Master Set 2 — Thoracic Spine Positioning

Which projections are considered routine for the thoracic spine?

AP and lateral

What SID is commonly used for an AP thoracic-spine projection?

40 inches

What CR angulation is used for a routine AP thoracic-spine projection?

Perpendicular to the IR

At which vertebral level is the CR centered for an AP thoracic-spine projection?

T7

Which surface landmark approximates the level of T7 posteriorly?

Inferior angle of the scapula

Which anterior surface landmark may be used to approximate T7 for an AP thoracic spine?

Approximately midway between the jugular notch and xiphoid process

Why may the knees be flexed for a supine AP thoracic-spine projection?

To reduce lumbar lordosis and place the spine more parallel and closer to the table

What breathing instruction is commonly used for an AP thoracic-spine projection?

Suspend respiration, commonly at the end of expiration

What anatomy should be included on a properly positioned AP thoracic-spine image?

The entire thoracic spine with the vertebral bodies and intervertebral disk spaces demonstrated

What image-evaluation finding helps confirm that an AP thoracic-spine image is not rotated?

The sternoclavicular joints should appear approximately equidistant from the vertebral column

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

40 inches

What CR angulation is normally used for a lateral thoracic-spine projection?

Perpendicular

At which vertebral level is the CR centered for a lateral thoracic spine?

T7

Which anatomy is demonstrated on a lateral thoracic-spine projection?

Thoracic vertebral bodies, intervertebral disk spaces, and intervertebral foramina

Which projection best demonstrates the thoracic intervertebral foramina?

Lateral thoracic spine

Why are the thoracic intervertebral foramina best demonstrated on the lateral projection?

Their orientation allows them to be viewed more directly in the lateral position

What breathing technique may be used during a lateral thoracic-spine exposure to blur overlying ribs and lung markings?

Shallow breathing during a longer exposure

What is the purpose of the breathing technique on a lateral thoracic-spine image?

To blur ribs and lung markings while keeping the thoracic vertebrae relatively sharp

What respiration may be used instead of the breathing technique for a lateral thoracic spine?

Suspended expiration, depending on technique and protocol

Which thoracic-spine projections best demonstrate the zygapophyseal joints?

Approximately 70° oblique projections

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

About 70°

A 70° thoracic oblique places the patient approximately how far from a true lateral position?

About 20°

What CR angulation is used for a routine thoracic-spine oblique?

Perpendicular

At which vertebral level is the CR centered for a thoracic-spine oblique?

T7

What SID is commonly used for thoracic-spine oblique projections?

Approximately 40 inches

What breathing instruction is commonly used for thoracic-spine oblique projections?

Suspend respiration at the end of expiration

Which thoracic zygapophyseal joints are demonstrated on an RPO projection?

Left zygapophyseal joints

Which thoracic zygapophyseal joints are demonstrated on an LPO projection?

Right zygapophyseal joints

Which thoracic zygapophyseal joints are demonstrated on an RAO projection?

Right zygapophyseal joints

Which thoracic zygapophyseal joints are demonstrated on an LAO projection?

Left zygapophyseal joints

Which side of the thoracic zygapophyseal joints is demonstrated on posterior obliques?

The side farthest from the IR, or the side up

Which side of the thoracic zygapophyseal joints is demonstrated on anterior obliques?

The side closest to the IR, or the side down

Which thoracic oblique positions demonstrate the left zygapophyseal joints?

RPO or LAO

Which thoracic oblique positions demonstrate the right zygapophyseal joints?

LPO or RAO

Why is approximately 70° of rotation required for thoracic-spine obliques?

The thoracic zygapophyseal joints lie approximately 70–75° to the MSP, so this rotation opens the joint spaces

What is one radiation-protection advantage of anterior thoracic-spine obliques compared with posterior obliques?

They can reduce radiation exposure to the breasts

Which projection is used when the shoulders obscure the C7–T1 cervicothoracic junction?

Swimmer’s lateral

What anatomy is primarily demonstrated on a Swimmer’s lateral projection?

Lower cervical and upper thoracic vertebrae, especially C7–T1

Where is the CR directed for a Swimmer’s lateral projection?

Toward the C7–T1 cervicothoracic junction

What CR angulation is commonly used for a Swimmer’s lateral projection?

Usually perpendicular; a slight 3–5° caudad angle may be used if necessary

How should the shoulders be positioned for a Swimmer’s lateral projection?

One shoulder is elevated while the opposite shoulder is depressed

Why are the shoulders offset during a Swimmer’s lateral projection?

To prevent the shoulders from superimposing over the cervicothoracic junction

Which projection best demonstrates cervical intervertebral foramina?

Cervical obliques

Which projection best demonstrates thoracic intervertebral foramina?

Lateral thoracic spine

Which projection best demonstrates cervical zygapophyseal joints?

Lateral cervical spine

Which projection best demonstrates thoracic zygapophyseal joints?

Approximately 70° thoracic obliques

Which projection best demonstrates lumbar zygapophyseal joints?

Approximately 45° lumbar obliques

How do thoracic and lumbar oblique angles differ?

Thoracic obliques use approximately 70° rotation, while lumbar obliques use approximately 45°