EBM Consult

Bimastoid Line on Radiographic Image


  • The bimastoid line is a line connecting the tip of the right and left mastoid bones. 
  • The distance below this line to the tip of the dens is used to assess for the presence of basilar invagination.  The distance should be less than 10 mm above this line.

Bimastoid Line

    Radiographic (X-Ray) Image

    Bimastoid Line Image

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    Editors & Reviewers

    Editors:  Anthony J. Busti, MD, PharmD, FNLA, FAHA
    Last Updated:  June 2015