X-RAY OF SECRUM

X-RAY OF SECRUM

X-ray  Sacrum AP View

Sacrum AP

Region: sacrum, lumbosacral joint, sacroiliac joint

Pathology: fracture and dislocation of sacrum

SID: 100 cm (40 inches)

Central Ray: beam directed at the point 5 cm (2 inches) above the pubic symphysis with 15°cephalic angulation

Respiration: suspended

Position: 

1. The patient is placed in a supine position.
2. Place a support under knees so the patient can maintain the position with comfort.
3. Align the patient's midsagittal plane to the center of image receptor (IR).

Collimation: Include the entire structure of the sacrum.

Evaluation: 

1. Sacrum must observed without superimposition, and the distal portion of sacrum should be shown at the center of pelvic cavity.
2. Sacroiliac Joint (S-I joint) and lumbosacral joint (L-S joint) should be observed.

kVp-92, mAs-8

Tip: 

1. Apply shielding to genital gland not to be covered by inspecting area.
2. For women, genital gland overlap with inspecting area, so shielding is impossible.
3. Make sure pelvis and the patient's body is not rotated.
4. Before this inspection, urine in bladder should be empty and intestinal gas or stool should be removed.
5. For patient with big curve of pelvis or sacrum, project Central X-ray 15° cephalad.
6. In prone position, project 20° caudad.

X-ray Sacrum Lateral View

Region: sacrum, lumbosacral joint

Pathology: fracture and dislocation of sacrum

SID: 100 cm (40 inches)

Central Ray: perpendicular beam directed at the point 8~10 cm (3~4 inches) below the anterior superior iliac spine (ASIS)

Respiration: suspended

Position

1. The patient is placed in a lateral decubitus position.
2. Place the point of anterior superior iliac spine (ASIS) 5 cm anterior to the back of sacrum at the center of the image receptor (IR).
3. Flex hips and knees and place a support under knees and ankles.

Collimation: Include the entire structure of the sacrum.

Evaluation: 

1. The entire structure of the sacrum must be observed.
2. Sacrum in true lateral projection should be shown at the center of image.

kVp-75, mAs-40

Tip

1. Apply shielding to genital gland not to be covered by inspecting area.
2. Place lead plate on patient's back side to prevent decline of subject contrast from scattered rays.