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Trigeminal cave

The trigeminal cavity, also known as Meckel's cave, is a cerebrospinal fluid (CSF)-filled space located in the middle cranial fossa, situated at the petrous apex of the temporal bone. It houses the trigeminal (Gasserian) ganglion and serves as a crucial anatomical landmark in neuroimaging and neurosurgery. The trigeminal cavity is bounded by dura mater and is closely related to several critical neurovascular structures, making its assessment vital in various pathological conditions.

Synonyms:

  • Meckel’s cave

  • Cavum trigeminale

  • Trigeminal cistern

  • Trigeminal ganglion cistern

Function:

  • Contains and protects the trigeminal (Gasserian) ganglion

  • Acts as a conduit for the trigeminal nerve (cranial nerve V) as it divides into its three main branches (ophthalmic, maxillary, mandibular)

  • Provides a CSF-filled space that cushions the ganglion and its nerve roots

MRI Appearance:

  • T2-Weighted Imaging:

    • The trigeminal cavity appears as a hyperintense (bright) CSF-filled space at the petrous apex, lateral to the cavernous sinus.

    • The trigeminal ganglion itself is often seen as a small, slightly hypointense structure within the cavity.

  • T1-Weighted Imaging:

    • The cavity appears hypointense (dark), matching CSF signal intensity.

    • The trigeminal ganglion may appear isointense to slightly hyperintense relative to the adjacent brain parenchyma.

  • FLAIR:

    • The CSF within the trigeminal cavity is suppressed (dark), making it appear hypointense.

    • Any pathological processes or lesions may stand out as hyperintense compared to the suppressed background.

  • Post-Contrast T1-Weighted Imaging:

    • The normal trigeminal cavity does not enhance.

    • Enhancement of the trigeminal ganglion or the presence of enhancing lesions may indicate pathology (e.g., schwannoma, meningioma, metastasis, inflammation).

CT Appearance:

  • Appears as a CSF-density (hypodense) space at the petrous apex, best seen on thin-section axial images.

  • No calcifications or contrast enhancement in normal cases.

  • Bony margins of Meckel’s cave can be visualized; any expansion, erosion, or abnormal soft tissue density suggests pathology.

MRI images

Trigeminal cavity (Meckel) mri 3t coronal image

MRI images

Trigeminal cavity (Meckel) mri 3t axial image