Free reference
FACS spiekbriefje
A visual guide to the Facial Action Coding System (FACS) and beyond: every action unit (AU) with a reference GIF, the muscles involved, and notes, plus actions FACS leaves out (marked #notFACS).
All actions are performed by the author, FACS-certified with 14 years of experience in facial muscle isolation.
#notFACS marks actions I have identified and named that do not exist in FACS. FACS was built to identify facial behavior, so it lacks documentation for some finer movements. To fill the gaps, I define my own: lip cincher (vertical lip tightener), y-axis and z-axis dimpler, open-eyed blink, and more. These distinctions are especially useful for lipsync technology and photoreal characters.
All actions at a glance
All 43 actions in one table, in numerical order, with #notFACS actions at the end. Select an action to jump to its entry.
| Code | Action | Muscle(s) | Region |
|---|---|---|---|
| AU1 | innerlijke wenkbrauwverhoger | frontalis, medial | Brows & forehead |
| AU2 | buitenste wenkbrauwverhoger | frontalis, lateral | Brows & forehead |
| AU4 | wenkbrauwverlager | corrugator supercilii, depressor supercilii en/of procerus | Brows & forehead |
| AU5 | bovenste dekselverhoger | levator palpebrae superioris (LPS) | Ogen en wangen |
| AU6 | wangverhoger | orbicularis oculi, orbital | Ogen en wangen |
| AU7 | dekselspanner | orbicularis oculi, preseptal palpebral | Ogen en wangen |
| AU8 | lippen naar elkaar | orbicularis oris | Lippen |
| AU9 | neusrimpelaar | levator labii superioris alaeque nasi (LLSAN) | Nose & mid-face |
| AU10 | bovenlipverhoger | levator labii superioris (LLS) | Nose & mid-face |
| AU11 | nasolabiale groefverdieping | kleine zygomaticus | Nose & mid-face |
| AU12 | lip hoektrekker | grote zygomaticus | Mondhoeken |
| AU13 | scherpe lip trekker | levator anguli oris (LAO) | Mondhoeken |
| AU14 | dimpler gedeeltelijk #notFACS | buccinator | Mondhoeken |
| AU15 | liphoekspatel | depressor anguli oris (DAO) | Mondhoeken |
| AU16 | onderlipspatel | depressor labii inferioris (DLI) | Lower lip & chin |
| AU17 | kinverhoger | mentalis | Lower lip & chin |
| AU18 | liprimpeltje | incisivus labii inferioris & incisivus labii superioris | Mondhoeken |
| AD19 | tongspel | it depends | Action descriptors |
| AU20 | lipstretcher | risorius | Mondhoeken |
| AU21 | nekspanner | platysma | Misc |
| AU22 | liptrechter | orbicularis oris, peripheral | Lippen |
| AU23 | lipspanner | orbicularis oris, marginal | Lippen |
| AU24 | lippendrukker | orbicularis oris, marginal | Lippen |
| AU25 | lippen gaan van elkaar | it depends | Misc |
| AU26 | kaakval | relaxation of masseter, temporalis, medial pterygoid | Kaak |
| AU27 | mond stretch | lateral pterygoid + suprahyoids | Kaak |
| AU28 | lippen zuigen | orbicularis oris, marginal + peripheral | Lippen |
| AD29 | jaw thrust | medial & lateral pterygoid, some masseter | Kaak |
| AD30 | jaw sideways | medial & lateral pterygoid, temporalis | Kaak |
| AU31 | jaw clencher | temporalis, masseter, medial pterygoid | Kaak |
| AD32 | bijten | it depends | Action descriptors |
| AD33 | klap | it depends | Action descriptors |
| AD34 | soes | it depends | Action descriptors |
| AD35 | zuigen | it depends | Action descriptors |
| AD36 | uitstulping | it depends | Action descriptors |
| AD37 | lip wipe | it depends | Action descriptors |
| AU38 | neusgatverwijderaar | dilator naris (alar nasalis) | Nose & mid-face |
| AU39 | neusvleugel compressor | compressor naris (transverse nasalis) + depressor septi | Nose & mid-face |
| AU45 | knipperen | orbicularis oculi, palpebral + relaxation of LPS | Ogen en wangen |
| AU46 | knipoog | orbicularis oculi | Ogen en wangen |
| oren omhoog & naar achteren #notFACS | auricular muscles | Brows & forehead | |
| met open ogen knipperen #notFACS | orbicularis oculi, pretarsal palpebral | Ogen en wangen | |
| lipverkleiner #notFACS | orbicularis oris, marginal | Lippen |
Brows & forehead
AU1 innerlijke wenkbrauwverhoger
frontalis spier (medial part)
Action: Wenkbrauwen omhoog Lift de mediale wenkbrauw en het voorhoofd.
Note: Inner brow raiser is variable in wrinkle formation and range. This variability is due to a number of factors, a prominent factor being frontalis spiervariabiliteit.
Inner Brow Raiser Deep Dive →The Secret Life of Inner Brow Raiser →In the FACS Study Guide →
AU2 buitenste wenkbrauwverhoger
frontalis spier (lateral part)
Action: Buitenste wenkbrauwverhoger Lift de laterale wenkbrauwen en het voorhoofd.
Note: As with inner brow raiser, outer brow raiser is variable in wrinkle formation and range. This variability is due to a number of factors, a prominent factor being frontalis spiervariabiliteit.
AU4 wenkbrauwverlager
corrugator supercilii, depressor supercilii en/of procerusspieren
Action: Wenkbrauwverlager knits (corrugator supercilii) and lowers (procerus, depressor supercilii, and parts of corrugator supercilii) the brow area and lower central forehead.
Note: Brow lowerer can be performed by any or all of the muscles listed above. Though FACS lumps together the actions of all three muscles, wanneer ik lesgeef in gezichtsanatomie en FACSIk scheid de bewegingen.
oren omhoog & naar achteren
#notFACS
auricular muscles (see notes)
Action: Oren omhoog & naar achteren tilt de oren op en duwt ze naar achteren.
Note 1: This is not a FACS action. I include this ear movement in the FACS spiekbriefje because I see it happen relatively often.
Note 2: There are multiple auricular muscles. The superior auricular moves the ears up. The posterior auricular moves the ears back. The anterior auricular moves the ears forward. At present, I cannot separate these movements. The reference here shows posterior auricular + superior auricular movement.
Ogen en wangen
AU5 bovenste dekselverhoger
levator palpebrae superioris muscle (LPS)
Action: Bovenste dekselverhoger trekt het bovenste ooglid omhoog en naar achteren om de ogen wijder te maken.
All About Upper Lid Raiser (members) →All About Upper Lid Raiser: preview (free) →Stylized Facial Expression Design →In the FACS Study Guide →
AU6 wangverhoger
orbicularis oculi muscle, orbital part
Action: Wangenverhoger spant de buitenste ringen van de oogkas aan en knijpt de laterale ooghoeken samen.
AU7 dekselspanner
orbicularis oculi muscle, preseptal part of the palpebral area
Action: Dekselaanspanner verstrakt de ringen rond de oogleden en duwt de huid van het onderste ooglid naar de binnenste ooghoeken.
met open ogen knipperen
#notFACS
orbicularis oculi muscle, pretarsal part of the palpebral area
Action: Knipperen met open ogen Haalt de binnenste ringen rond de oogleden aan in een cirkelvormige beweging naar de binnenste ooghoeken.
Note: The pretarsal area is the portion of the orbicularis oculi muscle involved in blinking.
AU45 knipperen
orbicularis oculi, palpebral part + relaxation of levator palpebrae superioris
Action: Knipperen Sluit en opent de ogen op een snelle, vloeiende manier.
Note: Beyond pretarsal activation, knipperen also often consists of (1) relaxation of levator palpebrae superioris and/or (2) forced closure from the preseptal portion of orbicularis oculi.
AU46 knipoog
orbicularis oculi
Action: Knipoog sluit één oog, meestal met enige druk.
Read the full note
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 include 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.
Nose & mid-face
AU9 neusrimpelaar
levator labii superioris alaeque nasi (usually co-activates with depressor supercilii and/or procerus)
Action: Neus rimpelen Lift de zijkanten van de neus, de neusvleugels en het centrale deel van de bovenlip.
Note: The brow lowering you see in neusrimpelaar wordt niet direct veroorzaakt door de m. levator labii superioris alaeque nasi (LLSAN). Het wordt eerder veroorzaakt door de wenkbrauwverlagende spieren die vaak gepaard gaan met neusrimpelaar: depressor supercilii en procerus. Er is een variabele interconnectiviteit tussen deze spieren en de LLSAN.
AU10 bovenlipverhoger
levator labii superioris (LLS)
Action: Bovenlipverhoger lifts the top lip in a manner more lateral than neusrimpelaar maar meer mediaal dan nasolabiale groefverdieping.
Upper Lip Raiser vs. Nasolabial Furrow Deepener (members) →Preview (free) →In the FACS Study Guide →
AU11 nasolabiale groefverdieping
kleine zygomaticus
Action: Nasolabiale groefverdieping tilt en strekt de bovenlip (op een meer laterale en schuine manier dan neusrimpelaar of bovenlipverhoger).
Upper Lip Raiser vs. Nasolabial Furrow Deepener (members) →Preview (free) →In the FACS Study Guide →
AU38 neusgatverwijderaar
dilator naris (alar portion of nasalis)
Action: Neusvleugel dilatator expands and widens the nostril wings, allowing for deeper air intake.
AU39 neusvleugel compressor
compressor naris (transverse portion of nasalis) + depressor septi
Action: Neuscompressor vernauwt de neusvleugels en verlaagt vaak ook de neustip.
Mondhoeken
AU12 lip hoektrekker
grote zygomaticus
Action: Lip hoektrekker trekt de liphoeken omhoog, naar achteren en zijwaarts.
AU13 scherpe lip trekker
levator anguli oris
Action: Scherpe lip trekker (voorheen bekend als wangpuffer) draws the lip corners upward.
superior + inferior portions of buccinator
posterior portion of buccinator
inferior + superior + posterior portions of buccinator
AU14 dimpler
gedeeltelijk #notFACS
buccinator spier
Action: y-axis type: Dimpler pinches the lip corners against each other on a vertical plane.
Action: z-axis type: Dimpler draws the lip corners back against the teeth.
Note: y-axis and z-axis dimplers are not FACS-official terms. Classic FACS describes dimpler als het y+z-as combo-type.
Why I coined the y and z distinctions (members) →Video reference: front, 3/4, intraoral, and slow motion (free) →
AU15 liphoekspatel
depressor anguli oris (DAO)
Action: Lippenhoekspatel trekt de liphoeken naar beneden.
AU18 liprimpeltje
incisivus labii inferioris & incisivus labii superioris
Action: Tuitlip 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: Tuitlip wordt doorgaans gelijktijdig geactiveerd lipverkleiner (vertical lip tightener). This example features both liprimpeltje en lipverkleiner. See lipverkleiner.
AU20 lipstretcher
risorius
Action: Lipstretcher trekt de liphoeken zijwaarts, waardoor het vlezige deel van de lippen wordt uitgerekt.
Note 1: Not to be confused with mond stretch, which refers to forced (not due to relaxation) jaw lowering.
Note 2: Risorius is one of the most variable facial muscles in humans. Depending on the study, it has been reported missing in anywhere from 1 to 94% of research subjects. Risorius is narrow and difficult to locate, so this discrepancy may be partly inflated by methodological errors. Boek voor meer informatie over anatomische variatie een studiolozing over gezichtsspierdiversiteit.
Leveraging Facial Muscle Variation →In the FACS Study Guide →
Lower lip & chin
AU16 onderlipspatel
depressor labii inferioris (DLI)
Action: Onderlipdrukker trekt de onderlip naar beneden en zijwaarts.
AU17 kinverhoger
mentalis
Action: Kinverhoger pulls up the lower lip and chin area.
Note: The lower lip may protrude to a degree in some instances of kinverhoger; however, if you see significant protrusion in a person attempting kinverhogerZe triggeren waarschijnlijk ook niet-doelwit orbicularis oris acties.
Video reference: frontal, 3/4, intraoral, and slow motion (free) →In the FACS Study Guide →
Lippen
These actions all come from orbicularis oris, the muscle that rings the mouth.
AU8 lippen naar elkaar
orbicularis oris
Action: Lippen naar elkaar toe brengt de boven- en onderlip naar elkaar toe door de bovenlip te verlagen en de onderlip op te tillen.
Note 1: Lippen naar elkaar toe brings the lips back together from actions that may separate them. In this reference, AU26 kaakval separates the lips, and AU8 closes the lips while the jaw stays open.
Note 2: In tools like ARKit and Android XR, AU8 is solely used to counteract the lip opening caused by AU26. On real faces, AU8 is not limited to counteracting jaw opening: it can counteract anything that separates the lips. For instance, if a strong AU9 causes the lips to part, AU8 can bring the lips together while retaining other aspects of AU9.
AU22 liptrechter
orbicularis oris, peripheral part
Action: Liptrechter projecteert de lippen naar voren en waaiert ze naar buiten.
AU23 lipspanner
orbicularis oris, marginal part
Action: Lipspanner maakt de lippen dunner. Zie het als de bovenlip en de onderlip die op elkaar vallen.
Note: Not to be confused with lipverkleiner, which constricts the lips toward the midline of the face.
lipverkleiner
#notFACS
orbicularis oris, marginal part
Action: Lipverkleiner vernauwt de lippen naar de middellijn van het gezicht.
Note: Lip cincher is not in official FACS. I previously called it verticale lipspanner, since FACS lumps it in with AU23. Only horizontal tightening qualifies as lipspanner in original FACS. I separate the two because the lips tighten in distinct manners. Orbicularis oris has rich variation in fiber direction, which yields more potential actions than have been documented so far. The distinction is especially useful when breaking down speech.
AU24 lippendrukker (or “lip pressor”)
orbicularis oris, marginal part
Action: Lippendrukker presses the top and bottom lips against each other.
Read the full note
Note: You may see lippendrukker spelled “lip pressor” in many sources. This variation can be attributed to Paul Ekman’s inconsistent documentation. The FACS Investigator’s Guide from 1978 has one instance of “lip pressor” (on page 6, a page ripe with differently spelled FACS actions such as “lip tightner” for lipspanner, “lip puckerer” for liprimpeltje, “cheek puffer” for scherpe lip trekker, and “lip suck” for lippen zuigen). The official 2002 FACS-handleiding solely uses “lip presser.” To further ail the prescriptivist mind, Ekman’s post-2002 writings (e.g. Wat het gezicht onthult, 2005) revert to the 1978 “pressor” spelling. Circa 2020, I asked Ekman’s protégé, Erika Rosenberg, whether “presser” or “pressor” was the canon spelling; her answer was that the spelling mattered less than the attribution of the AU number. The jury is still out, so we’ll have to wait at the edge of our seats for the next release of the FACS-handleiding om dit op te lossen druk op kwestie.
Lip presser asymmetries in speech: M-B-P Bilabial Visemes →In the FACS Study Guide →
AU28 lippen zuigen
orbicularis oris, marginal and peripheral parts
Action: Lippen zuigen trekt de lippen in de mondopening en sluit ze om de tanden.
Note 1: AU17 chin raiser appears during the in-between steps. I cannot perform this action without help from AU17 during the transition to the final pose, and mentalis likely shows up during lips suck for many others as well.
Note 2: Kaakval is bijna altijd nodig voor lippen zuigen.
Kaak
AU26 kaakval
relaxation of masseter, temporalis, and medial pterygoid
Action: Kaakval lowers the mandible (jaw) in a relaxed (unforced) manner.
AU27 mond stretch
lateral pterygoid and the suprahyoid (anterior digastric, geniohyoid, and mylohyoid)
Action: Mond stretch forcefully lowers the mandible (jaw). Unlike AU26, AU27 is not due to relaxation.
Read the full note
Note: Because “mouth” can colloquially refer to the lips and/or the jaw, mond stretch is easily confused with similarly named actions like lipstretcher. Watch the naming in toolkits such as ARKit and ICT-FaceKit, both of which renamed AU20 lipstretcher als mond stretch (lol). De mond stretch in ARKit and ICT-FaceKit is not the original mond stretch from FACS. It is unfortunate that mond stretch (1) was named so poorly to begin with, and (2) that ARKit and ICT-FaceKit made it worse with name swapping. A more pointed name like “jaw stretch” would have suited it better. Ultimately, it is what it is, so be careful out there.
AD29 jaw thrust
medial & lateral pterygoid and some masseter
Action: Kaakdruk pushes the mandible (jaw) forward.
Note: “AD” stands for action descriptor, a less fleshed-out action unit that works more as an event descriptor.
AD30 jaw sideways
medial & lateral pterygoid and temporalis
Action: Kaak opzij moves the mandible (jaw) to the side (either left or right).
AU31 jaw clencher
temporalis, masseter, and medial pterygoid
Action: Kaakklem brings the mandible (jaw) upward, pressing it against the upper jaw (maxilla).
Misc
AU21 nekspanner
platysma
Note: You may see some AU20 lip stretcher in the AU21 nekspanner example and vice versa. This is due to the close relationship between the risorius and platysma muscles.
AU25 lippen gaan van elkaar
it depends
Note: In FACS, AU25 lippen gaan van elkaar refers to the state of the lips being parted. Any action that separates the lips can cause it, e.g. relaxation of mentalis, relaxation of orbicularis oris, or contraction of other muscles.
Action descriptors
“AD” stands for action descriptor. An action descriptor is a less fleshed-out action unit (AU). ADs work more as event descriptors than as single muscle actions.
AD19 tongspel
it depends
AD32 bijten
it depends
AD33 klap
it depends
AD34 soes
it depends
AD35 zuigen
it depends
AD36 uitstulping
it depends
AD37 lip wipe
it depends
Want it taught, not just referenced?
Course
FACS promsessie
A high-density, visually driven FACS intensive. Saves months of research and reference hunting. Designed for rewatch. Built for long-term reference.
More reference guides
How to cite this page
For citations to track correctly, please refer to the officieel verslag op Google Scholar.
APA
Ozel, M. (2020, februari). FACS spiekbriefje. Zie het FACS onder ogen. https://melindaozel.com/facs-cheat-sheet/
BibTeX
@misc{ozel2020facs,
author = {Ozel, Melinda},
title = {FACS spiekbriefje},
jaar = {2020},
maand = feb,
howpublished = {{https://melindaozel.com/facs-cheat-sheet/}}
}References & further reading
- Hjortsjö, C.-H. (1970). Het gezicht van de man en mimische taal. Studentlitteratur.
- de Sanctis Pecora, C. (2020). One21: A novel, customizable injection protocol for treatment of the forehead with IncobotulinumtoxinA. Klinische, cosmetische en onderzoeksdermatologie, 13, 127-136. https://doi.org/10.2147/ccid.s237519
- Ekman, P., Friesen, W. V., & Hager, J. C. (2002). Coderingssysteem voor gezichtshandelingen. Nexus onderzoek.
- Netter, F. H. (2019). Atlas of human anatomy (7e ed.). Elsevier.
- Standring, S., & Tubbs, S. R. (2025). Gray’s anatomy. Elsevier.