Projections

Ribs, Bilateral PA or AP, above the diaphragm

CR Location & Positioning

• SID: 72 inches preferred (minimizes magnification); 40 inches acceptable
• Patient position: Upright preferred (better inspiration); PA or AP depending on injury location (front vs. back)
• Adjustments: Place affected area closest to IR; MSP centered to midline of IR
• CR: Perpendicular to IR at level of T7 (≈ 3–4″ below jugular notch or 7–8″ below vertebra prominens); top of IR about 1.5″ above shoulders
• Pt. Instructions: Take a deep breath in and hold (full inspiration)
• Exposure: On full inspiration

Evaluation Criteria

• Minimum of 9 posterior ribs visualized above diaphragm
• Sternoclavicular joints equidistant from spine (no rotation)
• Sharp diaphragm and heart borders, no motion
• Ribs visible through lung fields without overexposure of mid-lung region

Ribs, Bilateral PA or AP, below the diaphragm

CR Location & Positioning

• SID: 40–44 inches preferred
• Patient position: Supine preferred (allows diaphragm to rise)
• Adjustments: Place affected area closest to IR; MSP centered to IR
• CR: Perpendicular to IR at level midway between xiphoid process and lower rib margin; bottom of IR at iliac crest
• Pt. Instructions: Breathe out and hold (full expiration)
• Exposure: On full expiration

Evaluation Criteria

• Ribs 10–12 clearly visualized
• Lateral rib margins equidistant from spine (no rotation)
• Optimum exposure of ribs through abdominal organs

Ribs, Anterior or posterior obliques

CR Location & Positioning

• SID: 72 inches preferred for upper ribs; 40 inches acceptable for lower
• Patient position: Upright for upper ribs, supine for lower ribs if possible
• Adjustments: Rotate patient 45°
  • PA obliques (RAO/LAO): affected side closest to IR
  • AP obliques (RPO/LPO): affected side away from IR
  • Raise arm on elevated side above head; rest opposite arm down and behind torso
• CR:
  • Upper ribs: perpendicular to IR at T7 (3–4″ below jugular notch or 7–8″ below vertebra prominens)
  • Lower ribs: midway between xiphoid and lower rib margin; bottom of IR at iliac crest
• Pt. Instructions: Full inspiration for upper ribs; full expiration for lower ribs
• Exposure: On correct breathing phase

Evaluation Criteria

• Appropriate obliquity: affected-side ribs separated from spine (distance ≈ 2× that of opposite side)
• Axillary (lateral) portions of ribs free of superimposition
• Diaphragm included in field, sharp margins, no motion
• Upper rib obliques: ribs 1–10 demonstrated; lower rib obliques: ribs 8–12 demonstrated

Procedure Adaptation

• Localization of pain/fractures: Place a small marker (BB) over site of injury.
• Trauma patients: Use cross-table laterals or modify obliquity as tolerated.
• Breathing limitations: If patient cannot inspire fully due to pain, expect fewer than 10 ribs above diaphragm.
• Obese patients: Ensure CR landmarks (jugular notch, xiphoid, iliac crest) are palpated carefully to avoid miscentering.

Exposure Factors & Technical Considerations

• kVp: 70–85 (upper ribs), slightly higher for lower ribs to penetrate abdomen
• mAs: Adjust for body habitus; short exposure time to minimize motion
• Collimation: Tight to region of interest (upper vs. lower ribs)
• Shielding: Always, when feasible
• IR orientation: Place crosswise at 40″ SID to avoid cutting off ribs due to magnification