Chapter 9 Positioning

The largest individual vertebrae are the

five lumbar vertebrae

The strongest vertebrae in the vertebral column are the

Lumbar Vertebrae

The most common site for injury and pathologic processes in the lumbar vertebrae is at the

Cartilaginous Disks

The largest lumbar verterbrae is

L5

What part of the Lumbar Vertebrae is the most palpable?

The spinous process

In relation to the vertebral body, the spinous process lies ________ to the body.

Inferior

The Intervertebral Foramen is situated __ degrees relative to the midsagittal plane.

90

What passes between the two intervertebral foramina?

Spinal nerves and blood vessels.

The intervertebral foramina in the lumbar region is best demonstrated on a

Lateral position.

The zygaphophyseal joints form an angle open from __ degrees to __ degrees to the midsagittal plane

45, 65

The upper or proximal lumbar verterbae zygaphophyseal joints are closer to the __ degree angle.

65

The lower or distal lumbar verterbae zygaphophyseal joints are closer to the __ degree angle.

45

To see the mid-zygophyseal joints of the lumbar region in an image, you must

rotate the patient’s body 45 degrees.

The pars interarticularis is demonstrated radiographically on

Oblique lumbar position

The sacrum is shaped like what?

A shovel

The apex of the sacrum is pointed

inferiorly and anteriorly

The sacrum has four sets of

anterior and posterior pelvic sacral foramina.

The pelvic sacral foramina has what running through it?

Nerves and blood vessels

In a posterior prespective, the sacrum has a dominate ______ curve.

Convex

The curves of the sacrum determine how the

central ray must be angled for AP sacrum/coccyx.

What is the anatomical term for the anterior ridge of the first sacral segment (S1) that forms the posterior boundary of the pelvic inlet?

The promontory of the sacrum.

The promontory of the sacrum is best visualized on radiographic images with a

lateral position.

Posterior to the body of the first sacral segment is the opening to the

Sacral Canal

The sacral canal is a continuation of the ________ _____ and contains

vertebral canal, certain sacral nerves

The median sacral crest is formed by

fused sacral vertebrae spinous processes

Where does the sacrum articulates with the ilium of the pelvis? What does these two form?

at the Auricular Surface, The Scaroiliac Joint

The auricular surface gets name because it resemblence to the the shape of the

auricle of the ear

What are the sacral horns (cornua)?

Small tubercles representing the inferior articular processes of the fifth sacral segment (S5) that project inferiorly

The Sacral Horns prjoject ________ and ________ to articulate with the

inferiorly, posteriorly, horns of the coccyx

To open the sacroiliac joint, you must

oblique at an angle of 30 degrees

What direction do the articulating factes of the superior articular processes open?

They open posteriorly

Deteriorating bone leaves the part of the sacrum partially open.

The sacral canal.

The most distal portion of the vertebral column is the

Coccyx

The anterior surface of the tailbone is also called the

Pelvic Surface

The portion of the vertebral column that has greatly regressed is the

Coccyx

The single coccyx is formed in Adults when the

3 to 5 coccygeal sements fused.

Occasionally, the second segment does not

fuse solidly with the larger first segment.

Since the long axis of the sacrum is angled posteriorly, what type of angle do you need for an AP projection?

Cephalad

The posterior angle of the Coccyx is is greater in average _____ compared with average _______

Woman, Man

The apex of the coccyx curves _______ and points toward the _______ ______

anteriorly, symphysis pubis.

The forward curvature of the coccyx is more pronounced in _________ and is less pronounced/curved in ________

Men, Woman

If the coccyx is angled excessively forward in woman, this can impede

the birth process

The most common injury associated with the coccyx is

a direct blow to the lower vertebral column when a person is in a sitting position. This can happen from falling backward witha forceful sitting action

Who is more likely to experience a coccyx fracture? A man or female?

Female because they have a more vertical orientation of the coccyx.

To see the scottie dog in the lumbar vertebrae you need

a 45 degree obleque.

In the scottie dog, what forms the neck?

ONe pars interacrticularis

In the scottie dog, what forms the ear?

one superior articular process

In the scottie dog, what forms the eye?

One pedicle

In the scottie dog, what forms the nose?

One transverse process

In the scottie dog, what forms the front legs?

One inferior articular process

The zygapophyseal joints are between the

superior and inferior articular processes

The zyga joints are classifed as _______ joints and are ________ with a _______ type of movement

synovial, diathrodial, plane (gliding)

Intervertebral Joints are classified as _______ joints, and are ________ .

cartilaginous, amphiarthrodial

To view the downside zygapophyseal joints, you will need a

posterior oblique position.

The downside zyga joints are located where.

“Under” the bodies of the vertebrae

What postion may be more comfortable for that patient that may allow the natural lumbar curvature of the spine to coincide with the divergence of the x-ray beam?

Anterior Oblique

To view the upside/left zyga joints, you will need a

right anterior oblique

A ____ degree oblique is generally used for the lumbar region, but if you are specifically focuing on L1 or L2 you will use a ____ degree rotation

45, 50

The reason that the upper lumbar require more of an agle is because

they take on characteristics of the thoracic vertebrae

What are five lower spine landmarks?

Symphysis Pubis, ASIS (S1-S2), Illiac Crest (L4-L5), Lower Costal Margin(L2-3), Xiphoid Tip (T9-T10)

For AP lumbar recumbent, why are the knees flexed.

Reduces the lumbar curvature (lordosis), brings the back closer to the table, the lumbar vertebral are more parallel to the IR and greater patient comfort.

For AP Lumbar recument, what happens if you dont flex the knees?

The lumbar curvature becomes exaggerated.

Which of the two has an advantage over the other? AP Lumbar or PA Lumbar?

PA. The prone position places the Lumbar spine in its natural curvature that allows the disk spaces to open/better visualized and almost parallel to the beam.

Whats a benefit for PA Lumbar for women?

Lower ovarian dose by 25% to 30%.

Whats a disadvantage for PA Lumbar?

Increased OID, which results in magnification and reduced image resolution.

High kVp and low mAs reduces

patient dose

What will reduce scatter radiation?

Close collimatino, grids, table masking for laterals

What can you put under a patients waist for a lateral to ensure that the spine is parallel with the IR?

A sponge.

Short exposure time (associated with high use of high mAs) can reduce what?

Patient motion

Patients with severe kyphosis might be more comfotable positioned

erect for the images.

Because of high incidence of osteoprosis in geriatirc patients, you should

decrease kvp or mAs

To penetrate thicker tissue you will need to increase

kVp

In the vertebral column, what modality would show fractures, disk diseases, and neoplastic disease?

Computed Tomography (CT)

The superior way to view soft tissue structures in the lumbar spine, what modality would you use?

Magnetic Resonance (MR)

What modality uses a tracer injected in areas of increased bone acitivty (hot spot) to show skeletal pathologic processes?

Nuclear Medicine

Patients who go through skeletal metastases, inflammatory conditions, paget disease, neoplastic processes and osteomyelitis are shown in

Nuclear Med

What modality is the noninvasive measurement of bone mass?

Bone Densitometry

Bone densitometry is accurate to within ___ % and the radiation skin does is _____

1, low

What modality injects a contrast into the subarachnoid space via lumbar or cervical puncture to visualize soft tissue structures of the spinal canal

Myelography

What two modalities reduce the number of myelograms performed?

CT and MR

If you see anterior wedging of vertebrae and/or loss body of height, what injury do you have?

Compression fracture

Whats the exposure factor adjustment for compression fractures?

None or slight decrease depending on the severity.

What type of bone metastases involes destructive leasions with irregular margins?

Osteolytic

What type of bone metastases have proliferative bony leasions of increased density?

Ostoblastic

What type of bone metastases involves moth-eaten apperance of bone resulting from the mix of destructive and blastic lesions.

Combination osteolytic and osteoblastic

Whats the exposure factor adjustment for metastases?

None or increase or decrease depending on the state of pathologic process.