1. The Skeleton
Chapter 7
Part A

2. The Skeleton Skeleton = Greek for ‘dried up body’ or ‘mummy’
             
The Skeleton
Skeleton = Greek for ‘dried up body’ or ‘mummy’
Composed of bones, cartilages, joints, and ligaments
Mostly bone
Ligaments connects bones and reinforces joints

3. The Skeleton About 20% of body mass
160 pound person would have about 30 pound skeleton
Classified into 2 parts
Axial and Appendicular

4. The Axial Skeleton 80 bones in 3 regions Skull Vertebral column
Bony thorax
Supports the head, neck, trunk
Protects the brain, spinal cord, and the organs in the thorax

5. The Axial Skeleton Axial Skeleton in Green Slide 5.20b Figure 5.6
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

6. The Skull Most complex structure 22 bones – mostly flat
Two sets of bones
Cranium
Facial bones

7. The Skull Bones are joined by sutures Except mandible
Sutures are interlocking joints – saw-toothed or serrated appearance
Only the mandible is attached by a freely movable joint

8. The Skull
Major skull sutures are
Coronal
Sagittal
Squamous
Lambdoid

9. The Skull Cranial bones or cranium Protects brain
Site of attachment for head and neck muscles

10. The Skull Facial bones Framework for face
Cavities for special sense organs of sight taste and smell
Openings for air and food passage
Secure teeth
Anchor facial muscles of expression

11. Anatomy of the Cranium Eight cranial bones – two Parietal two Temporal
Frontal
Occipital
Sphenoid
Ethmoid
Cranial bones are thin and remarkably strong for their weight

12. Frontal Bone Forms the anterior portion of the cranium
Articulates posteriorly with the parietal bones via the coronal suture
In yellow

13. Frontal Bone Major markings Frontal squama (forehead)
supraorbital margins
Supraorbital foramen
the anterior cranial fossa
the frontal sinuses
glabulla

14. Parietal Bones
Two curved retangular bones that form most of the superior and lateral aspects of skull
In Green

15. Parietal Bones and Major Associated Sutures
Four sutures mark the articulations of the parietal bones
Coronal suture – articulation between parietal bones and frontal bone anteriorly
Sagittal suture – where right and left parietal bones meet superiorly

16. Parietal Bones and Major Associated Sutures
Four sutures mark the articulations of the parietal bones
Lambdoid suture – where parietal bones meet the occipital bone posteriorly
Squamosal or squamous suture – where parietal and temporal bones meet

17. Skull: Posterior View
Parietal bones in maroon
Figure 7.2b

18. Occipital Bone Forms most of skull’s posterior wall and base
Occiptal bone in brown
Figure 7.2b

19. Occipital Bone Forms most of skull’s posterior wall and base
Major markings
Posterior cranial fossa (inside)
Foramen magnum
Occipital condyles
Hypoglossal canal
External occipital protuberance (you can feel this)
Figure 7.2b

20. Human Skull, Inferior View
Figure 5.9
Slide 5.24
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

21. Temporal Bones Temple and temporal are latin words for ‘time’
Gray hair usually appears first at the temples

22. Temporal Bones Divided into four major regions Squamous Tympanic
Ear drum
Mastoid
Petrous
Contributes to the cranial base
Houses middle and inner ear cavities

23. Human Skull, Inferior View
Figure 5.9
Slide 5.24
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

24. Temporal Bones Major markings Zygomatic process (squamous region)
Zygomatic process meets zygomatic bone of face – you can feel this – your cheek bone

25. Temporal Bones Major markings
Styloid process (needle like projection in the tympanic region)

26. Temporal Bones Major markings
Mastoid process (felt as a lump posterior to the ear)
Mandibular fossae
Middle cranial fossae ( in Petrous region)

27. Temporal Bones Major openings stylomastoid foramina jugular foramina
external and internal auditory meatuses (ear canal)
carotid canal

28. Sphenoid Bone
Butterfly-shaped bone that spans the width of the middle cranial fossa
Forms the central wedge that articulates with all other cranial bones
Consists of a central body, greater wings, lesser wings, and pterygoid processes
Major markings: the sella turcica, hypophyseal fossa, and the pterygoid processes
Major openings include the foramina rotundum, ovale, and spinosum; the optic canals; and the superior orbital fissure

29. Human Skull, Superior View
Sphenoid Bone in pink
Figure 5.8
Slide 5.23
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

30. Sphenoid Bone
Figure 7.6a, b

31. Ethmoid Bone
Most deep of the skull bones; lies between the sphenoid and nasal bones
Forms most of the bony area between the nasal cavity and the orbits

32. Ethmoid Bone Major markings cribriform plate crista galli
perpendicular plate
nasal conchae
ethmoid sinuses

33. Human Skull, Superior View
Figure 5.8
Slide 5.23
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

34. Human Skull, Inferior View
Figure 5.9
Slide 5.24
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

35. Wormian Bones Also called sutural bones
Tiny irregularly shaped bones that appear within sutures
Structurally unimportant
Not all skulls exhibit them

36. Facial Bones

37. Facial Bones
Fourteen bones of which only the mandible and vomer are unpaired
The paired bones are the maxillae, zygomatics, nasals, lacrimals, palatines, and inferior conchae
Usually facial bones of men are more elongated than of women

38. Mandible and Its Markings
The mandible (lower jawbone) is the largest, strongest bone of the face

39. Mandible and Its Markings
Its major markings include the coronoid process, mandibular condyle, the alveolar margin, and the mandibular and mental foramina

40. Mandible and Its Markings
Dentists inject Novocain into the mandibular foramina to numb teeth

41. Maxillary Bones
Medially fused bones that make up the upper jaw and the central portion of the facial skeleton

42. Maxillary Bones
Facial keystone bones that articulate with all other facial bones except the mandible

43. Maxillary Bones
Their major markings include palatine, frontal, and zygomatic processes, the alveolar margins, inferior orbital fissure, and the maxillary sinuses

44. Zygomatic Bones
Irregularly shaped bones (cheekbones) that form the prominences of the cheeks and the inferolateral margins of the orbits
In Teal

45. Other Facial Bones
Nasal bones – thin medially fused bones that form the bridge of the nose

46. Other Facial Bones
Lacrimal bones – contribute to the medial walls of the orbit and contain a deep groove called the lacrimal fossa that houses the lacrimal sac

47. Other Facial Bones
Palatine bones – two bone plates that form portions of the hard palate, the posterolateral walls of the nasal cavity, and a small part of the orbits

48. Other Facial Bones
Vomer – plow-shaped bone that forms part of the nasal septum

49. Other Facial Bones
Inferior nasal conchae – paired, curved bones in the nasal cavity that form part of the lateral walls of the nasal cavity

50. Orbits
Bony cavities in which the eyes are firmly encased and cushioned by fatty tissue
Formed by parts of seven bones – frontal, sphenoid, zygomatic, maxilla, palatine, lacrimal, and ethmoid

51. Orbits
Figure 7.9b

52. Nasal Cavity Constructed of bone and hyaline cartilage
Roof – formed by the cribriform plate of the ethmoid

53. Nasal Cavity
Lateral walls – formed by the superior and middle conchae of the ethmoid, the perpendicular plate of the palatine, and the inferior nasal conchae
Floor – formed by palatine process of the maxillae and palatine bone

54. Paranasal Sinuses
Hollow portions of bones surrounding the nasal cavity
Figure 5.10
Slide 5.25a
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

55. Paranasal Sinuses
Mucosa-lined, air-filled sacs found in five skull bones – the frontal, sphenoid, ethmoid, and paired maxillary bones

56. Paranasal Sinuses
Air enters the paranasal sinuses from the nasal cavity and mucus drains into the nasal cavity from the sinuses

57. Paranasal Sinuses
Lighten the skull and enhance the resonance of the voice and amplifies
Figure 7.11

58. Hyoid Bone
Not actually part of the skull, but lies just inferior to the mandible in the anterior neck
Only bone of the body that does not articulate directly with another bone
Attachment point for neck muscles that raise and lower the larynx during swallowing and speech

59. The Hyoid Bone
The only bone that does not articulate with another bone
Serves as a moveable base for the tongue
Figure 5.12
Slide 5.26
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

60. The Fetal Skull
The fetal skull is large compared to the infants total body length
Figure 5.13
Slide 5.27a
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

61. The Fetal Skull
Fontanelles – fibrous membranes connecting the cranial bones
Allow the brain to grow
Convert to bone within 24 months after birth
Figure 5.13
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 5.27b

62. Complete study guide Pages 143 - 150
Quiz – Next time!
Complete study guide
Pages

63. Skull: Anterior View
Figure 7.2a

64. Parietal Bones and Major Associated Sutures
Form most of the superior and lateral aspects of the skull
Figure 7.3a

65. Occipital Bone and Its Major Markings
Figure 7.4b

66. Anterior Aspects of the Skull
Figure 7.2a

67. Posterior Aspects of the Skull
Figure 7.2b

68. External Lateral Aspects of the Skull
Figure 7.3a

69. Midsagittal Lateral Aspects of the Skull
Figure 7.3b

70. Inferior Portion of the Skull
Figure 7.4a

71. Inferior Portion of the Skull
Figure 7.4b

72. Quiz – Next time!
Complete study guide