Thumb flexion bends your thumb across the palm of your hand, toward the base of your little finger, and then straightens it again. You sit with your forearm supported on a table and the palm facing up, so the thumb can move without the wrist joining in. It is often part of a home program for a thumb that has stiffened after an injury, surgery or time in a splint.

How to do the thumb flexion

Sit upright on a chair at a table. Rest your forearm on the table with the palm facing up and the fingers relaxed.
Start with the thumb straight and lying beside your index finger.
Slowly bend the thumb across your palm, aiming the tip toward the base of your little finger. Let the thumb joints bend as it goes.
Pause, then straighten the thumb gradually back to where it started.
Repeat at an even pace, with the wrist and forearm resting still on the table.

What you should feel

A gentle pull through the thumb joints as they bend, and light work in the fleshy pad at the base of the thumb. A stiff thumb may not reach very far at first.

Common mistakes

Curling the fingers into a fist along with the thumb.
Lifting or turning the forearm on the table.
Forcing the thumb toward the little finger when it will not go any farther.
Snapping the thumb back straight instead of opening it slowly.

How often

Many programs start with 2 to 3 sets of 10 slow bends, 2 to 3 times a day. Your physio will adjust this.

Stop and check with your physio if

Sharp pain in any thumb joint while it bends.
A thumb that catches, clicks painfully or locks in the bent position.
Tingling or numbness in the thumb or fingertips. If one side of your face or body suddenly goes numb or weak, or your speech becomes slurred or muddled, call emergency services, even if it goes away.
Emergency: while you are in a cast or splint, your fingers turn blue, white or pale, or feel cold. Do not wait to see if raising your hand helps. Go to an emergency department straight away, and do not drive yourself. The cast or splint may be cutting off the blood supply, or pressure may be building up inside the forearm (compartment syndrome), and both need checking quickly.
In a cast or splint, the pain gets worse, your fingers feel numb or tingle or look more swollen, or the cast feels too tight. Stop, raise your hand above your head, keep moving your fingers and contact your fracture clinic or get medical advice straight away. If you cannot move your fingers, the pain is severe even after painkillers, or the numbness, tingling or swelling has not settled within 30 minutes of raising your hand, go to your fracture clinic or an emergency department straight away, and do not drive yourself.
Since the fracture or cast, the hand is getting more painful rather than less, the skin becomes very sensitive to light touch, or the hand changes color, temperature, swelling or sweating compared with the other one, or looks shiny. See your doctor or physio as soon as you can, within a few days at most, as this can be complex regional pain syndrome (CRPS) and early treatment may help.
Suddenly being unable to straighten the end of your thumb or lift it back, especially in the weeks after a wrist fracture. A thumb tendon can snap, so have a doctor check it within a few days.

From the clinic

The tip does not have to touch the base of the little finger. Bend only as far as the thumb goes easily and let the range come back in its own time. Keep the fingers relaxed and fairly straight. That way the thumb does all the work.

If your thumb catches or clicks as it bends, which can be a sign of trigger thumb, mention it to your physio or doctor. After a wrist fracture, keep moving your fingers and thumb as far as the cast or splint allows, unless your fracture clinic has told you otherwise. After a broken hand or finger, a tendon repair or other hand surgery, how far you may move the fingers and thumb is often limited for several weeks, so do only the movements your surgeon or hand therapist has shown you. After a flexor tendon repair in the thumb, active bending follows a strict timetable, so follow the one your surgeon or therapist gives you and do not start this from a video alone. For other ways to keep the thumb and fingers moving, see thumb opposition and tendon glides.

Written and checked by the PocketPhysio editorial team. Last updated 2026-09-28.

This page is general education, not a diagnosis or a personal treatment plan. If you have pain, an injury or a health condition, see a physiotherapist or doctor before starting new exercises.

Thumb flexion