Lumbosacral articulation

Question 1

clinical indications of lumbosacral articulation

Answer 1

*Spondylolisthesis involving L4-L5 or
L5-S1 and other L5-S1 pathologies.

Question 2

Basics projections

Answer 2

• Antero-posterior Axial (FERGUSON METHOD)
• Lateral

Question 3

Equipment required for AP

Answer 3

*24 x 30 cm detailed or fast image receptor
*Table bucky
*Pillow
*Small lead gonad shield

Question 4

A.P Axial projection centering point

Answer 4

to the level of the anterior superior
iliac spine (ASIS) at the midline of the body

Question 5

A.P Axial projection direction of beam

Answer 5

• Angled CR 30 degrees cephalad in males
• Angled CR 35 degrees cephalad in females

Question 6

Antero-posterior Axial projection

Answer 6

1. Lie the patient in supine position
2. Centralize the body on the x-ray table
3. Rest the patient’s shoulders on a pillow
4. Raise the patient’s knees
5. place a form pad underneath the patient’s knees for comfortability
6. collimate beam and include L5 and S1
7. Place anatomical marker

Question 7

Evaluation criteria

Answer 7

• L5-S1 joint space and sacroiliac joints
• Sacroiliac joints demonstrate equal distance
  from spine, indicating no pelvic rotation.
• Correct alignment of CR and L5-S1 evidenced
  by an open joint space.
• Collimation to area of interest
  Exposure
• Clear demonstration of bony margins and
  trabecular markings of L5-S1 region.
• No motion
• Exposed on arrested respiration

Question 8

Why does the tube angulation vary in males and females when doing Antero-posterior Axial projection of lumbosacral articulation

Answer 8

• Males have a small lumbosacral angle as compared to females

Question 9

Lateral projection of the lumbosacral articulation

Answer 9

*Lie the patient in the true lateral position in the centre of the x-ray couch with the arms raised
*Support the head with pillows
*Flex the hips and knees and place the legs in a
comfortable position
* lumbar spine is parallel to the
couch top
* Use padding underneath the lumbar region
*Place anatomical marker, collimate beam and
apply radiation protection where necessary

Question 10

Centering point of the lateral projection of the lumbosacral articulation.

Answer 10

Central Ray (CR) 4 cm inferior to
iliac crest and 5 cm posterior to ASIS

Question 11

Direction of central ray

Answer 11

CR vertical 90˚ to image receptor