Flat bone

A disk- bones (ossa plana, singular os planum ) is called in the anatomy sheet-like bone with a small thickness. They are, for example, the skull and as ribs ( costae ), shoulder blade (scapula ), chest (sternum ) and pelvic bones ( hip bones ) before. They are used for mechanical protection of internal organs and provide by their planar shape also plenty of space to the origin and insertion of skeletal muscles.

Bone plate made ​​outside of compact bone substance ( substantia compacta ) and the inside of spongy bone ( cancellous bone ), in whose interstices bone marrow is located. In the skull bone, the cancellous bone is also called the diploe. In some skull bones, the diploe is greatly reduced and thus liberated cavity lined by mucous membrane. Such bone is called " air-filled bones " ( Ossa pneumatica ), the sinus cavities.