This is a small, gap-like opening on the anterosuperior surface of the petrous temporal bone. It opens anteriorly to the arcuate eminence into a shallow groove that courses anteromedial toward the foramen lacerum. This transmits the greater petrosal nerve and petrosal branch of the middle meningeal artery out of the facial canal inside the petrosal bone.

Hiatus is a Latin term meaning a cleft or gap. It takes its origin from the Latin verb hiare meaning to yawn or gape. Petrous means like a rock. It comes from the Latin petra meaning rock. Galen was the first to use this term to describe the thick, rock-like region of the temporal bone.

Hiatus canalis nervi petrosi majoris

Hiatus du canal du nerf grand pétreux