 The needle tip was positioned such that the tip was at the posterior aspect of the articular pillar's waist and was then incrementally advanced until the tip was at the center of the pedicle, where the medial branch lies. 
The needle tip was positioned such that the tip was at the posterior aspect of the articular pillar 's waist and was then incrementally advanced until the tip was at the center of the pedicle , where the medial branch lies .