Which muscles are major facial muscles involved in Benign Essential Blepharospasm?

• A. Levator palpebrae superioris, Corrugator
• B. Orbicularis oculi, Frontalis
• C. Corrugator, Orbicularis oculi, Procerus
• D. Zygomaticus, Corrugator, Procerus

Answer: (C)

Blepharospasm is a focal dystonia of eyelid closure, so the muscles that close the lids and around the eye are the ones most involved. The primary muscle driving eyelid closure is the orbicularis oculi, which encircles the eye and contracts to squeeze the lids shut. In benign essential blepharospasm, nearby facial muscles that heighten lid tension and facial grimacing are commonly recruited as well, especially the corrugator supercilii, which pulls the brows together and downward, and the procerus, which compresses the nasal root and lowers the medial brow. Together, these three muscles are the main players in the spasms.

The elevator that opens the eyelid, the levator palpebrae superioris, is not a contributor to the spasms. The frontalis and zygomaticus are also not primary players in this condition, as they are more involved in eyebrow elevation and smiling, respectively, rather than eyelid closure.