Hemifacial spasm

Hemifacial spasm, similar to trigeminal neuralgia (CN V) and glossopharyngeal neuralgia (CN IX) is characterised by episodic discharges of the seventh cranial nerve (facial). As in the two other aforementioned conditions, irritation of the nerve at the root entry zone by an aberrant vascular structure may be the cause. In one study (1) all cases had a vessel contacting the nerve in symptomatic patients, whereas up to 21% of asymptomatic patients had a similar finding. This matches day to day experience, where an elongated and ectatic vertebrobasilar system is commonly seen incidentally.
Microvascular decompression is a useful treatment.
For an non-annotated image please visit Radiopaedia.org here.
Reference:
1. R Tash et al “Hemifacial spasm: MR imaging features” American Journal of Neuroradiology, Vol 12, Issue 5 839-842
Credit: Dr Frank Gaillard
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