Falciform crescent

The falciform crescent (or crista falciformis) is a horizontal ridge that divides the internal acoustic meatus into superior and inferior portions.


The facial nerve and superior vestibular nerve (SVN) travel in the superior portion of the IAM with the facial nerve anterior to the SVN and separated from it in the lateral portion by Bill's bar, a vertical ridge of bone.


The cochlear nerve and inferior vestibular nerve (IVN) run inferior to the falciform crescent with the cochlear nerve situated more anteriorly.

Head and neck anatomy
Share article

Article information

rID: 4518
System: Head & Neck
Tag: refs
Synonyms or Alternate Spellings:
  • Crista falciformis

Cases and figures

  • Drag
    Fig 1: nerves of the internal acoustic meatus
    Drag here to reorder.
  • Updating… Please wait.

    Alert accept

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

    Alert accept Thank you for updating your details.