The skull is the skeleton of the head region. It is located on the top of the vertical
It has two major functional subdivisions as follows:
• the cranium
• the facial (visceral) skeleton
Page 2 The Cranium
The cranium is a spherical container that protects the brain.
At the base of the cranium is a series of openings.
Blood vessels and nerves enter and leave the cranial cavity through these openings.
Page 3 The Facial Skeleton
The facial skeleton is also referred to as the visceral skull.
It is attached to the anterior and inferior surfaces of the cranium.
It is the skeleton of the entrances of the respiratory and digestive systems and
the orbits containing the eyes.
Page 4 The Rib Cage
The thoracic (rib) cage consists of the ribs, the sternum, and thoracic vertebrae.
The 12 pairs of ribs are attached posteriorly to the thoracic vertebrae.
Anteriorly, the upper 10 pairs of ribs attach directly or indirectly (via costal cartilages)
to the sternum.
Page 5 Functions of the Rib Cage
The functions of the rib cage are:
• To enable motion. Because of the segmentation of the thoracic cage into vertebrae and
ribs, motion can occur in the thoracic region of the body.
• To allow costal breathing. The special construction of the ribs and their costal
cartilages allows costal breathing to take place.
• To provide protection. The rib cage encloses such vital structures as the
lungs, the heart, and the liver and gives them protection.