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
Fourth metatarsal bone on the lateral side a single facet, for articulation with the fifth metatarsal. The head or anterior extremity articulates with the fourth proximal phalanx, the first bone in the fourth toe. The third and fourth dorsal interossei muscles attaches to the fourth metatarsal bone. The third dorsal interossei from the medial side of the bone and the fourth dorsal interossei from the lateral side. The function of the muscle is to spread the toes. The second Plantar interossei muscle originates from the medial side of the base and shaft of the fourth metatarsal. The function of the muscle is to