×
MedSchool: Ace Your OSCEsThe Medical Company
 
 
 
 
 
GET - On the App Store
View
Chest X-Ray
 
 

Mediastinal Borders

 
 
 
Bookmark

Silhouette Signs

  • Look For

  • Obliteration of normally clear outlines between the lung fields and adjacent structures such as the heart, aorta or hemidiaphragm.
  • Significance

  • Loss of normal borders appears when the adjacent area of lung is consolidated or collapsed.
  • Interpretation

  • Upper right heart border / ascending aorta - anterior right upper lobe
  • Upper left heart border - anterior left upper lobe
  • Aortic knob / arch - apical left upper lobe
  • Right heart border - right middle lobe
  • Left heart border - lingular lobe
  • Anterior hemidiaphragms - lung bases / lower lobes
  • Examples

  • Obscuration of the right hemidiaphragm suggesting right lower lobe consolidation
  • Obscuration of the right hemidiaphragm suggesting right lower lobe consolidation
     
  • Obscuration of the left hemidiaphragm suggesting right lower lobe consolidation
  • Obscuration of the left hemidiaphragm suggesting right lower lobe consolidation
     
  • Obscuration of the ascending aorta, suggesting right upper lobe consolidation
  • Obscuration of the ascending aorta, suggesting right upper lobe consolidation
     

Mediastinal Air

Air within the mediastinum is known as pneumomediastinum.
  • Look For

  • Overly sharp mediastinal borders
  • Lucencies around the cardiac apex and great vessels
  • Example

  • Pneumomediastinum and pneumoperitoneum in a post-trauma patient
  • No Overlay
    Overlay
    Pneumomediastinum and pneumoperitoneum in a post-trauma patient
     
  • Causes of Pneumomediastinum

  • Tracheal / major bronchial rupture - trauma, iatrogenic, spontaneous
  • Oesophageal rupture - trauma, iatrogenic, spontaneous
  • Alveolar rupture - asthma, airway foreign body, mechanical ventilation, coughing, vomiting, pneumonitis, emphysema, fibrosis
  • Tracking of air from the neck - facial fracture, dental extraction, tracheostomy
  • Tracking of air from the abdomen - hollow viscous perforation
Next Page
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Want more info like this?
  • Your electronic clinical medicine handbook
  • Guides to help pass your exams
  • Tools every medical student needs
  • Quick diagrams to have the answers, fast
  • Quizzes to test your knowledge
Sign Up Now
   
 
 

Snapshot: Initialising...