The locus of initial calcification in cartilage and bone.
D000818:Animals; D001842:Bone and Bones / Q000166:cytology / Q000378:metabolism*; D002113:Calcification, Physiologic; D002356:Cartilage / Q000166:cytology / Q000378:metabolism*; D002642:Chick Embryo; D003094:Collagen; D003460:Crystallization; D008854:Microscopy, Electron; D010006:Osteoblasts; D051381:Rats
D003094:Collagen