Bone structure has two related meanings. In anatomy, it refers to the skeleton itself: the articulated system of over 200 bones, with joints, ligaments, and cartilage, that supports the body, protects organs, and anchors muscles. At a finer level, it describes the organisation of individual bones, from dense cortical bone on the outside to the spongy trabecular network within, shaped to resist the loads each bone carries. In nutrition, the term appears when discussing how calcium, phosphorus, and vitamin D build and maintain this architecture, and how deficiencies in childhood can permanently alter bone shape and size.