Wrist anatomy. Macro photograph of a transverse section through an adult wrist. The bones (purple) at centre form part of the carpal group of bones, which articulate with the bones of the lower arm to form the wrist joint. From left to right these bones are: hamate bone, capitate bone, trapezoid bone and trapezium bone. Beneath the bones are a bundle of tendons (orange). These are the flexor tendons that extend from the forearm, through the wrist, to the fingers, which they flex. The muscle (dark red) at bottom right is the flexor pollicis brevis, which flexes the thumb. At bottom left is the abductor digiti minimi muscle, which moves the little finger. This slide dates from 1904.