As of the latest update, Google Chrome and Microsoft Edge have made a breaking change to how file uploads are handled. Once your system installs this update, you will not be able to upload new images. Please use another browser until we can get it fixed.

Extra-axial

Extra-axial is a descriptive term to denote lesions that are external to the brain parenchyma, in contrast to intra-axial which describes lesions within the brain substance. 

Often it is trivially easy to distinguish an intra-axial from an extra-axial mass. In many cases, especially when the mass is large and associated with parenchymal changes, such as edema, localization can be more difficult. A number of features are helpful in suggesting that a mass or lesion is extra-axial, including: 

Examples (non-exhaustive) of extra-axial lesions include:

Share article

Article information

rID: 7961
Section: Gamuts
Synonyms or Alternate Spellings:
  • Extraaxial

Support Radiopaedia and see fewer ads

Cases and figures

  • Case 1: subarachnoid hemorrhage (SAH)
    Drag here to reorder.
  • Case 2: hemangiopericytoma
    Drag here to reorder.
  • Case 3: extradural hemorrhage (EDH)
    Drag here to reorder.
  • Case 4: arachnoid cyst
    Drag here to reorder.
  • Case 5: subdural hemorrhage (SDH)
    Drag here to reorder.
  • Case 6: all three types of extra-axial hemorrhage
    Drag here to reorder.
  • Updating… Please wait.

     Unable to process the form. Check for errors and try again.

     Thank you for updating your details.