Is it carpal tunnel or trigger finger?

Numbness or tingling in the thumb, index and middle fingers points to carpal tunnel syndrome. A finger that catches, pops or locks points to trigger finger. The two are different problems. Carpal tunnel is pressure on a nerve at the wrist, and trigger finger is a tendon that catches in the sheath around it at the base of a finger. They can also happen in the same hand, so the answer is sometimes both.

Numbness in the thumb and first fingers means carpal tunnel

Carpal tunnel syndrome is felt as numbness, tingling or pins and needles, mainly in the thumb, index and middle fingers. The American Academy of Orthopaedic Surgeons says the numbness and pain are mainly felt in the thumb, index, middle and ring fingers, and that they often wake people at night ¹. The nerve involved is the median nerve, which runs through the wrist.

Night symptoms are a useful clue. Carpal tunnel numbness that wakes you is a nerve pattern. It is not a catch.

A catch, pop or lock means trigger finger

Trigger finger is a tendon problem. Its typical symptom is a catching, popping or locking sensation when you move the finger or thumb ². The band that holds the tendon in place is the A1 pulley, at the base of each finger in the palm, and it is the pulley most involved ³.

Stiffness is usually worst after rest. A finger that locks on waking and then loosens through the day with gentle use fits this pattern ⁴. Trigger finger is not rare. It affects 2 percent of the general population ⁵.

The key difference is the catch. Numbness in the fingers does not explain a finger that locks in a bent position, and a catch does not explain numbness that spreads into the thumb and first two fingers.

The two conditions often occur together

Carpal tunnel and trigger finger do not always come one at a time. In a 2009 study of 108 consecutive patients at a US hand clinic, 61 percent had both conditions when they were first seen ⁶. The study came from one clinic, so it does not give a rate for the general population.

This is why a single symptom rarely settles the question. If you have numbness in the thumb and fingers and also a catch in one of them, describe both to the clinician.

Side by side, the two conditions differ in where and how they feel

The table is a guide to the usual pattern, not a diagnosis. Each condition can be mild, and an ache in the hand can come from either one.

A clinician usually decides from the history and an examination

For carpal tunnel, the NHS says the condition can usually be diagnosed by asking about your symptoms and checking your hand ⁷. The AAOS says that in many cases no further testing is needed ⁸. Where the picture is unclear, a nerve conduction test can help, and the AAEM practice parameter says these tests confirm a clinical diagnosis with sensitivity above 85 percent ⁹.

For trigger finger, the examination is the test. The clinician moves the finger to check for the catch, and X-rays are not usually needed ¹⁰.

What to do

1. Note which fingers go numb, and whether the thumb is involved.
2. Note whether a finger catches, pops or locks, and when this happens.
3. Note when each symptom is worst, such as at night or on waking.
4. Describe both symptoms at the appointment, even if one seems minor.
5. See a doctor sooner if the numbness persists, the hand weakens, or neck or arm symptoms come with the hand symptoms.

If the numbness is the main symptom, read the guide to carpal tunnel syndrome and how carpal tunnel syndrome is diagnosed. If the pain is at the base of the thumb rather than in the fingers, the comparison with de Quervain's tenosynovitis is more useful. For the full picture of hand and wrist pain, see the guide to hand and wrist pain from typing, and for the wider subject, our accessibility and health overview.

Studies have not proved that typing or mouse use causes carpal tunnel syndrome ¹¹, so the link is unproven rather than established. This page is general information and not a diagnosis of your hands.