Ribs Anterior PA is a radiography positioning projection of the Thorax. PA anterior ribs, erect. SID 40". Full inspiration. The centering point is located level of T7, 7 to 8 inches (18 to 20 cm) below the vertebra prominens, at the midsagittal plane. Patient erect, anterior chest against IR. The central ray is perpendicular to IR, centered to T7 (7 to 8 inches [18 to 20 cm] below the vertebra prominens, as for a PA chest). Image-quality criteria include ribs 1 through 9 visualized above the diaphragm, no rotation of the thorax. A sample technique is 81 kVp with DR 10 or CR 20 mAs, at the chart's 72 in SID. The working SID is 40 inches (102 cm).
Watch the setup
All steps (3)
- Position patient erect (preferred) facing the IR, anterior chest against it, arms down at the sides; prone if necessary.
- Rotate the shoulders anteriorly to remove the scapulae from the lung fields; no rotation of the thorax or pelvis.
- Align the midsagittal plane to the CR and to the midline of the upright Bucky.
3D anatomy: BodyParts3D, © The Database Center for Life Science. Posed, rendered and labelled by RadTechPrepper. These animations are licensed CC BY-SA 4.0. Credits
Anatomy demonstrated
- Ribs 1-9 above the diaphragm (Bontrager); Merrill's: anterior ribs 1-7, with ribs 1-9 by posterior portions.
- Ribs seen through the lungs and heart shadow.
Patient preparation
- Verify patient identity using two identifiers.
- Remove all radiopaque objects from the chest and trunk.
- Position patient erect (preferred) facing the IR, anterior chest against it, arms down at the sides; prone if necessary.
- Instruct patient to take a deep breath in and hold for the exposure.
- Rotate the shoulders anteriorly to remove the scapulae from the lung fields; no rotation of the thorax or pelvis.
- Align the midsagittal plane to the CR and to the midline of the upright Bucky.
Position & centering point
Level of T7, 7 to 8 inches (18 to 20 cm) below the vertebra prominens, at the midsagittal plane. Patient erect, anterior chest against IR.
Central ray
Perpendicular to IR, centered to T7 (7 to 8 inches [18 to 20 cm] below the vertebra prominens, as for a PA chest).
Exposure / technique
- kVp
- 81
- mAs
- DR 10 / CR 20
- Chart row
- kVp and mAs at the chart's 72 in SID
- Working SID
- 40" (102 cm)
- Notes
- Grid required. Full inspiration held throughout the exposure. Sample technique: DR 10 / CR 20 mAs at 81 kVp, 72 in SID, for a 21 cm part (Merrill's sample chart). Adjust for your equipment. Bontrager prints digital 85 +/- 5 kV.
kVp and mAs are sample values. Use caution when applying them in your department.
Image-quality criteria
- Ribs 1 through 9 visualized above the diaphragm.
- No rotation of the thorax.
- Ribs seen through the lungs and heart, with sharp bony markings (no motion).
Common errors
- 1 Rotation tilts the ribs and obscures the costochondral junctions.
- 2 Inadequate inspiration elevates the diaphragm and hides the lower anterior ribs.
- 3 Patient not positioned with anterior chest flush against IR.
- 4 Shoulders not rotated forward leave the scapulae over the upper lung fields.
- 5 CR aimed above or below T7 clips anatomical structures.
- 6 Rotation of the thorax or pelvis.
- 7 Shoulders not rotated anteriorly, leaving the scapulae over the lung fields.
- 8 CR not centered to T7, 7 to 8 inches below the vertebra prominens.
Clinical indications
- Pathology of the ribs, including fracture or neoplastic processes.
- Assessment of anterior rib fractures.