Face the FACS

Facial Expressions in Art, Science, & Technology

Facial Action Coding System (FACS) Cheat Sheet

A visual reference guide for the Facial Action Coding System (FACS), featuring action units (AUs) and their corresponding musculature. 
NOTE: The former “cheat sheet” is available to premium members here: “FACS Study Guide.”

FACS name

muscle name

expression reference

AU1 – inner brow raiser

frontalis (the medial portion)

AU2 – outer brow raiser

frontalis (the lateral portion)

AU2 - outer brow raiser facial expression reference FACS - facial action coding system

AU4 – brow lowerer

corrugator supercilii, depressor supercilii, and/or procerus

AU5 – upper lid raiser

levator palpebrae superioris

AU5 - upper lid raiser - FACS reference

AU6 – cheek raiser

orbicularis oculi (the orbital portion)

AU6 - cheek raiser - FACS - Facial Action Coding System reference

AU7 – lid tightener

orbicularis oculi (the palpebral portion)

AU7 lid tightener FACS reference

AU8 – lips toward each other

orbicularis oris

AU8 -lips toward each other - FACS - Facial Action Coding System

AU9 – nose wrinkler

levator labii superioris alaeque nasi (+ usually depressor supercilii and/or procerus)

AU10 – upper lip raiser

levator labii superioris

AU10 - upper lip raiser - FACS - Facial Action Coding System

AU11 – nasolabial furrow deepener

zygomaticus minor

AU11 - nasolabial furrow deepener - FACS - Facial Action Coding System

AU12 – lip corner puller

zygomaticus major

AU13 – sharp lip puller

levator anguli oris

AU14 -dimpler

buccinator

y-axis type

AU14 - y-axis dimpler -FACS - Facial Action Coding System

z-axis type

AU14 - dimpler - z-axis - FACS - Facial Action Coding System

NOTE: y-axis and x-axis dimplers are not FACS-official terms. Learn why I’ve coined these distinctions here.

AU15 – lip corner depressor

depressor anguli oris

AU15 - lip corner depressor - FACS - Facial Action Coding System

AU16 – lower lip depressor

depressor labii inferioris

AU16 - lower lip depressor - FACS - Facial Action Coding System

AU17 – chin raiser

mentalis

AU17 - chin raiser - FACS - Facial Action Coding System

AU18 – lip pucker

incisivus labii inferioris & incisivus labii superioris

AU18 - lip pucker (kiss face) - FACS - Facial Action Coding System

NOTE 1: Incisivus labii superioris and incisivus labii inferioris are considered accessory bands to the orbicularis oris muscle.

NOTE 2: Lip pucker typically co-activates vertical lip tightener (as seen in this example).

AD19 – tongue show

it depends**

AD19 - tongue show - FACS - Facial Action Coding System

NOTE: “AD” refers to “action descriptor.” An action descriptor is basically a less fleshed out action unit (AU). ADs differ in that they function more as event descriptors. In this case, AD19 – tongue show, simply means the tongue is protruding in a notable way beyond typical protrusion for speech, eating, breathing, etc. For a deep dive into tongue actions and tongue-related muscles, book a mini course on tongue movements and tongue anatomy.

AU20 – lip stretcher

risorius

AU20 - lip stretcher - FACS Facial Action Coding System

NOTE: Risorius is one of the most variable facial muscles in humans. Depending on the study, it has been reported missing in anywhere from 1-94% of research subjects. Risorius is narrow and difficult to locate; so it is possible that this discrepancy in statistics is partly inflated due to methodological study errors. For more on anatomical variation, book a studio lecture on facial muscle diversity

AU21 – neck tightener

platysma

AU21 - neck tightener - FACS - Facial Action Coding System

NOTE: You may see some AU20 – lip stretcher in the AU21 – neck tightener example and vice versa. This concurrence is due to a close relationship between the risorius and platysma muscles.

AU22 – lip funneler

orbicularis oris (peripheral portion)

AU22 - lip funneler - FACS - Facial Action Coding System

AU23 – lip tightener

orbicularis oris (marginal portion)

horizontal type

AU23 - lip tightener - horizontal-type - FACS - Facial Action Coding System

vertical type

AU23 - vertical lip tightener - FACS - Facial Action Coding System

NOTE: This 2-type distinction is a deviation from official FACS. Only “horizontal type” qualifies as lip tightener in original FACS. I have chosen to divide lip tightener into two types, because the lips tighten in distinct manners. The muscle behind both movements, orbicularis oris, possesses rich variation in fiber directionality; such directional variation yields more potential actions for orbicularis oris than have thus far been documented. The distinction of horizontal vs. vertical lip tightening proves especially useful when breaking down speech. For speech references, visit the Viseme Cheat Sheet.

AU24 – lip presser

orbicularis oris (marginal portion)

AU24 - lip presser - FACS - Facial Action Coding System

AU25 – lips part

it depends**

AU25 - lips part - FACS - Facial Action Coding System

NOTE: In FACS, AU25 – lips part, refers to the state of the lips being parted. This parting can be caused by any action that separates the lips – e.g. relaxation of mentalis, relaxation of orbicularis oris, contraction of other muscles, etc.

AU26 – jaw drop

masseter, relaxed temporalis and relaxed internal pterygoid

AU26 - jaw drop - FACS - Facial Action Coding System

AU27 – mouth stretch

pterygoids, digastric

AU28 – lips suck

orbicularis oris (marginal and peripheral portions)

NOTE 1: AU17 – chin raiser appears during the in-between steps. I cannot perform this action without assistance from AU17 during the transition to the final pose. Mentalis appearance during lips suck is likely the case for many others as well.

NOTE 2: Jaw drop is almost always required for lips suck.

More free FACS guides!