Axial Skeleton

126 Bones

Bones of skull, thorax, and vertebral column

Form longitudinal axis of body

Appendicular Skeleton

Bones of the limbs and girdles that attach them to the axial skeleton

Functions of the Skeletal System

Support, Storage of Minerals, Blood Cell Production, Protection, and Leverage

6 Categories of Bones

Flat, Sutural, Long, Irregular, Sesamoid, and Short

Flat Bones

Thin, roughly parallel surfaces

Examples: cranial bones, sternum

Sutural Bones

Aka Wormian Bones

Irregular bones formed between cranial bones

Number, size, and shape vary

Long Bones

Relatively long and slender

Examples: various bones of the limbs

Irregular Bones

Complex shapes

Examples: vertebrae, bones of pelvis, facial bones

Sesamoid Bones

Small, flat, and somewhat shaped like sesame seed

Develop in tendons of knee, hands, and feet

Short Bones

Small and boxy

Examples: bones of the wrist (carpals) and ankles (tarsals)

Skull Surface Features

Canal or Meatus, Process, Sinus, Foramen, and Fissure

Humerus Surface Features

Head, Tubercle, Sulcus, Tuberosity, Diaphysis, Trochlea, and Condyle

Femur Surface Features

Trochanter, Head, Neck, Diaphysis, Facet, and Condyle

Pelvis Surface Features

Crest, Fossa, Line, Spine, and Ramus

4 Bone Cell Types

Osteocytes

Osteoblasts

Osteoprogenitor

Osteoclasts

Marfan Syndrome

1. Excessive cartilage formation at epiphyseal cartilage

2. Causes long, slender limbs

3. Other connective tissue abnormalities cause cardiovascular issues

Gigantism

Overproduction of growth hormone before puberty

Factors That Increase Blood Calcium Levels

1. Parathyroid Hormone (from parathyroid glands)

2. Calcitonin from thyroid gland C cells

Fracture

1. Crack or break due to extreme mechanical stress

2. Most heal as long as blood supply and cellular parts of periosteum and endosteum survive

Steps of Fracture Repair

1. Large Blood Clot Develops

2. Calluses Form

3. Calluses Replaced and Dead Bone Removed

4. Remodeling of Healed Bone

Types of Fractures

1. Closed or Simple

2. Open or Compound

3. Transverse

4. Spiral

5. Displaced

6. Compression

7. Greenstick

8. Comminuted

9. Epiphyseal

10. Pott

11. Colles

Closed or Simple Fractures

Completely internal

Only seen on X-rays

Open or Compound Fractures

Project through skin

More dangerous due to infection and uncontrolled bleeding

Transverse Fractures

Break shaft across long axis 

Spiral Fractures

Produced by twisting stresses

Spread along length of bone