Risorius

The risorius (Latin: musculus risorius) is a muscle of facial expression located laterally to the opening of the oral cavity. It is classified as the buccolabial facial muscle. The risorius pulls the angle of the mouth laterally.

Risorius, Risorius muscle, Facial muscles, Muscles of facial expression, Head muscles
Risorius by Anatomy Next
Risorius
OriginMasseteric fascia
InsertionSkin at angle of mouth
ActionPulls angle of mouth laterally
Innervation Buccal branch of facial nerve (CN VII)
Blood supply Superior labial artery of facial artery

 

Origin

The risorius originates from the masseteric fascia.

 

Insertion

The risorius inserts into the skin at the angle of the mouth.

Origin and insertion of risorius, Risorius muscle
Origin and insertion of risorius by Anatomy Next

 

Action

Upon activation, the risorius pulls the angle of the mouth laterally. Contractions of the risorius muscle produce facial expressions of pleasure and laughter.

Action of risorius, Risorius muscle
Action of risorius by Anatomy Next

 

Innervation

The risorius is innervated by the buccal branch of the facial nerve (CN VII).

 

Blood supply

The risorius muscle is mainly supplied by the superior labial branch of the facial artery.