Figures and Definitions of Major Action Units
164 The Upper Face Action Units according to the FACS system
AU1
AU 1 (Inner Brow Raise)
The inner corners of the brow are raised upwards. For many people, AU1 produces an oblique shape to the eyebrows.
In some people the brows do not take on this shape but more of a dip in the center with a small pull up at the inner corners. This action causes the skin in the center of the forehead to wrinkle horizontally. These wrinkles usually do not run across the forehead but are limited to the center.
AU2
AU 2 (Outer Brow Raise)
This action pulls the lateral (outer) portion of the eyebrows upwards. It produces an arched shape to the eyebrows.
In some people, AU2 causes short horizontal wrinkles to appear above the lateral portions of the eyebrows.
There may also be wrinkles produced in the medial portion of the forehead, but they are not as deep as the lateral ones.
AU 1+2
AU 1+2 (Inner and Outer Brow Raise)
The combination of AU 1 and 2 pulls the entire eyebrow (medial to lateral parts) upwards. It produces an arched, curved appearance to the shape of the eyebrow. Horizontal wrinkles appear across the entire forehead.
AU 4 (Brow Lowerer)
This action lowers and pulls the eyebrows together. It produces vertical wrinkles between the eyebrows, which may be deep.
AU4
165 AU5 (Upper Lid Raise)
The upper eyelid has been raised and the lower eyelids are relaxed. The sclera shows above the iris.
AU5 AU6
AU6 (Cheek Raise)
The outer band of muscle around the eye constricts. The cheeks are lifted upwards. This action can narrow the eye aperture by pushing the skin surrounding the eye towards the eye socket. The skin below the eye can bag or wrinkle.
Au 6 may cause crow's feet lines or wrinkles to appear, extending from the outer corners of the eye aperture.
AU7
AU7 (Lid Tightener)
This action tightens the eyelids and narrows the eye aperture. The lower eyelid is raised and covers more of the eyeball than usual. The raising of the skin below the lower eyelid causes a bulge to appear in the lower lid.
AU43 (Eyelid Droop)
The upper eyelid droops down reducing the eye aperture.
More surface of the upper eyelid is exposed than usual as the upper eyelid relaxes. In the FACS manual a strong AU43 indicates that the eyes are completely closed. For this study we choose instead to use additional “blink” code.
AU43C AU43B
AU43A
166 The Lower Face Action Units according to the FACS system
AU9
AU9 (Nose Wrinkler)
It lowers the medial portion of the eyebrows.
Wrinkles appear along the sides of the nose and across the root of the nose. The infra-orbital triangle is pulled upwards causing the infra-orbital furrow to wrinkle and to deepen in strong actions. The eye aperture is narrowed. This action pulls the center of the upper lip upwards. The nostril wings may be widened and raised.
AU10
AU10 (Upper Lip Raiser)
The upper lip is raised. This action causes an angular bend in the shape of the upper lip.
The nasolabial furrow deepens and its upper part is raised and pouched. The nostril wings widen and rise.
AU12
AU12 (Lip Corner Puller)
This action pulls the corners of the lips back and upward (obliquely). The skin adjacent to the nasolabial furrow is raised up and laterally.
AU11 (Nasolabial Furrow Deepener)
The upper lip is pulled upwards and laterally. The skin below the upper portion of the nasolabial furrow is pulled obliquely upwards. Both the upper and middle portion of the nasolabial furrow deepens. The middle portion of the furrow deepens typically more than in AU10.
AU11
167 AU13 (Sharp Lip Puller)
The cheeks and the infra-orbital triangle become very salient, puffing out, as the infra-orbital triangle is lifted primarily up, more than obliquely.
This action pulls the corners of the lips up but at a sharper angle than AU 12. While the corners of the lips are pulled up, the red parts of the lips do not move up with the lip corners. The lip corners appear to be tightened, narrowed, and sharply raised.
AU15
AU15 (Lip Corner Depressor)
This action pulls the lip corners down. The shape of the lips is angled down at the corner, and usually the lower lip is somewhat stretched horizontally.
AU16 (25)
AU16 (Lower Lip Depressor)
The lower lip is pulled down. Usually AU16 occurs with AU25 (lips are parted) exposing more of the lowera teeth, including the roots of the teeth, and in a strong action the lower gum is exposed as well.
AU14 (Dimpler)
This action tightens the corners of the mouth, pulling the corners somewhat inwards, and narrowing the lip corners. AU14 produces wrinkles and/or a bulge at the lip corner. It may cause a dimple-like wrinkle beyond the lip corner.
AU14 AU13
168 AU17
AU17 (Chin Raiser)
This action pushes the chin boss upward and the lower lip upward. It can cause the mouth to take on an inverted U shape.
AU20 (Lip Stretch)
The action pulls the lips back laterally; the lip corners may be raised or lowered to a limited extent but the main movement is horizontal. The mouth is elongated. The lips become flattened and stretched by the lateral pull. AU20 stretches the skin over the chin boss laterally. This causes the chin to appear flattened and/or wrinkled.
In addition to AU20 we added AU16, AU25 and AU26 to the illustration.
AU20 (16+25+26)
AU22 (25+26)
AU22 (Lip Funneler)
The lips funnel outwards taking on the shape as though the person were saying the word “flirt”. This action pulls in medially on the lip corners. Exposes the teeth and may expose gums.
AU23
AU23 (Lip Tightener)
The lips tightens, making the red parts of the lips appear narrower. The red parts of the lips may roll inwards and almost disappear from view. Small wrinkles or lines in the skin above and below the red parts of lips and muscle bulges below the lower lip may appear.
169 AU24 (Lip Presser)
The lips are pressed together, without pushing up the chin boss. This action lowers the upper lip and raises the lower lip to a small extent. The lips are tightened and narrowed.
AU24 AU25
AU25 (Lips Part)
The lips are parted, which may expose the inner mucosal area of the lips more.
AU26 (Jaw Drop)
The mandible is lowered by relaxation so that separation of the teeth can at least be inferred if AU25 is not present.
AU27
AU27 (Mouth Stretch)
The mandible is pulled down. The mouth is open quite far as the mandible is pulled down, changing the shape of the mouth opening from an oval with the long axis in the horizontal plane to one in the vertical AU26
170