1. ODONTOID ABNORMALITIES
Os Odontoideum :
 Refers to an independent osseous structure lying cephalad to the
axis body in the location of odontoid process.
 Cruciate lig incompetence & AAS common
 May mimic type II odontoid #
Os odontoideum
Type II fracture
Well corticated, convex
upper margin of C1
Hypertrophied & rounded
Sharp, jagged uncorticated margin of axis
Normal ant arch C1
Moves with ant arch C1
Does not

2. ODONTOID ABNORMALITIES
Persistent Ossiculum Terminale :
 Also called Bergman Ossicle.
 Results from failure of fusion of the terminal ossicle to
the rest of odontoid
 Normally fusion occurs by 12 yrs of age
 Stable anomaly when isolated with normal height of
dens

3. Persistent Ossiculum Terminale
May mimic type I odontoid # (avulsion of terminal ossicle) :
difficult to differentiate at times.

4. ODONTOID ABNORMALITIES
Os Odontoideum :
 Refers to an independent osseous structure lying cephalad to the
axis body in the location of odontoid process.
 Cruciate lig incompetence & AAS common
 May mimic type II odontoid #
Os odontoideum
Type II fracture
Well corticated, convex
upper margin of C1
Hypertrophied & rounded
Sharp, jagged uncorticated margin of axis
Normal ant arch C1
Moves with ant arch C1
Does not

5. Os odontoideum

6. Os odontoideum- Dystopic types

7. TRAUMA : Atlas and Occiput
Jefferson fracture :
 involves the anterior
&posterior arches of atlas
with instability
 Isolated # of post arch
due to hyper-extn injury

8. ODONTOID FRACTURE
 Type I : avulsion # of tip
of odontoid by the alar
ligament
 Type II : transverse # at
base f Dens
 Type III : # of superior
portion of axis body with
extn through one or both
articular facets

9. ODONTOID FRACTURE

10. CVJ-traumatic AAD

11. CVJ- trauma

12. CVJ-trauma

13. CVJ-trauma

14. HANGMAN FRACTURE
# of neural arch of C2
that occurs in sudden
hyperextension
injuries like windshield
injuries and in judicial
hanging

15. CHIARI MALFORMATIONS
 Chiari I- elongated, peg
like cerebellar tonsils are
displaced inferiorly
through Foramen
Magnum
 Syrinx in 20-40%
 25% show BI, KlippelFeil syndrome & atlantooccipital assimilation

16. ACM I with syrinx

17. ACM-II

18. CHIARI MALFORMATIONS
Chiari IIherniation of vermis, IV
ventricle & medulla into
spinal canal with kinking
and displacement of
normal structures.
Chiari IIIf/o Chiari II with
occipital encephalocele.

19. Inflammatory, Arthritic & Infectious Disorders
 Rheumatoid Arthritis (most common)
 Psoriatic arthritis, osteoarthritis, CPPD etc.
 Tuberculosis
 Fungal infections

20. RHEUMATOID ARTHRITIS
 Cervical spine involved in 44-88% patients. Degree






of Cx spine involvement correlates with the duration
& severity of disease.
Anterior AAS (MC, 50-70%)
Sub axial subluxation (20-25%)
BI (less common, 10-15%),most dangerous
Posterior & Rotatory AAS rare
Neurological impairment in 11-58% cases
Vascular compression of basilar, spinal arteries

21. RHEUMATOID ARTHRITIS

22. CVJ-rheumatoid

23. RA- Sub axial Subluxation
 2nd MC subluxn in RA
(MC is ant AAS). Occurs
d/t facet joint arthritis,
ligamentous laxity & disc
involvement that lead to
‘step ladder’ deformity
 Normal Cx sag diameter
at C3-7 is 14-23 mm. <14
mm is critical for cord
compression (10mm
cord, 2mm dura & 2mm
CSF)

24. TUBERCULOSIS
Tuberculosis of atlanto-axial region is rare (<1% of
cases of spinal TB)
It may present withi) retropharyngeal abscess
ii) AAD/AAI
iii) varying grades of bone destruction

25. TUBERCULOSIS

26. TUBERCULOSIS

27. Koch’s

28. CVJ Koch’s
Pre ATT
Post ATT

29. Tuberculoma:

30. TUMORS: Astrocytoma

31. Multiple myeloma

32. Neurofibroma

33. Intradural Lipomatosis

34. CVJ-meningioma

35. Tumors: Meningioma

36. MISC I : OPLL with Cord Myelomalacia

37. Misc II :Demyelinating

38. 3D-MDCT IN CVJ

39. 3D-VRT

40. 3D-VRT

41. THANK YOU!