Cervical Spine Flashcards
How many vertebrae are in the vertebral column?
33
7 cervical, 12 thoracic, 5 lumbar, 5 sacral (fused) and 4 coccygeal (fused)
What 3 anatomical regions is the cervical spine best analyzed on plain films?
- First cervical segment (C1)
- Second cervical segment (C2)
- Remainder of distal cervical segments
2 reasons why C1 is unique to other cervical vertebrae
- it has no vertebral body, which means it has no annulus for stabilization
- It is wrapped around a cephalad projection of vertebral body of C2 known as “odontoid” or “dens”
Which ligament holds the dens in proper alignment
Transverse ligament
The transverse ligament prevents ______ displacement of C1 on C2
anterior
The articular facets at C1 are more horizontally oriented in AP plane to facilitate which movement?
rotation
Transverse ligament incompetence can be due to what 3 things?
1) Congenital laxity
2) Rupture of the ligament by trauma
3) Progressive diseases such as RA
Does C1 have an intervertebral disc?
NO
Because C1 does not have an IVD what two things are decreased?
Shock absorption and stabilization
The articular facets of C1 are _____ in the AP plane, but they are wedge shaped in the ML plane with the ___ dimension smaller than the ____ dimension
horizontal
medial
lateral
The _____ is the “pillar” around which ring of C1 rotates and to which C1 anchored by transverse ligament
odontoid/dens
Odontoid/dens fractures may be caused by what 3 things?
- Trauma
- Developmental congenital malformation
- Failure to fuse
Odontoid fractures are categorized as types I, II, and III based on what?
Location and direction of fracture
Describe a Type I odontoid fracture
oblique fracture through upper ⅓ of the odontoid
Describe a Type II odontoid fracture
transverse fracture through the base of the odontoid where it joins and is joins with the body of C2
Describe a Type III odontoid fracture
fracture of odontoid down into body of C2 (most serious)
In what view can you see a dens fracture?
AP Open Mouth (APOM)
What are the 5 standard views required to perform basic evaluation of the cervical spine with plain film x-rays?
1) Odontoid (open-mouth) view (APOM)
2) AP
3) Left oblique
4) Right oblique
5) Lateral
Which views are only taken when absolutely necessary?
The oblique views
What is APOM used to see?
CI and C2
What is a Jefferson’s fracture?
a bone fracture of the anterior and posterior arches of the C1 vertebra
How is a Jefferson’s fracture diagnosed?
APOM view and it is demonstrated by lateral overhanging of lateral mass beyond the lateral margins of C2 superior articular processes
Greater than _ mm of bilateral offset of the lateral masses of C1 relative to C2 is considered abnormal.
2
In the APOM view, if there is overhang of the lateral masses of C1 relative to C2, but it is less than 2 mm what can it be attributed to?
head rotation/tilt
In the APOM view the articular surfaces of the facets should be ____ to one another and equally spaced.
parallel
An AP view of the cervical spine allows you to view what?
The anteroposterior portion of the cervical spine from C3 to C7
How can you determine any segmental rotation between the lower cervical spine in an AP view?
A vertical line can be drawn along the spinous processes from superior to inferior
What 3 other things (other than spinous process alignment) can you check in the AP view?
- Identify the pedicles at each segment and assessed for indications of segmental rotation
- Vertically assess the lateral borders of the vertebral bodies to assess any segmental lateral displacement or unilateral segmental “tilting”
- Evaluate uncinate joints (two at each superior and inferior portion of vertebral bodies) and look for any osteophytes or degenerative changes
How do you asses bone density and dimension of the lower C-spine?
Segments above and below can be used for comparison and if necessary you can measure horizontal and vertical dimensions in millimeters for comparison
In the AP view which soft tissue structure can be seen very clearly?
the air-filled trachea
What 3 things may be present if the trachea is not midline?
- Tumor (Pancoast’s-lung tumor)
- Pneumothorax
- Hemothorax
How many oblique views should be taken of the cervical spine?
Two (a right and left side) to compare side-to-side consistency
Oblique views are used to evaluate what two things?
1) The status of intervertebral foramina (primarily)
2) Also provides excellent views of pedicles and articular facets
When examining the IVF in the oblique view, what things are you looking for?
Evaluate the dimensions of the foramina above and below for good measures of appropriate patency of each opening. From this you can determine if there is any existence of osteophytes or stenotic changes
Which view of cervical spine is usually the most informative?
Lateral view
Assessment of lower cervical spine cartilage is best evaluated with what view?
Lateral cervical view
In the lateral view anterior and posterior bodies should align themselves in a smooth ____ curve.
lordotic
If the usual lordotic curve is missing what does this suggest?
spasm of cervical muscles
What is the first landmark on the lateral view that requires specific evaluation?
The atlantodens interval (ADI)
The atlantodens interval (ADI) most not exceed _ mm
3 mm
If the ADI is greater than 3 mm what does this suggest?
There is instability between C1 and C2 (ominous)
What are the 3 risk factors for ADI compromise?
1) Significant cervical trauma
2) Connective tissue/autoimmune disease, such as RA, juvenile rheumatoid arthritis (JRA), systemic lupus erythematosus
3) Congenital disease, such as Down syndrome
Does the ADI widen with cervical flexion?
NO, unless there is trauma or a pathological condition that would allow C1 to sublux anteriorly with cervical flexion
Alignment is evaluated in the lateral view by drawing lines superior to inferior along what 3 structures?
1) Anterior longitudinal ligament (ALL)
2) Posterior longitudinal ligament (PLL)
3) Along the line created by junctions of lamina and spinous processes
If the portion of one segment appears slightly anterior to the ALL and PLL and yet the laminar-spinous process line appears posterior to the segments above and below what type of fracture might this indicate?
Hangman’s fracture
How do hangman’s fractures typically occur?
rapid deceleration (hanging) or with hyperextension (MVA – chin to dashboard)
Can a hangman’s fracture occur without displacement of the vertebral body?
Yes, there may be a fracture though the pedicles, but no displacement
What is Ankylosing Spondylitis?
It is an inflammatory disease that can cause some of the vertebrae in your spine to fuse together. This fusing makes the spine less flexible and can result in a hunched-forward posture
An x-ray of ankylosing spondylitis (bamboo spine) has what to distinct characteristics?
- Vertical whitening represented by trolley track signs
- Dagger signs where the interspinous ligaments and supraspinous ligaments are calcifying
How can you determine if a patient has RA by viewing their x-ray?
There is decreased mineralization of cervical spine which may result in anterior subluxation
How can you determine if someone has a compression fracture?
The height of one of their vertebral bodies is less than the other vertebrae
Pathological IVD conditions are divided into diseases of what two structures?
1) annulus fibrosis
2) Nucleus Pulposus
Describe the vacuum phenomenon
When an HNP occurs, over time, nitrogen moves from cartilaginous endplates of vertebral bodies into potential space created by evacuation of NP and becomes visible as an area of ↓ density within confines of intervertebral space
Areas of decreased density in the prevertebral tissue region may be indicative of what?
hemorrhage from an occult fracture of vertebrae that is immediately posterior to lucency
An increased distance between spinous processes may indicate what?
tear of interspinal ligament and supraspinal ligament, indicating potentially severe segmental instability
In addition to cervical spasm, what can cause a loss of lordosis?
a decreased disk space at C3-4 and possible incomplete segmentation at this level in columns two and three of C3 to C4
Dislocation of C5 is also known as what?
A bow-tie deformity
Dislocation of C5 is represented by ____ displacement of the vertebral body
anterior
An absence of space between 2 vertebral bodies may represent what?
herniation of NP or failure of embryonic segmentation at one or multiple levels
Spina bifida occulta of atlas indicated by what 2 things?
1) absence of spinal laminal line in lateral projection
2) incompletely ossified posterior arch in APOM projection
Block segments are secondary to either ____ or ____
surgery (pathology) or congenital
How can you tell the difference between congenital and surgical block segments?
Congenital block segment often has “wasp waist” transverse narrowing
Surgical or pathologic block segments tend to appear more columnar
