2. Skeletal System

3. Learning Objectives Define terms relating to the skeletal system
Describe the five functions of the skeletal system
Identify at least 10 structures of the skeletal system
Identify methods of assessment of the skeletal system
Describe disorders of the skeletal system

4. Bones Inorganic salts (calcium phosphate) Water Organic material
Bone tissue is composed of:
Inorganic salts (calcium phosphate)
Water
Organic material
(bone cells, blood vessels, nerves, and collagen)
Bone cells must continually receive food and oxygen
Bones continue to grow for the first 18 to
20 years of life
Bone cells die and are replaced by new ones

5. Bones (Cont.) Bones may have cartilage
- fibrous connective tissue / prevents friction
Bones are attached to other bones by ligaments
Bones are joined to muscles by tendons
Two major types of bone tissue:
Compact – dense
Cancellous – spongy / loosely packed

6. Common Skeletal Bones

7. Types of Bones Two major groups of bones: Axial skeleton
Includes 80 bones of the head & trunk
Appendicular skeleton
Includes 126 bones of the pelvis, shoulders, arms, and legs

9. Bones by Shapes
Bones are also classified by shape: Long bones – longer than wide Short bones – have similar length and width Flat bones – have two layers with space between them Irregular bones – all bones that do not fit in the other categories

12. Skull Cranium Eight bones
Includes bones of the:
Cranium
Eight bones
At birth, bones of the cranium have two openings (fontanels) which close by age 2
Face
14 bones
Ear
The mandible (lower jaw) is the only movable bone of the skull

15. Teeth Adult has 32 teeth Each tooth has parts:
Crown is the white section above the gum
Root is below the gum
Enamel, the hardest substance in the body, covers the crown
Cementum is the hard, bonelike substance covering the root
Dentin is located between the enamel and the pulp
Pulp is the soft living portion of the tooth, containing the nerves and blood vessels

16. Parts of a Tooth

17. Types of Teeth
Four major types of teeth (each have different shape and function):
Incisor
Cuspid
Bicuspid
Molar

18. Table Teeth Types

19. Tooth Development

20. Thorax Thorax protects the heart & lungs and includes: Ribs
7 pair of “true” ribs – attached to sternum
5 pair of “false” ribs – not attached directly to sternum, costal cartilage of each false rib attaches to the rib above it
2 pair of “floating” ribs – attach only to spine
Sternum
Vertebral bones

22. Vertebral Column * Consists of five parts (total of 26 vertebrae):
Cervical vertebrae (7 vertebrae)
Thoracic vertebrae (12 vertebrae)
Lumbar vertebrae (5 vertebrae)
Sacrum
Coccyx
* Curvature gives it strength and flexibility
* Cartilage between vertebrae cushions bones
and allows movement

23. Vertebral Column

24. Long Bones of the Extremities
Long bones of the arms and legs contain marrow
Makes blood cells for the body
Long bones grow and lengthen from a layer of cartilage (epiphyseal plate)
Shaft of the long bone (diaphysis) contains fatty tissue and yellow marrow
Fatty tissue provides stored energy

25. Long Bones of the Extremities (Cont)
End of the long bone (epiphysis) contains red marrow that produces red blood cells
Red marrow destroys old red blood cells, forms white blood cells, and produces platelets
Periosteum (membrane)
Covers the bone
Contains osteoblasts
Medullary cavity
Contains osteoclasts which enlarge the diameter of the cavity by removing bone cells

26. Anatomy of a Long Bone

27. Bone Markings Four major types of bone markings:
Projections bulge from a bone and attach to muscles, ligaments, and tendons
Openings are holes or spaces in bones
Depressions include openings and cavities in bone
Ridges are lines on a bone surface

28. Joints Articulation Two or more bones join together at a joint
Joints are named by the bones that are joined

29. Types of Joints Three types of joints: Immovable (synarthrosis)
Example: sutures of the cranium
Slightly movable (amphiarthrosis)
Bones of the pelvis
Freely movable (diarthrosis)

30. Types of Diarthrosis Joints
Ball and socket joints of the shoulders and hips
Hinge joints of the elbow and knee
Gliding joints of the wrists
Pivot joint at the base of the skull
Saddle joint of the thumb
Gomphosis, such as the attachment of a tooth in its socket in the jaw

31. Types of Joints (Cont.)
A. Ball & Socket (shoulder/Hips) B. Hinge (elbow/knee) C. Gliding (wrist) D. Pivot (base of skull) E. Saddle (thumb) F. Gomphosis (tooth in socket)

32. Assessment Techniques of the Skeletal System

33. Assessment Techniques
Bone x-rays
Bone marrow aspiration
Bone marrow biopsy
Radionuclide bone scan
Computed axial tomography (CAT)
Magnetic resonance imaging (MRI)
Bone densitometry

34. X-Ray
Use electromagnetic energy that is absorbed by the body’s tissues to produce images on photographic film
X-ray machines may be portable or stationary
Can determine fractures, tumors, infection, arthritis, deformities, and bone age
Painless
Minimal risk
Less sensitive than a bone scan in detecting bone destruction

35. Bone Marrow Aspiration
Insertion of a long needle into the bone to remove marrow
Used to determine cause of blood disorders, some Cancers, chromosome abnormalities
May be performed in hospital or outpatient setting
Local anesthesia is used to ease discomfort

36. Bone Marrow Biopsy
Used to obtain a piece of bone with intact marrow to identify abnormalities
Similar to Aspiration except that a core of the bone is removed for examination

37. Radionuclide Bone Scan
Also known as bone scintigraphy
Used to detect bone cancer when X-rays do not show abnormalities but malignancy is suspected
May also be used to locate bone infections
Stress fx that do not show on X-rays may be seen
Involves injection of the radionuclide, which spreads through the bone
Increased concentration of the material indicates a diseased area

38. Computerized Tomography
CAT scan or CT scan
Several beams of X-rays are sent simultaneously from different angles
A computer determines relative density of the tissue examined by the strength of the beams
May be used to picture every part of the body

39. Magnetic Resonance Imaging
MRI
Uses magnetic and radio waves to show computerized images of the body
No exposure to x-rays or other damaging forms of radiation
Very detailed – best technique to identify tumors in the brain
Also used to examine heart, blood vessels, joints, spine, and sometimes soft parts of the body such as the liver, kidneys, and spleen

40. Bone Densitometry
Measures bone mass density to determine the extent of osteoporosis and fracture risk