Any of usually four small kidney-shaped glands that lie in pairs near or within the posterior surface of the thyroid gland and secrete a hormone necessary for the metabolism of calcium and phosphorus.甲状旁腺：四个很小的肾形腺体之一，它们成对地长在甲状腺表皮的后部或其附近，并且分泌钙代谢和磷代谢所需的激素