Anatomy Guide › Upper limb
Scaphoid
The scaphoid is the largest bone of the wrist's first row, shaped — as its Greek name says — like a little boat. It sits on the thumb side of the wrist, bridging the two rows of carpal bones and gliding directly against the radius. You can locate it precisely: stretch your thumb out and a small triangular hollow appears at the base of it, the 'anatomical snuffbox.' The floor of that hollow is the scaphoid.
Because it bridges both carpal rows, the scaphoid is the wrist's linchpin, coordinating their motion like a tie-rod. The same job puts it in the path of danger: when you fall onto an outstretched hand, the scaphoid is caught between the radius and the rest of the wrist, and it is the most commonly fractured carpal bone. Tenderness deep in the snuffbox after a fall is treated as a scaphoid fracture until proven otherwise — often even when the first X-ray looks clean, because hairline breaks here famously hide.
The reason for all this caution is the bone's peculiar blood supply. Blood enters the scaphoid mainly near its far end and flows backward through the bone, so a fracture through the middle can cut off circulation to the near half. Deprived of blood, that fragment can slowly die — avascular necrosis — leading to collapse and wrist arthritis. It is a vivid example of how vascular plumbing, not just mechanics, decides how bones heal.
In Anamo, the scaphoid anchors the wrist cluster: trapezium and capitate beside it, radius above. Wrist rounds are won by knowing this eight-bone mosaic, and the scaphoid is the corner piece to learn first.
- Its name means 'boat-shaped' in Greek
- Forms the floor of the 'anatomical snuffbox' at the thumb base
- The most commonly fractured wrist bone
- Its reversed blood supply makes fractures prone to poor healing
Think you could find the scaphoid on a 3D model? Play Anamo and test yourself — every guess is color-coded by how close it lands to the mystery structure.