Bone: the organ – flat bones

Bones that form the cranial vault or calvarium (e.g., frontal and parietal bones) are classified as flat bones. Cranial bones consist of an inner diploë of spongy bone sandwiched between inner and outer tables of compact bone. This structure reflects the embryonic process (intramembranous ossification) by which these bones form. Additional flat bones include sternum, ribs, scapula and pelvis (e.g., ilium). These bones are formed by endochondral ossification. 10x (top)

Bones that form the cranial vault or calvarium (e.g., frontal and parietal bones) are classified as flat bones. Cranial bones consist of an inner diploë of spongy bone sandwiched between inner and outer tables of compact bone. This structure reflects the embryonic process (intramembranous ossification) by which these bones form. Additional flat bones include sternum, ribs, scapula and pelvis (e.g., ilium). These bones are formed by endochondral ossification. 10x (top)

Bones that form the cranial vault or calvarium (e.g., frontal and parietal bones) are classified as flat bones. Cranial bones consist of an inner diploë of spongy bone sandwiched between inner and outer tables of compact bone. This structure reflects the embryonic process (intramembranous ossification) by which these bones form. Additional flat bones include sternum, ribs, scapula and pelvis (e.g., ilium). These bones are formed by endochondral ossification. 10x (top)

Where cranial bones meet, they form suture joints, consisting of a thin layer of fibrous connective tissue between the bones. Suture (fibrous) joints are immobile or only slightly mobile. The connective tissue is not preserved in this dried specimen and so a gap is visible between the bones.