Author Question: What is the necessary degree of rotation to imaging the SI joints? 15 degrees 40 degrees 30 ... (Read 79 times)

danielfitts88 · **on:** Jul 17, 2018

What is the necessary degree of rotation to imaging the SI joints?

15 degrees
40 degrees
30 degrees
60 degrees

Question 2

A patient positioned in a 45 degree posterior oblique for the cervical spine will require:

a 15 degree caudal tube angle
a perpendicular beam
a 15 degree cephalic tube angle
a 30 degree cephalic tube angle

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

Answer to Question 1

30 degrees

Rationale: To open up the SI joints, a rotation of 25-30 degrees is applied. Using rotation degrees greater than 30 degrees will close off the joint space.

Answer to Question 2

a 15 degree cephalic tube angle

Rationale: The AP oblique projections will require a 15 degree cephalic tube angle to demonstrate the intervertebral foramina. The degree of rotation of 45 degrees is essential along with the added tube angle to match the slope of the vertebrae.