2. Cervical Anatomy

Biomechanically Specialized
 Support of “large” Cranial mass
 Large range of motion
○ Flexion/extension
○ Axial rotation

Unique osteological characteristics

3. C1 - Atlas
No body
 2 articular pillars

 Flat articular surface
 Vertebral artery
foramen

2 arches
 Anterior
 Posterior
○ Vertebral artery groove

4. C2 Anatomy

Dens
 Embriological C1 body
 Base poorly vascularized
 Osteoporotic


Flat C1-2 joints
Vertebral artery
foramena
 Inferomedial to
superolateral

5. Anatomy – The Ligaments


Allow for the wide ROM of upper C-spine while
maintaining stability
Classified according to location with respect to
vertebral canal
 Internal:
○ Tectorial membrane
○ Cruciate ligament – including transverse ligament
○ Alar and apical ligaments
 External
○ Anterior and posterior atlanto-occipital membranes
○ Anterior and posterior atlanto-axial membranes
○ Articular capsules and ligamentum nuchae

6. AtlantoAxial Anatomy
Tectorial Membrane

7. AtlantoAxial Anatomy
Tranverse Ligament
occiput
C1-C2 joint
C1
C2
Alar Ligament

8. AtlantoAxial Anatomy
Facet for
Occipital
Condyle
Transverse
Ligament

9. AtlantoAxial Anatomy
Vertebral
Artery

10. APPROACH TO C-SPINE
INJURIES

Following trauma or complaint of neck pain
 Obtain lateral
 AP, and
 odontoid views
 The lateral view is only adequate if T1 can be
visualized

If there is any doubt of fracture or prevertebral
swelling , obtain oblique views and consider CT
All patients with sign/symptoms of cord injury require
MRI


11. Cervical Views
Odontoid
AP

12. Swimmer’s View

13. LATERAL VIEW





1. Anterior vertebral line (anterior
margin of vertebral bodies)
2. Posterior vertebral line
(posterior margin of vertebral
bodies)
3.Articular pillar (where superior
and inferior articular processes of
cervical vertebrae have fused on
either or both sides)
4. Spinolaminar line (posterior
margin of spinal canal)
5. Posterior spinous line (tips of
the spinous processes)

14. C1-C2

Predental space
(distance between posterior
aspect of anterior arch of C1
and anterior aspect of
odontoid process )

should be< 3mm In adult
and less <5mm in children
Or less
 ring sign of C2

15. C3-C7

Anterior spinal, posterior spinal and
spinolaminar lines: should be
smooth lines

Disc Spaces should be approximately same
anterior narrowing = flexion injury.
Widening = extension injury

Facet joints should be parallel
Interspinous distance should
decrease from C3 to C7
 Transverse process of C7 points downward and
T1 UPWARDS

INTERVERT
EBRAL
DISC
SPACE
S

16. 
Prevertebral Soft
Tissue

Nasopharyngeal space (C1) - 10
mm (adult)

Retropharyngeal spaceC 2-C4 (
between posterior pharyngeal wall
and anterior border of vertebrae).
10m
m

5mm
Retro tracheal space C5-7 (space
between posterior tracheal wall and
anterior inferior body C6 )
c3-4 5mm from vertebral body is normal
C4-7 20mm from vertebral body is normal
22mm

18. AP View

The height of the cervical
vertebral bodies should
be approximately equal

The height of each joint
space should be roughly
equal at all levels.

Spinous process should
be in midline and in good
alignment.

19. Odontoid View
An adequate film should include the
entire odontoid and the lateral
borders of C1-C2.
Occipital condyles should line up with
the lateral masses and superior
articular facet of C1.
The distance from the dens to the
lateral masses of C1 should be equal
bilaterally.
The tips of lateral mass of C1 should
line up with the lateral margins of the
superior articular facet of C2.
The odontoid should have
uninterrupted cortical margins
blending with the body of C2.

20. Classification of
Fractures of c-spine

HYPERFLEXION INJURIES







Hyper extention injuries






Hangman fracture
Extention teardrop fracture
laminar fracture
Pillar fracture
Posterior arch of c1 fracture
FRACTURE DUE TO AXIAL LOADING



Flexion teardrop fracture
Hyper flexion Strain
Wedge Compression fracture
Bilateral facet Lock
Unilateral facet dislocation
Clay-shoveler’s fracture
Jefferson fracture
Burst fracture
OTHER INJURIES


Odontoid fracture
Rotational Injuries

21. Hyperflexion
 Distraction creates
tensile forces in
posterior column
 Can result in
compression of
body (anterior
column)
 Most commonly
results from MVC
and falls

22. Compression
 Result from axial
loading
 Commonly from
diving, football,
MVA
 Injury pattern
depends on initial
head position
 May create burst,
wedge or
compression fx’s

23. Hyperextension
 Impaction of posterior
arches and facet
compression causing many
types of fx’s
○ lamina
○ spinous processes
○ pedicles
 With distraction get
disruption of ALL
 Evaluate carefully for
stability
 LOOK FOR CENTRAL
CORD SYNDROME

24. Types of Injuries

25. Flexion Teardrop Fracture C5-6
fracture is the result of a combination
of flexion and compression ,most commonly at C5-6
 The teardrop fragment comes from the
anteroinferior aspect of the vertebral body. The
larger posterior part of the vertebral body
is displaced backward into the spinal canal.

Best seen on lateral view
 It is an completely unstable fracture associated with
complete disruption of ligaments and anterior cord
syndrome and quadriplegia
 70% of patients have neurologic deficit.

common in MOTOR VECHICLE ACCIDENT


26. Signs:
Prevertebral swelling
associated with anterior
longitudinal ligament tear.
Teardrop fragment from
anterior vertebral body
avulsion fracture.
Posterior vertebral body
subluxation into the spinal
canal.
Spinal cord compression
from vertebral body
displacement.
Fracture of the spinous
process.

27. Fracture of
the spinous
process of
C4
Fracture of the body
of c5 with a small
fragment
anteriorly
Acute angulation at the level of C5C6
with displacement of C5 in posterior
direction

32. Wedge fracture
 Compression
fracture resulting from
flexion.
Flexion compression injury
 Best seen on lateral view
 Stable
 Common in
 Elderly patients
with osteoporosis or osteogenesis
imperfecta


34. Wedge shape
vertebra
Antersuperio
r body
fracture

35. Hangman’s Fracture C-2

Fx through the pars
interarticularis of C2
secondary to
hyperextension

Best seen on lateral
view
Hyperextention injury
Stable fracture ?



38. 

The most common scenario
would be
 frontal motor
vehicle(hitting dash
board)
 Hanging
 falls,
 diving injuries
 contact sports.
Neurological involvement is
rare

40. 
Classification of Hangman' s fractures

Type I (65%)
 hair-line fracture
 C2-3 disc normal
Type II (28%)
 displaced C2
 disrupted C2-3 disc
 ligamentous rupture with
instability
 C3 anterosuperior compression
fracture
Type III (7%)
 displaced C2
 C2-3 Bilateral interfacet dislocation
 Severe instability



41. TYPE 1 HANGMAN FRACTURE
There is a hair-line fracture and there is no displacement.
C23 NORMAL

42. 
HANGMAN FRACTURE
TYPE 3
Prevertebral soft
tissue swelling
Anterior
dislocation of the
C2 vertebral body
BILATRAL C2 pars
interarticularis
fractures.

43. 
The CT-images
confirm the
fracture-lines of
the hangman's
fracture.
They run
through the
pars
interarticularis
resulting in a
traumatic
spondylolysis.
In this case
there was no
neurologic
deficit, because
the spinal canal
is widened at
the level of the
fracture.

45. Extention tear drop fracture
AVULSION FRACTURE of anterio inferior content
of the axis resulting from hyperextention
 This injury is



stable in flexion
but highly unstable in extension.
common in diving accidents
 It also may be associated with the central cord
syndrome .


48. bony
fragment.
This fragment
is a true
avulsion, in
contrast to the
flexion teardrop
fracture in
which the
fragment is
produced by
compression of
the anterior
vertebral
aspect due to
hyperflexion.

49. Jefferson Fracture C-1
Fracture is caused by a compressive
downward force that is transmitted evenly
through the occipital condyles to the superior
articular surfaces of the lateral masses of C1.
This process displaces the masses laterally and
causes fractures of the anterior and posterior
arches, along with possible disruption of the
transverse ligament.
•
•
•
•
Best seen on odontoid view
Unstable fracture
Fracture due to AXIAL LOADING
frequently associated with
•
diving into shallow water(axial
•
•
blow to the vertex of the head )
impact against the roof of a vehicle
fall from playground equipments

50. SIGNS ON XRAY:
Displacement of the
lateral masses of
vertebrae C1 beyond the
margins of the body of
vertebra C2.
<2mm bilateral is always
abnormal
<1-2 mm or unilateral
displacement can be due
to head rotation

51. CT is required to
1. define the extent of fracture
2. detecting fragment in spinal cord

52. BURST FRACTURE C3-7






Same mechanism as jefferson fracture i.e axial compression
but
Located at c3-7
Stable fracture
The intervertebral disc is driven into the vertebral body below.
Posterior fragments dislocation common
Require ct for fracture evaluation and bone fragment in spinal
cord

55. Odontoid Fracture C2

Fracture of the odontoid (dens) of C2
 3 categories, I-III

Best seen on open-mouth odontoid view or lateral radiograph
result from blunt trauma to head leading to cervical hyperflexion or
hyperextension
Unstable fracture
Occur in both elderly and young patients
75% cases are children





56. Classification
Type I: Avulsion of the tip of
the dens where it is attached
to C1.
This is a rare fracture.
It is potentially stable.?
Type II: Through the base of
the dens.
Most common fracture.
Always unstable and poor
healing.
Type III: Fracture through the
body of the axis and
sometimes facets.
Can be unstable, but has a
better prognosis than type II
due to better healing of the
fracture which runs through
the metaphyseal body of C-2

57. Type 1 odontoid fracture

58. Type II

59. Type III

60. CT IMAGE

61. DENS
Dens

62. The image through the lateral part of C2 nicely shows, that the fracture runs
through the body of C2, i.e. a type III odontoid fracture.
The posterior dura is in a normal position, but the anterior dura is displaced
(arrow).

63. Showing Central location of spinal cord injury

64. Clay Shoveler’s Fracture
Oblique avulsion fracture of a spinous process C6-T1
 C7>C6>T1








Best seen on lateral view
Powerful Hyperflexion injury(shoveling)
Stable fracture
Common in
motor vehicle accidents
sudden muscle contraction
direct blows to the spine

66. Ap view show ghost sign with 2 spinous processes ???

67. Case 1
5 yo girl
 Hit by car while
riding bike
 VSA at scene
 Vitals recovered
by EMS

Rose et al, Am J Surg 2003;185(4)

68. Atlanto-Occipital Dislocation




2.5 x more common in
children than adults
Due to small occipital
condyles and horizontal
atlanto-occipital joints
Suspect if distance
between occipital
condyles and C1 is
> 5mm at any point
Usually have ++ soft
tissue swelling

69. OccipitoAtlantal Dissociation (OAD)
Commonly Fatal
Present 6-20% of post mortem studies
– Alker et al, 1978
– Bucholz & Burkhead,1979
– Adams et al, 1992
50% missed injury rate
1/3 Neurological Worsening
– Davis et al, 1993

70. OccipitoAtlantal Dissociation (OAD)
Symptoms/Findings
– Wallenberg Syndrome
Lower Cranial nerve deficits
Horner’s syndrome
Cerebellar ataxia
Cruciate paralysis
Contralateral loss of pain and
temperature

71. Radiographic Lines
Powers’ Ratio

BC/OA
 >1 considered abnormal



Limited Usefulness
Positive only in Anterior
Translational injuries
False Negative with pure
distraction
Powers et al, Neurosurg, 1979

72. QUESTIONS

73. REFERRENCES
Text Book of Radiology and imaging
(DAVID SUTTON)
 Primer of Diagnostic Imaging
 Radiology Review Manual(Dahnert)


74. Thank You!