The eyelid muscle responsible for opening and closing the eyelid, the orbicularis oculi, “is the fastest-working muscle in the human body, so when it goes into a spasm, it goes into a spasm ...

Discovered by French anatomist Duchenne de Boulogne in 1862, the key difference between this “real” happy smile and a “fake” happy smile lies in the orbicularis oculi – muscles that wrap ...

He named it after himself, which is awesome.” The smile employs two muscle groups, the zygomatic major and orbicularis oculi muscles, which are in “the top of the cheeks and the corner of the ...