This document discusses cranio-vertebral (CV) anomalies, including their classification, anatomical aspects, specific anomalies like atlanto-axial dislocation and dens dysplasia, Arnold-Chiari malformation (ACM), syringomyelia, clinical features, and management. CV anomalies can involve bony or soft tissue structures and are classified accordingly. Radiological evaluation utilizes various lines and angles to assess anomalies like platybasia or basilar invagination. Specific anomalies like atlanto-axial dislocation and dens dysplasia are further classified. ACM and syringomyelia are discussed in detail along with their diagnosis and presentation. Clinical features vary depending on the underlying anomaly. Treatment involves conservative management or

1. Cranio-Vertebral
Anomalies
DR. ANKUR NANDAN VARSHNEY
IMS, BHU
Varanasi

2. Dedicated to Prof. B.C.
Katiyar

3. Contents
 Classification of CV Anomalies
 Anatomical and radiological aspects
 Specific anomalies – AA dislocation, Dens
dysplasia, KFS
 ACM, Syrinx
 Clinical features
 Management

4. Classification
I. Bony Anomalies
A. Major Anomalies B. Minor Anomalies
1. Platybasia 1.Dysplasia of Atlas
2. Occipitalization 2.Dysplasia of occipital
condyles, clivus, etc.
3. Basilar Invagination
4. Dens Dysplasia
5. Atlanto- axial dis.
II. Soft Tissue anomalies
1. Arnold-Chiari Malformation
2. Syringomyelia/ Syringobulbia

5. Anatomical and Radiological Aspects
• Anatomical Landmarks
• Nasion, Tuberculum Sellae,
Clivus, Basion, Opisthion,
Indion
• Lines , angles and
indexes •Basal Angle
• Chamberlain’s Line •Boogard’s angle
• McGregor’s Line •Bull’s angle
• McRae’s Line •A-O interval
•EDFM
• Klaus Height Index
• AT Index

6. Table : Lines and angles used in radiologic diagnosis
of C.V anomalies.
Parameter Normal range limits
A. PLATYBASIA
• Basal angle < 150 degree
• Boogard’s angle < 136 degree
• Bull’s angle < 13 degree
B. BASILAR INVAGINATION
• Chamberlain’s line < one third of odontoid above this line
• Mcgregor’s line < 5 mm
• Mcrae line odontoid lies below this
• Klaus height index > 35 mm
• Atlanto-temporo > 22mm.
mandibular index
C. ATLANTO-AXIAL DISLOCATION *
• Atlanto-odontoid space upto 3 mm in adults
upto 5 mm in children
• EDFM > 19mm
* May be reducible, partially reducible or irreducible

9. Atlanto-Axial Dislocation
– Traumatic
– Spontaneous (Hyperemic)
– Congenital
Wadia Classification (1973)
• Group 1- associated with occipitalization &
frequent fusion of C2,C3
• Group 2- Associated with Dens Dysplasia-
frequently totally reducible
• Group 3- No Congenital Bony abnormality

10.  Type 1 : Syringomyelia with obstruction of Foramen Magnum and dilatation of
central canal ( Developmental Type)
1. With type 1 Chiari malformations
2. With other obstructive lesion of foramen magnum
 Type 2 : Syringomyelia without obstruction of Foramen Magnum
( Idiopathic Developmental Type)
 Type 3: Syringomyelia with other diseases of spinal cord (
Acquired Types )
1. Spinal cord tumors ( usually intramedullary hemangioblastoma)
2. Traumatic myelopathy
3. Spinal Arachdnoitis and pachymeningitis.
4. Secondary myelomalacia from cord compression ( tumour , spondylosis ) ,
infarction , hematomyelia
 Type 4 : Pure hydromyelia ( developmental dilatation of the cental canal ) with
or without hydocephalus.

12. Types of dens dysplasia
 Type 1 (Os odontoideum) separate odontoid process
 Type 2 (Ossiculum terminale) failure of fusion of .
apical segment with its base
 Type 3 – Agenesis of odontoid base & apical segment . .
lies separately.
 Type 4 – Agenesis of odontoid apical segment
 Type 5 –Total agenesis of odontoid process.

14. Klippel- Feil Syndrome
• Type 1- Massive fusion of cervical and often
upper thoracic vertebra. Associated with short
neck, low hairline and restricted neck movements
• Type 2- associated with fusion of several cervical
vertebra
• Type 3 – associated with fusion of 2 cervical
vertebra.
Other associated anomalies:- Sprengel shoulder

27. Cervical canal stenosis in CV
anomalies
 Foramen Magnum: 25-30mm
 C1 25-30mm
 C2 20-25mm
 C3-C7 ≥ 14mm
 EDFM >19mm

30. Clinical manifestations of CV
anomalies
 Age
 Sex
 Familial occurrence
 Precipitating factors
 Onset

31. Presenting Features
A. Cervical symptoms and signs
B. Myelopathic Features- long tract involvement and
wasting
C. CN involvement- IX, X,XI,XII,V, AND rarely
VIII,VII
D. Cerebellar symptoms/signs- Nystagmus, Ataxia,
intention tremor, dysarthria
E. Transient Attack of V-B insufficiency
F. Features of Raised ICT- usually seen in Pts.
Having basilar impresssion and/or ACM

32. Importants Points to remember
1. Short neck, low hairline, restricted neck movements
are frequently seen in KF anomaly, Occipitalization,
and basilar invagination
2. Transient Attacks of VB insufficiency are usually
encountered in Pts. With A-A dislocation.
3. Several bony and soft tissue anomalies often co-exist
4. Neurological deficit is usually produced by A-A
dislocation, Basilar Invagination, ACM and
Syringomyelia / Syringobulbia

33. Arnold-Chiari Malformation
• Type 1- Cerebellomedullary malformation without
meningocoele with variable downward
displacement of cerebellar tonsils into spinal canal
• Type 2. Cerebello-medullary malformation with
meningocoele or meningomyelocoele along with
variable downward displacement of inferior vermis
of cerebellum, brainstem and IVth ventricle into
cervical canal

34. ACM - Diagnosis

35. ACM Diagnosis

37. Syringomyelia/ Syringobulbia
Progressive degenerative/ developmental disorder of the
spinal cord, characterized clinically by brachial
amyotrophy, suspended dissociative sensory loss, and
pathologically by cavitation in the central region of the
spinal cord. 90% cases associated with ACM type I.
Types I: Syrinx with obstn of the foramen magnum
Type II: Syrinx without obstn of the foramen magnum
Type III: Syrinx with other diseases of the spinal cord
Type IV: Pure hydromyelia
Syringobulbia: the lower brainstem equivalent of
syringomyelia, usually co-exists

38. Syringomyelia - pathological

39. Syringomyelia -clinical

40. Syringomyelia -Myelogram

41. Syringomyelia - MRI

42. Treatment of CV anomalies
1. Treatment of A-A dislocation
a) Conservative treatment- For patients having only
cervical symptoms or transient VB insufficiency
with or without mild neurological deficit maybe
initially managed conservatively using –
1. Cervical Collar
2. Head- Halter Traction- if there is associated
myelopathic features
b) Surgical Management

43. Treatment of Basilar Invagination
and ACM
A. Conservative management
B. Surgical treatment
A. Upper cervical laminectomy and enlargement of
Foramen Magnum

44. Treatment of CV anomalies

45. THANK YOU