Location:
• Lies in petrous part of the temporal bone
• Opens into posterior cranial fossa.
• It is divided by a transverse ridge (crista falciformis) and vertical crest (Bill’s bar):
Quadrant | Structure |
Anterosuperior | Facial nerve |
Anteroinferior | Cochlear nerve |
Posterosuperior | Superior vestibular nerve |
Posteroinferior | Inferior vestibular nerve |
Mnemonic : “Seven up, Coke down, Balance behind”
• Seven up – VII (facial) → anterosuperior
• Coke down – Cochlear → anteroinferior
• Vestibular nerves → posterior quadrant
