This patient had episodic electric/shooting/radiating pain of the left face. An MRI was done.

[Top]: Axial heavily T2-weighted image (bright = CSF, dark = not CSF) at the level of trigeminal nerve (cranial nerve V / CN5), shows a normal right CN5 (green). The left CN5 seems to be splayed out by another tubular structure (red), which is the superior cerebellar artery (SCA).

[Bottom Left]: Sagittal reconstruction of the normal right CN5 (along the blue line).

[Bottom Right]: Sagittal reconstruction of the left CN5 shows the left SCA contacting the left CN5. The close proximity of the left SCA and its arterial pulsations likely irritate the cranial nerve, which is the primary sensory nerve of the face, causing trigeminal neuralgia.