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

Sharp, jagged un-corticated margin of axis

Hypertrophied & rounded

Normal ant arch C1

Moves with ant arch C1 Does not

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

Persistent Ossiculum Terminale

May mimic type I odontoid # (avulsion of terminal ossicle) :

difficult to differentiate at times.

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

Sharp, jagged un-corticated margin of axis

Hypertrophied & rounded

Normal ant arch C1

Moves with ant arch C1 Does not

Os odontoideum

Os odontoideum- Dystopic types

TRAUMA : Atlas and Occiput

Jefferson fracture : involves the anterior

&posterior arches of atlas with instability

Isolated # of post arch due to hyper-extn injury

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

ODONTOID FRACTURE

CVJ-traumatic AAD

CVJ- trauma

CVJ-trauma

CVJ-trauma

HANGMAN FRACTURE

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

CHIARI MALFORMATIONS

Chiari I- elongated, peg like cerebellar tonsils are displaced inferiorly through Foramen Magnum

Syrinx in 20-40% 25% show BI,

Klippel-Feil syndrome & atlanto-occipital assimilation

ACM I with syrinx

ACM-II

CHIARI MALFORMATIONS

Chiari II-

herniation of vermis, IV ventricle & medulla into spinal canal with kinking and displacement of normal structures.

Chiari III-

f/o Chiari II with

occipital encephalocele.

Inflammatory, Arthritic & Infectious Disorders

Rheumatoid Arthritis (most common) Psoriatic arthritis, osteoarthritis, CPPD etc. Tuberculosis Fungal infections

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

RHEUMATOID ARTHRITIS

CVJ-rheumatoid

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)

TUBERCULOSIS

Tuberculosis of atlanto-axial region is rare (<1% of cases of spinal TB)

It may present with-

i) retropharyngeal abscess

ii) AAD/AAI

iii) varying grades of bone destruction

TUBERCULOSIS

TUBERCULOSIS

Koch’s

CVJ Koch’s

Pre ATT Post ATT

Tuberculoma:

TUMORS: Astrocytoma

Multiple myeloma

Neurofibroma

Intradural Lipomatosis

CVJ-meningioma

Tumors: Meningioma

MISC I : OPLL with Cord Myelomalacia

Misc II :Demyelinating

3D-MDCT IN CVJ

3D-VRT

3D-VRT

THANK YOU!