Cervical Spine Flashcards
What is the structure of the Atlas - C1?
Has no vertebral body
Lateral masses
Superior facet
Inferior facet
Transverse processes
Transverse foramen
Anterior arch & tubercle
Posterior arch & tubercle
What is the function of Atlas - C1?
Function
Supports the skull
Articulates with the anterior facet of C2, t he occipital condyles and the superior facets of C2
What is the structure of Axis - C2?
Dens
Average height is 18mm in males and 17mm in females
Articulates with posterior portion of anterior arch of atlas
Apical and Alar ligaments
Large pedicles and lamina
TVP’s very small
Foramen transmit vertebral artery
SP large, irregular and bifid
Lower lip-like projection from anterior inferior body
Strongest cervical vertebra
What size are vertebral bodies in the Cervical spine?
small
What shape are vertebral foramen in the cervical spine?
Triangular Shaped
What are the transverse processes of the cervical spine like?
Have holes called transverse foramina (passage to vertebral artery, vein and sympathetic nerves.)
What are the spinous processes of the cervical spine?
Bifid Processes (excluding C1)
How do the articular processes of the cervical spine articulate?
Articulate in oblique planes that slope downward laterally and posteriorly
What are clinical indications of the cervical spine?
trauma
infection
atypical pain
limb pain
osteoporosis
degenerative changes
Canadian C-Spine Rule
What are the Canadian C-Spine Rules?
The Canadian C-spine rule is a well-validated decision rule that can be used to safely rule out cervical spine injury (CSI) in alert, stable trauma patients without the need to obtain radiographic images
When do you use the Canadian C-Spine Rules?
When to use?
Alert and stable trauma patients with neck pain
Not applicable:
non-trauma cases, if the patient has unstable vital signs, acute paralysis, known vertebral disease or previous history of Cervical Spine surgery and age <16 years.
What are the routine projections of the cervical spine?
AP
Lateral
Odontoid/Peg view
What is deemed as an adequate image in an AP cervical spine?
Adequate image:
Cervical spine IVD spaces open
SPs in the midline, equidistant to the pedicles = no rotation
Visualise C3-C7 clearly
No artifacts
15° cephalad tube tilt
What is deemed as an adequate image of the lateral cervical spine?
Adequacy:
Clear visualisation of C1 to T1 (T1 minimum)
VBs are superimposed laterally
Articular pillars and zygapophyseal joints (facet) superimposed
Left side is placed up against the IR = LEFT LATERAL
Right side is placed up against the IR = RIGHT LATERAL
What is deemed as an adequate image for an Odontoid/peg view of cervical spine x-ray?
Adequacy:
Patient is instructed to open their mouth as wide as possible
Dens free from superimposition of the adjacent atlas lateral masses or other tissues
Zygapophyseal jointspace between C1 and C2 is symmetrical
What is the focus of the odontoid/peg view cervical spine x-ray?
Odontoid process of C2, useful when looking forodontoidandJefferson fractures.
What are the additional projections of the cervical spine?
Cervical Obliques
Anterior (LAO/RAO)
Posterior (LPO/RPO)
Cervicothoracic View (Swimmer’s)
Cervical Lateral Flexion/Extension
What is the setup for a cervical - anterior oblique RAO/LAO?
Anterior Oblique RAO/LAO
Patient in LAO (Left anterior oblique) Position
Anatomical marker placed on side closest to the IR
Shows “same side” intervertebral foramen
a left anterior oblique is being performed, therefore the left IVF will be shown.
Marker behind the spine = Anterior Oblique
What is the setup for a cervical - posterior oblique RPO/LPO?
Posterior Oblique RPO/LPO
Patient in RPO (Right Posterior oblique) Position
Anatomical marker placed on side closest to the IR
Shows “opposite side” intervertebral foramen
a right posterior oblique is being performed, therefore the left IVF will be shown.
Marker in front of spine = Posterior Oblique
Where will the L marker be on a LAO Cervical?
Behind the spine
Anterior Obliques show same side structures (IVF)
Where will the R marker be on a RPO Cervical?
Right Marker IN FRONT of spine
RPO
Posterior Obliques show opposite side structures (IVF)
What is the Cervicothoracic View (Swimmer’s)?
Modified lateral projection of the cervical spine to visualise the C7/T1 junction.
CT has replaced this projection (some areas don’t have CT readily available
What is the Cervical lateral/Extension adequacy?
Clear visualization of C1 to T1
Image should be labelled as ‘flexion’ or ‘extension’
flexion images = well separated SPs
extension images = “crowding” of the SPs
assess for spinal stability
NOT FOR TRAUMA!
What are the lines of measurement for the cervical spine?
Chamberlain’s Line
McGregor’s Line
McRae’s Line
Spinal Alignment Lines
Sagittal Canal Measurement
Atlantodental Interspace/interval
Cervical Pre-vertebral Soft tissue Spaces
What is Chamberlain’s line?
Line of measurement
Lateral skull/cervical radiographs
Recognise Basilar Impression tip of dens is >3mm above line
What is McGregor’s line?
Line of measurement
Used when the opisthion is not identified on plain radiographs
If the tip of the dens lies more than 4.5 mm above basilar impression
What is McRae’s Line?
Anterior and posterior margins of the foramen magnum(basionto opisthion)
Normal = The tip of the odontoid process/dens about 5 mm below this line
Basilar impression = tip crosses this line
What is Basilar Impression?
Congenital or acquired cranio-cervical junction abnormality where the tip of the odontoid process projects above the foramen magnum
Congenital causes include:
Osteogenesis Imperfecta
Klippel-Feil syndrome
Achondroplasia
Chiari I malformation/Chiari II malformation
Cleidocranial Dysostosis
Schwartz-Jampel Syndrome
Acquired causes include:
Rheumatoid Arthritis
Paget Disease
Hyperparathyroidism
Osteomalacia/Rickets
The terms basilar invagination and basilar impression are often used interchangeably because in both cases there is upwards migration of the upper cervical spine, but they are not synonyms.
Basilar invaginationis defined as the congenital upward displacement of vertebral elements into a normal foramen magnum with normal bone.
Basilar impressionis a similar upward displacement of the dens due to, however, acquired softening of bones at thebase of skull.
Can be identified using 5 lines of assessment:
Digastric Line
Bimastoid Line
Chamberlain Line
McGregor Line
McRae Line
What is Basilar Impression?
Congenital or acquired cranio-cervical junction abnormality where the tip of the odontoid process projects above the foramen magnum
Congenital causes include:
Osteogenesis Imperfecta
Klippel-Feil syndrome
Achondroplasia
Chiari I malformation/Chiari II malformation
Cleidocranial Dysostosis
Schwartz-Jampel Syndrome
Acquired causes include:
Rheumatoid Arthritis
Paget Disease
Hyperparathyroidism
Osteomalacia/Rickets
The terms basilar invagination and basilar impression are often used interchangeably because in both cases there is upwards migration of the upper cervical spine, but they are not synonyms.
Basilar invaginationis defined as the congenital upward displacement of vertebral elements into a normal foramen magnum with normal bone.
Basilar impressionis a similar upward displacement of the dens due to, however, acquired softening of bones at thebase of skull.
Can be identified using 5 lines of assessment:
Digastric Line
Bimastoid Line
Chamberlain Line
McGregor Line
McRae Line
What are the spinal alignment lines?
Four parallel lines :
Anterior Vertebral Line: anterior margin of the vertebral bodies
Posterior Vertebral Line: posterior margin of the vertebral bodies
Spinolaminar Line: posterior margin of the spinal canal
Posterior Spinous Line: tips of the spinous processes
Slightly lordotic curve, smooth and without step-offs
Any malalignment evidence of bony or ligamentous injury
What is the Sagittal Canal Measurement (Cervical)?>
posterior border of the mid-vertebral body nearest surface of the same spinolaminar junction
Increased distance spinal cord neoplasm
Narrowed distance stenosis
What is the Atlantodental Interspace/Interval?
used in the diagnosis ofatlanto-occipital dissociation injuriesand injuries of the atlas and axis”
Distance between Posterior Cortex of the anterior arch C1 and Anterior cortex of Dens
Normal:
Adults = <3mm
Children = <2mm
What are the Cervical Pre-vertebral Soft tissue Spaces?
Increase may be seen with post traumatic haematoma, retropharyngeal abscess, or neoplasm from adjacent bone or ST
Retropharyngeal Soft Tissue Space
Anterior to the lower border of C2 posterior to the adjacent pharyngeal air shadow
no greater than 7 mm.
Retrotracheal Soft Tissue Space
Anterior to the lower border of C6 to the posterior border of the adjacent tracheal air shadow.
Adult <22mm
Child <14mm
What are the Anatomical variants, congenital and acquired abnormalities of the cervical spine?
Agenesis of Posterior Arch of C1
Accessory Ossicles
Stylohyoid Ligament Calcification
Congenital Block Vertebrae
Cervical Rib
Arcuate Foramen
Nuchal Bone
Occipital Spur
What is Agenesis of Posterior Arch of C1?
What is it?
“Agenesis = Failure of organ/structure to develop in embryonic growth”
Rare (well document as incidental finding)
What causes them?
Congenital
Currarino classification – types A to E; subtypes 1 to 5
How are they diagnosed?
X-ray : ranges from clefts to complete absence of the posterior arch – radiolucent area in the region of the posterior arch
Clinical significance:
Usually asymptomatic
can present with neurological deficits from structural instability
atlantoaxial instability can occur
CONTRAINDICATION FOR CERVIAL MANIPULATION
What is the Accessory Ossicle - Anterior Arch of Atlas?
What is it?
Secondary ossification centre located at the inferior aspect of the anterior arch of the atlas
What causes them?
unfused ossification centres
congenital or from previous trauma
How are they diagnosed?
X-ray : circular and corticated osseous density that articulates with the inferior aspect of the anterior arch of the atlas
Clinical significance:
Asymptomatic
Can sometimes be mistaken for avulsion #
What is the Accessory Ossicle - Os Odontoideum?
What is it?
Secondary ossification centre located at the dens of C2
What causes them?
Unfused ossification centre of the dens (congenital)
unrecognised fracture through the dens growth plate < 5-6years
How are they diagnosed?
X-ray : smooth, well-corticated ossicle at the superior aspect of a hypoplastic dens; about ½ the size of a normal dens; associated with hypertrophied and rounded anterior arch of theatlas
Clinical significance:
abnormal mobility of the dens with respect to C2
Associated syndromes: Morquio syndrome and Multiple Epiphyseal Dysplasia
What is Stylohyoid Ligament Calcification?
What is it?
Calcification of the stylohyoid ligament(s)
What causes them?
tonsillectomy or other regional surgery
abnormal calcium/phosphorus metabolism
~5% of the population
How are they diagnosed?
X-ray : elongated styloid process; radioopaque/white/sclerotic appearance of the stylohyoid ligament; may be bilateral
Clinical significance:
can compress the cranial nerves and carotid arteries
“Eagles Syndrome = symptomatic elongation of thestyloid processor calcifiedstylohyoid ligament”
What is Congenital Block Vertebrae?
What is it?
failure of separation of 2 or more adjacent vertebral bodies. Sacrum is a normal block vertebra
What causes them?
Congenital
How are they diagnosed?
X-ray : combined vertebrae may be of normal height, short, or tall. Partial/complete fusion of cortex and bony matrix is continuous.
Disc space is frequently absent or extremely small
Clinical significance:
Associations:
hemivertebra or absent vertebrae
Klippel-Feil Syndrome and can cause angulation of the spine
What is a cervical rib?
What is it?
Extra rib arising from C7
Uni- or Bilateral
What causes them?
Congenital
Represents persistent ossification of C7 lateral costal element (usually ‘re-absorbed’ during foetal development)
How are they diagnosed?
X-ray : Fully ossified, symmetrical (if bilateral) ribs.
TVPs of C7 will project infero-laterally; thoracic spine TVPs will project supero-laterally
AP cervical spine and CT
Clinical significance:
Usually asymptomatic
Thoracic Outlet Syndrome – compression of the contents of the thoracic outlet = symptoms
What is a cervical rib?
What is it?
Extra rib arising from C7
Uni- or Bilateral
What causes them?
Congenital
Represents persistent ossification of C7 lateral costal element (usually ‘re-absorbed’ during foetal development)
How are they diagnosed?
X-ray : Fully ossified, symmetrical (if bilateral) ribs.
TVPs of C7 will project infero-laterally; thoracic spine TVPs will project supero-laterally
AP cervical spine and CT
Clinical significance:
Usually asymptomatic
Thoracic Outlet Syndrome – compression of the contents of the thoracic outlet = symptoms
What is Arcuate Foramen C1?
What is it?
AKA ponticulus posticusorposterior ponticle
Bony ridge of C1 (atlas) forming a foramen
What causes them?
Calcification of theposterior atlanto-occipital membrane. – vertebral arteries pass through it
How are they diagnosed?
X-ray : lateral x-ray
complete or incomplete bony arch in the posterosuperior aspect of C1
Clinical significance:
Typically insignificant
May be associated with vasobasilar stroke, headaches and MSK Pain
What is the nuchal bone - sesamoid?
What is it?
Sesamoid bone embedded in the Nuchal Ligament
m/c at C5/6 and C6/7
What causes them?
Form in response to strain
Anatomical variant
How are they diagnosed?
X-ray : lateral cervical x-ray
well-defined, corticated, round or oval opacity posterior to SPs
Clinical significance:
DDXs:
myositis ossificans
Clay-shoveler fracture
calcareous bursitis
nuchal fibrocartilaginous pseudotumour
and more…
What is the occipital spur?
What is it?
“Exaggerated External Occipital Protuberance (EOP)”
What causes them?
Anatomical variant
Potentially a “Neanderthal trait”
How are they diagnosed?
X-ray : bony projection at the EOP with clear bony cortex and continuous matrix with the skull.
(If EOP included in x-ray of Cx)
Clinical significance:
Usually asymptomatic
If symptomatic = conservative management: soft pillows; analgesics
Symptoms persist surgical intervention
What is the occipital spur?
What is it?
“Exaggerated External Occipital Protuberance (EOP)”
What causes them?
Anatomical variant
Potentially a “Neanderthal trait”
How are they diagnosed?
X-ray : bony projection at the EOP with clear bony cortex and continuous matrix with the skull.
(If EOP included in x-ray of Cx)
Clinical significance:
Usually asymptomatic
If symptomatic = conservative management: soft pillows; analgesics
Symptoms persist surgical intervention
