You Might Be Missing Some Facial Muscles
Researchers think that the Risorius muscle can be used to create fake smiles as well as a terrified expression. However, just because you might be missing as much as 40% of the available facial muscles doesn't mean you're at a disadvantage. Dr. Bridget Waller, a scientist who conducted the 2008 study on facial muscles and emotion, said that people are able to make most fundamental facial expressions regardless of whether or not they're missing some muscles. Those that have the maximum number of muscles might simply be able to make more uncommon and nuanced faces.
from Brit Lab
Key Facts In This Video
There are 14 facial bones that affect how your face looks. (1:00)
The orbicularis oris muscle, also called the kissing muscle, is what puckers up your lips. (1:40)
Some scientists say that there are six universal facial expressions. (3:03)