Occiput/C1 Anomalies Flashcards
Flattening of the skull base is known as what?
Platybasia
Superior position of the upper cervical vertebrae in relation to the skull is known as:
Basilar impression
What two lines are helpful in determining basilar impression on a lateral skull radiograph?
- McGregor’s line
- Chamberlain’s line
This radiographic line goes from the hard palate to the base of the occiput
McGregor’s line
The odontoid process of C2 should be no more than ___mm MAX above McGregor’s line
8-10mm
The diagnoses for this type of anomaly is not made with X-Ray, but MRI or Ct. The findings are low-lying cerebellar tonsils, triangular shaped cerebellar tonsils, and kinking of the fourth ventricle
Arnold-Chiari Malformation - Type 1
This anomaly is the most common of the craniovertebral junction.
Occipitalization of the atlas (AKA atlanto-occipital fusion)
Occipitalization of the atlas is more common in ___ 5:1
Males
When the most inferior somite fails to fuse to the other occipital somites, it remains by itself usually and is referred to as what?
Occipital vertebra
A midline bony projection bridging the anterior aspect of the foramen magnum with the apex of the odontoid or the anterior arch of the atlas
Third condyle
Radiographs of this type of common anomaly show an absence of the spinolaminar junction line of the atlas
Posterior spina bifida oculta of the atlas
On a lateral cervical view, the anterior tubercle of C1 appears bulbous and indistinct
Anterior spina bifida oculta of the atlas
This anomaly is produced by ossification of the oblique portion of the Atlanto-occipital membrane. It has even associated with vertebrobasilar insufficiency, barre-lieou syndrome, and chronic upper cervical syndrome.
Posterior ponticle of the atlas
