1. Vertebral Column

2. Vertebral Column (Spine)
Extends from the skull, which it supports, to the pelvis, where it transmits the weight of the body to the lower limbs
The spine is formed from 26 irregular bones connected and reinforced by ligaments in such a way that a flexible curved structure results

3. Vertebrae
Before birth, the spine consists of 33 separated bones called vertebrae, but 9 of these eventually fuse in to 2 composite bones
Of the remaining 24 single bones:
7 vertebrae of the neck (cervical vertebrae)
12 thoracic vertebrae
5 lumbar vertebrae supporting the lower back

4. Intervertebral disks Cushion the vertebrae and absorb shocks
In a young person, the disks have a high water content
As a person ages, the water content of the disks decreases, and the disks become harder and less compressible
Drying of the disks, along with a weakening of the ligaments of the vertebral column predisposes older people to herniated (slipped) disks

5. Spinal Curvatures
Functions: 1. The disks and the S-shaped structure of the vertebral column work together to prevent shock to the head when we walk or run 2. They also make the body trunk flexible

6. Spinal Curvatures
Primary curvatures: The curvatures that are present when we are born.
e.g. The spinal curvatures in the thoracic and sacral (lower spine) regions
Secondary curvatures: The curvatures that are present after we are born.
e.g. The cervical (neck) curvature

7. Abnormal Spinal Curvatures

8. Vertebrae Structure Body or Centrum:
Disk like, weight- bearing part of the vertebra facing anteriorly in the vertebral column
Vertebra Foremen: Canal through which the spinal cord passes

9. Vertebrae Structure
Spinous process: Single projection arising from the posterior aspect of the vertebrae
Transverse processes: Two lateral projections from the body

10. Vertebrae Structure Superior and inferior articular processes:
Paired projections lateral to the vertebral foramen, allowing a vertebra to form joints with adjacent vertebrae

11. Cervical Vertebrae
The 7 cervical vertebrae (C1-C7) form the neck region of the spine.
The first 2 vertebrae are different because they perform functions not shared by the other cervical vertebrae

12. Cervical Vertebrae C1
The 7 cervical vertebrae (C1-C7) form the neck region of the spine.
C1 is called the atlas. It has no body, and large depressions on the surface where the skull sits. It articulates with the occipital condyles, and allows you to nod “yes”

13. Cervical Vertebrae C2
C2 is called the axis, and acts as a pivot point for rotation of the atlas and the skull.
It has a large process called the odontoid process, which sticks into the atlas.
The joint between C1 and C2 allows us to rotate the head from side to side “no”

14. Cervical Vertebrae C3-C7
The C3 through C7 vertebrae are typical vertebrae with some features that will identify them as cervical vertebrae:
They are the smallest and lightest vertebrae
They have short spinous processes that are divided in two

15. Cervical Vertebrae C3-C7
They have foramen in their transverse processes – this is what one can use to identify these vertebrae as cervical vertebrae;
The foramina are where the vertebral arteries run through

16. Superior and lateral views of the cervical vertebrae

17. Thoracic Vertebrae
The 12 thoracic vertebrae (T1-T12) are all typical

18. Thoracic Vertebrae T1-T12
Their bodies are heart-shaped
They have long spinous processes that point sharply downward
From the side, thoracic vertebrae look like giraffe’s head, this is what one can use to identify these vertebrae as thoracic vertebrae

19. Lumbar Vertebrae
The 5 lumbar vertebrae are the sturdiest of the vertebrae since most of the stress on the vertebral column occurs in the lumbar region

20. Lumbar vertebrae L1-L5 Their bodies are massive and block like
From the side, a lumbar vertebrae look like a moose head – this is what one can use to identify these vertebrae as lumbar vertebrae

21. Sacrum The sacrum is formed by the fusion of 5 vertebrae
Superiorly, it articulates with L5
Inferiorly, it articulates with the coccyx (tail bone)

22. Sacrum The sacrum forms the posterior wall of the pelvis
The vertebrae canal continues inside the sacrum as the sacral canal

23. Coccyx
The coccyx is formed by the fusion of 3 to 5 small, irregularly shaped vertebrae
It is the human “tailbone”, a remnant of the tail that other vertebrate animals have

24. Identify the following vertebrae