1. Chapter 5 Gross & Microscopic Bone Anatomy

2. The Skeletal System Parts of the skeletal system
Bones (skeleton)
Joints
Cartilages
Ligaments
Divided into 2 divisions
Axial skeleton
Appendicular skeleton

3. Functions of Bones Support body Protect soft organs
Movement due to attached skeletal muscles
Storage of minerals and fats
Blood cell formation

4. Bones of the Human Body The skeleton has 206 bones
Two types of bone tissue
Compact bone
- Homogeneous
Spongy bone
- Small needle-like pieces of bone
- Many open spaces

5. Classification Based on Shape

6. Paranasal Sinuses Hollow parts of bones surrounding nasal cavity
Functions:
Lighten the skull
Resonate and amplify voice

7. The Hyoid Bone Only bone that doesn’t articulate with another bone
Moveable base for tongue

8. Gross Anatomy of a Long Bone
Know 7 Structures
1. Diaphysis
Shaft
compact bone
2. Epiphysis
Ends of the bone
mostly spongy bone

9. 3. Periosteum 4. Sharpey’s fibers 5. Arteries
Outside covering of diaphysis
Fibrous connective tissue membrane
4. Sharpey’s fibers
Secure periosteum to bone
5. Arteries
Supply bone cells with nutrients

10. 6. Articular cartilage 7. Medullary cavity Covers the ends
hyaline cartilage
Decreases friction
7. Medullary cavity
Cavity of shaft
Contains yellow marrow (mostly fat) in adults
Contains red marrow (for blood cell formation) in infants

11. Microscopic Anatomy of Bone
Know 6 parts:
1. Osteon (Haversian System)
A unit of bone
2. Central (Haversian) canal
Opening in the center
For blood vessels & nerves
3. Perforating (Volkmann’s) canals
perpendicular to central canal

12. 6. Canaliculi 4. Lacunae 5. Lamellae
Cavities containing bone cells (osteocytes)
Arranged in rings
5. Lamellae
Rings around central canal
6. Canaliculi
Tiny canals
Radiate from central canal to lacunae
Transport system

13. Changes in the Growing Skeleton
In embryos, the skeleton is hyaline cartilage
During development, much of this cartilage is replaced by bone
-Cartilage remains in isolated areas
Bridge of the nose
Parts of ribs
Joints

14. Bone Growth Epiphyseal (growth) plates
- growth of long bone during childhood
- New cartilage is continuously formed
- Older cartilage ossified (broken down & replaced by bone)

15. Remodeled & lengthened
- until growth stops
- Bones change shape somewhat & grow in width

16. Types of Bone Cells 1. Osteocytes 2. Osteoblasts – b for build
Mature bone cells
2. Osteoblasts – b for build
Bone-forming cells
3. Osteoclasts – hard c for kill
Bone-destroying cells
Break down bone matrix for remodeling and release of calcium
Bone remodeling is a process by both osteoblasts and osteoclasts

17. Developmental Aspects
At birth, skull bones incomplete
Bones joined by fibrous membranes – fontanelles
Fontanelles replaced by bone within 2 years
Fetal skull is large compared to total body length

18. Upper Lower (UL) Ratio - Reaches 1:1 about age 10

19. Bone Fractures A break in a bone Types
1. Closed (simple) fracture –does not penetrate skin
2. Open (compound) fracture –penetrates through skin
Bone fractures are treated by reduction and immobilization
- Realignment of the bone

20. Common Types of Fractures

21. Repair of Bone Fractures
1. Hematoma (blood-filled swelling) is formed
2. Break is splinted by fibrocartilage to form a cartilaginous callus
3. Fibrocartilage callus is replaced by a bony callus
4. Bony callus is remodeled to form a permanent patch