L-Spine Positioning

Question 1

What kvp is used for AP and oblique?

Answer 1

80-90kv

Question 2

What kvp is used for lateral and L5/S1?

Answer 2

90-100kv

Question 3

What AEC cell is used for all lumbar spine projections

Answer 3

Center cell

Question 4

What projections are part of the basic L spine routine?

Answer 4

-AP
-oblique
-lateral
-lateral L5/S1

*special - AP axial L5/S1

Question 5

What vertebral level is the xiphoid tip?

Answer 5

T9/10

Question 6

What vertebral level is the lower costal margin?

Answer 6

L2/3

Question 7

What vertebral level is the iliac crest?

Answer 7

L4/5

Question 8

What vertebral level is the ASIS?

Answer 8

S1/2

Question 9

-supine of upright
-MSP centered to midline
-arms crossed on chest or along sides
-flex knees and hips to place lower back closer to table
*reduces lordosis

Answer 9

AP projection

Question 10

How is the lordosis of the L spine reduced for a AP projection?

Answer 10

Flex knees and hips

Question 11

-enters at iliac crest (L4)
-includes lumbar vertebrae, sacrum and possibly coccyx

Answer 11

Larger IR
35x43cm

Question 12

-enters at 1.5” above iliac crest (L3)
-includes primarily all 5 lumbar vertebrae

Answer 12

Smaller IR
30-35cm

Question 13

-true lateral with MCP vertical
-knees flexed and superimposed
-arms, with elbow flexed at right angle to body
-radiolucent support under lower spine if needed

Answer 13

Lateral

Question 14

What projection best demonstrates the intervertebral foramina of L spine?

Answer 14

Lateral

Question 15

If the spine is not horizontal in the lateral position, what angulation can be added?

Answer 15

5-8 degrees caudad
*more for females

Question 16

T/F
Lead should be used behind the patient to reduce scatter

Answer 16

True

Question 17

What position is the patient in for L5-S1?

Answer 17

Lateral recumbent

Question 18

-MCP perpendicular to IR
-hips extended
-superimposed, slightly flexed knees
-support lower spine to be in horizontal position.

Answer 18

Lateral L5-S1

Question 19

CR centered perpendicular to coronal plane (with support), 2” posterior to ASIS and 1.5” inferior to iliac crest
*angle 5-8 degree caudad if spine not parallel

Answer 19

Lateral L5-S1

Question 20

T/F
The CR should be parallel to the interiliac line (often requires 5-8 degrees caudad) for lateral L5-S1

Answer 20

True

Question 21

CR centered 1.5” above iliac crest, 2” medial to upside ASIS

Answer 21

AP/PA oblique lumbar spine

Question 22

What position best demonstrates the zygapophyseal joints of L3/4 and L4/5?

Answer 22

Oblique positions

Question 23

What does the collimated field for oblique L spine demonstrate?

Answer 23

5 lumbar and top of sacrum

Question 24

What joints are demonstrated in a posterior oblique position?

Answer 24

Downside joints

Question 25

What joints are demonstrated in an anterior oblique position?

Answer 25

Upside joints

Question 26

What oblique position demonstrates the right zyga joints?

Answer 26

RPO LAO

Question 27

What oblique position demonstrates the left zyga joints?

Answer 27

LPO RAO

Question 28

What does the nose of the Scotty dog represent?

Answer 28

Transverse process

Question 29

What does the eye of the Scotty dog represent?

Answer 29

Pedicle

Question 30

What does the neck of the Scotty dog represent?

Answer 30

Pars interarticularis

Question 31

What does the front leg of the Scotty dog represent?

Answer 31

Inferior articular process

Question 32

What does the ear of the Scotty dog represent?

Answer 32

Superior articular process

Question 33

What can obstruction of disk spaces be caused by?

Answer 33

CR angulation, CR centering, patient position (spine curvature)