80 bones 

• Bones of skull, thoraz, and verebral column
• form longitudinal axis of body 

126 bones

• Bones of the limbs and gridles that attach them to the axial skeleton 

• Supports
• storage of minerals
• blood cell production
• protection
• leverage

1. Flat bones- Thin, roughly parallel surfaces
2. Sutural Bones - Irregular bones formed between cranial bones
3. Long bones - Relatively long and slender 
4. Irregular bones- complex shapes
5. Sesamoid bones- small, flat (shaped like a seed)
6. Short bones- small and boxy 

Four Bone cell types 

Calcium phosphate 

Accounts for 2/3 of the bone weight 

Spongy bone 

Located where bones not  heavily stressed or in many directions 

Appositional bone growth 

Increses bone diameter of existing bones

1. Fibrous outer layer 
2. Cellular inner layer 

1. Isolate bone from surrounding tissues 
2. Route for blood and nervous supply
3. Actively participates in bone growth and repair 

Perforating Fibers

• Created by osteoblasts in periosteum cellular layer
• Strongly connect tendons, ligaments, and joint capsules to bone through periosteum 

• excessive cartilage formation aat epiphyseal cartilage
• Causes, long, slender limbs 
• Other connective tissue abnormalities cause cardiovascular issues 

• Growth hormone levels rise after epiphyseal plates close 
• Bones get thicker 

Most abundant mineral in the body 

• 99% deposited in skeleton 

Fracture 

• Transverse 
• Spiral
• Displaced 
• Compression 
• Greenstick 
• Commminuted 
• Epiphyseal
• Pott
• Colles

• Smaller blood Vessels 
• Lymphatic vessels 
• Sensory Nerves 

• Nutrient artery/vein
• metaphyseal atery/vein