Your wrist is not one joint.
It’s eight small bones in two rows, sliding against each other and against the two forearm bones, which is why wrist pain is so location-specific and why “wrist sprain” is such a weak diagnosis.
Learn roughly where four of those eight sit and most wrist articles on this site suddenly make sense.
Two rows, eight bones
- The near row, closest to your forearm: scaphoid, lunate, triquetrum, pisiform.
- The far row, closest to your hand: trapezium, trapezoid, capitate, hamate.
The old mnemonic runs: Some Lovers Try Positions That They Can’t Handle. Thumb side to little finger side, near row then far row.
The near row is the troublesome one. It has no muscles attached to it at all — it’s suspended entirely by ligaments, moving as a linked unit. Which is why one torn ligament in that row unbalances the whole wrist.
The four that matter clinically
Scaphoid. Thumb side, sitting in the hollow at the base of your thumb (the anatomical snuffbox). Bridges both rows, which is why it breaks. Its blood supply enters from the far end and runs backwards, so a fracture can starve the near half. This is the whole reason a scaphoid fracture is treated so seriously.
Lunate. Middle of the near row, directly under the dip on the back of your wrist. Also has a precarious blood supply, which is what Kienböck’s disease is about. When the wrist dislocates badly, it’s this bone the others displace around — see perilunate dislocation.
Hamate. Little-finger side, with a hook sticking out into the palm. That hook is right where a golf club or bat handle presses, which is why the hook of hamate fracture exists and why routine X-rays miss it.
Trapezium. Base of the thumb, the saddle joint that lets your thumb swing across the palm. It’s this joint that wears out in thumb base arthritis, and this bone that gets removed in a trapeziectomy.
Point to where it hurts and you have usually named the bone. That’s why I ask people to point rather than describe.
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 ligament injury in the wrist.
Tear it and the two bones drift apart and start rotating independently. 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”. See scapholunate injury and SLAC wrist.
And the cushion on the little-finger side
Between the ulna and the near row sits a disc of cartilage and ligament: the TFCC. It cushions load on that side and stabilizes rotation.
It’s why little-finger-side wrist pain is so common with twisting and pressing — TFCC injury — and why an ulna that sits slightly long compresses it, which is ulnar impaction.
Eight bones, two rows, no muscles holding the near one. Everything else about wrist injury follows from that.
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.