubital tunnel syndrome. Numbness in both pinkies, or in both hands more broadly, is less typical of a pinched nerve and more suggestive of a neck problem or a medical condition, and should be evaluated.

Can a pinched nerve in the neck cause pinky numbness?

Yes. The nerve roots that eventually form the ulnar nerve leave the spine at the base of the neck, and a herniated disc or arthritis there can produce numbness in the small and ring fingers. Neck-related numbness more often involves the inside of the forearm as well, and it frequently comes with neck or shoulder-blade pain. A specialist's exam, and nerve testing when needed, can tell the elbow apart from the neck.

Will pinky numbness go away on its own?

Mild cubital tunnel syndrome often settles when the pressure is removed — straighter elbows, no leaning, different phone posture. Whether it goes away depends on what is causing it and how long the nerve has been compressed. Positional numbness from leaning on the elbow typically fades within minutes; cubital tunnel numbness comes and goes at first and can become constant. Numbness that persists despite those changes, has been recurring for more than a few weeks, or has progressed to weakness is less likely to resolve without treatment, and muscle that has wasted from long-standing compression may not recover.

Numbness in the pinky and ring fingers is common, it is usually explainable, and in most cases it is very treatable once the source is found. The finger pattern narrows the search before you ever reach an exam room; the exam finishes it.

This article is for general information and is not a substitute for medical advice. Please consult a physician about your individual situation.

Header illustration: "Ulnar Nerve" by BruceBlaus, via Wikimedia Commons, CC BY-SA 4.0.

Meet Our Hand & Wrist Specialists

Ring and pinky numbness that keeps coming back deserves a closer look. Our fellowship-trained hand, wrist and elbow surgeons treat nerve compression at the elbow and wrist, and the first job is finding where the pressure is coming from.