1. Axial Skeleton: Vertebral Column
HESC310
4/23/2017
Axial Skeleton: Vertebral Column
Slides by Vince Austin;
figures from Marieb & Hoehn 7th & 8th eds.;
modifications and some slides by W. Rose
Portions copyright Pearson Education
Axial Skeleton

2. Vertebral Column
26 irregular bones (vertebrae) connected to form a flexible curved structure
Cervical vertebrae – 7 bones of neck
Thoracic vertebrae – 12 bones of torso
Lumbar vertebrae – 5 bones of lower back
Sacrum – bone inferior to the lumbar vertebrae that articulates with the hip bones (fusion of 5, starts ~> puberty, done mid-20s)

3. Vertebral Column Spinal nerves C1-C7 exit above vertebrae C1-C7
Lordotic
Spinal nerve C8 exits above T1
Kyphotic
Spinal nerves T1-T12, L1-L5, S1-S5 exit below vertebrae T1-T12, L1-L5, S1-S5
Lordotic
Kyphotic
Figure 7.13

4. Vertebral Column: Curvatures
Kyphosis = posteriorly convex curvature. Thoracic and sacral normally kyphotic (but not too much).
Lordosis = posteriorly concave curvature. Cervical and lumbar normally lordotic (but not too much).
Abnormal spinal curvatures
Scoliosis (lateral curve)
Excessive kyphosis (hunchback)
Excessive lordosis (swayback)
What happens in pregnancy?

5. Vertebral Column: 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

6. Vertebral Column: Ligaments

7. Vertebral Column: Intervertebral Discs
Cushion-like 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

8. Vertebral Column: Intervertebral Discs

9. General Structure of Vertebrae
Body or centrum – disc-shaped, weight-bearing region
Vertebral arch – composed of pedicles and laminae that, along with the centrum, enclose the vertebral foramen
Vertebral foramina – make up the vertebral canal through which the spinal cord passes

10. 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

11. General Structure of Vertebrae
transverse costal facet for tubercle of rib
part of the facet joint
superior demifacet; must be a T
heart-shaped in Ts, oval in Ls

12. Cervical Vertebrae
Seven vertebrae (C1-C7): smallest, lightest vertebrae
C3-C7: Distinguished by oval bodies, short spinous processes, large, triangular vertebral foramina. Articular facets (sup & inf) form joints with vetrebrae above & below.
Each transverse process contains a transverse foramen. (Only cervical have transverse foramina.)

13. Cervical Vertebrae
Table 7.2.2

14. Cervical Vertebrae: Atlas (C1)
No body, no spinous process
Anterior and posterior arches, and two lateral masses
Superior surfaces of lateral masses articulate with occipital condyles

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

16. Cervical Vertebrae: Axis (C2)
Body, spine, and vertebral arches, like other cervical vertebrae
Unique feature: dens, or odontoid process, projects superiorly from body, cradled in the anterior arch of the atlas
The dens is a pivot for the rotation of the atlas
The “missing body” of the atlas?

17. Cervical Vertebrae: The Axis (C2)
Figure 7.16c

18. Cervical Vertebrae: Atlas, Axis (C1, C2)
Figure 7.17a

19. Regional Characteristics of Vertebrae
Table 7.2.1

20. Regional Characteristics of Vertebrae
Table 7.2.2

21. Thoracic Vertebrae
Twelve vertebrae (T1-T12), each of which articulates with one or two of the twelve ribs
Major markings include:
Superior, inferior articular facets (vertebrae above, below)
Sup, inf costal facets (“demifacets”) on heart-shaped body (rib heads) (T10, T11, T12 have single costal facets)
Circular vertebral foramen
Transverse processes with transverse costal facets (rib tubercles) (not T11, T12)
Long spinous process
Location, orientation of articular facets prevents sagittal plane flexion and extension, but allows rotation and limited lateral flexion, of thoracic spine

22. Thoracic Vertebrae
Figure 7.17b

23. Lumbar Vertebrae
The five lumbar vertebrae (L1-L5) are located in the small of the back and have an enhanced weight-bearing function
They have short, thick pedicles and laminae, flat hatchet-shaped spinous processes, and a triangular-shaped vertebral foramen
Orientation of articular facets locks the lumbar vertebrae together to provide stability

24. Lumbar Vertebrae
Figure 7.17c

25. Sacrum
Sacrum
Consists of five fused vertebrae (S1-S5), which shape the posterior wall of the pelvis
It articulates with L5 superiorly, and with the auricular surfaces of the hip bones
Major markings include the sacral promontory, transverse lines, alae, dorsal sacral foramina, sacral canal, and sacral hiatus

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

27. Sacrum and Coccyx: Anterior View
Figure 7.18a

28. Sacrum and Coccyx: Posterior View
Figure 7.18b