Power’s ratio
Atlanto-occipital dislocation
Classification
Definition
The distance of the basion to the posterior arch of C1, divided by the distance of the opisthion to the anterior arch of C1.
Interpretation
Power's ratio < 1 is one of the indications for atlanto-occipital dislocation.
Reference(s)
The Neurosurgeon's Handbook. Ed. G Samandouras. Oxford University Press, 2010.