1. The Skeletal System

2. The Thorax Forms a cage to protect major organs 3 Parts: Sternum Ribs
Thoracic Vertebrae
Figure 5.19a

3. Sternum 3 Parts: Ossification begins at age 6-10
Manubrium (large, triangular)
Body
Xiphoid Process
Ossification begins at age 6-10
Completed fusions occurs at age 25
Manubrium
Body
Xiphoid Process
Figure 5.19a

4. Ribs 12 pair in each sex Ribs 1-7 are “TRUE” ribs: connected
to the sternum and separated by
cartilaginous extensions (costal cartilage)
Ribs 8-12 are “FALSE” ribs: do not attach directly to the sternum
Ribs 8, 9, 10 fuse with the cartilage of rib 7
Ribs 11 and 12 are “floating” ribs – do not attach to the sternum at all

5. Thoracic Cage
Figure 6-20(b)

6. The Vertebral Column Vertebrae separated by intervertebral discs
Each vertebrae is given a name according to its location

7. Vertebral Column
7 cervical
12 thoracic
5 Lumbar
1 sacrum
1 coccyx

8. The Vertebral Column Concave – curved inward Convex – curved outward
Cervical Vertebrae
Lumbar Vertebrae
Convex – curved outward
Thoracic Vertebrae
Sacrum

9. Structure of a Typical Vertebrae
Figure 5.16

10. Vertebral Column/Thoracic Cage
Typical Vertebrae of the Cervical, Thoracic, and Lumbar Regions
Figure 6-17(a)

11. Vertebral Column/Thoracic Cage
Typical Vertebrae of the Cervical, Thoracic, and Lumbar Regions
Figure 6-17(b)

12. Vertebral Column/Thoracic Cage
Typical Vertebrae of the Cervical, Thoracic, and Lumbar Regions
Figure 6-17(c)

13. The Vertebral Column Atlas (C1) Axis (C2) First cervical vertebrae
Holds up the head
Articulates with the skull
Axis (C2)
Articulates with C1 through the DENS (odontoid process)
Creates a pivot joint between C1 and C2
Nodding/shaking head “no”

14. Vertebral Column
The Atlas and Axis
Figure 6-18