Face

The face is the front part of the head containing the eyes, nose, mouth, teeth, lips and skin. In humans, the face serves many functions: vision, smell, respiration, eating, speech and expression of emotion. For this reason the face is not merely a bodily part, but also a communication tool.

The structure of the face is based on the facial skeleton (such as the jawbone, nasal bones and teeth), the muscles attached to the skull, and a network of nerves. The variation in this structure is why each person has a unique facial appearance, which is fundamental to how people recognize one another.

Structure of bone and muscle

The face is built on a set of bones forming the front part of the skull beneath it. These include the upper jaw (maxilla), the lower jaw (mandible) which is the only bone that moves significantly, the cheekbones, and the nasal bones. The facial muscles mostly run from bone to muscle; when they contract they change the shape of the muscles, which is how emotional expressions such as smiling and frowning occur.

Nerves and function

Two major nerves serve the face: the trigeminal nerve, which carries sensation of touch, pain and temperature, and the facial nerve, which controls the movement of the muscles of expression. Injury to these nerves can result in reduced movement or loss of sensation on one side of the face.

Communication and society

The face is used to convey non-verbal information. Certain emotional expressions—such as happiness, anger, fear and sadness—are considered by many researchers to be widespread across cultures, although the rules governing when and where they are displayed vary. Eye contact conveys different things depending on context, with some behaviors indicating respect and others suggesting confidence or intent.

Facial recognition

The human brain has a specialized area for recognizing faces, which allows it to distinguish among many similar-looking people. Modern technology has attempted to replicate this ability by measuring facial proportions; such systems are used to unlock devices and verify identity, raising questions about privacy and accuracy.