In FACS, upper lid raiser, or AU5, is the action that raises and retracts the upper eyelid; this movement causes the eyes to appear wider and reveal more sclera (the white part of eye). The appearance changes we see in upper lid raiser are the result of an increase in contraction of levator palpebrae superioris, an extraocular muscle that works to keep the upper eyelid elevated.
Inner brow raiser is one of the most difficult facial actions to find clean references for. Many sources fail to find actors who can separate their inner brow raiser from other facial actions such as outer brow raiser (from frontalis, pars lateralis) and brow lowerer (from corrugator).
The smile is an essential expression for emotion and communication. Smiles form when our lip corners are pulled diagonally by a muscle called “zygomaticus major.”
