Subarcuate Fossa Of The Temporal Bone, Posterior View

Description

Subarcuate fossa on the posterior surface of the petrous portion of the temporal bone sits just superoposterior to the internal acoustic meatus, forming a small, comma-shaped depression within the posterior cranial fossa. The rim of the internal acoustic meatus lies anterior and slightly inferior to this pit, where the porus acusticus opens toward the cerebellopontine angle. Surrounding landmarks typically include the smooth posterior petrous face medially, with the broader petrous pyramid tapering anterolaterally toward the cranial base. Small but specific. Anatomically, the subarcuate fossa marks the entrance to the subarcuate canal, a tract that can transmit the subarcuate artery and venous channels and that extends toward the mastoid antrum, a relationship that helps explain why this depression is more conspicuous in infants and often shallow or nearly absent in adults. For skull base surgeons, its proximity to the internal acoustic meatus matters because the facial nerve (CN VII) and vestibulocochlear nerve (CN VIII) traverse the meatus, and posterior petrous drilling for approaches to vestibular schwannoma, endolymphatic sac surgery, or posterior fossa decompression demands disciplined orientation to these fixed bony cues. The posterior perspective makes the fossa-to-meatus relationship easy to teach without conflating it with the anterior petrous landmarks used for middle cranial fossa approaches. Use this illustration in gross anatomy labs, neuroanatomy teaching, or otology and neurotology course materials to anchor discussions of the posterior petrous surface, the internal acoustic meatus, and transmastoid versus posterior fossa corridors. It also suits surgical atlases and radiology adjuncts when labeling subtle temporal bone landmarks on CT of the petrous temporal bone. Anatomical accuracy verified by SciePro's Medical Advisory Board.