Definition of petrosal in English:

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Pronunciation: /pɪˈtrəʊs(ə)l/


The dense part of the temporal bone at the base of the skull, surrounding the inner ear.
Example sentences
  • The otic capsule became somewhat separated from the rest of the braincase as a pair of petrosals.
  • Minimum basioccipital width is narrow relative to cavity width, suggesting the petrosals would have been moderately enlarged (in width two to three times the shortest distance between them).
  • In pakicetids, the ectotympanic has already overgrown, giving rise to a large bulla surrounding the petrosal.


Relating to or denoting the petrosal, or the nerves which pass through it.
Example sentences
  • Drilling begins directly over the bisection of the angle between the greater superficial petrosal nerve and arcuate eminence and the dura of IAC is exposed beneath the petrous ridge.
  • Impulses are conveyed via the glossopharyngeal nerve then via its tympanic branch to the tympanic plexus thence to the otic ganglion via the lesser superficial petrosal nerve.
  • The temporal lobe, now slack from the mannitol, is retracted from the bone of the middle fossa floor, with care taken not to cause traction on the greater superficial petrosal nerve.


Mid 18th century: from Latin petrosus 'stony, rocky' (from petra 'rock') + -al.

For editors and proofreaders

Line breaks: pe|tro¦sal

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