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Your Wrist Isn’t One Joint. It’s Eight Small Bones That Have to Agree.
Your wrist has 8 carpal bones in two rows of four, sitting on the ends of your two forearm bones, the radius (thumb side) and the ulna (little-finger side).
Near row, closest to the forearm, thumb side to little-finger side: scaphoid, lunate, triquetrum, pisiform.
Far row, closest to the hand, thumb side to little-finger side: trapezium, trapezoid, capitate, hamate.
That’s the textbook answer. Here’s why it matters to you.
Those eight bones slide against each other and against the radius, which is why wrist pain is so location-specific…and why “wrist sprain” is such a weak diagnosis. A sore wrist after a fall could be a bruise. It could also be a broken scaphoid or a torn ligament between the scaphoid and lunate, and both of those can look NORMAL on the first X-ray.
Called “just a sprain” and left alone, either one can quietly turn into wrist arthritis years later.
So learn roughly where a few of these bones sit, and most wrist problems suddenly make sense. Below: the names, two mnemonics that actually stick, how to find the key bones on your own wrist, and what goes wrong in each part of it, with a link to the full article for each.
What are the 8 carpal bones called?
- Scaphoid. Thumb side of the near row. Boat-shaped, and the one that breaks most.
- Lunate. Middle of the near row. Half-moon shaped, sitting in the center of the wrist.
- Triquetrum. Little-finger side of the near row. Pyramid shaped.
- Pisiform. The pea-sized bump in the heel of your hand on the little-finger side. It sits inside a tendon and rides on top of the triquetrum.
- Trapezium. Base of the thumb. Forms the thumb’s saddle joint.
- Trapezoid. Small wedge between the trapezium and capitate, at the base of the index finger.
- Capitate. The largest carpal bone, dead center, the keystone of the wrist.
- Hamate. Little-finger side of the far row, with a hook that sticks out into the palm.
Add the radius and ulna, plus the five long bones of the palm (the metacarpals) that the far row connects to, and that’s the whole wrist.
Carpal bones mnemonic: two that actually stick
The old one runs: Some Lovers Try Positions That They Can’t Handle. Scaphoid, Lunate, Triquetrum, Pisiform, Trapezium, Trapezoid, Capitate, Hamate. Near row first, then far row, both read thumb side to little-finger side.
The cleaner one, if you’re saying it out loud in a classroom: So Long To Pinky, Here Comes The Thumb. This one goes in a loop: near row from the thumb side out to the pinky, then the far row back from the pinky to the thumb. Same eight bones.
The bit everyone mixes up is trapezium vs trapezoid. Easy fix: trapezi-UM sits under the th-UM-b.
How the wrist actually moves
There isn’t one wrist joint. There are three, working together.
- Radiocarpal joint. Where the radius meets the near row. Most of your bending forward and back happens here and at the next joint.
- Midcarpal joint. Between the near and far rows. It shares the bending, and it handles the side-to-side tilt.
- Distal radioulnar joint (DRUJ). Where the radius rolls around the end of the ulna. This is what turns your palm up and down. Rotation happens in the forearm, not in the carpal bones.
The radius carries roughly 80% of the load that goes through the wrist. The ulna side carries the rest, through a cartilage cushion called the TFCC. That split explains a lot: fall on your hand and the radius usually breaks first, and twist and press under load and the little-finger side complains.
Here’s the bit most anatomy pages skip. Apart from the pisiform, which is tucked inside a tendon, no tendon attaches to the near row at all. The scaphoid, lunate and triquetrum are suspended entirely by ligaments, moving as a linked unit, steered by the bones around them.
Which is why one torn ligament in that row unbalances the whole wrist.
Where are the scaphoid and lunate? Find them on your own wrist
Two minutes, your other hand, no textbook needed.
- Scaphoid. Stick your thumb out like you’re hitchhiking. Two tendons pop up at the base of the thumb with a hollow between them. That hollow is the anatomical snuffbox, and the scaphoid is at the bottom of it. Press there after a fall and it hurts? Read the scaphoid section below before you do anything else.
- Lister’s tubercle. On the back of your wrist, run a finger over the end of the radius in line with your index and middle fingers. There’s a small bony ridge. That’s your landmark.
- Lunate and the scapholunate ligament. Slide about 1 cm (half an inch) past that ridge toward your fingers and bend your wrist down slightly. You drop into a soft dip. The lunate is under it, and the ligament joining it to the scaphoid sits just on the thumb side of that spot. This is also exactly where most wrist ganglions pop up.
- Pisiform. Little-finger side of the heel of your hand, right at the wrist crease. The hard pea you can wiggle slightly.
- Hook of hamate. From the pisiform, go about 2 cm (one thumb-width) diagonally toward your index finger and press deep. That firm point is the hook. Usually tender even in a normal hand, so compare sides.
- Trapezium. Follow the thumb’s long bone down toward the wrist until it meets a joint at the base. That joint is the trapezium meeting the thumb.
Point to where it hurts and you have usually named the bone. That’s why I ask people to point rather than describe.
What goes wrong where: the wrist by location
Same “wrist pain”, completely different problems depending on which side of the wrist you point at. For the full symptom-first version, see wrist pain causes by location.
Thumb side (radial side)
- Scaphoid fracture. The scaphoid bridges both rows, which is why it snaps when you land on an outstretched hand. Its blood supply enters at the far end and runs backwards, so a fracture can starve the near half. A typical waist fracture needs about 8 to 12 weeks in a cast, longer if it’s near the top of the bone. This is the whole reason a scaphoid fracture is treated so seriously.
- De Quervain’s. Two thumb tendons share one tight tunnel over the end of the radius. Thickening there gives sharp pain with lifting and thumb use, classic in new parents. See de Quervain’s tenosynovitis.
- Thumb base arthritis. The trapezium’s saddle joint lets your thumb swing across the palm, and it wears out. It’s this joint that grinds in thumb base arthritis, and this bone that gets removed in a trapeziectomy.
- Intersection syndrome. Pain and sometimes a squeaky creak a few inches up the back of the forearm from the thumb side of the wrist, where two tendon groups cross. Often confused with de Quervain’s. See intersection syndrome.
Back of the wrist, middle (dorsal)
- Scapholunate ligament tear. Tenderness in that dip past Lister’s tubercle after a fall, sometimes with a clunk on gripping. More on this ligament below. See scapholunate ligament injury.
- Kienböck’s disease. The lunate has a precarious blood supply too. When it fails, the bone slowly softens and collapses. Deep, central ache and stiffness without a big injury. See Kienböck’s disease.
- Perilunate dislocation. When the wrist dislocates badly, it’s the lunate that the other bones displace around. A high-energy injury, and one of the classic missed ones. See perilunate dislocation.
- Dorsal wrist ganglion. A smooth, sometimes rubbery lump, most often rising from the scapholunate area. See wrist ganglion cyst.
- Carpal boss. A hard, bony bump on the back of the hand where the index and middle finger long bones meet the trapezoid and capitate. Doesn’t move, doesn’t squash. See carpal boss.
Little-finger side (ulnar side)
Between the end of the ulna and the near row sits a disc of cartilage and ligament: the TFCC. It cushions load on that side and stabilizes rotation.
- TFCC injury. It’s why little-finger-side wrist pain is so common with twisting, pressing up from a chair, or turning a door handle. See TFCC injury.
- Ulnar impaction. An ulna that sits slightly long presses up into the TFCC and the lunate and triquetrum. See ulnar impaction syndrome.
- ECU tendon problems. The ECU tendon runs in a groove on the back of the ulna. Irritated, it aches. Loose, it snaps over the bone when you turn your palm up, with a visible flick. See ECU tendinopathy and subluxation.
- Triquetrum chip fracture. The second most commonly broken carpal bone, usually a small flake off the back after a fall. Tender just past the end of the ulna on the back of the wrist.
Palm side (volar)
- Carpal tunnel. The carpal bones form a U-shaped floor, and a tough ligament forms the roof, anchored to the scaphoid and trapezium on one side and the pisiform and hook of hamate on the other. Through it run the median nerve and 9 tendons. Squeeze that tunnel and you get carpal tunnel syndrome: tingling thumb, index and middle fingers, worse at night.
- Guyon’s canal. A smaller tunnel between the pisiform and the hook of hamate, carrying the ulnar nerve to the ring and little fingers. Cyclists know this one. See Guyon’s canal syndrome.
- Hook of hamate fracture. That hook sits right where a golf club, bat or racquet handle presses. It breaks from a mishit or a fall, and routine X-rays often miss it. See hook of hamate fracture.
The whole wrist
- Distal radius fracture. The radius takes most of the load, so it’s the bone that breaks most often in a fall onto the hand. Six weeks or so in a cast or splint is common, with rehab running for months after. See the wrist fracture recovery timeline.
- Wrist arthritis. Most wrist arthritis that isn’t from a fracture through the joint follows two routes: a missed scapholunate tear, or a scaphoid that never united. See SLAC wrist.
The ligament that holds it together
The scapholunate ligament joins the scaphoid to the lunate. It is small, it is critical, and it is the commonest serious ligament injury in the wrist.
Tear it and the two bones drift apart and start rotating independently. On X-ray a widened gap between them is sometimes called the David Letterman sign, after that famous gap in his front teeth. (Radiologists have a sense of humor. Not much of one, but some.)
The wrist keeps working at first, which is exactly the problem. A missed scapholunate tear is one of the two main routes to wrist arthritis in someone’s forties, the other being a non-united scaphoid. Both begin as “just a sprain”.
Both also run on a Closing Window. Caught early, a scaphoid fracture usually heals in a cast and a fresh ligament tear can often be repaired directly. That window is measured in WEEKS. Leave either for months and the option of a simple fix closes, and the job becomes managing a wrist that’s already shifting toward arthritis. If you’re not sure which one you had, read wrist sprain or something worse.
How wrist problems are diagnosed
- Pointing. Where it hurts narrows the list to two or three structures before anyone touches you.
- X-rays. Usually several views, including dedicated scaphoid views if there’s snuffbox tenderness. A normal first X-ray does NOT rule out a scaphoid fracture or a ligament tear.
- MRI. Shows hidden scaphoid fractures, ligament tears, the TFCC and early Kienböck’s. See your hand and wrist MRI report explained.
- CT scan. Best for detail of a fracture, whether a scaphoid has healed, and a hook of hamate break.
- Arthroscopy. A camera in the joint. The final word on ligament and TFCC tears, and sometimes the treatment too.
What a hand therapist checks that a quick look doesn’t
A wrist assessment isn’t “move it, does it hurt?” It’s a set of specific tests, each one loading one structure.
- Scaphoid shift test. Pressing the scaphoid while moving the wrist side to side. A painful clunk points to the scapholunate ligament.
- Finkelstein’s test. Thumb tucked, wrist tilted toward the little finger. Sharp pain on the thumb side points to de Quervain’s.
- Ulnar fovea sign. Pressing in the soft spot just past the end of the ulna. Tenderness there points to the TFCC.
- ECU synergy test. Resisted thumb movement with the forearm in a set position, to tell an ECU tendon problem from a TFCC tear.
- Tinel’s and Phalen’s tests. Tapping and holding positions over the carpal tunnel and Guyon’s canal, to see which nerve is unhappy.
- Grip strength. Measured on a dynamometer and compared side to side. A number, not a guess.
Most of what wrists need after that is splinting, load management and graded strengthening, not surgery. See what a hand therapist does and which wrist splint, and for how long.
Get it checked today if
- You fell on an outstretched hand and pressing in the snuffbox hurts, even if the X-ray was normal. Treat it as a scaphoid fracture until proven otherwise: a splint now, and repeat imaging or an MRI within about 2 weeks.
- The wrist looks deformed, or you heard a crack and can’t use the hand.
- Numbness in the thumb, index and middle fingers after a wrist injury, especially if it’s getting worse.
- The hand turns pale, cold or blue.
- A hot, red, swollen wrist with a fever. See septic arthritis.
Get it checked if
- A “sprain” isn’t clearly better after 2 weeks.
- You feel a clunk, catch or give-way when you grip or push up from a chair.
- Little-finger-side pain with twisting that hasn’t settled in 6 weeks.
- Night numbness in your fingers, or the muscle at the base of your thumb looks flatter than the other side.
- A lump on the wrist that’s growing, painful, or pressing on a nerve.
Eight bones, two rows, and not one tendon steering the near row. Everything else about wrist injury follows from that.
Written by Nigel Chua, hand occupational therapist in practice since 2005. Thousands of hands, wrists and elbows assessed and treated. My credentials are here. This article explains; it doesn’t examine. If you can point to the spot and it’s been sore for more than 2 weeks, that spot deserves a proper assessment.
Every article on this site is written using the Closing Window Method: name the window your condition runs on, find where you are in it, and act while it’s still open.