Atlanto Occipital Articulation

With the first frost we see more patients coming after fall trauma due to gliding on ice. It is important to evaluate the Atlanto Occipital Articulation on CT. Look carefully at the relation of basion (lowest tip of clivus) and tip of dens. The distance between basion and superior tip of dens (Basion Dens Interval) should not be grater than 12mm. Evaluate the ligaments for continuity or possible surrounding hematoma. The image above shows those important ligamentous structures (arrows from left to right):

1. Anterior Longitudinal Ligament

2. Atlanto-Occipital Ligament

3. Apical Odontoid Ligament

4. Tectorial Membrane.

In case you suspect pathology - make MRI.

Interesting articles:

1. Lustrin - Pediatric Cervical Spine: Normal Anatomy, Variants, and Trauma

2. Malanga - Cervical Spine Sprain/Strain Injuries