Content:

1. Anatomical Directional Terms and Body Planes

2. Functions/structures/classifications of bone

3. Appendicular skeleton

4. Axial Skeleton

5. Fracture classification principles

Anatomical Directional Terms and Body Planes

Lateral Plane or Sagittal Plane:
This plane divides the body into right and left regions.

Frontal Plane or Coronal Plane:
This plane divides the body into front (anterior) and back (posterior) regions.

Transverse Plane:
This plane divides the body into upper (superior) and lower (inferior) regions.

• The outermost layer, the periosteum, is a thin, tough membrane of fibrous tissue.
• Beneath the periosteum lie the dense, hard layers of bone tissue called compact bone.
• Encased within these layers is the tissue called cancellous or spongy bone because it contains little hollows like those of a sponge.
• The innermost portion of the bone is a hollow cavity containing marrow.
• Blood vessels course through every layer of bone, carrying nutritive elements, oxygen, and other products.
• Bone tissue also contains a large number of nerves.

Epiphysis: Location of red bone marrow. Epiphyseal line seperates the diaphysis from the epiphyses.

Metaphysis: The zone of growth between the epiphysis and diaphysis during development of a bone.

Diaphysis: Composed of compact bone that surronds the medullary cavity. Yellow bone marrow (fat) is contained in the medullary cavity.

Classification of bones on the basis of shape:

Long bones:

• Cylindrical in shape, being longer than it is wide
• Have a shaft with heads at both ends
• Contain mostly compact bone
• Examples: Femur, humerus.

Short bones:

• Generally cube-shaped
• contain more spongy bone than compact bone
• Examples: Carpals, tarsals

Flat bones:

• Thin and flattened
• Usually curved
• They have two thin layers of compact bone sandwiching a layer of spongy bone
• Examples: Skull, ribs, sternum

Irregular bones:

• Do not fit into other bone classificaiton categories
• Irregular shape
• Example: vertebrae

• Protection: Provide a protective case for the brain, spinal cord, and vital organs
• Energy storage (fat in yellow marrow)
• Blood cell formation:  Hematopoiesis occurs within the marrow cavities of bones
• Mineral storage: Reservoir for minerals, especially calcium and phosphorus
• Movement: Provide levers for muscles
• Support: Form the framework that supports the body and soft organs

Bones are the organ of skeletal system. The basic chemical in bone, which gives bone its hardness and strength, is calcium phosphate.
There are 206 separate bones in the human body.