McRae line

McRae line is a radiographic line drawn on a lateral skull radiograph or midsagittal section of CT or MRI, joining the basion and opisthion.

Normal position of the tip of dens is 5mm below this line. If the tip of the dens migrates above this line it indicates the presence of basilar invagination (atlanto-axial impaction).

See also

Share article

Article information

rID: 25669
Section: Gamuts
Synonyms or Alternate Spellings:
  • McRae's line

Support Radiopaedia and see fewer ads

Cases and figures

  • Figure 1: McRae line
    Drag here to reorder.
  • Figure 2
    Drag here to reorder.
  • Figure 3
    Drag here to reorder.
  • Updating… Please wait.

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

     Thank you for updating your details.