Petromastoid canal

Dr Henry Knipe and Dr Ayush Goel et al.

Petromastoid canal or subarcuate canal joins the mastoid antrum to the posterior cranial fossa 1 and contains the subarcuate vein and artery.


  • type I - invisible
  • type II - less than 0.5 mm width
  • type III - 0.5-1 mm width
  • type IV - greater than 1 mm width 1

Radiographic features


On petrous temporal bone fine slices, the petromastoid canal is seen as a thin canal between the anterior and posterior part of the superior semicircular canal. It can be easily be mistaken for a fracture line.

Head and neck anatomy
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Article information

rID: 25368
System: Head & Neck
Section: Anatomy
Tag: cases, stub, refs
Synonyms or Alternate Spellings:
  • Subarcuate canal

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