Skeletal System

OBJECTIVES:

1. Divisions of the Skeletal System

2. Classifications of Bones

3. Anatomy of a Bone

4. Fractures & Surgery

Human Skeleton

The human skeleton is divided into 2 groups: Axial: Bones that form the

longitudinal axis of the body

Appendicular: Bones of the limbs & girdles.

Bone Classification

There are 206 bones in the human body.

Two types of bone tissue: Compact Bone: Dense,

looks smooth Spongy Bone: Composed

of small, needle-like pieces.

Shapes of Bones

Long Bones: Longer than they are wide Have a shaft with a head at

both ends Made of mostly compact

bone. Found in the limbs of the

body.

Shapes of Bones

Short Bones: Generally cubed-

shaped Contain mostly

spongy bone Found in the

wrists and ankles

Shapes of Bones

Flat Bones: Thin, flattened, and

usually curved. Two thin layers of

compact bone covering spongy bones.

Found in the skull, ribs, and sternum

Shapes of Bones

Irregular Bones: Bones that do not fit

into the previous catergories

Vertebrae and hip bones.

Structure of a Long Bone

Diaphysis: Shaft (long, thin part of the bone) makes up most of the bones length. Made of compact bone.Periosteum: Fibrous connective tissue that covers the diaphysis.

Structure of a Long Bone

Epiphyses: Ends of the long bone. Made of compact and spongy bone.Articular Cartilage: Slippery cartilage that covers the epiphyses. Provides a smooth surface at the joint for movement.

Structure of a Long Bone

Epiphyseal Plate: Cartilage found in the epiphyses of a young, growing bone. Allow for a bone to grow. By the end of puberty the cartilage is replaced by bone making an epiphyseal line.

Bone Marrow

In adults, the shaft of long bones store adipose called yellow marrow. The only place to find red marrow is in the cavities of spongy flat bones and the epiphyses of some long bones.**-The bones of most young children are made of hyaline cartilage. As you grow into an adult, the cartilage hardens into bone by a process called ossification.

Making & Destroying Bone

osteoblasts: bone-forming cells (make bone) Bone Buildingosteoclasts: bone-destroying cells. Activated when calcium levels fall below homeostatic levels

Fractures

A fracture is a break in the bone.

8 Types of Fractures: Simple

Compound

Comminuted

Fractures

8 Types of fractures Compression Depressed Impacted Spiral Greenstick

Surgery

A fracture is treated by reduction, realignment of the broken bone ends. Closed Reduction: Bone

ends are realigned by a doctor.

Open Reductions: Surgery is performed and bone ends are secured by pins/wires.