The skeleton

1. The axial skeleton

Which includes the head and the trunk.

2. The appendicular skeleton

Which includes the sholders, arms, hips, and legs.

The bony framework of the head called the skull, it subdivided in to two parts : the cranium and the facial portion.

It is a rounded box that encloses the brain. It composed of eight distinct cranial bone.

1. One Frontal bone

It form the forehead and the front of the skulls roof.

2. Tow Parietal bones

Forms the most of the top and the side walls of the cranium.

3. Tow Temporal bones

Forms part of the sides and some of the base of the skull

4. One Ethmoid bone.

Located between the eyes in the orbetal cavities.

5. One Sphenoid bone.

It is located at the base of the skull in front of the temporal bone.

6. One Occipital bone.

Forms the back and apart of the base of the skull.

It composed of 14 bones:

1. Mandible or lower jaw bone

It is the only movable bone of the skull

2. Two maxillae

Fuse in the midline to form the upper jaw bone, and it form the front part of the hard palate.

3. Two zygomatic bones

they forms the prominence of the checks, one on each side.

4. Two nasal bones

They lie side by side forming the bridge of the nose

5. Two lacremal bones

Each about the size of a fingernail, lie near the inside corner of the eye

6. The vomer

It form the lower part of the nasal septum

7. Two palatine bones

They form the back part of the hard palate.

8. Two inferior nasal conchea

Extended horizontally along the lateral wall of the nasal cavities.

The bones of the trunk include the vertebral column and the bone of the chest.

1. Vertebral Column: is made of series of irregular shaped bone. In children are 33 to 34 bone. But because of fusion that occur later in the lower part of spine, there usually are just 26 separate bones in the adult spinal column.

Each of these vertebra (except the first two cervical vertebra) has a drum shaped body located toward the front (interiorly) that service as the weight bearing part.

Disk of cartilage between the vertebral body act as the shock absorber and provide flexibility. In the center of each vertebra is a large hole or foramen for the spinal cord. Projecting backward from the boney arch that encircle the spinal cord, is the spinous process. Which usually can be felt just under the skin of the back.

The bones of the vertebral column are named and numbered from above downward:

1. Cervical vertebra: located in the neck 7 in number.

2. Thoracic vertebra: located in the chest (thorax) 12 in number.

3. Lumber vertebra: located in the small of the back 5 in number. They are larger and heavier than other vertebra.

4. Sacral vertebra: in adult is a single bone called sacrum. While in children is 5 separate bone.

5. Coccyx (tail bone): Consist of 4 or 5 small bone in the child. Fuse to form a single bone in the adult.

It form a cone shaped cage and it consist of:

A. the sternum: Located along the center of the chest.

B. Ribs: There are 12 pairs of ribs attached to the vertebral column posteriorly, and there are variations in the anterior attachment, so there are two types of ribs according to there anterior attachment

• True ribs: The first 7 pairs that attached directly to the sternum by means of the individual extension called costal cartilage.

• False ribs: The remaining 5 pairs. The 8th 9th and 10th pairs are attached to the cartilage of the rib above(7th). The last two pairs have no anterior attachment at all and are known as floating ribs.

Upper division of the appendicular, which consist of:

1. Shoulder girdle

a. Clavicle

b. Scapula

2. Upper extremities

a. Arm bone (Humerus): Form a joint with the scapula above and the two forearm bone at the elbow.

b. Forearm bone:

Ulna lies on the little finger side

Radius

lies on the thumb side.

1. Wrist: Contain 8 small bone (carpal bone) arranged in two rows of 4 each.

2. Meta Carpal Bones: 5 bones which form the framework of the body of each hand.

3. Phalanges or Finger bone: 14 bones 3 for each finger and 2 for the thumb.

1. Pelvic girdle: is a place where the lower limb is attached to the body and is a strong boney ring that forms the walls of the pelvis. It consist of:

a. Ilium: Which form the upper flared portion (most superior)

b. Ischium: Which is the lowest posterior and strongest bone.

c. Pubis: Which form the anterior and inferior part.

1. Thigh bone (femur): Is the longest and strongest bone in the body.

2. Patella (Kneecap)

3. Leg bone (two bones) Between the ankle and the knee.

1. Tibia: Is the longer, weight bearing bone lies on the big toes side (medially)

2. Fibula: does not reach the knee joint, so it is not a weight bearing. Lies on the little toes side (laterally).

3. Tarsal bone (7 bones): The largest one is the calcaneus or heal bone

4. Meta tarsal bone (5 bones): form the frame work of the foot.

5. Phalanges (toes) 14 bones 3 in each toes and two in big toes.

1. Processes: Bone projection serves as region for muscle attachments. Example: Mastoid processes of the temporal bone, behind the external part of the ear.

2. Foramina: Holes that extend into or through bones permit the passage of blood vessels. Example: Foramen Magnum; located at the base of the occipital bone.

3. Fossae: Valley like depression on the bone surface. Example: Fossae of the scapula.

4. Grooves: A narrow depression on a bone for passage of blood vessels or nerves. Example: Grooves of the ribs.

It is an area or junction or union between two or more bones.

1. Synarthrosis: Immovable joint the bones of this joint held together by fibrous connective tissue. Example: suture between the bones of the skull.

2. Amphiarthrosis: Slightly movable joint. The bone of this joint are connected by cartilage. Example: the joints between the body of the vertebra.

3. Diarthrosis: Freely movable joint. The bones of this joint have space between them( joint cavity) filled with a fluid called synovial fluid. Example: wrist and ankle.