anatomy_axial_skeleton_pearson.ppt

1. PowerPoint® Lecture Slides prepared by Leslie Hendon, University of Alabama, Birmingham HUMAN ANATOMY fifth edition MARIEB | MALLATT | WILHELM 7 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Bones, Part 1: The Axial Skeleton PART 1

2. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings The Skeleton  Consists of  Bones, cartilage, joints, and ligaments  Composed of 206 named bones grouped into two divisions  Axial skeleton (80 bones)  Appendicular skeleton (126 bones)

5. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Bone Markings  Projections that provide attachment for muscles and ligaments  Projections that help form joints  Depressions and openings for passage of nerves and blood vessels

8. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings The Face  Facial bones serve to  Form framework of the face  Form cavities for the sense organs of sight, taste, and smell  Provide openings for the passage of air and food  Hold the teeth in place  Anchor muscles of the face

9. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Overview of Skull Geography  Facial bones form anterior aspect  Cranium is divided into cranial vault and the base  Internally, prominent bony ridges divide skull into distinct fossae

10. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Overview of Skull Geography  The skull contains smaller cavities  Middle and inner ear cavities – in lateral aspect of cranial base  Nasal cavity – lies in and posterior to the nose  Orbits – house the eyeballs  Air-filled sinuses – occur in several bones around the nasal cavity

11. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Overview of Skull Geography  The skull contains approximately 85 named openings  Foramina, canals, and fissures  Provide openings for important structures Spinal cord Blood vessels serving the brain 12 pairs of cranial nerves

12. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Cranial Bones  Formed from eight large bones  Paired bones include Temporal bones Parietal bones  Unpaired bones include Frontal bone Occipital bone Sphenoid bone Ethmoid bone

13. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Frontal Bones  Forms the forehead and roofs of the orbits  Forms superciliary arches  Internally, it contributes to the anterior cranial fossa  Contains frontal sinuses

14. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Parietal Bones and Sutures  Sutures of the cranium (continued)  Sagittal suture – occurs where right and left parietal bones meet superiorly  Lambdoid suture – occurs where the parietal bones meet the occipital bone posteriorly

15. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Sutural Bones  Small bones that occur within sutures  Irregular in shape, size, and location  Not all people have sutural bones

16. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Occipital Bone  Forms the posterior portion of the cranium and cranial base  Articulates with the temporal bones and parietal bones  Forms the posterior cranial fossa  Foramen magnum located at its base

17. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Occipital Bone  Features and structures  Occipital condyles  Hypoglossal foramen  External occipital protuberunce  Superior nuchal lines  Inferior nuchal lines

19. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Temporal Bones  Lie inferior to parietal bones  Form the inferolateral portion of the skull  Term “temporal”  Comes from Latin word for time  Specific regions of temporal bone  Squamous, temporal, petrous, and mastoid regions

22. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings The Sphenoid Bone  Spans the width of the cranial floor  Resembles a butterfly or bat  Consists of a body and three pairs of processes  Contains five important openings

24. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings The Ethmoid Bone  Lies between nasal and sphenoid bones  Forms most of the medial bony region between the nasal cavity and orbits

27. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Facial Bones  Unpaired bones  Mandible and vomer  Paired bones  Maxillae  Zygomatic bones  Nasal bones  Lacrimal bones  Palatine bones  Inferior nasal conchae

28. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Mandible  The lower jawbone is the largest and strongest facial bone  Composed of two main parts  Horizontal body  Two upright rami

30. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Maxillary Bones  Articulate with all other facial bones except the mandible  Contain maxillary sinuses – largest paranasal sinuses  Forms part of the inferior orbital fissure

33. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Other Bones of the Face  Zygomatic bones  Form lateral wall of orbits  Nasal bones  Form bridge of nose  Lacrimal bones  Located in the medial orbital walls  Palatine bones  Complete the posterior part of the hard palate

34. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Other Bones of the Face  Vomer  Forms the inferior part of the nasal septum  Inferior nasal conchae  Thin, curved bones that project medially form the lateral walls of the nasal cavity

40. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Figure 7.12 The Hyoid Bone  Lies inferior to the mandible  The only bone with no direct articulation with any other bone  Acts as a movable base for the tongue

41. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings The Vertebral Column  Formed from 26 bones in the adult  Transmits weight of trunk to the lower limbs  Surrounds and protects the spinal cord

42. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings The Vertebral Column  Serves as attachment sites for muscles of the neck and back  Held in place by ligaments  Anterior and posterior longitudinal ligaments  Ligamentum flavum

44. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Intervertebral Discs  Cushion-like pads between vertebrae  Act as shock absorbers  Compose about 25% of height of vertebral column  Composed of  Nucleus pulposus and annulus fibrosis

45. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Intervertebral Discs  Nucleus pulposus  The gelatinous inner sphere of intervertebral disc  Enables spine to absorb compressive stresses

46. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Intervertebral Discs  Annulus fibrosis  An outer collar of ligaments and fibrocartilage  Contains the nucleus pulposus  Functions to bind vertebrae together, resist tension on the spine, and absorb compressive forces

48. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Herniated Disc  May be caused by trauma to the spine  Aging is also a contributing factor  Nucleus pulposes loses cushioning properties  Anulus fibrosis weakens Figure 7.14c

49. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Regions and Normal Curvatures  Vertebral column is about 70 cm (28 inches)  Vertebral column is divided into five major regions  Cervical vertebrae 7 vertebrae of the neck region  Thoracic vertebrae 12 vertebrae of the thoracic region

50. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Regions and Normal Curvatures  Vertebral column is divided into five major regions (continued)  Lumbar vertebrae 5 vertebrae of the lower back  Sacrum Inferior to lumbar vertebrae Articulates with coxal bones  Coccyx Most inferior region of the vertebral column

51. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Regions and Normal Curvatures  Four distinct curvatures give vertebral column an S-shape  Cervical and lumbar curvature Are concave posteriorly  Thoracic and sacral curvatures Are convex posteriorly  Curvatures increase the resilience of the spine

54. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Regions Vertebral Characteristics  Specific regions of the spine perform specific functions  Types of movement that occur between vertebrae  Flexion and extension  Lateral flexion  Rotation in the long axis

55. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Cervical Vertebrae  Seven cervical vertebrae (C1 – C7) – smallest and lightest vertebrae  C3 – C7 are typical cervical vertebrae  Body is wider laterally  Spinous processes are short and bifid (except C7)  Vertebral foramen are large and triangular  Transverse processes contain transverse foramina  Superior articular facets face superoposteriorly

58. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings The Atlas  C1 is termed the atlas  Lacks a body and spinous process  Supports the skull  Superior articular facets receive the occipital condyles  Allows flexion and extension of neck  Nodding the head “yes”

61. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings The Axis  Has a body and spinous process  Dens (odontoid process) projects superiorly  Formed from fusion of the body of the atlas with the axis  Acts as a pivot for rotation of the atlas and skull  Participates in rotating the head from side to side

63. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Thoracic Vertebrae (T1 – T12)  All articulate with ribs  Have heart-shaped bodies from the superior view  Each side of the body of T1 – T10 bears demifacts for articulation with ribs  T1 has a full facet for the first rib  T10 – T12 only have a single facet

65. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Thoracic Vertebrae  Spinous processes are long and point inferiorly  Vertebral foramen are circular  Transverse processes articulate with tubercles of ribs  Superior articular facets point posteriorly  Inferior articular processes point anteriorly  Allows rotation and prevents flexion and extension

66. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Lumbar Vertebrae (L1 – L5)  Bodies are thick and robust  Transverse processes are thin and tapered  Spinous processes are thick, blunt, and point posteriorly  Vertebral foramina are triangular  Superior and inferior articular facets directly medially  Allows flexion and extension – rotation prevented

69. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Sacrum (S1 – S5)  Shapes the posterior wall of pelvis  Formed from 5 fused vertebrae  Superior surface articulates with L5  Inferiorly articulates with coccyx  Sacral promontory  Where the first sacral vertebrae bulges into pelvic cavity  Center of gravity is 1 cm posterior to sacral promontory

70. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Sacrum  Sacral foramina  Ventral foramina Passage for ventral rami of sacral spinal nerves  Dorsal foramina Passage for dorsal rami of sacral spinal nerves

73. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Bony Thorax  Forms the framework of the chest  Components of the bony thorax  Thoracic vertebrae – posteriorly  Ribs – laterally  Sternum and costal cartilage – anteriorly  Protects thoracic organs  Supports shoulder girdle and upper limbs  Provides attachment sites for muscles

76. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Sternum  Formed from three sections  Manubrium – superior section Articulates with medial end of clavicles  Body – bulk of sternum Sides are notched at articulations for costal cartilage of ribs 2–7  Xiphoid process – inferior end of sternum Ossifies around age 40

77. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Sternum  Anatomical landmarks  Jugular notch Central indentation at superior border of the manubrium  Sternal angle A horizontal ridge where the manubrium joins the body

78. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Ribs  All ribs attach to vertebral column posteriorly  True ribs - superior seven pairs of ribs Attach to sternum by costal cartilage  False ribs – inferior five pairs of ribs  Ribs 11–12 are known as floating ribs

81. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Disorders of the Axial Skeleton  Abnormal spinal curvatures  Scoliosis – an abnormal lateral curvature  Kyphosis – an exaggerated thoracic curvature  Lordosis – an accentuated lumbar curvature – “swayback”  Stenosis of the lumbar spine  A narrowing of the vertebral canal

82. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings The Axial Skeleton Throughout Life  Membrane bones begin to ossify in second month of development  Bone tissue grows outward from ossification centers  Fontanels  Unossified remnants of membranes

85. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings The Axial Skeleton Throughout Life  Many bones of the face and skull form by intramembranous ossification  Endochondral bones of the skull  Occipital bone  Sphenoid  Ethmoid bones  Parts of the temporal bone

86. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings The Axial Skeleton Throughout Life  Curvatures of the vertebral column  Primary curvatures – thoracic and sacral curvatures An infant's spine is C-shaped at birth  Secondary curvatures – cervical and lumbar curvatures Develop when a baby begins to walk Redistributes weight of the upper body over the lower limbs

87. Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings The Axial Skeleton Throughout Life  Aging of the axial skeleton  Water content of the intervertebral discs decreases  By age 55, loss of a few centimeters in height is common  Thorax becomes more rigid  Bones lose mass with age

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