Table 2.
FACS AUs and related muscles.
| AU | FACS name | Facial muscle | Videotape | EMG |
|---|---|---|---|---|
| AU1 | Inner brow raiser | Frontalis (pars medialis) | X | — |
| AU2 | Outer brow raiser | Frontalis (pars lateralis) | X | — |
| AU4 | Brow lowerer | Depressor glabellae, depressor supercilii, and CS | X | — |
| AU6 | Cheek raiser | OO (pars orbitalis) | X | X |
| AU7 | Lid tightener | OO (pars palpebralis) | X | X |
| AU9 | Nose wrinkler | LLSAN | X | — |
| AU10 | Upper lip raiser | LLS, caput infraorbitalis | — | X |
| AU12 | Lip corner puller | Zygomaticus Major | X | — |
| AU20 | Lip stretcher | Risorius | X | — |
| AU23 | Lip tightener | Orbicularis Oris | X | — |
| AU25 | Lips part | Depressor labii inferioris | X | — |
| AU27 | Mouth stretch | Pterygoids, digastric | X | — |
| AU45 | Blink | Contraction OO | — | X |
| AU46 | Wink | OO | — | X |