- There are eight carpal bones of the wrist, arranged in two rows of four.
- proximal row (radial to ulnar) : scaphoid, lunate, triquetrum, pisiform
- distal row (radial to ulnar) : trapezius, trapezoid, capitate, hamate
- The carpals articulate with:
- the radius primarily, but also with the ulna proximally, forming the wrist joint (radiocarpal, ulnocarpal joints).
- the metacarpals distally, forming the carpometacarpal joints.
- Specifically, the joint between the trapezius and the metacarpal of the thumb is the 1st carpometacarpal joint, aka the famous saddle joint of the thumb.
- The walls of the carpal tunnel are formed by the tubercles of the scaphoid and trapezium laterally and the pisiform and the hook of the hamate medially.
- There is a mnemonic for learning the carpal bones: Some Lovers Try Positions That They Can’t Handle. Scaphoid, Lunate, Triquetrum, Pisiform, Trapezium, Trapezoid, Capitate, Hamate.