1. Introduction to the Skeletal System

2. The Skeletal System Skeletal system includes:
bones of the skeleton
cartilages, ligaments, and connective tissues
Main Functions of the Skeletal System
Protection (ex: skull/vertebral column)
Movement (Leverage/force of motion)
Support (ex: femur supports upper body)
4 Storage of minerals (calcium) and lipids (yellow marrow)
Blood cell production (in red bone marrow)

3. Classification of Bones
Bones are identified by SHAPE
Long bones
Flat bones
Sutural bones
Irregular bones
Short bones
Sesamoid bones

4. Long Bones Are found in limbs, hands, feet, fingers, and toes
Are longer than they are wide
Are found in limbs, hands, feet, fingers, and toes

5. Flat Bones Are thin (sometimes curved)
Are found in the skull, sternum, ribs, and scapula

6. Sutural Bones Classified by LOCATION
Are found between the flat bones of the skull

7. Irregular Bones Many different and complex shapes
Ex: ear bones/vertebrae

8. Short Bones
Are small and thick; cube-shaped
Ex: ankle & wrist bones

9. Sesamoid Bones small and flat
Develop inside tendons near joints of knees, hands, and feet

10. Two Divisions of the Skeletal System
Total Bones: 206
Axial
Total Bones: 80
Includes the longitudinal axis of the body
Skull (29 Bones)
Vertebral Column (26 Bones)
Bony Thorax (25 Bones)

11. Two Divisions of the Skeletal System
Appendicular
Total Bones: 126
Upper Limbs (60 Bones)
Lower Limbs (60 Bones)
Pectoral Girdle (4 Bones)
Pelvic Girdle (2 Bones)

12. Long Bone Structure Diaphysis - the shaft
A heavy wall of compact bone, or dense bone
A central space called marrow cavity
Epiphysis - wide part at each end of bones
Mostly spongy bone
Covered with compact bone
Metaphysis - where diaphysis and epiphysis meet
(PHYSIS = growth, dia = between, epi = on/upon, meta = middle)

13. Long Bone Structure
Epiphyseal Line: where bone has stopped growing (plate = where bone is actively growing)

14. Long Bone Structure
Articular Cartilage: Thin layer of hyaline cartilage at end of bones where bones connect

15. Long Bone Structure
Periosteum: Covers bones; made up of tough fibrous membrane

16. Long Bone Structure
MEDULLARY CAVITY: Space within diaphysis that contains bone marrow

17. Long Bone Structure
Endosteum: Layer that lines the medullary cavity

18. Long Bone Structure
Spongy Bone: cancellous bone that forms the epiphyses of long bones

19. Long Bone Structure
Yellow Marrow: made up of lipids/fats

20. Flat Bones
Resembles a sandwich of spongy bone between 2 layers of compact bone
The parietal bone & other flat bones of the cranium