Pathology demonstrated when taking lateral position is a lateral view of coccyx and sacrum. The L5-S1 joints are also seen. These two are commonly together. A separate AP projection is necessary because of variance in tube angulation. but in this lateral projection can be taken with one exposure centering to include both the sacrum and coccyx. This projection is recommended to decrease in genital dose. High amounts of secondary and scatter radiation are generated in this projection. Close collimation is primary needed to reduce patient dose and achieve a high quality image.
Image receptor size is: 24 x 30 cm or 10 x 12 inches. Cassette in lengthwise.
Moving or stationary grid.
90 or add more or less 5 kV.
Lead mats on table behind patient to reduce scatter radiation to image receptor.
If coccyx is to be included, a boomerang-type filter is useful to ensure optimal density.
mAs 55
Complete ovarian shielding on females may obscure a portion of sacrum in not correctly placed.
Position patient lateral recumbent, with a pillow for head.
Place a support under waist and between knees and ankkles to maintain patient position and ensure comfort.
Align long axis of sacrum and coccyx to central ray and to midline of table or gird.
Ensure no rotation of body and pelvis for true lateral position.
Center CR 3 to 4 inches (8 to 10 cm) posterior to ASIS ( centering for sacrum).
IR is centered to CR.
SID is 40 inches or 100cm.
Collimation is in four-sided to area of interest.
Suspend breathing on expiration.
Proper Patient position: greater sciatic notches and femoral head are superimposed.
Correct Collimation and Central Ray: Sacrum and coccyx appear in center of Image receptor, with closely collimated field.
Exposure Criteria: Optimal contrast and density should clearly demonstrated the sacrum.
The coccyx may appear slightly overexposed, depending on patient size and filter use.
Sharp bony margins indicate no motion.
Technical Factors:
Image receptor size is: 24 x 30 cm or 10 x 12 inches. Cassette in lengthwise.Moving or stationary grid.
90 or add more or less 5 kV.
Lead mats on table behind patient to reduce scatter radiation to image receptor.
If coccyx is to be included, a boomerang-type filter is useful to ensure optimal density.
mAs 55
Shielding and Patient Position:
Shield gonads without obscuring area of interest for male patients.Complete ovarian shielding on females may obscure a portion of sacrum in not correctly placed.
Position patient lateral recumbent, with a pillow for head.
Part Position:
Patients knee is flexed.Place a support under waist and between knees and ankkles to maintain patient position and ensure comfort.
Align long axis of sacrum and coccyx to central ray and to midline of table or gird.
Ensure no rotation of body and pelvis for true lateral position.
Central Ray, Correct Collimation and Respiration:
Cental ray is perpendicular to image receptor.Center CR 3 to 4 inches (8 to 10 cm) posterior to ASIS ( centering for sacrum).
IR is centered to CR.
SID is 40 inches or 100cm.
Collimation is in four-sided to area of interest.
Suspend breathing on expiration.
Radiographic Criteria | Lateral view Sacrum and Coccyx
Proper Patient position: greater sciatic notches and femoral head are superimposed.
Correct Collimation and Central Ray: Sacrum and coccyx appear in center of Image receptor, with closely collimated field.
Exposure Criteria: Optimal contrast and density should clearly demonstrated the sacrum.
The coccyx may appear slightly overexposed, depending on patient size and filter use.
Sharp bony margins indicate no motion.
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