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
Frontalis muscle paler in color. It is located on the front of the head. The muscle has no bony attachments. Its medial fibers are continuous with those of the procerus; its immediate fibers blend with the corrugator and orbicularis oculi muscles, thus attached to the skin of the eyebrows; and its lateral fibers are also blended with the latter muscle over the zygomatic process of the frontal bone. From these attachments the fibers are directed upward, and join the galea aponeurotica below the coronal suture. The medial margins of the frontalis muscles are joined together for some distance above the root of