C1 Anomalies Flashcards
When looking at a lateral view x-ray of the cervical spine, you notice there is no spinolaminar junction line at C1, and the anterior tubercle seems abnormally large. What is the diagnosis?
Spondyloschiesis (technical name)
(=SBO at C1, can just call it an SBO)
A patient with spondylosciesis is predisposed to what?
Jefferson Fx
What other anomaly is often associated with spondylosciesis?
Occipitalization
What are the 2 forms of posterior arch agenesis?
partial or complete
What is the differential diagnosis for posterior arch agenesis?
osteolysis
Where does posterior arch agenesis occur?
only in C1
How is posterior arch agenesis differentiated from osteolysis?
- stress hypertrophy of anterior tubercle
- C2 megaspinous
If you discover your patient has posterior arch agenesis, what is your next step?
flexion/extension views for transverse ligament insufficiency
What other anomalies are associated with posterior arch agenesis?
- C2-C4 congenital block vertebrae
- Klippel-Feil Syndrome
Name 2 radiographic findings.
(Posterior arch agenesis)
- stress hypertrophy of ant. Tubercle
- C2 megaspinous
What follow up (if any) is needed?
(Posterior arch agenesis)
Flexion/extension radiographs for transverse ligament insufficiency
What is the diagnosis, and what is the clinical significance?
(Partial) posterior arch agenesis
Transverse ligament insufficiency
What is the diagnosis?
(Partial) Posterior arch agenesis
What is a posterior ponticulum?
ossification of oblique part of atlantooccipital membrane (aka arcuate lig. of C1) which bridges the post. lateral mass and post. arch
What are the 2 possible forms of a posterior ponticulum?
partial or complete
What is the clinical significance of a posterior ponticulum?
Questionable
- possible correlation w/ migraines
- no evidence for VBA stroke risk
What is the diagnosis?
Posterior ponticulum
What is the diagnosis?
Lateral ponticle
What is a lateral ponticle?
Ossification in the oblique occipital membrane as it passes laterally from the superolateral aspect of atlas to the TP
What are the radiographic features of a lateral ponticle?
(seen only on APOM)
curvilinear ossification between TP and lat. mass of C1, often forming a distinct foramen (full circle)
What is the clinical significance of a lateral ponticle?
none
What is one of the most significant anomalies associated with Down Syndrome?
transverse ligament anomaly (lig. laxity or dens abnormality; 20% of pts) causing atlantoaxial instability
What is another name for Down Syndrome?
Trisomy 21
What radiographic finding is commonly seen in patients with Down Syndrome?
increased ADI
(>2mm adult)
(>5mm child)
What is the cutoff age between child and adult for ADI measurements?
16 years
What is needed before providing neck treatment to a patient with Down Syndrome?
5-view c/s radiographs
What MRI sequence was used?
T2
What 2 diagnoses are present?
- Occipitalization
- SBO
What 2 diagnoses are present?
- Occipitalization
- SBO
What is the diagnosis?
Chiari malformation
Name 2 findings at C1, and the diagnosis.
SBO
- Stress hypertrophy of ant. tubercle
- absent spinolaminar junction line
What is the diagnosis?
Posterior arch agenesis
