Sternum PA Oblique RAO is a radiography positioning projection of the Thorax. PA oblique sternum (RAO), 15-20 degrees. SID 30". Breathing technique. The centering point is located midpoint of the sternum. patient in rao position, 15-20 degrees oblique.. The central ray is perpendicular to ir (patient is the rotated element, not the tube).. Image-quality criteria include sternum visualized in the center of the field, free from rib superimposition., sternal body, angle, and xiphoid process all visible.. Standard exposure ranges from 65 to 75 kVp, 30 to 60 mAs, at an SID of 30 inches (76 cm).
Anatomy demonstrated
- Manubrium.
- Sternal body.
- Xiphoid process.
- Sternal angle and articulations.
- Mediastinal structures (blurred).
- Proximal ribs (blurred by breathing).
Patient preparation
- Verify patient identity using two identifiers.
- Remove all radiopaque objects from the chest.
- Position patient in RAO position, right anterior side closest to IR.
- Rotate 15-20 degrees from true PA position.
- Explain breathing technique: shallow breathing during exposure to blur structures.
Position & centering point
Midpoint of the sternum. Patient in RAO position, 15-20 degrees oblique.
Central ray
Perpendicular to IR (patient is the rotated element, not the tube).
Exposure / technique
- kVp
- 65–75
- mAs
- 30–60
- SID
- 30" (76 cm)
- Notes
- High mAs for breathing technique. Patient breathes during exposure to blur ribs and mediastinal structures.
Image-quality criteria
- Sternum visualized in the center of the field, free from rib superimposition.
- Sternal body, angle, and xiphoid process all visible.
- Ribs blurred from motion, with the sternum sharp.
- Mediastinal structures blurred from breathing motion.
- Vertebral column visible but not overlapping the sternum.
- No rotation evident; sternum in the midline.
Common errors / ARRT traps
- 1 Inadequate obliquity (less than 15 degrees) fails to clear the sternum from ribs.
- 2 Excessive obliquity (more than 20 degrees) projects the sternum off midline.
- 3 Breathing technique not performed leaves ribs sharp and overlapping.
- 4 Rotation forward or backward moves the sternum off the midline.
- 5 Inadequate SID (closer than 30 inches) magnifies and distorts the sternum.
Clinical indications
- Evaluation of sternal fractures.
- Assessment of sternal osteomyelitis or infection.
- Detection of sternal metastases or pathology.
- Post-operative follow-up after cardiac surgery.
Aligned to the 2025 ARRT Content Specifications.