RAO-mance Is in the Air
The two routine projections performed for a sternum examination.
What are the RAO and lateral projections?
The type of mA selection used with a breathing technique.
What is low mA?
The vertebral level used for centering PA sternoclavicular joints.
What is T2 to T3?
The centering level for AP bilateral ribs above the diaphragm.
What is T7, located 3 to 4 inches (8 to 10 cm) below the jugular notch, and MSP?
Equal distances from the vertebral column to each medial clavicle indicate absence of this positioning error.
What is rotation?
Below-diaphragm rib images should include these numbered ribs.
What are ribs 8 through 12?
The centering point for PA unilateral ribs above the diaphragm.
What is the level of T7 and halfway between the thoracic vertebrae and the axillary rib margin?
The reason the chin is elevated when imaging the bony thorax.
What is to prevent superimposition of the mandible or soft tissue over the pertinent anatomy?
The amount of rotation typically required for a thin-chested patient in an oblique sternum projection.
What is approximately 20°?
During positioning for a lateral sternum, the shoulders and arms should be moved in this direction.
What is backward (drawn back)?
The CR is centered approximately this distance below the vertebra prominens for a PA SC joints projection.
What is 3 inches (7 cm)?
Deep breathing during a sternum projection causes this problem.
What is sternum blur from motion?
This spinal condition may mimic rotation on rib images.
What is scoliosis?
AP oblique ribs are preferred because they minimize this image characteristic.
What is rib magnification?
The centering point for AP bilateral ribs below the diaphragm.
What is midway between the xiphoid process and the inferior costal margin and MSP?
This image quality indicator confirms there was no patient motion during the exposure when imaging ribs.
What are sharp bony cortices (margins/detail)?
The recommended collimated field size for sternum imaging.
What is 10 × 12 inches (24 × 30 cm)?
The evaluation criterion indicating no patient rotation on a lateral sternum.
What is the sternum demonstrated without rib superimposition?
Respiration should be suspended on this phase for PA SC joints.
What is expiration?
The sternum should be centered approximately this distance left of the thoracic spinous processes.
What is 3 inches?
*Martensen
If the sternum remains partially superimposed by the vertebral column in an RAO, this positioning error occurred.
What is insufficient obliquity?
If the sternum is adjacent to the vertebral column on an AP oblique rib image, this positioning error occurred.
What is insufficient obliquity?
The sternum should lie approximately here on a properly positioned AP oblique rib image.
What is halfway between the vertebral column and the lateral rib surface?
The reason the thoracic spine must be included on unilateral rib projections.
What is because the rib articulates with the thoracic vertebrae (need to include the entire rib)?
If a breathing technique cannot be performed for an oblique sternum, respiration should be suspended on this phase.
What is expiration?
This adaptation for the lateral sternum projection may be used for trauma patients unable to stand.
What is a horizontal beam (x-table) lateral projection?
Correct positioning is demonstrated when both SC joints are this relationship from the spine.
What is equidistant from the vertebral column?
This structure should be blurred on a properly performed PA oblique sternum.
What are lung markings?
On a PA oblique sternum, the sternoclavicular joints should appear within this structure.
What is the heart shadow?
When torso obliquity exceeds 15 degrees during an SC articulation study, the joint appears this way.
What is closed?
In the PA rib projection, the side closest to the IR demonstrates this clavicular appearance when rotated into an oblique position.
What is superimposition of the clavicle on the vertebral column?
The two types of chest pathology that may accompany rib fractures.
What is pneumothorax and hemothorax?
The CR location for an RAO sternum projection.
What is the center of the sternum, 1 inch left of midline and midway between the jugular notch and xiphoid process?
The recommended amount of rotation for oblique sternoclavicular joint projections.
What is 10° to 15°?
In an RAO projection, this sternoclavicular joint is best demonstrated.
What is the right (downside) sternoclavicular joint?
This many posterior ribs should ideally be seen above the diaphragm on a proper above-diaphragm study.
What are eight to nine posterior ribs?
Tight collimation, a grid, and a lead sheet help reduce this imaging problem on a lateral sternum.
What is scatter radiation?
Rotating the chest away from the affected side during AP oblique ribs causes this appearance.
What is excessive foreshortening of the axillary ribs?
If the sternum is lateral to the midpoint between the vertebral column and anterior ribs, this error occurred.
What is excessive obliquity?
On a properly positioned AP oblique rib projection, the width between the thoracic spine and the lateral margin of the thorax on the affected side is approximately how much of the opposite side, demonstrating the axillary ribs in profile.
What is twice as much?
The IR should be positioned approximately this distance above the jugular notch for sternum imaging.
What is 1-1½ inches (3-4 cm)?
In an LPO projection, this sternoclavicular joint is best demonstrated.
What is the right (upside) sternoclavicular joint?
Less obliquity of 5° to 10° demonstrates this SC joint in a PA oblique projection.
What is the upside sternoclavicular joint?
Excessive RAO rotation causes this appearance of the sternum.
What is transverse foreshortening?
*Martensen
The superior heart border can help identify this side of the chest on a rotated lateral sternum.
What is the left side?
A PA oblique sternum image demonstrates sharp ribs, visible lung markings, and poor sternum visualization. The positioning factor most likely omitted was this.
What is the breathing technique (shallow breathing with long exposure)?
A lateral sternum image shows the left lung field extending anterior to the sternum and the superior heart border continuing beyond the sternum. This thoracic side is rotated anteriorly.
What is the left thorax?
For a PA oblique sternoclavicular (SC) articulation projection, the central ray is directed this distance lateral from the midsagittal plane toward the elevated side.
What is 1 to 2 inches (2.5 to 5 cm) lateral?