Master Set 2 — C-Spine Positioning

Which anatomy should be demonstrated on an AP open-mouth cervical-spine projection?

The dens, C1 lateral masses, and C1–C2 region

What CR angulation is used for an AP open-mouth cervical-spine projection?

Perpendicular, with no routine angulation

Where should the CR be centered for an AP open-mouth cervical-spine projection?

Through the open mouth at the level of C1–C2

What SID does Clover use for an AP open-mouth cervical-spine projection?

Approximately 30–40 inches

How should the upper incisors and skull base be aligned for an AP open-mouth projection?

They should be aligned so neither structure obscures the dens

Why may the patient be instructed to say “ah” during an AP open-mouth projection?

To depress the tongue so it does not obscure the upper cervical anatomy

The skull base is superimposed over the dens on an AP open-mouth image. What positioning error is present and how should it be corrected?

The chin is too high; lower or flex the chin, or use a slight caudad correction if necessary

What evaluation finding indicates that the patient was not rotated on an AP open-mouth image?

The dens should be approximately equal distance from the right and left lateral masses of C1

Which anatomy is primarily demonstrated on an AP axial cervical-spine projection?

C3 through the lower cervical spine, with the upper thoracic region included when possible

What CR angle is used for an AP axial cervical-spine projection?

15–20° cephalad

Where should the CR be centered for an AP axial cervical-spine projection?

C4 at the midsagittal plane

What SID is typically used for an AP axial cervical-spine projection?

40 inches

How should the MSP be positioned for an AP axial cervical-spine projection?

Centered to and perpendicular to the middle of the IR

What breathing instruction is used for an AP axial cervical-spine projection?

Suspend respiration

What should the intervertebral disk spaces look like on a properly positioned AP axial cervical-spine image?

They should appear open

What evaluation findings indicate that an AP axial cervical-spine image was obtained without rotation?

Spinous processes are centered and the pedicles appear symmetric

Why are cervical-spine oblique projections performed?

To demonstrate the intervertebral foramina

Approximately how much should the patient be rotated for a cervical-spine oblique projection?

45°

In a cervical-spine oblique projection, what does the 45° measurement refer to?

Patient or body rotation

In a cervical-spine oblique projection, what does the 15–20° measurement refer to?

CR angulation

What CR angulation is used for AP axial cervical obliques, such as RPO and LPO?

15–20° cephalad

What CR angulation is used for PA axial cervical obliques, such as RAO and LAO?

15–20° caudad

What SID does Clover use for cervical-spine oblique projections?

72 inches

Why is a long SID such as 72 inches used for cervical-spine oblique projections?

It helps reduce magnification caused by the increased OID created by rotating the patient

Which intervertebral foramina are demonstrated on AP cervical obliques?

The foramina farthest from the IR

Which intervertebral foramina are demonstrated on PA cervical obliques?

The foramina closest to the IR

Which intervertebral foramina are demonstrated on an RPO cervical-spine projection?

Left intervertebral foramina

Which intervertebral foramina are demonstrated on an LPO cervical-spine projection?

Right intervertebral foramina

Which intervertebral foramina are demonstrated on an RAO cervical-spine projection?

Right intervertebral foramina

Which intervertebral foramina are demonstrated on an LAO cervical-spine projection?

Left intervertebral foramina

What should the intervertebral foramina look like on a properly positioned cervical oblique image?

Open and well demonstrated as round or oval openings

Which anatomy should be included on a routine cervical-spine oblique projection?

C1–C7 and approximately T1

Which cervical-spine projection best demonstrates the intervertebral foramina?

Oblique cervical-spine projections

What SID is commonly used for a lateral cervical-spine projection?

72 inches

What CR angulation is used for a routine lateral cervical-spine projection?

Perpendicular, with no routine angulation

Where should the CR be centered for a routine lateral cervical-spine projection?

C4

What breathing instruction is commonly used for a lateral cervical-spine projection?

Suspend on expiration to help lower the shoulders

Which anatomy should be included on a properly positioned lateral cervical-spine image?

C1 through C7 and ideally the C7–T1 junction

Which cervical joints are best demonstrated on a lateral cervical-spine projection?

Zygapophyseal joints of C2–C7

What should the vertebral bodies and intervertebral disk spaces look like on a properly positioned lateral cervical-spine image?

They should be demonstrated in profile

What should the spinous processes look like on a true lateral cervical-spine image?

They should appear in profile

If C7–T1 is not demonstrated on the routine lateral cervical-spine image because of shoulder superimposition, which additional projection should be performed?

Swimmer’s lateral

Which anatomy should immediately make you think of a cervical oblique rather than a lateral projection?

Intervertebral foramina

Which anatomy should immediately make you think of a lateral cervical-spine projection rather than an oblique?

Zygapophyseal joints