RAD 232 positioning sacrum and coccyx

CR lateral sacrum

perpendicular to level of ASIS and to a point 3.5in posterior

How should the coccygeal segment be seen in an AP coccyx projection

not superimpose by pubic bones

what demonstrates no rotation for the lateral sacrum and coccyx

closely superimposed posterior margins of ischia and ilia

CR for PA coccyx (prone)

10 degrees cephalad enters MSP coccyx

how can you tell that there’s no rotation in the AP coccyx projection

demonstrated by distal segment in line with pubic symphysis

what helps reduce scatter radiation for the lateral projection of the coccyx and sacrum

lead rubber behind pt

open or close collimation should be used for lateral sacrum and coccyx

closed to improve visibility

for the sacrum and coccyx projection should a low kvp or high kvp be used

low kvp

how should the sacrum be demonstrated in a AP axial projection

free of foreshortening with sacral curvature straightened

CR AP axial sacrum (supine)

15 degrees cephalad enters MSP at 2in superior to pubic symphysis

CR for PA axial sacrum (prone)

15 degrees caudad enters MSP at level of sacral curve

CR for lateral coccyx

perpendicular to 3.5in posterior and 2in inferior to ASIS

how should the pubic bones be demonstrated in a AP axial sacrum projection

not overlapping sacrum

why are the AP axial of sacrum and coccyx preferred over PA axial

sacrum and coccyx are closer to the IR

why is an angled CR used instead of a perpendicular CR used for the AP axial sacrum

sacrum will appear foreshorten with perpendicular CR

CR for AP coccyx (supine)

10 degrees caudad enters MSP 2in superior to pubic symphysis

why is low kvp used for AP axial sacrum and coccyx

to improve contrast and reduce scatter

how can you tell there’s no rotation in an AP axial sacrum projection

demonstrated by symmetric alae