Author Question: Imaging the L5-S1 joint with an AP projection requires the CR to be directed: perpendicular 15 ... (Read 55 times)

OSWALD · **on:** Jul 17, 2018

Imaging the L5-S1 joint with an AP projection requires the CR to be directed:

perpendicular
15 degrees cephalic
30 degrees cephalic
20 degrees cephalic

Question 2

Which positioning error occurred if the zygapophyseal joint isn't perfectly visible and the intervertebral foramen are starting to align?

overrotation
the patient's spine wasn't parallel
underrotation
no error occurred

aburgess · **Reply #1 on:** Jul 17, 2018

Answer to Question 1

30 degrees cephalic

Rationale: The L5-S1 AP axial projection requires a 30 degree cephalic tube angle to aid in opening up the joint space.

Answer to Question 2

overrotation

Rationale: The pedicle should be nearly centered on the vertebral body to indicate proper rotation was achieved. Underrotation will result with the pedicle still anterior on the vertebral body. Overrotation will result with the pedicle too posterior on the vertebra.