Seven cervical vertebrae Identified by the presence of foramen in their transverse processes called foramen transversarium 3rd to 6th are typically have common features 1st, 2nd,and 7th are atypical Ring-shaped and has no body and no spine Consists of: Right and left lateral masses Short anterior arch and a long curved posterior arch (c) Right and left transverse processes

1. Atlas(C1) & Axis(C2) Vertebrae
Presenter: Rahul Sharma

2. Content
• Atlas (C1)Vertebra
• Axis (C2) Vertebra
• Radiograph
• Clinical aspect
• MCQ’s
• References

3. • Seven cervical vertebrae
• Identified by presence of foramen in their
transverse processes called foramen
transversarium
• 3rd to 6th are typical have common features
• 1st, 2nd,and 7th are atypical
Image Superior view

4. First Cervical Vertebra(Atlas)
From Above
• Ring shaped and has no body and no spine
Consists of:
(a) Right and left lateral masses
(b) Short anterior arch and a long curved posterior arch
(c) Right and left transverse processes

5. From Below
lateral mass presents the following features
1. Superior articular facet is concave and elongated
2. Inferior articular facet is flat and circular
3. Medial surface of lateral mass has a small roughened tubercle to
provide attachment transverse ligament of atlas
4. Transverse processes project laterally, strong and larger than that
of other cervical vertebrae

6. From front
From behind

7. Radiograph of dried Atlas
A-P Projection

8. ATTACHMENTS

9. Ossification
• Ossifies from 3 centre
1. One for each lateral mass appear during 7th week of
intrauterine life & unite posteriorly about 3 year
after birth.
2. One for anterior arch appear at first year after birth
and unite about 7th year with lateral mass

10. Second Cervical Vertebra (Axis)
features:
• Tooth-like process projecting upwards
from body called odontoid process.
• Anterior margin of inferior surface of
body projects downwards.
• Spine is massive, tip is bifid.
• Transverse processes are very small and
lack anterior tubercles.
• Superior articular facets on upper
surface of body extend onto pedicles
• Inferior articular facet lies posterior to
the transverse process

11. Front view
From behind
1. Apex of dens
2. Impression for alar ligament
3. Anterior articulating surface of dens
4. Superior articular process
5. Transverse process
6. Body
7. Posterior articular surface of dens
8. Lamina
9. Bifid spinous process

12. Superior view
Inferior view
5. Transverse process
6. Body
8. Lamina
9. Bifid spinous process
11. Foramen of transverse process
12. Inferior articular process
13. Pedicle

13. Side view
15. Anterior arch
16. Dens of axis

14. ATTACHMENT

15. Ossification
• Ossifies in 5 primary centre
One for each vertebral arch
One for centrum
Two for dens

16. Adult patient, plain film radiograph, “odontoid view”
through open mouth

17. Axial CT C1–2 bony window
Axial CT soft-tissue window of atlas and
odontoid peg
1. lateral mass of atlas
2. Odontoid peg
3. Foramen transversarium
4. Masseter muscle
5. Pterygoid muscle
6. Lateral pharyngeal fat space
7. Theca
8. Parotid gland

18. Lateral cervical spine radiographs of an adult

19. Clinical Aspect
Hangman’s fracture
• Fracture of pedicles of axis vertebra
• Severe extension injury of neck that occurs from
automobile accident or a fall from height
• Executive hanging can also cause fracture of odontoid
process

20. Fractures of odontoid process of axis vertebra
• Usually occurs due to fall or blow on head
• Excessive mobility particularly if associated
with rupture of transverse ligament of atlas
can cause compression of spinal cord

21. Occipitalization of atlas
• Congenital fusion of ring of atlas vertebra to base of
occiput

22. Klippel - feil Syndrome
Cervical vertebrae are fused and deformed congenitally

23. References
• BD_Chaurasia’s_Human_Anatomy, Volume 3 -
Head-Neck and Brain 6th Edition
• Gray's Anatomy_ The Anatomical Basis of
Clinical Practice, 41e.
• Human Osteology and Skeletal Radiology_ An
Atlas and Guide by Carrie Allen.

24. THANK YOU