The reasoning: RIPE
| Check | Criterion | Consequence if poor |
|---|---|---|
| Rotation | medial clavicular ends equidistant from spinous processes | rotated side: unilateral hyperlucency, distorted mediastinum. Rotation is toward the side where the clavicular end is farther from the spinous process |
| Inspiration | 6 anterior ribs or 9–10 posterior ribs above the right hemidiaphragm (mid‑clavicular line) | poor inspiration: crowded bases (fake consolidation), wide mediastinum, big heart |
| Penetration | lower thoracic vertebral bodies just visible through the heart | under‑penetrated: retrocardiac pathology hidden; over‑penetrated: subtle opacities lost |
| Exposure / field | apices, CP angles and lateral chest walls included | missed apical or basal disease |