Last reviewed 01/2018

Bone forms the rigid structural element of the body. It is a composite of a mineral - calcium in the form of hydroxyapatite - and organic matrix - osteoid of largely type I collagen.

Bone is either mature or lamellar, which makes up the normal cortical and trabecular bone, or immature and woven, which forms in developing or regenerating regions.

Bone is constantly being remodelled throughout life as osteoclast cells resorb bone only for osteoblasts to resynthesise organic matrix and osteocytes to mineralize this framework. The dynamic balance between these two processes is homeostatically adjusted by the hormones vitamin D, parathormone and calcitonin.