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Other Terms: Glaserian fissure, Fissura petrotympanica, Fissure pétrotympanique
This fissure forms as the junction of the tympanic plate, the under-turned tegmen tympani of the squamous temporal bone, and the petrous temporal bone. This fissure forms immediately posteromedial to the tympanosquamosal fissure. It forms a channel that leads to the tympanic cavity transmitting the anterior malleolar ligament and the anterior tympanic branch of the maxillary artery. The canaliculus for the chorda tympani opens at the medial end of the petrotympanic fissure providing exit from the temporal bone for this nerve.
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. There is no clear evidence of the mention of the tympanic membrane or eardrum in ancient anatomical history. It was first described in the literature in 1255 by Albertus Magnus. He named it the tympanum auris because of its resemblance to a drum. It comes from the Greek word tympanon meaning drum. Fissure is from the Latin fissura meaning a cleft. Fissures are gaps in bones or gaps between neighboring bones.