Editing Ossification (section)

==Intramembranous ossification==
{{Expand section|date=January 2021}}
[[Intramembranous ossification]] forms the [[flat bone]]s of the [[skull]], [[mandible]] and [[hip bone]]. 

Osteoblasts cluster together to create an ossification center. They then start secreting osteoid, an unmineralized collagen-proteoglycan matrix that has the ability to bind calcium. As calcium binds to the osteoid, the matrix hardens, and the osteoblasts become entrapped, transforming into osteocytes.

As osteoblasts continue to secrete [[osteoid]], it surrounds blood vessels, leading to the formation of trabecular (cancellous or spongy) bone. These blood vessels will eventually develop into red bone marrow. Mesenchymal cells on the bone surface form a membrane known as the periosteum. Osteoblasts secrete osteoid in parallel with the existing matrix, creating layers of compact (cortical) bone.<ref>{{Citation |last=Breeland |first=Grant |title=Embryology, Bone Ossification |date=2024 |work=StatPearls |url=http://www.ncbi.nlm.nih.gov/books/NBK539718/ |access-date=2024-05-15 |place=Treasure Island (FL) |publisher=StatPearls Publishing |pmid=30969540 |last2=Sinkler |first2=Margaret A. |last3=Menezes |first3=Ritesh G.}}</ref>