Imaging of the Cervical Spine > Pseudosubluxation

Pseudosubluxation

Pseudosubluxation, is a physiologic misalignment that normally occurs in children. (40% of <7 yr, still present in 20% up to 16 yr). It usually occurs at C2-C3.

How do I decide if such subluxation is physiologic or traumatic?

Well, there are three methods:

1. If subluxation is >= 3mm, it is not physiological.

2. Posterior cervical line may be used to determine whether C2-C3 subluxation is physiologic or traumatic. A line is drawn between the spinolaminar lines of C1 and C3. It should either pass through the C2 spinolaminar line or lie within 2 mm anterior to the C2 spinolaminar line. If the C2 spinolaminar line lies anterior to the posterior cervical line the subluxation must be considered traumatic.

3. If the subluxation degree is within normal limits, and neck is not tender at that level, flexion-extension views may clarify the situation. Pseudosublaxation disappears with extension. Again, Flexion-extension views should not be obtained until the entire cervical spine is otherwise cleared radiographically.