Bony Thorax

Published on 03/05/2015 by admin

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Last modified 03/05/2015

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Bony Thorax

Bony Thorax—Positioning Considerations

The routine for a sternum generally includes a lateral and an oblique wherein the sternum is shifted to the left of the spine and is superimposed over the homogeneous heart shadow. A 15°–20° RAO achieves this best. An orthostatic-breathing technique generally is used to blur out the lung markings and the ribs overlying the sternum. If preferred, exposure can also be made on suspended expiration.

Ribs

Each technologist should determine the preferred routine for his or her department.

Two-Image Routine

One suggested two-image routine is an AP or PA with the area of injury closest to the image receptor (IR) (above or below diaphragm) and an oblique projection of the axillary ribs on the side of injury. Therefore the oblique for this routine on an injury to the left anterior ribs would be an RAO shifting the spine away from the area of injury and to increase visibility of the left axillary ribs. The oblique for an injury to the right posterior ribs would be an RPO wherein the spine again is rotated away from the area of injury.

Three-Image Routine

Another three-image routine required in some departments for all rib trauma consists of AP above diaphragm or AP below diaphragm and RPO and LPO of the site of injury.

Above and Below Diaphragm

The location of the injury site in relationship to the diaphragm is important for all routines. Those injuries above the diaphragm require less exposure (nearer to a chest technique) when taken on inspiration and those below the diaphragm require an exposure nearer to that of an abdomen technique when taken on expiration.

Right Anterior Oblique (RAO) Sternum ^*

• 24 × 30 cm L.W. (10 × 12″)

• Orthostatic-breathing technique or suspended expiration

• AEC not recommended

Fig. 7-1 Erect 15°–20° RAO sternum (insert: trauma option).

Position

• Erect (preferred) or semiprone, turned 15°–20° with right side down. (A thin-chested patient requires slightly more obliquity than a thick-chested patient.)

• Center sternum to CR at midline of table or IR holder

Central Ray:

CR ⊥, to midsternum (midway between jugular notch and xiphoid process)

SID:

40-44″ (102-113 cm)

Collimation:

Long, narrow collimation field to region of sternum

Respiration:

Orthostatic-breathing technique of 2-3 seconds or suspend upon expiration

Lateral Sternum ^*

• 24 × 30 cm L.W. (10 × 12″) or 30 × 35 cm (11 × 14″)

• AEC not recommended

• Place lead blocker anterior to sternum (for recumbent position)

Fig. 7-2 Lateral, erect sternum (trauma option).

Position

• Erect (seated or standing), or recumbent lying on side with vertical CR; or supine with cross-table CR for severe trauma

• Draw shoulders and arms back.

• Align sternum to CR at midline of IR holder.

• Top of IR 1.5″ (4 cm) superior to level of jugular notch

Central Ray:

CR ⊥, to midsternum

SID:

60-72″ (153-183 cm)

Collimation:

Long, narrow collimation field to region of sternum

Respiration:

Expose upon full inspiration.

Oblique (RAO) Sternum

Evaluation Criteria

Anatomy Demonstrated:

• Entire sternum superimposed on heart shadow

Position:

• Correct rotation, sternum visualized alongside vertebral column

Exposure:

• 2- to 3-second exposure using breathing technique; lung markings appear blurred

• Optimal contrast and density (brightness) to visualize entire sternum

Fig. 7-3 RAO sternum.

Lateral Sternum

Anatomy Demonstrated:

• Entire sternum

Position:

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