- Melinda Ozel
- Published: Feb. 20, 2020
- Updated: Oct. 30, 2025
The FACS Cheat Sheet is a visual guide for the Facial Action Coding System (FACS) and beyond. Here you will find FACS-based action unit (AU) references and the facial muscles they map to. You will also find references and descriptions for anatomically-based facial movements that do not exist in FACS; these additional breakdowns serve to supplement areas where FACS is deficient.
- Quick FACS reference sheet with photos only: FACS Lite: Photos (FREE).
- Comprehensive FACS guide with stills + GIFs: FACS Study Guide (PAYWALL).
- Viseme and phoneme reference sheet: Viseme Cheat Sheet (FREE).
- ARKit to FACS translation sheet: ARKit to FACS Cheat Sheet (FREE).
FACS Action Unit References
FOREHEAD AREA & EARS
AU1 ACTION: Inner brow raiser lifts the medial brow and forehead area.
NOTE 1: Inner brow raiser is variable in wrinkle formation and range. This variability is due to a number of factors, a prominent factor being frontalis muscle variability.
NOTE 2: Further reading on inner brow raiser – 1) Inner Brow Raiser Deep Dive, 2) The Secret Life of Inner Brow Raiser.
AU2 ACTION: Outer brow raiser lifts the lateral brow and forehead areas.
NOTE: As mentioned with inner brow raiser, outer brow raiser is also variable in wrinkle formation and range. This variability is due to a number of factors, a prominent factor being frontalis muscle variability.
AU4 - brow lowerer
corrugator supercilii, depressor supercilii, and/or procerus muscles
AU4 ACTION: Brow lowerer knits (corrugator supercilii) and lowers (procerus, depressor supercilii, and parts of corrugator supercilii) the brow area and lower central forehead. **Read NOTE below for important considerations.
NOTE: Brow lowerer can be performed by any or all of the above listed muscles. Though FACS lumps together the actions of all three of these muscles, when I teach facial anatomy and FACS, I separate out the movements. See more in the FACS Study Guide.
#notFACS indicates actions I have identified and coined that do not exist in FACS. Due to FACS’s original purpose as a facial behavior identification system, FACS lacks documentation for some finer, more nuanced facial movements. To fill this void, I have further defined my own nonFACS movements such as: vertical lip tightener, y-axis dimpler, open-eye blink, etc. If you work on lipsync technology or photoreal characters, these distinctions will be particularly useful.
ears up & back
#notFACS
auricular muscles (see notes below)
EARS UP & BACK ACTION: Ears up & back lifts the ears and pushes them back.
NOTE1: This is not a FACS action. I have included this ear movement in the FACS Cheat Sheet, because I observe it happening relatively frequently.
NOTE 2: There are multiple auricular muscles. The superior auricular moves the ears up. The posterior auricular moves the ears back. The anterior auricular the moves ears forward. At present, I cannot separate these movements. The reference here shows posterior auricular + superior auricular movement.
EYE & CHEEK AREA
AU5 - upper lid raiser
levator palpebrae superioris muscle
AU5 ACTION: Upper lid raiser pulls the top eyelid up and back to widen the eyes.
NOTE: For more on upper lid raiser: (1A) – If you are a subscriber, view All About Upper Lid Raiser – or – (1B) View Stylized Facial Expression Design. (2) If you are not a subscriber, you can view the preview post of All About Upper Lid Raiser here.
AU6 - cheek raiser
orbicularis oculi muscle (the orbital portion)
AU6 ACTION: Cheek raiser tightens the outer rings of the eye orbit and squeezes the lateral eye corners.
NOTE: For help differentiating cheek raiser from lid tightener, see Cheek Raiser vs. Lid Tightener.
AU7 - lid tightener
orbicularis oculi muscle (the pre-septal portion of the palpebral area)
AU7 ACTION: Lid tightener tightens the rings around the eyelids and pushes the lower eyelid skin toward the inner eye corners.
NOTE: For help differentiating cheek raiser from lid tightener, see Cheek Raiser vs. Lid Tightener.
open-eyed blink
#notFACS
orbicularis oculi muscle (the pretarsal portion of the palpebral area)
OPEN-EYED BLINK ACTION: Open-eyed blink tightens the innermost rings around the eyelids in a circular motion toward the inner eye corners.
NOTE: The pretarsal area is the portion of our orbicularis oculi muscle that is involved with blinking. See more breakdowns here.
AU45 - blink
orbicularis oculi muscle (the pretarsal portion of the palpebral area)**
AU45 ACTION: Blink closes and opens the eyes in a swift, fluid manner.
NOTE: Beyond pretarsal activation, blink also often consists of: (1) relaxation of levator palpebrae superioris and/or (2) forced closure from the preseptal portion of orbicularis oculi.
AU46 - wink
orbicularis oculi muscle
AU46 ACTION: Wink closes one eye, usually with some compression.
NOTE: Unless you are a facial coder conducting behavioral research (and even then, the official FACS Manual lists AU46 – wink as “optional”), the FACS shape for wink is not the most useful. I have included it because other FACS lists include it; however, I find it to be a clunky, unnecessary addition to most shape sets. That being said, orbicularis oculi does deserve better functional breakdowns beyond cheek raiser, blink, and lid tightener – but wink is not the way to go. In the near future, I will post a functional breakdown of orbicularis oculi. Sign up for monthly post updates to keep tabs on the latest content and breakdowns.
MIDDLE FACE & NASOLABIAL AREA
AU9 - nose wrinkler
levator labii superioris alaeque nasi (+ usually depressor supercilii and/or procerus) muscle(s)
AU9 ACTION: Nose wrinkler lifts the sides of the nose, nostrils, and central upper lip area.
NOTE: The brow lowering you see in nose wrinkler is not directly caused by the levator labii superioris alaeque nasi (LLSAN) muscle. Rather, it is caused by the brow lowering muscles often paired with nose wrinkler: depressor supercilii and procerus. There is variable interconnectivity between these muscles and the LLSAN.
AU10 - upper lip raiser
levator labii superioris muscle
AU10 ACTION: Upper lip raiser lifts top lip in a manner more lateral than nose wrinkler but more medial than nasolabial furrow deepener.
NOTE: For help differentiating between upper lip raiser and nasolabial furrow deepener: (1) If you are a subscriber view: Upper Lip Raiser vs. Nasolabial Furrow Deepener. (2) If you are not a subscriber, you can view the preview post of Upper Lip Raiser vs. Nasolabial Furrow Deepener here.
AU11 - nasolabial furrow deepener
zygomaticus minor muscle
AU11 ACTION: Nasolabial furrow deepener lifts and stretches the top lip (in a more lateral and oblique manner than nose wrinkler or upper lip raiser).
AU38 - nostril dilator
dilator naris (alar portion of nasalis) muscle
AU38 ACTION: Nostril dilator expands / widens the nostril wings allowing for deeper air intake.
AU39 - nostril compressor
compressor naris (tranverse portion of nasalis)+ depressor septi muscles
AU39 ACTION: Nostril compressor narrows the nostril wings while also often lowering the nose tip.
LIP CORNER MOVERS
AU12 - lip corner puller
zygomaticus major muscle
AU12 ACTION: Lip corner puller draws the lip corners up, back, and laterally.
AU13 - sharp lip puller
levator anguli oris muscle
AU13 ACTION: Sharp lip puller (formerly known as cheek puffer) draws the lip corners upward.
AU14 - dimpler
partially #notFACS
See “NOTE” below.
buccinator muscle
y-axis type
(superior + inferior portions of buccinator)
z-axis type
(posterior portion of buccinator)
y-axis type + z-axis type
(inferior + superior + posterior portions of buccinator)
AU14-y ACTION: Dimpler of the y-axis type pinches the lip corners against each other on a vertical plane.
AU14-z ACTION: Dimpler of the z-axis type draws the lip corners back against the teeth.
NOTE: y-axis and z-axis dimplers are not FACS-official terms. Classic FACS describes dimpler as the y+z-axis combo type. Learn why I’ve coined y and z distinctions here.
AU15 - lip corner depressor
depressor anguli oris muscle
AU15 ACTION: Lip corner depressor draws the lip corners downward.
AU18 - lip pucker
incisivus labii inferioris & incisivus labii superioris muscles
AU18 ACTION: Lip pucker draws the lip corners medially causing the fleshy part of the lips to collect toward the midline of the face and protrude.
NOTE 1: Incisivus labii superioris and incisivus labii inferioris are considered accessory muscles to orbicularis oris.
NOTE 2: Lip pucker typically co-activates vertical lip tightener (as seen in this example). Learn more about vertical lip tightener under the “ORBICULARIS ORIS ACTIONS” section below.
AU20 - lip stretcher
risorius muscle
AU20 ACTION: Lip stretcher draws the lip corners laterally, stretching the fleshy part of the lips.
NOTE1: Not to be confused with mouth stretch. Mouth stretch refers to forced (not due to relaxation) jaw lowering (see “JAW ACTIONS” section below).
NOTE2: 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.
LOWER LIP & CHIN AREA
AU16 - lower lip depressor
depressor labii inferioris muscle
AU16 ACTION: Lower lip depressor draws the lower lip downward and laterally.
AU17 - chin raiser
mentalis muscle
AU17 ACTION: Chin raiser pushes the up lower lip and chin area.
NOTE: The lower lip may protrude to a degree in some instances of chin raiser; however, if you are seeing significant protrusion in a person attempting chin raiser, they are likely triggering non-target orbicularis oris actions as well.
ORBICULARIS ORIS ACTIONS
AU8 - lips toward each other
orbicularis oris muscle
AU8 ACTION: Lips toward each other brings the upper and lower lips toward each other by lowering the top lip and raising the bottom lip. Lips toward each other functions as a way to bring the lips back together from actions that may separate the lips. In the above reference, AU26 – jaw drop is the cause of separated lips, and AU8 is used to close the lips while allowing the jaw to remain open. In tools like ARKit and Android XR, AU8 is solely used to counteract the lip opening caused by AU26; however, on real faces, AU8 is not limited to counteracting jaw opening. In fact, AU8 can be used to counteract anything that causes the lips to separate. For instance, if a strong AU9 causes the lips to part, the action of AU8 can bring the lips together while retaining other aspects of AU9.
AU22 - lip funneler
orbicularis oris muscle (peripheral portion)
AU22 ACTION: Lip funneler projects the lips forward and fans them outward.
AU23 - lip tightener
partially #notFACS
See “NOTE” below.
orbicularis oris (marginal portion)
horizontal type
AU23 ACTION (horizontal type): Lip tightener thins the lips. Think of it as the top lip and the bottom lip each collapsing upon itself.
vertical type
(thinking of calling it lip cincher)
AU23 ACTION (vertical type): Lip cincher constricts the lips toward the midline of the face.
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 muscle (marginal portion)
AU24 ACTION: Lip presser compresses the top and bottom lip against each other.
NOTE: You may see lip presser spelled as “lip pressor” in many sources. The widespread misspelling of “pressor” can be traced back to a small typo in the FACS Investigator’s Guide. In the Inv. Guide there is one instance on page 6 ( which is also home to other typos such as “lip tightner” for lip tightener), where lip presser is spelled “lip pressor.” Though the entire FACS Manual refers to AU24 as “lip presser,” the “pressor” typo from the Investigator’s Guide has somehow spiraled out of control and is misspelled almost everywhere, including in Google’s Android XR and Meta’s OpenXR.
FURTHER READING: Read about lip presser asymmetries in speech here: M-B-P Bilabial Visemes. (Useful for those working on lipsync and automated speech solutions.)
AU28 - lips suck
orbicularis oris muscle (marginal and peripheral portions)
AU28 ACTION: Lips suck draws the lips into the mouth opening and wraps them around the teeth.
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.
JAW ACTIONS
AU26 - jaw drop
relaxation of masseter, temporalis, and medial pterygoid muscles
AU26 ACTION: Jaw drop lowers the lower mandible (jaw) in a relaxed (unforced) manner.
AU27 - mouth stretch
lateral pterygoid and the suprahyoid (anterior digastric, geniohyoid, and mylohyoid) muscles
AU27 ACTION: Mouth stretch forcefully lowers the lower mandible (jaw). Unlike AU26, the action of AU27 is not due to relaxation.
NOTE: Because the word “mouth” is quite ambiguous and can colloquially refer to either the lips and/or jaw, mouth stretch can be easily confused with similarly-named actions like lip stretcher. Be aware of the nuances in naming when working with toolkits such as ARKit and ICT-FaceKit, both of which have renamed AU20 – lip stretcher as mouth stretch (lol). The mouth stretch in ARKit and ICT-FaceKit is not the same as the official and original mouth stretch from FACS. It is both unfortunate and confusing that mouth stretch (1) was named so poorly to begin with, and (2) that ARKit and ICT-FaceKit have exacerbated the confusion with name swapping. Mouth stretch would have been better suited with a more pointed name like “jaw stretch.” Ultimately, it is what it is; so be careful out there.
AD29 - jaw thrust
medial & lateral pterygoid muscles and some masseter
AD29 ACTION: Jaw thrust pushes the lower mandible (jaw) forward.
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.
AD 30 - jaw sideways
medial & lateral pterygoid muscles and temporalis
AD30 ACTION: Jaw sideways moves the lower mandible (jaw) to the side (either left or right).
AU31 - jaw clencher
temporalis, masseter, and medial pterygoid muscles
AU31 ACTION: Jaw clencher brings the lower mandible (jaw) upward causing it to press against the upper mandible.
MISCELLANEOUS ACTIONS
AU21 - neck tightener
platysma muscle
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.
AU25 - lips part
it depends**
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.
ACTION DESCRIPTORS
“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.
AD19 - tongue show
it depends**
AD32 - bite
it depends**
AUD33 - blow
it depends**
AD34 - puff
it depends**
AD35 - suck
it depends**
AD36 - bulge
it depends**
AD36 - lip wipe
it depends**
How to Cite This Page
APA:
Ozel, M. (2020, February). FACS Cheat Sheet. Face the FACS. https://melindaozel.com/facs-cheat-sheet/
BibTeX:
@misc{ozel2020facs,
author = {Ozel, Melinda},
title = {FACS Cheat Sheet},
year = {2020},
month = feb,
howpublished = {\url{https://melindaozel.com/facs-cheat-sheet/}}
}
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