Intramembranous and Endochondral Ossification
Ossification (or osteogenesis) is the generic term for bone formation. There are two basic types: membranous ossification and endochondral ossification.
There are two ways bones are formed, intramembranous ossification, and endochondral ossification. Intramembranous ossification is how the flat bones are formed, while the long bones are formed with endochondral ossification.
osteoblast
Ossification
Intramembranous ossification
Intramembranous ossification
ossification
The femur is formed through the endochondral ossification process. This is where bone replaces the cartilage. There are six steps in this type of ossification and they are as follows; one the development of cartilage model, two the growth of the cartilage model, three the development of the primary ossification center, four the development of the medullary cavity, five the development of the secondary ossification centers, and six the formation of articular cartilage and the epiphyseal plate.
Ossification means bone growth or formation. I will be disscussing breifly normal or physiological ossification because there is pathological ossification.There are two types of ossification in the human body: endochondral and intramembranous. Most of the bones in the human skeleton , especially the long and short bones, develop via endochondrial ossification, but some including the clavicle and most of the bones of the skull( flat bones) are formed by the intramembranous type. Intramembranous ossification , the source of most of the flat bones, is so called because it takes place within condensations of mesenchymal tissue and not by replacement of pre-existing piece of hyaline cartilage as the case in endochondral ossification. The frontal and parietal bones of the skull, as well as parts of the temporal and occipital bones and the mandible and maxilla, are formed by intra membranous ossification. This process also contributes to the growth of short bones and the thickening (not the lengthening) of long bones.
Endochondral ossification
Intramembranous ossification
Endochondral ossification! :)