Chest X-ray Abnormalities
Diaphragmatic abnormalities

Key points

  • Do not miss a pneumoperitoneum
  • An obscured hemidiaphragm may be due to adjacent lung disease
  • An abnormal diaphragm position may indicate a serious pathology

Pneumoperitoneum

Every time you check a chest X-ray you should make sure there is no free intra-abdominal air under the diaphragm (pneumoperitoneum). This is a sign of bowel perforation.

Pneumoperitoneum on an erect chest X-ray

Hover on/off image to show/hide findings

Tap on/off image to show/hide findings

Click image to align with top of page

Pneumoperitoneum on an erect chest X-ray

  • The lungs are normal
  • The diaphragm is crisply defined on both sides (arrowheads)
  • Air under the diaphragm (asterisks) is seen as crescents of relatively low density (black)
  • Black air can be seen on both sides of the bowel wall (blue line) – this is known as the double-wall sign or Rigler's sign (usually only seen on abdominal X-rays)

Clinical information

  • Acute, severe abdominal pain
  • Abdominal guarding on examination
  • Risk factors for peptic ulceration included smoking, high alcohol intake, and long term use of non-steroidal anti-inflammatory drugs

Diagnosis

  • Pneumoperitoneum – at laparotomy a perforated duodenal ulcer was found

Diaphragm contour abnormalities

The normal hemi-diaphragms form distinct dome-shaped contours against the adjacent lungs. If these contours are obscured it is often possible to determine the location of lung disease. For example, the lower lobes of both lungs lie directly in contact with each hemi-diaphragm. Consolidation of the lower lobes, therefore, obscures the crisp contour of the adjacent hemi-diaphragm.

Left lower lobe consolidation

Hover on/off image to show/hide findings

Tap on/off image to show/hide findings

Click image to align with top of page

Left lower lobe consolidation

  • The left hemidiaphragm is obscured (red line = normal position)
  • Consolidation of the left lung base (highlighted area) extends behind the heart

Clinical information

  • Cough, high temperature and raised white cell count

Diagnosis

  • Left lower lobe pneumonia

Raised hemidiaphragm

The right hemi-diaphragm usually lies at a level slightly above the left. There are many possible causes of a raised hemidiaphragm such as damage to the phrenic nerve, lung disease causing volume loss, congenital causes such as a diaphragmatic hernia, or trauma to the diaphragm.

Diaphragmatic rupture

Hover on/off image to show/hide findings

Tap on/off image to show/hide findings

Click image to align with top of page

Diaphragmatic rupture

  • The left hemidiaphragm is not visible
  • There is bowel in the lower half of the left hemi-thorax
  • The mediastinum is displaced to the right

Clinical information

  • History of severe chest trauma

Diagnosis

  • Left hemi-diaphragmatic rupture with herniation of bowel into the left-hemithorax

Phrenic nerve palsy

Hover on/off image to show/hide findings

Tap on/off image to show/hide findings

Phrenic nerve palsy

  • Raised left hemidiaphragm (red to blue lines)
  • Left upper zone mass contacts the mediastinum

Clinical information

  • Known inoperable lung cancer
  • Rapid worsening of shortness of breath

Diagnosis

  • Left phrenic nerve palsy due to direct invasion of the nerve

Caution!

  • Occasionally a raised hemidiaphragm may be mistaken for a pleural effusion
  • They can have similar X-ray appearances and both can cause dullness to percussion, but only an effusion should be drained!
  • A CT may be necessary prior to chest drain insertion if there is doubt

Page author: Salisbury NHS Foundation Trust UK (Read bio)

Last reviewed: September 2016