Posteromedial (Kawase's) Triangle

: the line connecting the arcuate eminence and the postero-medial corner of the geniculate ganglion – nerve V – the line connecting the arcuate eminence and posterior aspect of nerve V where it crosses the crest of the petrous apex.

The Kawase triangle is shown to be a safe anatomical landmark for anterior petrosectomy.

Landmarks described by Borghei-Razavi et al. avoid damage to the vital anatomical structures during access to the posterior fossa through middle fossa, despite temporal bone anatomical variations and different tumor sizes 1)

This area is also known as The Rhomboid.

Removal of the petrous bone within this triangle/quadrangle is an anterior petrosectomy.

Borders: Mandibular Nerve (V3)

greater superficial petrosal nerve (GSPN)

Arcuate Eminence

Superior Petrosal Sinus

-or-

GSPN

Arcuate Eminence

A line connecting the hiatus fallopii and Meckel's Cave

Contents:

Petrous Apex

IAC

Vertebrobasilar Junction

1)
Borghei-Razavi H, Tomio R, Fereshtehnejad SM, Shibao S, Schick U, Toda M, Kawase T, Yoshida K. Anterior petrosal approach: The safety of Kawase triangle as an anatomical landmark for anterior petrosectomy in petroclival meningiomas. Clin Neurol Neurosurg. 2015 Oct 28;139:282-287. doi: 10.1016/j.clineuro.2015.10.032. [Epub ahead of print] PubMed PMID: 26552034.