Which bone forms by intramembranous ossification and not endochondral?

Which bone forms by intramembranous ossification and not endochondral?

• A. Clavicle
• B. Femur
• C. Tibia
• D. Humerus

Answer: (A)

Ossification methods reveal how bones form during development. Intramembranous ossification is when mesenchymal cells directly become bone, producing flat bones such as those of the skull and the clavicle, without a cartilage template. Endochondral ossification uses a cartilage model that is gradually replaced by bone, and this is the route for most long bones like the femur, tibia, and humerus. Among these bones, the clavicle forms primarily through intramembranous ossification, while the others develop via endochondral ossification. So the bone formed by intramembranous ossification is the clavicle.

Ossification methods reveal how bones form during development. Intramembranous ossification is when mesenchymal cells directly become bone, producing flat bones such as those of the skull and the clavicle, without a cartilage template. Endochondral ossification uses a cartilage model that is gradually replaced by bone, and this is the route for most long bones like the femur, tibia, and humerus.

Among these bones, the clavicle forms primarily through intramembranous ossification, while the others develop via endochondral ossification. So the bone formed by intramembranous ossification is the clavicle.