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C- Spine
Adult vs Pediatric
Caroline Kowal
C – spine views
•
•
•
•
•
AP
Lateral
Odontoid
Swimmers: lower C - spine
Oblique: posterior structures of vertebral
column (e.g. intervertebral foramen and
articular facet joints. R/O facet dislocation)
• Lateral flexion/extension: exclude
ligamentous injury and potential instability
ABC’s
• A – adequacy/alignment
– Vertebral curves on lateral view
– Dens equidistant from lateral masses of C1
• Facets of C1/C2 should align
– AP – spinous processes should align
• B – bones
• Boney deformity or # lines
– Ant/post height nearly equal
– Pedicles, facets, spinous processes
ABC’s
Pediatric Emerg Med Reports 1996;1:83.
• C – Cartilage
– Disc spaces (symmetrical and similar)
• S – Soft Tissue
– Lateral view can tell you about occult fracture and
rupture of transverse ligament
– Predental space < 3mm (< 5 mm if <8 y.o.)
– Prevertebral space at C3 < 5mm (< 7 mm kids or
<1/3 width vertebral body)
– Prevertebral space at C7 < 22mm (<14mm C6)
• Lateral view to r/o
retropharyngeal
abcess
• If true prevertebral
swelling, increased
space will persist
despite neck
positioning
• No “step off” at C4
Optimal if pt neck extended (and x ray taken at END
inspiration – less false +).
Subglottic narrowing
• Normally a "step-off"
between the posterior
wall of the pharynx
and the posterior wall
of the trachea at the
level of the larynx
(approximately at the
level of C4).
Retropharngeal Abcess
• Air-soft tissue interface is
indistinct
• Contour of prevertebral
soft tissues should follow
anterior vertebrae
• Retropharyngeal
abscesses are the 2nd
most common deep neck
infections in children (first
is peritonsillar abscesses
which account for up to
50% of the deep neck
infections)
Neck alignment
• Normally positioned with lordosis
(extension).
• In adults, a straight C-spine (lack of lordosis)
indicates the presence of muscle spasm and
a possible occult fracture.
• In children, the absence of lordosis is
commonly seen.
• When on a spine board, the large occiput of
most children positions their neck in a
straight positoin.
– This is common and does not necessarily
indicate the presence of a significant injury.
Nexus Criteria
• According to NEXUS low-risk criteria,
cervical spine radiography is indicated for trauma
patients unless they exhibit all of the following
criteria:
• 1. No posterior midline cervical tenderness
• 2. No evidence of intoxication (EtoH, ataxia,
dysmetria, cerebellar findings)
• 3. Normal level of alertness (GSC >14, A&O x3)
• 4. No focal neurologic deficit
• 5. No painful distracting injuries – long bone #, burn,
degloving injury
Canadian C – Spine Criteria
• GCS 15
• High risk factors?
– >65 years age
– Dangerous mechanism
– Paresthesias in extremities
• Dangerous mechanism
– Fall >1 m or 5 stairs, axial load, MVC >100km/h, rollover or
ejection, bike collision
• Low risk factors?
– Simple rear end MVC, sitting position in ED, ambulatory at
any time, delayed onset neck pain, no midline tenderness
– If have low risk criteria and no high risk and can rotate neck
45 degrees with no pain – NO RADIOGRAPHS.
Anatomy Review
• 7 cervical vertebra C1 – C7
– C1, C2, and occiput are called the cervicocranium
– C1 and C2 are atypical vertebrae
– As many as 80-90% of cervical spine injuries can be
detected on the lateral view alone.
• Neural arch ( pedicles, laminae,spinous process,
articular processes and facets, and transverse
processes)
–
–
–
–
structures dorsal to the vertebral body
protect the spinal cord
attachment sites for ligaments and muscles
forms synovial joints that facilitate movement of the
vertebral column.
Ligaments
SP - spinous process
L - lamina (forms roof of
the neural arch)
P - pedicle (forms
supports of the neural
arch)
SC - spinal canal
VB - vertebral body
SAF - superior articular
facet
IAF - inferior articular
facet
TF - transverse foramen
Gr - groove for spinal
nerve (transverse
process)
U - uncinate process
Child vs. Teen Lateral View
Lateral film, the body is a rhomboid with the posterior portion slightly taller
than the anterior portion
Cervical Lines
•
•
•
•
Anterior longitudnal line
Posterior longitudnal line
Posterior facet margins
Spinolaminal line
– anterior border with the laminae
– Posterior limits of spinal canal
F - facet
joint
SP - spinous
process
L - lamina
Od odontoid
AP View
On an AP view, the lateral superior edges of the body form
bilateral ridges, called the uncinate processes (U).
Fractures to the Unicate
• Axial compression
• Strong lateral force with shearing
• Hyperflexion or hyperextension
– Teardrop # to lateral vertebral bodies
Spinous Process
• Spinous processes of C3 through C6 are typically bifid at the
tips
• C7 is an easily visible surface landmark
– vertebra prominens
• Muscles attached
– trapezius, the levator scapularis, and the rhomboids
– Excessive load on these muscles may result in avulsion of
the spinous processes of C6 and C7, commonly known as
the clay shoveller's fracture
Clay Shoveller’s Fracture
Odontoid Views
• To examine C1 – C2 complex
– R/O fracture dens (ruptured transverse
ligament)
– Dens should be equidistant from lateral
masses of C1
– Facets of C1 and C2 should align evenly
– Sum of overhang of both sides should not be
>7 mm
Odontiod View
3 Types Odontoid Fractures
• Type I is an oblique fracture through the
upper portion of the odontoid.
– The upper incisors can obscure portions of the
upper odontoid and simulate a Type I fracture.
• Type II fractures occur at the base of the
odontoid where it joins the body of C2.
– This is the most common odontoid fracture.
Unfortunately, this is also the location of the
subdental synchondrosis.
• A Type III odontoid fracture extends into the
vertebral body of C2
What type of odontoid # is this?
Type 2 most common
and most
therapeutically
challenging. In
children the fracture
breaks through the
cartilage plate and
heals spontaneously.
Inadults due to
disruption of blood
supply, it may require
surgery to heal.
Type 1 and 3 generally heal spontaneously but in
type 3 the prognosis is worse if the fracture extends
into the articular facets.
Type II Dens Fracture
Subdental Synchondrosis
• The most common normal radiographic
pattern mistaken for an odontoid fracture.
• A linear lucency at the base of the dens.
• The dens usually fuses with the body of
C2 between 3 and 6 years.
– A thin, sclerotic "scar" of the synchondrosis
may be appreciable on the lateral view for
many years thereafter.
CT image of a burst # of C1.
Usually occurs with axial
compression.
C1 vulnerable to burst
fractures because it is a ring
of bone (no vertebral body).
Horizontal Arrow indicates a
growth plate.
Child’s odontoid
• The odontoid of children may have a
separate ossification center at the tip of
the odontoid--the os terminale.
• A finding of a fragment at the superiormost tip of the odontoid may be due to a
fracture or it may a normal ossification
pattern.
Craniocervical Junction
• First, extension of a line down the slope of
the clivus should point to the superior end of
the dens (the os terminale).
• The posterior margin of the foramen
magnum should be in line with the
spinolaminar line.
• Such an alignment places the foramen
magnum in-line with the spinal canal, this
corresponds to the junction of the brain stem
and the spinal cord.
Extension of a
line down the
slope of the
clivus should
point to the
superior end of
the dens (the os
terminale).
Hangman’s Fracture
The hangman's
fracture is an unstable
fracture of the C2
pedicles, with forward
displacement of C1 and
the body of C2 on C3.
This traumatic
spondylolisthesis of C2
is the result of
hyperextension of the
head relative to the
neck.
Hangman’s Fracture
• The upper portion of the cervical spine (skull, C1,
C2) separates from the lower cervical spine.
• Hyperextension will initially cause fracture of the C2
neural arch (pedicles) and disruption of the anterior
ligaments.
• The return to neutral position will cause the body of
C2 to become anteriorly displaced over C3.
• In a hangman's fracture, the anterior and posterior
cervical lines will usually be abnormal because of
the anterior displacement of C2 on C3.
• Spinolaminal line can be normal.
Subluxation vs. Pseudosubluxation
• Developmental variants of the cervical
spine in young children
– Make reading x – ray more difficult
– In a patient with a hangman's fracture,
when the fracture of the neural arch
(pedicle) of C2 is not visible on the lateral
neck view (an uncommon occurrence), the
only evidence of the fracture may be
modest malalignment of C2-C3.
Pseudosubluxation vs. Hangman’s
#
• 1.Mechanism inj in pseudosubluxation is generally more
benign.
– A hangman's fracture is typically an
acceleration/deceleration mechanism (motor vehicle crash)
or a hanging mechanism.
• 2. A pseudosubluxation is ONLY seen on lateral neck
radiograph views that are positioned without lordosis (i.e., in
flexion, or neutral).
– If C2-C3 malalignment is noted on a lateral neck radiograph
with good lordotic (extension) positioning, this is probably a
TRUE subluxation (a hangman's fracture), and NOT a
pseudosubluxation.
• 3. A visible fracture of the neural arch is usually evident on the
lateral neck view in a hangman's fracture. The absence of a
visible fracture does not rule out a hangman's fracture since it
may be difficult to visualize radiographically at times.
Swischuk line
Anterior aspect of
the posterior arch of
C1 to the anterior
aspect of the
posterior arch of C3.
The anterior aspect of
the posterior arch of
C2 should be within
1-2 mm of this line. If
it is deviated > 2 mm,
this is indicative of a
true subluxation.
Hangman’s # - N line
Normal pt – head in flexion
with pseudosubluxation
If it is deviated < 2
mm, it is consistent
with a
pseudosubluxation,
(this alone is
insufficient to r/o a
hangman's fracture.)
Case
• A 7-year-old male was diving off a ledge
when he landed head first in shallow
water. He was pulled semiconscious from
the water by lifeguards. While maintaining
his airway, the lifeguards placed the
patient in full C-spine immobilization.
When the patient became more alert, he
complained of pain to his upper neck
region. Paramedics transported the patient
to the ED.
Jefferson’s fracture
• Lateral displacement of one or both of the
atlantal lateral masses (black arrow) is
suggestive of a Jefferson fracture in which the
ring of C1 is fractured, bursting it open
displacing the lateral masses outward.
What is the matter?
Lateral masses displaced!
The lateral masses of C1 are displaced outward, indicating a "bursting" of
the ring of C1 (the Jefferson Fracture).
Normal odontoid views
Jefferson Fracture
• Compression and/or bursting fracture of
C1.
– Unstable fracture secondary to axial
compression load,
• Fall or strike on head.
• Neurologic injury is rare but can occur if there is
involvement of C2.
• Axial load on C1 lateral masses, causes them to
be compressed against the superior articular
facets of C2
Lateral Jeffersons Fracture
Anterior displacement of C1 on C2
• In the most classic cases, the damage to C1 usually
occurs in four places, with fractures in two sites
anteriorly and two sites posteriorly.
• When C1 is fractured in less than four places,
transverse ligament tears are common and can lead
to more instability.
• If the transverse ligament is ruptured, C1 will move
forward on C2, and the spinal cord will be
compressed.
• 1/3 of Jefferson fractures are associated with other
cervical spine fractures, with C2 associated
fractures being the most common.
Practice radiographs . . .
Summary
• Do your C-spine ABC’s
• C1 Fracture – Jefferson’s burst fracture
• C2 Fracture – Hangman’s
– Don’t forget about pseudosubluxation!
• Increased prevertebral space
(retropharyngeal abcess or soft tissue
swelling). Predental <3 or < 5 if under 8, C3
<5 or <7 kids, C7 <22 (<14 at C6 in kids)
• Clivus and Swischuk line
References
•
•
•
•
http://www.hawaii.edu/medicine/pediatrics/pemxray/v5c03.html
Pediatric Emerg Med Reports 1996;1:83.
Lecrture Notes Terry O’Brien (NYGH Emergency Medicine conference 2002)
Perry, Clayton. Handbook of Fractures. McGraw Hill, 2000.