The Skeletal System

1. The Skeletal System Overview And The Skull

2. The Skeletal System • Includes the following: • Bones (206) • Cartilages • Ligaments

3. Functions of Skeletal System • Support and protection • Storage of calcium • Blood cell production • Movement

4. Bone is a Living Organ Fig. 6.8 & 6.9 OSTEOCYTE – bone cell OSTEON – basic functional unit of bone, a cylindrical canal consisting of blood vessels, nerves and osteocytes.

5. Osteoporosis • Major pathology of bone • Decrease in bone density • Results in bone fractures mainly in wrist (Colles fracture), hip and vertebrae • 2 types (estrogen-dependent and age-related) • Read p. 169

6. Osteoporosis

7. Types of Bone Fractures

8. Organization of Skeleton • Two Divisions • Axial • Bones associated with skull, thorax and vertebral column….80 bones • Appendicular • Bones associated with extremities and shoulder and hip joints….126 bones TOTAL = 206 bones in human skeleton

9. Bone Vocabulary (p. 168)

10. Axial Skeleton

11. Axial Skeleton

12. Axial Skeleton • Consists of: • Skull – • Auditory ossicles – • Hyoid – • Thoracic cage – • Vertebral column – TOTAL = in axial skeleton

13. The Skull • 22 bones • Cranial – • Those in direct contact with the brain • Facial – • Those not in contact with the brain

14. The Skull CRANIAL (8) FACIAL (14)

15. Sutures SUTURES – immovable joints shared between skull bones

16. Cranial Bones (8) 1. Frontal Bone (1)

17. 1. Frontal Bone (1)

18. 1. Frontal Bone (1)

19. 2. Parietal Bone (2)

20. Frontal or Coronal Suture

21. Sagittal Suture

22. 3. Temporal Bone (2)

23. Squamosal Suture

24. 3. Disarticulated Temporal Bone

25. Squamosal suture Squamous region

26. Mastoid process

27. External auditory meatus

28. Styloid process

29. Zygomatic process

30. Mandibular fossa

31. LATERAL VIEW

32. MEDIAL VIEW

33. Internal acoustic meatus

34. Petrous region

35. ANTERIOR

36. 4. Sphenoid Bone (1)

37. 4. Sphenoid Bone (1)

38. 4. Sphenoid Bone

39. 4. Sphenoid Bone (1) • Considered center bone of skull • Shaped like a four-winged, two legged flying creature • Which skull bones articulate (form joints with) this bone? • Which skull bones do not articulate with this bone?

40. Sphenoid Bone Superior to Inferior View

41. Lesser Wings Superior To Inferior Greater Wings Lesser Wings Posterior To Anterior

42. Sella Turcica Pterygoid Processes Pterygoid Processes

44. Pterygoid Processes Located just posterior to the last upper molar teeth

45. 5. Ethmoid Bone (1) • Forms roof of nasal cavity • Forms upper half of nasal septum • Forms lateral wall of both • nasal cavities • Comes in contact with the brain • therefore it is a cranial bone

46. 5. Ethmoid Bone (1)

47. 5. Ethmoid Bone (1) Crista galli – separates 2 cribriform plates and continues down into nasal cavity as perpendicular plate Cribriform plates (2) – perforated bones leading to the nasal cavity

48. Two points – cribriform plate and nasal cavity

49. 5. Ethmoid Bone (1) Superior and Middle conchae are features of the ethmoid bone and form the lateral mass of the ethmoid bone and the lateral wall of the nasal cavities.

50. 5. Ethmoid Bone (1) Perpendicular plate Forms upper half of nasal septum