Bill bar

Bill bar is a bony anatomical landmark that divides the superior compartment of the internal acoustic meatus into an anterior and posterior compartment. Anterior to Bill bar, in the anterior superior quadrant, are the facial nerve (CN VII) and nervus intermedius, and posterior to it, in the posterior superior quadrant is the superior division of the vestibular nerve (see figure 1). 

A recent study comparing the ability of a clinical 7 T magnet to distinguish the finer inner ear anatomy, in comparison with a 3 T magnet, found that Bill bar was occasionally visible at both field strengths 4. It has generally not been possible to see on HRCT of the temporal bone.

History and etymology

Bill bar was named after William Fouts House (1923-2012), an American otologist, who was known informally as "Dr. Bill".

Anatomy: Head and neck
Share article

Article information

rID: 994
Section: Anatomy
Synonyms or Alternate Spellings:
  • Bill's bar

Support Radiopaedia and see fewer ads

Cases and figures

  • Drag
    Figure 1: diagram of a saggital view of the IAM
    Drag here to reorder.
  • Updating… Please wait.
    Loadinganimation

    Alert accept

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

    Alert accept Thank you for updating your details.