1. The Vertebral Column and the Bony Thorax
The Skeleton Part B
The Vertebral Column and the Bony Thorax

2. The Vertebral Column

3. The Vertebral Column Flexible curved structure
Extends from Skull to Pelvis
26 irregular bones in adults
33 separate bones in the fetus and infants
9 of the 33 fuse to form the sacrum and coccyx

4. The Vertebral Column Transmits weight from trunk to lower limbs
Surrounds and protects the spinal cord
Provides attachment points for ribs and muscles of the back and neck

5. The Vertebral Column
Vertebrae separated by intervertebral discs (fibrocartilage)
Each vertebrae is given a name according to its location

6. The Vertebral Column Has five major divisions Cervical vertebrae
7 bones in neck
Thoracic vertebrae
12 bones in torso
Lumbar vertebrae
5 bones in lower back

7. The Vertebral Column Has five major divisions Sacrum
Bone inferior to the lumbar
Articulates with hip bones

8. The Vertebral Column Has five major divisions Coccyx
4 (sometimes 3 to 5) fused bones
Everyone has same number of cervical vertebrae, but other areas vary in number in 5% of people

9. All mammals have 7 cervical vertebrae

10. The Vertebral Column Vertebrae has four curvatures
Sinusoid shaped (S-shaped)
Cervical and lumbar curvatures are Concave
Thoracic and Sacral curvatures are Convex

11. The Vertebral Column
Abnormal spine curvatures

12. Abnormal spine curvatures
Scoliosis
Abnormal lateral curve

13. Abnormal spine curvatures
Kyphosis
hunchback

14. Abnormal spine curvatures
Lordosis
swayback

15. Vertebral Column Major Supporting Ligaments
Anterior and posterior longitudinal ligaments
continuous bands down the front and back of the spine from the neck to the sacrum
Short ligaments connect adjoining vertebrae together

16. Vertebral Column: Ligaments
Figure 714a

17. Intervertebral Discs Cushionlike pad composed of two parts
Nucleus pulposus – inner gelatinous nucleus that gives the disc its elasticity and compressibility
Annulus fibrosus – surrounds the nucleus pulposus with a collar composed of collagen and fibrocartilage

18. Vertebral Column: Intervertebral Discs
Nucleus pulposus
Figure 7.14b

19. Vertebral Column: Intervertebral Discs
Annulus fibrosus
Figure 7.14b

20. Intervertebral Discs Acts as shock absobers
Thickest in the lumbar and cervical regions
Enhances the flexibility of these regions

21. Intervertebral Discs
Account for about 25% of the height of the vertebral column
Flatten some during the day
We are always a few centimeters shorter at night

22. Intervertebral Discs Herniated (prolapsed) disc
Commonly called ‘slipped disc’

23. Intervertebral Discs Slipped discs
Usually involves rupture of the annulus fibrousus followed by protrusions of the spongy nucleus pulposus
If protrusion presses on spinal cord or on spinal nerves, numbness or excruciating pain may result

24. General Structure of Vertebrae
Spinous processes project posteriorly, and transverse processes project laterally
Superior and inferior articular processes – protrude superiorly and inferiorly from the pedicle-lamina junctions
Intervertebral foramina – lateral openings formed from notched areas on the superior and inferior borders of adjacent pedicles

25. General Structure of Vertebrae
Body or centrum – disc-shaped, weight-bearing region
Figure 7.15

26. General Structure of Vertebrae
Vertebral arch – composed of pedicles and laminae that, along with the centrum, enclose the vertebral foramen
Figure 7.15

27. General Structure of Vertebrae
Vertebral foramina – make up the vertebral canal through which the spinal cord passes
Figure 7.15

28. General Structure of Vertebrae
Spinous processes project posteriorly
Attachment sites for muscles that move the vertebral column and for ligaments that stabilize it
Figure 7.15

29. General Structure of Vertebrae
Transverse processes project laterally
Figure 7.15

30. General Structure of Vertebrae
Spinous and transverse processes are attachment sites for muscles that move the vertebral column and for ligaments that stabilize it

31. General Structure of Vertebrae
Superior and inferior articular processes
Protrude superiorly and inferiorly from the pedicle-lamina junctions

32. General Structure of Vertebrae
Intervertebral foramina
Lateral openings formed from notches areas on the superior and inferior borders of adjacent pedicles
Spinal nerves from spinal cord pass through

33. Structure of a Typical Vertebrae
Figure 5.16
Slide 5.29
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

34. The Vertebral Column and the Bony Thorax
The Skeleton Part B - 2
The Vertebral Column and the Bony Thorax

35. Regional Characteristics of Vertebrae
Figure 5.17a, b
Slide 5.30a
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

36. Cervical Vertebrae
Seven vertebrae (C1-C7) are the smallest, lightest vertebrae
C3-C7 are distinguished with an oval body, short spinous processes, and large, triangular vertebral foramina
Each transverse process contains a transverse foramen

37. Regional Characteristics of Vertebrae
Figure 5.17a, b
Slide 5.30a
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

38. Cervical Vertebrae: The Atlas (C1)
The atlas has no body and no spinous process
It consists of anterior and posterior arches, and two lateral masses
The superior surfaces of lateral masses articulate with the occipital condyles

39. Cervical Vertebrae: The Atlas (C1)
Figure 7.16a, b

40. Cervical Vertebrae: The Atlas (C1)
Figure 7.17a

41. Cervical Vertebrae: The Axis (C2)
The axis has a body, spine, and vertebral arches as do other cervical vertebrae
Unique to the axis is the dens
The dens is a pivot for the rotation of the atlas

42. The Axis (C2)
The dens projects superiorly from the body and is cradled in the anterior arch of the atlas

43. Cervical Vertebrae: The Axis (C2)
Dens
Figure 7.17a

44. Cervical Vertebrae C3 through C7
Table 7.2

45. Regional Characteristics of Vertebrae Thoracic
Figure 5.17c, d
Slide 5.30b
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

46. Thoracic Vertebrae
There are twelve vertebrae (T1-T12) all of which articulate with ribs
Figure 7.17b

47. Thoracic Vertebrae
Major markings include two facets and two demifacets on the heart-shaped body, the circular vertebral foramen, transverse processes, and a long spinous process
Figure 7.17b

48. Thoracic Vertebrae
The location of the articulate facets prevents flexion and extension, but allows rotation of this area of the spine
Figure 7.17b

49. Regional Characteristics of Vertebrae Lumbar
Figure 5.17c, d
Slide 5.30b
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

50. Lumbar Vertebrae
The five lumbar vertebrae (L1-L5) are located in the small of the back and have an enhanced weight-bearing function
Figure 7.17c

51. Lumbar Vertebrae
They have short, thick pedicles and laminae, flat hatchet-shaped spinous processes, and a triangular-shaped vertebral foramen
Figure 7.17c

52. Lumbar Vertebrae
Orientation of articular facets locks the lumbar vertebrae together to provide stability
Figure 7.17c

53. Sacrum
Consists of five fused vertebrae (S1-S5), which shape the posterior wall of the pelvis
Figure 7.18a

54. Sacrum
It articulates with L5 superiorly, and with the auricular surfaces of the hip bones
Figure 7.18a

55. Sacrum
Major markings include the sacral promontory, transverse lines, alae, dorsal sacral foramina, sacral canal, and sacral hiatus
Figure 7.18a

56. Coccyx - Tailbone
The coccyx is made up of four (in some cases three to five) fused vertebrae that articulate superiorly with the sacrum
Figure 7.18a

57. Sacrum and Coccyx Anterior view

58. Sacrum and Coccyx Posterior View
Figure 7.18b

59. The Bony Thorax Thoracic cage Rib cage

60. The Bony Thorax
Made up of three parts
Sternum
Ribs
Thoracic vertebrae

61. The Bony Thorax
The thoracic cage is composed of the thoracic vertebrae dorsally, the ribs laterally, and the sternum and costal cartilages anteriorly

62. Bony Thorax (Thoracic Cage)
Functions
Forms a protective cage around the heart, lungs, and great blood vessels
Supports the shoulder girdles and upper limbs
Provides attachment for many neck, back, chest, and shoulder muscles
Uses intercostal muscles to lift and depress the thorax during breathing

63. Bony Thorax (Thoracic Cage)
Figure 7.19a

64. Bony Thorax (Thoracic Cage)
Figure 7.19b

65. Sternum (Breastbone)
A dagger-shaped, flat bone that lies in the anterior midline of the thorax
Results from the fusion of three bones – the superior manubrium, the body, and the inferior xiphoid process
Anatomical landmarks include the jugular (suprasternal) notch, the sternal angle, and the xiphisternal joint

66. Ribs
There are twelve pair of ribs forming the flaring sides of the thoracic cage
All ribs attach posteriorly to the thoracic vertebrae

67. Ribs
The superior 7 pair (true, or vertebrosternal ribs) attach directly to the sternum via costal cartilages

68. Ribs
Ribs 8-10 (false, or vertebrocondral ribs) attach indirectly to the sternum via costal cartilage

69. Ribs
Ribs (floating, or vertebral ribs) have no anterior attachment

70. Ribs
Figure 7.19a

71. Structure of a Typical True Rib
Bowed, flat bone consisting of a head, neck, tubercle, and shaft
Figure 7.20

72. Quiz – Next Time!
Study guide