- Continuing Education
The risorius is a small trapezoidal muscle which is broadest at its origin in the fascia covering the parotid gland in the cheek and inserts at the corner of the mouth in concert with the buccinator along with other muscles which we will cover later at the corner of the mouth. This pulls the corner of the mouth laterally and posteriorly. This is a component of a smile. As we go through the other muscles of facial expression pay attention to how many are involved in smiling as that expression, “It takes more muscles to frown than smile,” will prove to be wrong.