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
Bone mineral of the hydroxyapatite. Bone mineral is dynamic in living animals; it is continually being resorbed and built anew in the bone remodeling process. In fact, the bones function as a bank or storehouse in which calcium can be continually withdrawn for use or deposited for storage, as dictated by homeostasis, which maintains the concentration of calcium ions in the blood serum within a particular range despite the variability of muscle tissue metabolism. Parathormone and calcitonin are the principal hormones with which the neuroendocrine system controls this ongoing process. The parathyroid and thyroid glands in the neck produce those hormones; thus,