19 AUG 2020 · BONE FORMATION / OSSIFICATION :-
INTRAMEMBRANEOUS- within membrane
ï‚· Ossification takes place in the membranes of connective tissue.
ï‚· Cells in the membrane differentiate into osteoblasts,
ï‚· A collagen matrix is formed, which undergoes ossification
ï‚· So basically, these bone is formed from collagen matrix.
ï‚· Mostly flat Bones: maxilla, majority of mandible & cranial vault*
ENDOCHONDRAL – within cartilage
ï‚· Bone formation takes place From within a hyaline cartilage
ï‚· Cartilage cells are replaced by bone cells,ie. osteocytes replace chondrocytes.
ï‚· short and long bones are formed this way
ï‚· ethmoid, sphenoid, occipital (synchondrosis of bones of cranial base*)
ï‚· Some part of mandible (condylar head region)
ï‚· MANDIBLE BONE FORMATION IS BY BOTH endochondral + intramembraneous