Within the skeletal system of the body, there are bones that are made of two layers of compact bone with porous bone between them. Referred to as flat bones, they either offer substantial protection to other organs, such as the skull, which protects the brain, or provide extensive attachment points for muscles, such as in the pelvis. Flat bones also provide most of the red blood cell production within the body.
Cranium
The cranium, or skull, is actually comprised of several different bones, connected to form the skull. The flat bones within the cranium include the frontal, occipital, parietal, nasal and lacrimal bones.
Within the womb and for a period of time after being born a baby's cranium is only partially joined. As the child grows and the skeleton matures, the sutures, or joints, between the bones fuse together permanently.
Ribs
The ribs are long, curved, flat bones that attach at the spine and wrap around the chest cavity to join the sternum. Ribs are aligned in rows and connected with intercostal muscles that form the rib cage. There are 12 pairs of rib bones. The rib cage protects the heart, lungs and major blood vessels within the chest cavity. It also helps protect the stomach, spleen, liver and kidneys and provides support to the entire body.
Sternum
The sternum is the long, flat vertical bone that connects the ribs and the clavicle bone in the front of the chest. Also referred to as the breast bone, the sternum acts as an anchor for the rib cage and helps to protect the organs within the chest cavity. Three distinct parts make up the sternum, including the manubrium at the top of the sternum, the body or blade in the center, and small cartilaginous bone at the bottom called the xiphoid process.
Scapula
Scapula is a flat triangular bone that lies over the back side of the rib cage just under each shoulder. Commonly called the shoulder blade, this bone serves as an attachment point for several different muscles within the shoulder and back. The end of the upper arm bone, called the humerus, fits into a small, shallow depression in the corner of the scapula referred to as the glenoid cavity to help form the shoulder socket.
Pelvis
The pelvis, similar to the skull, is made up of it several different bones which fuse together as the skeletal system matures. The pubic bone, ischium and ilium enjoying to form the pelvic girdle which connects to the sacrum to complete a ring of bone that supports the organs within the abdominal cavity and provides a foundation for the body. These flat bones also provide socket points for the femur bones of the legs. Large and strong, the pelvic girdle provides substantial connecting points for muscles of the legs, back and abdomen.
