Facial Muscles and Expressions

Overview

Muscles Function: Muscles primarily contract and shorten, generally moving bones, but in the face, they often move skin.
Facial Muscles: Used for speech, ingestion, emotional expression, and symbolic gestures.

Darwin: Facial expressions as residual actions of complete behavioral responses.
Sylvan Tompkins: Emotion as the basis of human motivation, rooted in facial expressions.
Ekman: Universality of facial expressions, proven with studies in New Guinea.

Botox Experiment: Paralyzing frown muscles can affect anger emotions, showing that expressions influence internal feelings.

Disgust: Wrinkling of the nose, exposure of canine teeth—like a dog snarling.
Anger: Furrowed brow, raised nostrils, widened eyes, sometimes exposed teeth.
Happiness: Two types of smiles:
- Polite (corners of the mouth raised).
- True (eye sockets contracted).
Surprise vs. Fear:
- Both involve raised eyebrows and eyelids.
- Surprise: Jaw drops.
- Fear: Mouth stretches horizontally.
Sadness: Inner eyebrow raised, corners of mouth pulled down.
Contempt: Asymmetric smirk, showing superiority, often a negative indicator.

Origin and Insertion: Terms for where a muscle starts and ends, often bone-related but sometimes involving skin.
Action: Muscle contraction results in movement.
Innervation: Most facial muscles are innervated by the facial nerve (cranial nerve VII).

Frontalis Muscle: Raises eyebrows, wrinkles forehead; located at the front of the head attached to skin of eyebrows and nose.
Corrugator Supercilii Muscle: Lowers brows, causing vertical forehead wrinkles; involved in frowning and sun glare prevention.
Orbicularis Oculi Muscle: Surrounds the eye; responsible for closing eyelids and creating crow's feet.

Trigger Points: Areas in muscles like the frontalis where pressure can relieve tension-related pain.
Botox Use: Can be used for aesthetic and therapeutic reasons (e.g., migraines), affecting muscle activity.