Ulnar head: a normal bump
The ulna is the forearm bone on the little finger side. Its end forms a visible knob on the back of the wrist, more prominent in slim people, with lax joints, and when the palm faces down. This is normal. It may look more prominent on one side due to differences in bone length or posture.
When the ulnar head becomes painful or unstable
Injury to the ligaments around the distal radioulnar joint or the triangular fibrocartilage complex (TFCC), often after a fall or twisting, can make the ulnar head more prominent and painful. Symptoms include pain on the little finger side, clicking, pain when turning a key or doorknob, weak grip and a feeling of looseness.
See wrist pain and sprained wrist.
Ganglion cyst
A ganglion is a fluid-filled lump that grows from a joint or tendon sheath. On the back of the wrist, it can feel firm and be mistaken for bone. It may change size and is usually harmless.
See ganglion cyst.
Carpal boss
A carpal boss is a bony bump on the back of the hand, where the index or middle finger bones meet the wrist bones. It is hard, does not move and may ache with gripping or pressure. It is sometimes accompanied by a ganglion. Most need no treatment; a splint or injection may help pain, and surgery is rarely needed.
Arthritis
Osteoarthritis at the base of the thumb causes a bony bump and pain with pinching. Rheumatoid arthritis can cause swelling and prominence of the ulnar head with tendon problems. Arthritis usually comes with stiffness and pain.
Old fractures
A wrist fracture, especially of the end of the radius, may heal with a small change in shape, making the ulna appear more prominent. This may be painless or cause discomfort with rotation.
After a fall: fracture or dislocation
A sudden, visible deformity after a fall, often with severe pain, swelling and inability to move the wrist, suggests a fracture or dislocation. Keep the arm still, apply ice wrapped in a cloth and seek urgent care.
How the cause is found
- Examination of the wrist, comparing both sides.
- Tests of rotation, grip and stability.
- X-ray to show bones, arthritis and old fractures.
- Ultrasound to confirm a ganglion.
- MRI for ligament or TFCC injuries.
Treatment options
- Normal anatomy: reassurance.
- Ligament or TFCC injury: splint, physiotherapy, sometimes injection or surgery.
- Ganglion: watchful waiting, aspiration or surgery.
- Carpal boss: padding, splint or injection; surgery if persistent.
- Arthritis: activity changes, splints, exercises and medicines.
Exercises for wrist stability
- Grip strengthening with a soft ball.
- Forearm rotation with a light hammer or weight.
- Wrist extension and flexion with a band.
- Isometric holds in neutral wrist position.
Stop exercises that cause sharp pain or clicking. See forearm pain.
Everyday tips
- Avoid leaning on the little finger side of the wrist for long periods.
- Use a wrist support for heavy lifting.
- Adjust desk and keyboard to keep wrists neutral.
- Take breaks from repetitive gripping.
When to see a doctor
- Deformity, severe pain or swelling after a fall.
- A lump that is growing, hard and fixed, or painful.
- Numbness, tingling or weakness in the hand.
- Clicking with pain and instability.
- Red, hot swelling.
Key points to remember
- A prominent ulnar head is usually normal anatomy.
- Ganglions, carpal boss, arthritis and old fractures are other causes.
- Pain, clicking and instability suggest a ligament injury.
- Deformity after a fall needs urgent care.
Questions about a bone sticking out of the wrist
These answers are general information and do not replace an examination or individual medical advice.
Why does a bone stick out on my wrist?
Usually the normal end of the ulna; other causes include ganglions and carpal boss.
Is it normal for the wrist bone to stick out?
Yes, the ulnar head is visible in many people.
Why is my wrist bone more prominent on one side?
Differences in anatomy, an old injury or ligament laxity.
What is a carpal boss?
A bony bump on the back of the hand at the base of the index or middle finger.
Can a ganglion feel like bone?
Yes, a tense ganglion can feel firm.
Why does my wrist click when I rotate it?
It may be the TFCC or distal radioulnar joint; get it checked if painful.
Should I see a doctor for a wrist bump?
Yes, if it is new, painful, growing or after an injury.
Can a bump on the wrist be cancer?
Rarely; most are harmless, but unusual lumps should be checked.
Can physiotherapy help wrist instability?
Yes, strengthening and splints help many people.
Can a wrist bump go away?
Ganglions may disappear; bony bumps usually remain but may stop hurting.
Sources
This guide is for general information and does not replace medical advice. How a problem is diagnosed and treated depends on your examination and medical history. If you think you have an emergency, contact your local emergency services.