Week 2 Flashcards
What is spina bifida occulta (SPO)?
Failure of fusion of the two posterior arch ossification centers producing a midline defect
Occult means?
Hidden, small hidden
What can not be seen on xray with spina bifida occulta?
Can not see the spinal laminar junction
What are some associated conditions w/ SPO
Posterior disc herniation, and association w/ isthmic spondylolisthesis
What is anterior arch agenesis?
Absence of D-shaped anterior arch on lateral cervical film (rare)
For stability b/t C1/C2 w/ anterior arch agenesis we need what?
An intact dens, anterior arch, lateral masses and transverse processes, don’t really need a posterior arch
How do we test for hypermobility w/ anterior arch agenesis?
Perform flex/ext study to screen hypermobility
What is posterior arch agenesis?
Lack of cartilage template (partial or complete) for absence of a posterior arch
What happens to the anterior arch and C2 w/ posterior arch agenesis?
Hypertrophy and sclerosis of anterior arch and megaspinous of C2
What is a posterior ponticle?
Partial or complete ossification of the oblique portion of the atlanto-occipital membrane
What does the posterior ponticle/arcuate foramen contain?
Vertebral artery and 1st cervical nerve
How common is a posterior ponticle?
15% of the pop.
Is a posterior ponticle more common uni or bilaterally?
Unilaterally
What are some other names for posterior ponticle?
Arcuate foramen, Kimmerly anomaly, ponticulus posticus
What might the posterior ponticle do to the nerves?
May compress and traction
Down’s syndrome?
Trisomy 21, 1 in 600 births
What can Down’s syndrome lead to?
Atlanto-axial instability due to lax transverse ligament
What % of Down’s syndrome patients are born w/out transverse ligaments?
20%
What are Down’s syndrome patients prone to?
Cervical spondylosis and myelopathy
What increased space is seen in Down’s syndrome patients?
Increased atlanto-dental interspace (ADI) flexion lateral view
What is Ossiculum Terminale/Persistens of Bergman?
Non-fusion of secondary growth center of dens, separate ossicles in patients over 12 y/o
What is Os Odontoideum?
Two halves of the odontoid unite do not fuse to C2, probably due to old fracture w/ non-union
Is the transverse ligament usually intact or not intact w/ Os ondontoideum?
Intact
What is the exception for dx before 5 y/o w/ Os Odontoideum?
Hypermobility of the dens is demonstrated
What type of translation is seen w/ Os Odontoideum?
Sagittal translation, see if masses of C1 slide over C2
What is hypoplastic/ageneic odontoid?
The odontoid halves do not develop fully or at all (extremely rare), possible surgery
What is a block vertebra/synostosis?
Non-segmentation of two adjacent segments
What is the appearance of block vertebra/synostosis?
Wasp wasted appearance of AP diameter where two levels were joined together
What are some complications of block vertebra?
Premature DJD at adjacent levels, laxity at adjacent levels d/t increased stresses
Where in the neck is block vertebra/synostosis the most common at?
C2/C3 and C5/C6
Where in the lumbar is block vertebra/synostosis the most common?
L4/L5
Radiographs showing block vertebra/synostosis what becomes no longer visible?
Discs and roughened endplates
What is Klippel-Feil Syndrome?
Multiple block vertebra, SBO, scoliosis, Sprengel’s deformity, platybasia
What is the classic triad associated w/ KFS?
Shortness (d/t loss of disc spaces)
Webbed neck (pterygium coli)
Lowered hairline
Decreased Cx ROM
What soft tissue anomalies are associated w/ KFS?
GU anomalis (horseshoe kidney or 2 ureters off one kidney) intravenous urogram or pylogram
What is Sprengel Deformity?
Congenitally undescended scapula
Where is Sprengel’s Deformity normally at?
Inferior angle at T7
What is an omovertebral bone?
In Sprengel’s deformity it is a chunk of bone that fixes the scapula to the spine present only sometimes
Is KFS and Sprengel’s deformity isolated from each other or associated w/ each other?
Both
What is cervical spondylolisthesis?
Congenital form caused by bilateral agenesis of pedicles and dysplasia (malformation) of articular processes
At what level is cervical spondylolisthesis most common?
C6 (C6 slipped forward compared to C7)
Is cervical spondylolistheses more common in males or females?
M>F
What is commonly associated at the same level as cervical spondylolisthesis?
SBO
Is cervical spondylolisthesis symptomatic or asymptomatic?
Both
What does a lateral view of cervical spondylolisthesis show?
Lucencies b/t pedicle and SP
Where are cervical ribs most common at?
C5-7
What do the cervical ribs articulate w/?
The TPs. Articulations w/ TP differentiates from hyperplastic TP
If a patient as a cervical rib at C5 what else will the patient present w/?
Cervical ribs the rest of the way down
What are apparent defects in the medial aspects of lateral masses in the cervical spine?
C1 lateral mass notches
What is a C1 lateral mass notch?
Apparent defects in the medial aspects of lateral masses in the cervical spine
What do the lucencies of the atlas in C1 lateral mass notches represent?
Attachment sites of the transverse ligament
What are the central maxillary incisors?
May look like vertical fracture through the dens but is actually a space b/t teeth
What may look like a vertical fracture through the dens?
Central maxillary incisors
What is the match effect?
Overlapping structure of posterior arch of C1 we see lucency at bottom of C1, shadow formed by diverging xrays, may be lips, tongue and occiput
What are the paraodontoid notches?
Notches next to the dens
What do the paraodontoid notches represent?
Part of the growth centers/synchondrosis (didn’t fill w/ bone)
What is Eagles Syndrome?
It is a stylohyoid ossification
What view shows Eagles syndrome the best?
APOM, but can still be seen on lateral view
What is associated w/ Eagles syndrome?
Dysphagia and anterior neck pain
What can PLL ossification cause?
Spinal stenosis
What is facet notching?
Mimics erosion or fracture, no trauma yet trauma can cause it
Articular pillars overlapping due to what may mimic vertebral pillar fracture?
Rotation
What is a pseudofracture and arthrosis?
Lucency seen through the body but actually unco-vertebral joint arthrosis, (look like they have become slightly horizontal)
What is a pyriform sinus?
Lucency medial to v-body on AP film, may look like a destructive lesion, but just air space overlying the bone
What is the transverse foramen of C2
Looks like holes in the bone but are very symmetric looking, not a destructive lesion
What are Hahn’s venous clefts?
Vascular channels seen as horizontal lucencies thorugh the mid-vertebral body
Where are Hahn’s venous cleft most common at?
Lower thoracic spine
Are Hahn’s venous clefts normal or abnormal findings?
normal
What is a lumbar block vertebra?
Non segmentation in thoracic and lumbar
Are block vertebra more common in the cervicals or lumbar spine?
Cervicals
Where are lumbar block vertebra m/c found?
L4/L5
What do we assume if there is multiple block vertebra?
KFS
What is a butterfly vertebra?
Central hourglass shaped lucency in the body on AP radiographs. Continuous disc material vertebra from adjacent discs
How do butterfly vertebra and SBO differ?
In butterfly vertebra the body is separated compared to SBO where posterior elements are separated
What happens to the vertebral body in butterfly vertebra?
Becomes wider
Are butterfly vertebra stable or unstable?
Usually stable
What type of fracture does a butterfly vertebra look like?
Burst fracture
What is a hemivertebra?
Failure of ossification center, becomes a wedge shaped vertebra and adjacent endplate deformities
Where are hemivertebra m/c?
Laterally m/c and dorsal/ventral l/c
What are hemivertebra usually associated w/?
Block vertebra, KFS, diastematomyelia (spinal cord split into two halves)
If a hemivertebra is isolated what does it often cause?
Scoliosis
What does the term scrambled spine refer to?
When hemivertebra is w/ block vertebra
How do we know hemivertebra are congenital?
B/c of the absence of osteophytes
