Muscles for Facial Expressions

The muscles responsible for facial expressions usually originate in the fascia of deeper muscles or skull bones and insert into the skin.

As a result, any contraction in facial muscles moves the overlying skin and changes facial expressions.

For instance, the occipitofrontalis is a two-part scalp muscle. It has two muscular portions—frontal and occipital bellies—held together by the epicranial aponeurosis.

The opposing action of these two muscular parts is to pull the scalp forward and backward for expressions like lifting the eyebrows.

Other muscles that cover the facial bones control expressions by supporting the movement of the eyes, nose, cheeks, and mouth.

For example, the orbicularis oris is a circular muscle that originates from other muscles attached to the maxillae and mandible and inserts around the lips.

It also acts as the insertion for the buccinator, which also originates from the maxillae and mandible. 

Together, these muscles control mouth movements, such as pouting and puckering.