Week 5 Flashcards
What were canadian C-spine rules developed for?
Used to rule in the need for a radiograph following cervical spine trauma
What does it mean when a person is negative on the cervical spine rule?
It is almost certain that they do not have a c-spine fracture. (High sensitivity)
What does it mean when a person is negative on the cervical spine rule?
It does not necessarily mean that they have a fracture, but that a x-ray is needed to further rule out a possible C-spine fracture
What are the standard x-ray views for a cervical spine?
- Lateral view (standard)
- AP view (standard)
- Oblique view (special)
- Odontoid view (special)
- Swimmer’s view (special)
What are the characteristics of the lateral view that is used in a x-ray of the C-spine?
- Initial view
- Evaluate alignment, spacing, soft tissues & vertebrae\
- Stress View
- Standard cervical view
What is the AP view in a x-ray of the C-spine used to see?
Alignment, oblique fractures. This is a standard cervical view
What are the characteristics of the oblique view that is used in a x-ray of the C-spine?
Done only after fracture or dislocation are ruled out – neural foraminal narrowing and alignment of facet joints. This is a special cervical view to compare IV foramina
What is the odontoid view in a x-ray of the C-spine used to see?
C1-C2 relationship (mouth open). This is a special cervical view to assess atlas and axis
What is the swimmer’s view in a x-ray of the C-spine used to see?
View of C7–T1. This is a special cervical view used when
shoulder superimposition obscures C7 on a lateral view
What is the patient position during an AP view of the C-spine?
• Patient standing or supine
• Chin extended slightly
• Central ray centered on
C4, angled 15-20° cephalad (toward the head)
What part of the spine does the AP projection of the c-spine allow visualization of?
• Lower 5 cervical vertebral bodies • Upper 2-3 thoracic vertebral bodies • Interpediculate spaces • Intervertebral disc spaces • Superimposed transverse processes and articular pillars • Spinous processes
What types of conditions can be seen in an AP projection of the c-spine?
- Fractures: vertebral bodies C3-C7
- IVD space abnormalities
- Uncovertebral joint abnormalities
What is the patient position during a lateral view of the C-spine?
- Patient sitting or standing
- Shoulders depressed
- Chin elevated slightly
- Central ray centered on C4
What part of the spine does the lateral projection of the c-spine allow visualization of?
• Cervical vertebral bodies and interspaces • Articular pillars • Lower 5 facet joints • Spinous processes • C7-T2 may be visualized with enough shoulder depression, but usually starts to get radioopaque
What types of conditions can be seen in a lateral projection of the c-spine?
- Occipito-cervical dislocation, esp in stress views when the person is in 60degs or more of flexion
- Fractures
- Unilateral and bilateral locked facets
- IVD space and Atlanto-odontoid space abnormalities
What types of fractures can be seen in a lateral projection of the c-spine?
- Anterior and posterior arches of C1
- Odontoid process
- Vertebral bodies of C2-7
- Spinous processes
- Hangman’s fracture
- Burst fracture
- Teardrop fracture
- Clay-shoveler’s fracture
- Compression fracture
What are the characteristics of the performance of Hyperflexion or Hyperextension during a lateral c-spine x-ray?
- NOT attempted until fracture ruled out
- Performed to demonstrate normal movement (or lack of) due to trauma or disease
- Becomes less diagnostic if someone can’t get to 60 degs of flexion
What is the patient position during an oblique view of the C-spine?
• Patient upright or supine • Patient’s body and head adjusted to a 45° angle • Elevate chin slightly • Central ray centered on C4, angled 15-20° cephalad
What part of the spine does the oblique projection of the c-spine allow visualization of?
• Intervertebral foramina
and pedicles farthest from
film (closest to the central ray)
• Vertebral bodies
What types of conditions can be seen in an oblique projection of the c-spine?
- Intervertebral (neural) foramina abnormalities
* Apophysial joint abnormalities
What is the patient position during an odontoid/open mouth view of the C-spine?
• Patient supine • Patient opens mouth as wide as possible • Central ray centered on the midpoint of the open mouth
What part of the spine does the odontoid/open mouth projection of the c-spine allow visualization of?
- Atlas and axis through the open mouth
- C1-2 interspace
- Dens of C2 (primary target)
- Occipital base
- Occlusal surface of teeth
- Mandibular ramus
- Lateral mass of atlas
- Inferior articular process of atlas
- Spinous process
What types of conditions can be seen in an odontoid/open mouth projection of the c-spine?
• Fractures including: - Lateral masses of C1 - Odontoid process - Vertebral body of C2 - Jefferson fracture • Atlantoaxial joint abnormalities
What is the patient position during a swimmer’s view of the C-spine?
• Arm closest to film extended overhead
• Patient can rest head on arm in sidelying position
• Depress shoulder closest to central ray as much as possible
• Central ray centered on C7-T1
interspace
What part of the spine does the swimmer’s projection of the c-spine allow visualization of?
Lateral projection of the cervicothoracic vertebrae (C7-T2) between the shoulders
What types of conditions can be seen in a swimmer’s projection of the c-spine?
Fractures of C7, T1, and T2
What are the structures seen in the AP view of the c-spine?
- Uncus
- Spinous process
- Body
- Pedical
- Transverse process
- Superior articular process
- Inferior articular process
- Facet joint
- Transverse process T1
- 1st rib
What are the structures seen in the lateral view of the c-spine?
- Anterior arch C1
- Dens of C2
- Posterior arch C1
- Spinous process C2
- Vertebral body C3
- Intervertebral disc
space C3-4 - Lamina C5
- Articular pillar C6
What are the structures seen in the oblique view of the c-spine?
- Posterior arch C1
- Lamina C2
- Pedicle C4
- Intervertebral foramen C4-5
- Inferior articular process C5
- Vertebral body C6
- Superior articular process C7
What are the structures seen in the odontoid/open mouth view of the c-spine?
- Dens of C2
- Lateral mass C1
- Inferior articular facet C1
- Superior articular facet C2
- Lateral C1-C2 joint
- Spinous process C2
- Teeth
What are the structures seen in the swimmer’s view of the c-spine?
- Right humerus
- Right clavicle
- Left clavicle
- Left humerus
- Body C7
What are the things that should be seen/done on an x-ray in order to determine whether or not it is normal?
- Count the vertebrae
- Alignment of the ALL, PLL, posterior spinal canal and spinous processes on AP and lateral views
- All 7 vertebral bodies and C7-T1 joint space should be seen
What more than anything will key you into degenerative changes in the c-spine?
• Vertebral body irregularity looking at possible: - compression fracture - Schmoral nodes - osteoporosis - osteophytes • Disk space
What is the chamberlain line?
A line that we look at in terms of looking for alignment in the upper c-spine and is the line between the posterior margin
of the hard palate and the posterior aspect of the foramen
magnum.
True or False
The Odontoid process should not project above the chamberlain line for > 3mm
True, The Odontoid process should not project above the chamberlain line for > 3mm
What does it mean when the odontoid is >7 mm above the chamberlain line?
Indicative of cranial setting, which is often associated it neurologic issues
What are the common causes of the odontoid being >7 mm above the chamberlain line?
Bone softening diseases such as Paget’s, osteomalacia, and RA
What is McGregor’s Line?
A line associated with the upper c-spine and is drawn from the
posterosuperior margin of the hard palate to the most inferior surface of the occipital bone.
True or false
The Odontoid process should not project above the McGregor’s line for > 3mm
False, The Odontoid process should not project above the McGregor’s line for > 4.5mm
When does cranial setting exist when looking at the McGregor’s line?
Cranial setting exists if the apex of the dens is > 8mm above this line in males or >10mm in females
What is the Anterior Atlantodental Interval (AADI)?
On lateral views, measure the distance between the posterior margin of the anterior tubercle and the anterior surface of the dens.
What is indicative of instability when looking at the Anterior Atlantodental Interval (AADI)?
Distance >2.5mm difference is indicative of instability
Why are flexion and extension lateral views needed when visualizing the Anterior Atlantodental Interval (AADI)?
To see how dynamic the instability might be, because radiographs in neutral may miss 48% of cases of anterior atlantoaxial subluxation, and extension view may reduce
subluxation.
What is the most frequent cause of an increase in the Anterior Atlantodental Interval (AADI)?
Most frequent causes of increase AADI include trauma, Down syndrome, AS, RA,
psoriatic arthritis, and Reiter syndrome.
What are the factors for the elevated risk of instability?
• Trauma Patient with connective tissue disorders such as: • RA • Down’s Syndrome • Ankylosing Spondylitis • Os Odontoideum • Klippel-Feil Syndrome • Morquios Syndrome • Ehler-Danlos (Type 3) • Marfans Syndrome • Post-fusion
What are the clinical indicators of a cervical subluxation?
• Neck pain most common complaint • Feeling o head falling forward with flexion • Occipital headaches • Ear & facial pain • Weakness • Loss of endurance • Loss of dexterity • Parasthesias • Ataxia • Tinnitus/ringing of the ears • Vertigo • Visual disturbances • Dysphagia
What are the physical examination findings that are indicative of a cervical subluxation?
- Lhermitte’s sign
- Modified Sharp-Purser test
- Tone changes
- Gait disturbances
- UMN signs like hoffmans or babinski
What is a george line?
A smooth curve found on the lateral view, which connects the
posterior vertebral bodies
What are the characteristics of the george line?
• There should be a smooth curve. • Flexion & extension views my be useful for appreciating disruption. • Anterolisthesis(slipping forward of a vertebral body) or retrolisthesis (slipping backward of a vertebral body) may be evidence of instability due to fracture, dislocation, ligamentous laxity, or DJD
What is the cervical gravity line?
A vertical line drawn from
the apex of the dens, which should pass through the 7th cervical body.
What is the function of the cervical gravity line?
Allows gross assessment of where the gravitational stresses are acting at the cervicothoracic junction.
What is a prevertebral soft tissue?
A measure of the soft tissue in front of the vertebral bodies and behind the air shadow of the pharynx, larynx, and trachea
What is the measurement of the prevertebral soft tissue from C2-4?
Distance should not be >
7mm in the neutral position
What is the measurement of the prevertebral soft tissue from C5-7?
This distance should not be >
20mm.
What causes an increase in the prevertebral soft tissue?
Any soft tissue mass, post-traumatic hematoma, or neoplasm from adjacent structures will cause an increase.
What does a whiplash injury result in?
Results in sprain or intervertebral disc injury without fracture or dislocation
What is the typical radiographic appearance of a whiplash injury?
Straightening of the cervical spine due to severe muscle spasm, with the normal curvature reduced or reversed. Some anterolisthesis can be seen in the middle c-spine, but mostly shows the loss of lordosis
What are the most common sites of spinal fractures?
C1-C2, C5-C7 and T9-L2.
What is the cause of most spinal fractures?
Trauma due to:
• MVA – 50%
• Falls – 25%
• Sports injuries – 10%
What are the indications for imaging a spinal trauma?
Canadian C-spine rules.
If a head CT is indicated, when should it be performed?
C-spine CT also done at the
same time of an image.
What are the radiographic signs of instability?
• Displacement of vertebrae
• Widening of interspinous or interlaminar spaces
• Widening of facet joints
• Widening and elongation of the vertebral canal (seen
by a widening of interpedicular distances)
• Disruption of posterior vertebral line
What is a jefferson fx?
Burst fx of C1.
What is an Odontoid fx?
Fx of odontoid process of C2
What is a hangman’s fx?
Fx of posterior aspects of C2
What is a teardrop fx?
Avulsion of anterior vertebral
body with posterior subluxation
What is a clay-shoveler’s fx?
Fx of the spinous process
of either C6, C7, T1 or T2.
What is the usual MOI of a jefferson fx?
Blow to vertex of head
What happens in a jefferson fx?
Axial load transmitted through the cranium and occipital condyles into the atlas drives lateral masses of atlas outward
What does a jefferson fx result in?
Bilateral, symmetrical fractures of the anterior and posterior arches of C1 and disruption of
transverse ligaments
What is the MOI of an Odontoid Process Fracture?
Typically hyperflexion injuries or a congenital abnormality. Usually a high impact injury in younger people and is usually associated with low energy falls in adults
What is the usual direction of an Odontoid Process Fracture?
Odontoid process is usually displaced anteriorly, with associated forward subluxation of C1 or C2
What is an odontoid fracture classification based on?
Stability
What is a type 1 odontoid fracture classification?
A fx of upper part of
odontoid. It is a stable fx
What is a type 2 odontoid fracture classification?
A transverse fx through
the odontoid base, regardless of whether or not the tranverse ligament is intact. It is an unstable fx
What is a type 3 odontoid fracture classification?
A fx through the odontoid
base and extending into
body of axis. It is a stable fx
What is the MOI of a hangman’s fracture?
• Hanging described as a hyperextension and distraction
injury
• Hyperextension (face striking windshield during MVA) is
more common mechanism
What happens in a hangman’s fx?
Bilateral fractures through the pedicles of C2, with anterior dislocation / subluxation of the C2 body over C3. It is often with spinal cord compromise/tearing
What is a type 1 hangman’s fracture classification?
Fx through C2 pedicle,
extend between superior and inferior facets
What is a type 2 hangman’s fracture classification?
Type I fracture with concomitant disruption of C2-3 IVD
What is a type 3 hangman’s fracture classification?
Type II injury with C2-3 dislocation, usually in an anterior direction
___ is the most severe and most unstable cervical injury
A teardrop fx is the most severe and most unstable cervical injury
What causes odontoid process fxs?
Lower c-spine stiffness and osteoporotic changes in the upper c-spine, including missing trabeculae or thinning of the cortical bone
What is a teardrop fx?
A posterior displacement of the involved vertebra into the spinal canal, fracture of posterior elements, and disruption of soft tissues (ALL, PLL, ligamentum
flavum, etc.)
What happens in a teardrop fx?
As ALL tears, it avulses from the anterior vertebral body (leaves a small triangular “teardrop-shaped” fragment) and displaces anteriorly and inferiorly
What is the MOI of a Clay-Shoveler’s fx?
• Initially described as an acute powerful flexion injury, as
produced by shoveling in Australian clayminers
• Direct blow or indirect trauma from MVA may produce similar injury (hyperflexion)
What are the characteristics of a Clay-Shoveler’s fx?
- Fracture of posterior spinous process.
- Stable fx as posterior ligaments remain intact
- Occurs at C6, C7, T1 or T2.
What is the psychometrics of a CT of the c-spine?
Highly sensitive and fairly specific
___ may be indicated in instances where a fx is suspected, but is not seen on a x-ray
CT scan may be indicated in instances where a fx is suspected, but is not seen on a x-ray
___ are common areas in which degenerative changes occur – appear by age 30-40.
C4 – C7 are common areas in which degenerative changes occur – appear by age 30-40.
What are the signs of degenerative changes in the c-spine?
Decreased disk space, sclerosis and spurring of the
margins of the vertebral bodies
In patients with arm pain, an ___ plain film can often show narrowing of the foramina
In patients with arm pain, an oblique plain film can
often show narrowing of the foramina
A ___ is indicated for evaluation of a suspected herniated disk or neuological deficit.
A MRI is indicated for evaluation of a suspected herniated disk or neuological deficit.
How much bony destruction has to occur before metastatic lesions can be seen on a x-ray?
Upwards of 70-80%
True or False
Radiographs are highly specific, but not sensitive for metastatic lesions of the spine
True, Radiographs are highly specific, but not sensitive for metastatic lesions of the spine
What are the characteristics of metastatic lesions and radiographs?
- Low signal intensity relative to marrow signal.
- C3 lesion causing compression of the cord.
- Presented with rapidly worsening weakness of arms and legs.
What is normal on a T1 weighted MRI of the c-spine?
- High signal bodies
- Low signal cortical bone
- Intervertebral disks are well visualized
- Spinal cord with dark or low intensity
- CSF
What is normal on a T2 weighted MRI of the c-spine?
• Low signal bodies • Low signal cortical bone • Intervertebral disks appear with a lower signal • Spinal cord is a shade of grey • CSF is bright white
What does a decrease hydration & proteoglycan content, increased collagen & fibrosis appear like when looking at a MRI?
Decreased T2 signal and disk height.
What does annular tears appear like when looking at a MRI?
Focal increase T2 and diffuse disk bulge
What does a nuclear herniation thru annular tears appear like when looking at a MRI?
Focal disk contour abnormalities.
What does a nitrogen-filled nuclear clefts (vacuum disk) appear like when looking at a MRI?
Horizontal signal void T1 & T2. May fill with fluid (increase T2) when supine or flexed.