workbook Ch9

A portion of the lamina located between the superior and inferior articular processes is called the

Pars interarticularis

The superior and inferior vertebral notches join together to form the:

Intervertebral foramina

Which radiographic position best demonstrates the structure identified in the previous question?

Lateral position

The anterior and superior aspect of the sacrum that forms the posterior wall of the pelvic inlet is called the

Promontory

What is another term for the sacral horns?

Cornua

The sacroiliac joints lie at an oblique angle of ___degrees to the coronal plane.

25-30

True/False: Placing a lead blocker mat behind the patient for lateral lumbar spine positions improves image quality.

True

For lumbar spine imaging, close collimation is an important factor for dose reduction to the gonads.

True

True/False: The AP projection of the lumbar spine opens the intervertebral joint spaces better than the PA projection.

False

True/False: The knees and hips should be extended for a recumbent AP projection of the lumbar spine.

False

True/ False: An increased (SID) of 44-48 inches (110-120 cm) reduces magnification of the spine anatomy.

True

True/False: When positioning a bariatric patient, the iliac crest is typically at the level of the inferior margin of the flexed elbow.

True

Which two structures can be evaluated to determine whether rotation is present on a radiograph of an AP projection of the lumbar spine

Sacroiliac joint space equidistant from spine

Spinous process should be midline to vertebral column

How much rotation is required to visualize the zygapophyseal joints properly at the L5-S1 level?

65 degrees

Which specific set of zygapophyseal joints is demonstrated with an LAO position?

Right (upside)

The ___ which is the eye of the Scottie dog, should be near the center of the vertebral body on a correctly oblique lumbar spine position.

Pedicle

Which positioning error has been committed if the structures described in the previous question are projected too far posterior with a 45-degree oblique position of the lumbar spine?

excessive rotation

Which position or projection of the lumbar spine series best demonstrates a possible compression fracture?

Lateral

A patient with a wide pelvis and narrow thorax may require a central ray angle of__degrees (caudad or cephalad) for a lateral position of the lumbar spine.

5 cuaded

How should the spine of a patient with scoliosis be positioned for a lateral position of the lumbar spine?

With the sag or convexity of spine closest to the IR

Why should the knees and hips be flexed for a recumbent AP lumbar spine projection?

Reduce lumbar curvature, to open up intervertebral disk space

The female ovarian dose used for a PA lumbar spine projection is approximately 25%-30% less than the dose for an AP projection. True/false

True

Where is the central ray centered for a lateral LS-S1 projection of the lumbar spine?

1½ Inch Inferior to iliac crest and 2 inch posterior to ASIS

What amount and direction of central ray angulation is required for an AP axial L5-S1 projection on a male patient?

30 degrees cephalad

PA or an AP projection for a scoliosis series frequently includes one erect and one recumbent position for comparison. True/False

True

The lower margin of the image receptor must include the symphysis pubis for a scoliosis series. True/False

False

True/ False: A PA projection for a scoliosis series produces only about one-tenth of the dose to the breast tissue as compared with the AP projection, even if proper collimation is used.

True

Which of the following techniques or devices produces a more uniform density along the vertebral column for an AP/PA scoliosis projection?

1. Use of a 14- x 36-inch (35- × 90-cm) field size

2. Lower kVp

3. Higher mAs

4. Compensating filter

Compensating filter

Which side of the spine should be elevated for the second exposure for the AP/PA projection (Ferguson method) scoliosis series (by having the patient stand on a block with one foot)?

Convex side of spine

Which projections should be taken to evaluate flexibility following spinal fusion surgery?

Hyper extension and hyperflexion lateral projections

What is the recommended kVp range for lateral hyperflexion and hyperextension positions of the spine for a digital imaging system?

80-95

How much central ray angulation is required for an AP projection of the sacrum for a typical male patient?

15 degrees cephalad

If a patient cannot lie on his back for the AP sacrum because it is too painful, what alternate projection can be taken to achieve a similar view of the sacrum?

A PA with 15 degrees cuaded angle

Where is the central ray centered for an AP projection of the coccyx?

2 inches superior to the symphesis pubis

True/False: The AP projections of the sacrum and coccyx can be taken as one single projection to decrease gonadal dose?

False

Patients should be asked to empty the urinary bladder before performing which projections of the vertebral column?

AP of sacrum and coccyx

In addition to good collimation, what should be done to minimize scatter radiation on a lateral lumbar spine or lateral sacrum and coccyx radiograph?

place leadblocker on tabletop hehind patient

Which sacroiliac (SI) joint is visualized with an RPO position?

Left

How much rotation of the body is required for oblique positions of the SI joints?

25-30 degrees

What type of CR angle is recommended for the AP axial projection of the SI joints on a female patient?

35 degrees

A radiograph of an AP proiection of the lumbar spine shows the spinous processes are not midline to the vertebral column and distortion of the vertebral bodies is present. Which specific positioning error is present on this radiograph?

Rotation of the spine

A radiograph of an LPO projection of the lumbar spine shows the downside pedicles and zygapophyseal joints are projected over the anterior portion of the vertebral bodies. Which specific positioning error is present on this radiograph?

insufficient rotation of the spine

3A radiograph of a lateral projection of a female lumbar spine shows the mid to lower intervertebral joint spaces are not open. The technologist supported the midsection of the spine with sponges to straighten the spine. What else can be done to open the joint spaces during the repeat exposure?

If pt has a wide pelvis the CR can be angled 5-8 cuaded

A radiograph of a lateral L5-S1 projection shows the joint space is not open. The technologist did support the middle aspect of the spine with a sponge. What else can the technologist do to open up the joint space during the repeat exposure?

place additional support beneath the spine, or use a 5-8° cuaded angle

A radiograph of an AP axial projection of the coccyx shows the distal tip is superimposed over the symphysis pubis.

What must the technologist do to eliminate this problem during the repeat exposure?

increased CR angle angle to seperate the coccyx from symphesis pubis

A radiograph of an oblique position of the lumbar spine shows the downside pedicle and zygapophyseal joint are posterior in relation to the vertebral body. What modification of the position must be made during the repeat exposure to produce a more diagnostic image?

Decrease rotation of body and spine

A patient comes to the radiology department for a follow-up study for a compression fracture of L3. The radiologist requests that collimated projections be taken of L3. Which specific projections and centering would provide a quality study of L3 and the intervertebral joint spaces?

AP or PA and collimated

A patient with an injury to the coccyx enters the emergency room. When attempting the AP projection, the patient complains that it is too uncomfortable to lie on his back. He is unable to stand. What other options are available to complete the study?

PA rather than AP, and reverse direction of CR from cuaded to cephalad

A patient with a clinical history of spondylolisthesis at the L5-S1 level comes to the radiology depart-ment. Which specific lumbar spine position is most diagnostic in demonstrating the extent of this condition?

a lateral L5-Sl position demonstrates degree of foward displacement

positioning series for SI joints is performed on a patient. The resultant radiographs do not demonstrate the inferior portion of the joints. What can be done during the repeat exposure to, demonstrate this aspect of the SI joints?

angle CR 15-20 degrees cephalad

A patient comes to the radiology department for a lumbar spine series. He has a clinical history of advanced spondylolysis. Which specific projections of the lumbar spine series will best demonstrate this condition?

posterior or anterior oblique positions best.

A patient comes to the radiology department with a clinical history of HNP. Which of the following imaging modalities provide the most diagnostic study for this condition?

MR

patient comes to the radiology department for a lumbar spine study following spinal fusion surgery. Her surgeon wants a study to assess mobility of the spine at the fusion site. Which radiographic positions provide this information?

hyperflexion and hyperextention lateral positions

A patient comes to the radiology department for a lumbar spine series. She has a clinical history of severe kyphosis. How should the lumbar spine series be modified for this patient?

routine lumbar spine projections should be performed erect.