De Thoracale Kooi: Het Borstbeen

The sternum is a T-shaped flat bone in the anterior midline of the thoracic wall that connects to the rib cage. It protects the thoracic organs and attaches to different muscles.

It is formed by the fusion of three bones: the manubrium, body, and xiphoid process.

The manubrium attaches to the clavicles at the clavicular notch and articulates with the first two pairs of ribs.

The body joins the manubrium at the sternal angle. Its notched sides articulate with the costal cartilages of the second to the seventh pair of ribs.

The xiphoid process fuses with the body at the xiphisternal joint. Primarily cartilaginous, it is ossified after the age of forty. It is located at the ninth thoracic vertebrae level, where it binds to the diaphragm and rectus abdominis muscles. The heart lies below this joint.

During cardiopulmonary resuscitation or CPR, the hands are placed mid-sternum while compressing the chest. This prevents any physical thrust that can break the xiphoid process and push it into the heart or liver, which can cause severe bleeding.