Atlas(C1) & Axis(C2) Vertebrae.pptx

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 S uperior view

4. First Cervical Vertebra(Atlas) From Above 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

5. From Below lateral mass presents the following features Superior articular facet is concave and elongated Inferior articular facet is flat and circular Medial surface of lateral mass has a small roughened tubercle to provide attachment transverse ligament of atlas 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 One for each lateral mass appear during 7 th week of intrauterine life & unite posteriorly about 3 year after birth. One for anterior arch appear at first year after birth and unite about 7 th 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 Apex of dens Impression for alar ligament Anterior articulating surface of dens Superior articular process Transverse process 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 lateral mass of atlas Odontoid peg Foramen transversarium 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.

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