Radiology Guides Anatomy Physio & Path Medicine Physics Contact


1. FRONTAL X-RAY: AP orientation

  • Advantages: better for intubated, sick patients.
  • Disadvantages: mediastinal structures may appear magnified, poorly inspired, rotated; poor inspiration causes crowding of the vessels and the mediastinum to be wider than normal.
  • Beware: may not be labeled as such! In which case look at the: clavicles (appear more vertical in AP orientation, more horizontal in PA orientation), label (will be labeled SUPINE), number of lines (sick patients have more lines).

2. FRONTAL X-RAY: PA orientation

  • Advantages: better visualization of the mediastinum and lung fields.
  • Disadvantages: must be able to stand erect.

3. Lateral orientation

  • Labeled with the side closest to the cassette.
  • Used to confirm the presence + location of opacities on frontal X-rays.
  • Left lateral view: stomach bubble present under the left hemidiaphragm, right hemidiaphragm appears higher + more complete (as the right is closer to the beam), left hemidiaphragm is less distinct due to the cardiac silhouette.

4. Lateral decubitus

  • The patient is laying either left lateral or right lateral on a trolley on top of a radiolucent sponge.
  • The detector is placed landscape posterior to the patient running parallel with the long axis of the thorax.
  • The patient’s hands should be raised to avoid superimposing on the region of interest, legs may be flexed for balance.
  • Problem-solving film. Used to differentiate pneumothorax vs. pleural effusion; pneumothorax vs. pneumomediastinum.
  • Also useful in detecting foreign-body inhalation in kids.


1. Goodman, L. and Felson, B. (2015). Felson's principles of chest roentgenology. 3rd ed. Philadelphia, PA: Elsevier, Saunders.
2. Dähnert W. Radiology Review Manual. LWW. (2011) ISBN:1609139437. Read it at Google Books - Find it at Amazon
3. Elizabeth Puddy, Catherine Hill; Interpretation of the chest radiograph, Continuing Education in Anaesthesia Critical Care & Pain, Volume 7, Issue 3, 1 June 2007, Pages 71–75, https://doi.org/10.1093/bjaceaccp/mkm014

Ⓒ A. Manickam 2018

+ Home