Chp. 9 Lumbar, sacrum, coccyx

Where is the central ray centered for a lateral L5-S1 projection of the lumbar spine?

1 1/2 inches (4cm) inferior to iliac crest and 2 inches (5cm) posterior to ASIS

Where is the CR centered for an oblique projection of the SI joints?

1 inch (2.5cm) medial from upside ASIS

A young female patient comes to the radiology department for a scoliosis series. She has had repeated radiation exposure throughout a period of time and is understandably concerned about the radiation. What three things can the technologist do to minimize the dose delivered to the patient's breast?

1.-use high kV technique 2. perform a PA rather than an AP projection 3. use breast shields

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

1.Sacroiliac (SI) joints are equidistant from the spine 2. Spinous process should be midline to the vertebral column (transverse processes are equal length)

How much is the CR angled for the AP axial coccyx projection?

10 degrees caudad

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

15 degrees cephalad

Where is the CR centered for an AP axial projection of the sacrum?

2 inches (5cm) superior to pubic symphysis

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

2 inches (5cm) superior to the symphysis pubis

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

25 to 30 degrees cephalad

For the Ferguson method, the elevated foot must be raised a minimum of _________________(inches/cm)

3 to 4 inches/8 to 10cm

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

30 degrees

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

30 degrees

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

30 degrees cephalad

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 to 8 degrees, caudad

The degree of obliquity required for an oblique projection at the T12-L1 level is approximately ______________, whereas the L5- S1 spine level requires a (n) ___________________oblique. Therefore, a (n) ____________oblique is performed for the general lumbar spine.

50 degrees 30 degrees 45 degrees

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 (prone) with 15 degrees caudad central ray angle

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

A lateral L5-S1 position would demonstrate the degree of forward displacement of L5 onto S1

List the specific joints or foramina that are demonstrated with the following lumbar spine positions. A. Left posterior oblique (LPO) B. right anterior oblique (RAO) C. Lateral D. Right posterior oblique (RPO) E. Left anterior oblique (LAO)

A. LPO = left zygapophyseal joints B. RAO = left zygapophyseal joints C. lateral = intervertebral foramina D. RPO = right zygapophyseal joints E. LAO = right zygapophyseal joints

Patients should be asked to empty the urinary bladder before performing which projection(s) of the vertebral column?

AP of sacrum and coccyx

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 lateral projections would provide the best view of the L3 region. The central ray should be about 2 inches (5cm) above the iliac crest.

Match each of the following topographic landmarks to the correct vertebral level. (Use only one) _______1. ASIS A. L2-L3 _______2. Xiphoid process B. L4-L5 _______3. Lower costal margin C. S1-S2 _______4. Iliac crest D. Prominence of greater trochanter _______5. Symphysis pubis E. T9-T10`

ASIS= S1-S2 Xiphoid process= T9-T10 lower costal margin= L2-L3 Iliac crest= L4-L5 Symphysis pubis= prominence of greater trochanter

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

Although AP and lateral projections of the lumbar spine are helpful, posterior or anterior oblique positions best demonstrate advanced signs of spondylolysis.

A radiograph of an AP axial projection of the coccyx show that the distal tip is superimposed over the symphysis pubis. What must the technologist do to eliminate this problem during the repeat exposure?

An increase in central ray angle is required to separate the coccyx from the symphysis pubis

Inflammatory condition that is most common in males in their 30s

Ankylosing spondylitis

The superior and inferior vertebral notches join together to form the: A. Vertebral foramen B. Intervertebral foramina C. Pedicle D. Lamina

B. Intervertebral foramina

List the structure classification and movement classification and type for the following joints of the vertebrae. classification Mobility type movement type Zygapophyseal __________________ ____________________ Intervertebral __________________ ____________________

Classification Mobility Movement Zygapophyseal Synovial, diarthrodial, plane or gliding Intervertebral Cartilaginous, amphiarthrodial (slightly movable) none

A type of fracture that rarely causes neurologic deficits

Compression fracture

What type of CR angle is recommended for the 'AP axial projection of the SI joints on a female patient? A. 20 degrees cephalad B. 30 degrees cephalad C. 30 degrees caudad D. 35 degrees cephalad

D. 35 degrees cephalad

What is recommended kV range for lateral-hyperflexion and hyperextension positions of the spine for a digital imaging system? A. 70 to 75 B. 80 to 85 C. 85 to 95 D. 95 to 100

D. 95 to 100

Which of the following techniques or devices produces a more uniform density along the vertebral column for an AP/PA scoliosis projection? A. Use of a 35- x 90-cm (14- x 36- inch) image receptor B. Lower kV C. Higher mAs D. Compensating filter

D. Compensating filter

A radiograph of an oblique position of the lumbar spine shows that 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 the body and spine

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

Hyperextension and hyperflexion lateral projections

A 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 hyperextension lateral positions

A radiograph of a lateral projection of a female lumbar spine shows that 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 the patient has a wide pelvis, the central ray can be angled 5 to 8 degrees caudad.

With a 35- x 43-cm (14-x17-inch) IR, the central ray is centered at the level of the ___________________for AP and lateral lumbar spine projections.

Iliac crest

A radiograph of an LPO projection of the lumbar spine shows that 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 (pedicle "eye" should be to midvertebral bodies)

Which radiographic position best demonstrates the structure identified in the previous question. (the Intervertebral foramina)

Lateral position

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

Pars interarticularis

A radiograph of a lateral L5-S1 projection show that 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 to 8 degrees caudad angle

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

Reduces lumbar curvature, which opens the intervertebral disk space

Dissolution and separation of the pars interarticularis

Spondylolysis

A positioning series for sacroiliac (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.

The CR should be angled 15 to 20 degrees cephalad

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 the spine closest to the IR

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? A. sonography B. MRI C. nuclear medicine D. radiography

b. MRI

What is the name of the superior broad aspect of the coccyx?

base

Fracture of the vertebral body caused by hyperflexion force

chance fracture

What is the formal term for the tailbone?

coccyx

What is another term for the sacral horns?

cornua

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

True/False The lead blocker mat and close collimation must not be used when performing digital imaging of the lumbar spine

false

true/false The use of higher kV and lower mA seconds (mAs) for lumbar spine radiography improves radiographic contrast but increases patient dose.

false

true/false The anteroposterior (AP) projection of the lumbar spine opens the intervertebral joint spaces better than the posteroanterior (PA) projection.

false ( PA would open intervertebral joint spaces better)

true/false The lower margin of the cassette must include the symphysis pubis for a scoliosis series.

false (lower margin 1 to 2 inches (3 to 5 cm) below iliac crest)

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

false (need different central ray angles for AP projections; can combine lateral but not AP projections)

True/False Gonadal shielding should always be used for male and female patients for studies of the lumbar spine, sacrum, and coccyx

false (not used for females if the shield would obscure essential anatomy)

true/false The knees and hips should be extended for an AP projection of the lumbar spine

false should be flexed

Most common at the L4-L5 level and may result in sciatica

herniated nucleus pulposus (HNP)

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

lateral

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

left

Select the imaging modality that best demonstrates each of the following pathologic features or conditions. (answer may be used more that once) ____A. Osteoporosis 1.-MRI ____B. Soft tissues of lumbar spine 2.- CT ____C. Structures within subarachnoid space 3.-myelography ____D. Inflammatory conditions such as 4. Bone densitometry Paget's disease 5. nuclear medicine ____E. Compression fractures of the lumbar spine

osteoporosis ===bone densitometry soft tissues of lumbar spine===MRI Structures within subarachnoid space==MRI and myelography inflammatory conditions such as Paget's disease=nuclear medicine Compression fractures of the lumbar spine==CT

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

The small foramina found in the sacrum are called

pelvic sacral foramina

During the AP(PA) right and left bending projections of the lumbar spine, the ___________________serves as a fulcrum during positioning.

pelvis

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?

perform a PA rather than an AP projection and reverse the direction of the central ray from caudad to cephalad

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

place lead blocker on tabletop behind patient

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

promontory

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

right (upside)

A radiograph of an AP projection of the lumbar spine shows that 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 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.

lateral curvature of the vertebral column

scoliosis

congenital defect in which the posterior elements of the vertebrae fail to unite

spina bifida

Forward displacement of one vertebra onto another vertebra

spondylolisthesis

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

the convex side of the spine

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

true

true/false A PA or an AP projection for a scoliosis series frequently includes one erect and one recumbent position for comparison.

true

true/false A PA projection for a scoliosis series produces only about 1/10 the dose to the breasts as compared with the AP projection, even if proper collimation is used.

true

true/false An increased source image receptor distance (SID) of 44 to 46 inches (112 to 117 cm) reduces magnification of the spine anatomy.

true

true/false Placing a lead blocker mat behind the patient for lateral lumbar spine positions improves image quality.

true

true/false When positioning the obese patient, the iliac crest is typically at the level the inferior margin of the flexed elbow.

true