1. Section 5.2- Axial Skeleton Skull, Vertebral Column, and Rib Cage

2. Surface Features of Bones

3. Objectives 1. Distinguish between the axial and appendicular skeletons 2. Name the bones of the skull and state the important features 3. Name the bones of the vertebral column and describe the important features 4. Name the three types of ribs and the three parts of the sternum 5. Be able to label diagrams

4. Axial Skeleton 1. The skeleton is divided into 2 parts: axial and appendicular 2. The axial skeleton lies in the midline of the body 3. Includes the skull, ear bones (6), hyoid bone, vertebral column, and the thoracic (rib) cage

5. A) SKULL 1. Formed by the cranium and facial bones 2. Bones contain sinuses- air sacs lined by mucous membranes. 3. Sinuses reduce the weight of the skull and give your voice a resonant (rich) sound. 4. The cranium protects the brain.

6. 1. Bones of the Cranium Eight bones make up the cranium. They are separated by immovable joints called sutures. Newborns have membranous regions called fontanels, where 2 bones meet. Fontanels permit the bones of the skull to shift during birth as the head passes through the birth canal. Anterior fontanel- called the soft spot

12. 2. Paranasal Sinuses

13. 3. Bones of the Face 1. There are 14 major facial bones. 2. These bones help to form your eyes, nose, cheeks, and jaw.

14. B) HYOID BONE 1. The only bone that does not articulate with another bone 2. Serves as a moveable base for the tongue

15. C) VERTEBRAL COLUMN 1. Each vertebrae is given a name according to its location. 2. There are 5 sections to the vertebral column: cervical, thoracic, lumbar, sacrum, and coccyx. 3. Vertebrae are separated by intervertebral discs. 4. The spine has a normal curvature that changes in each region.

17. 1. Structure of a Typical Vertebrae

19. 2. The Atlas (C1) and Axis (C2) a. Not typical vertebrae b. Atlas supports and balances the head. Has no body. c. The axis has an odontoid process, which projects through the ring of the atlas. This feature pivots on the atlas and allows you to move your head from side to side.

21. 3. Intervertebral Discs a. Fibrocartilaginous discs b. Located between each vertebra and act as a cushion. c. They prevent the vertebrae from grinding against each other. d. They act as shock absorbers during running, jumping, and walking. e. They weaken with age and can even slip or rupture with trauma. (herniated disc) f. They can damage the spinal cord or nerves.

23. D) THE STERNUM & RIB CAGE 1. The sternum (breastbone) and rib cage, along with the thoracic vertebrae, make up the bony thorax. 2. The sternum consists of the manubrium, the body, and the xyphoid process. 3. This is what is pressed down upon during chest compressions.

25. 1. The Ribs 1. There are 12 ribs (just like thoracic vertebra). 2. There are 7 true ribs that connect to the sternum and vertebrae. 3. There are 5 false ribs that are fused and connect to the sternum and vertebrae. 4. There are 2 floating ribs that connect to the vertebrae only.