The risorius is a variable muscle. It may be absent, single, or multiple on each side. Its lateral pull on the lip corner produces a retracted, grimacing smile rather than the upward curve of zygomaticus major.
An expanded entry for Risorius.
| Origin | Parotid fascia and skin over the masseter |
|---|---|
| Insertion | Modiolus and skin at the lip corner |
| Nerve Supply | Facial nerve, buccal branch (VII) |
| Blood Supply | Facial artery |
| Actions |
|
|---|
It draws the corner of the mouth laterally, producing a tight-lipped smile or grimace.
Risorius variability is clinically important in smile reanimation surgery. Reconstructive surgeons must account for the patient's native smile pattern (zygomaticus-dominant vs risorius-dominant) when planning the vector of the reanimating muscle transfer.
Visible as a horizontal lip corner retraction during a forced smile or grimace.
Preoperative smile analysis identifying a risorius-dominant horizontal smile pattern, directing the gracilis muscle transfer to a more lateral vector to replicate the native smile.
This website uses cookies to enhance your experience. Some are essential for site functionality, while others help us analyze and improve your usage experience. Please review your options and make your choice.
If you are under 16 years old, please ensure that you have received consent from your parent or guardian for any non-essential cookies.
Your privacy is important to us. You can adjust your cookie settings at any time. For more information about how we use data, please read our privacy policy. You may change your preferences at any time by clicking on the settings button below.
Note that if you choose to disable some types of cookies, it may impact your experience of the site and the services we are able to offer.
Some required resources have been blocked, which can affect third-party services and may cause the site to not function properly.
This website uses cookies to enhance your browsing experience and ensure the site functions properly. By continuing to use this site, you acknowledge and accept our use of cookies.
