Sesamoid bone Sesamoid bone In anatomy, a sesamoid bone () is a bone embedded within a tendon or a muscle. It is derived from the Latin word ("sesame seed"), due to the small size of most sesamoids. Often, these bones form in response to strain, or can be present as a normal variant. The kneecap is the largest sesamoid bone in the body. Sesamoids act like pulleys, providing a smooth surface for tendons to slide over, increasing the tendon's ability to transmit muscular forces. The sesamoid is a small nodular bone most often present embedded in tendons in the region of the
Trapezium (bone) tubercle found on the anterior surface of the bone. It is where sometimes abductor pollicis brevis muscle attaches. The carpal bones function as a unit to provide a bony superstructure for the hand. The trapezium is the most radial of the bones surrounding the carpal tunnel. It is important in thumb movement. The trapezium is susceptible to arthritis at the joint with the metacarpal bone of the thumb, due to overuse. The etymology derives from the Greek "trapezion" which means "a little table", from "trapeza" meaning "table", itself from "(te)tra-" "four" and "pod-" "foot". The bone was first documented in