EBM Consult

Digastric Line on Radiographic Image


  • The digastric line is drawn by connecting a line from the right and left digastric grooves on a coronal cut of a CT scan or AP skull radiograph.
  • It is used to measure the distance from the tip of the dens (odontoid process) to help evaluate the presence of a basilar invagination (a craniocervical junction abnormality where the tip of the dens project up into the foramen magnum). 
  • The tip of the dens should be around 11-12 mm below this line.

Digastric Line

    Radiographic (X-Ray) Image

    Diagstric Line Image 

    Related Content

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    Bimastoid Line           Lateral X-Ray      Odontoid View

    Editors & Reviewers

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