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
Third metatarsal bone third proximal phalanx. The second and third dorsal interossei muscles attaches to the third metatarsal bone. The second dorsal interossei from the medial side of the bone and the third dorsal interossei from the lateral side. The function of the muscle is to spread the toes. The first Plantar interossei muscle originates from the medial side of the base and shaft of the third metatarsal. The function of the muscle is to move the third toe medially and move the toes together. The horizontal head of the adductor hallucis also originates from the lateral side of the metacarpophalangeal joint and