Risorius

Risorius
Superficial muscles of the head and neck, showing the risorius in red. This version of the muscle does not match that shown in most sources.
Muscles of the head, face, and neck. Risorius shown in red. This is the most standard version of the direction and origin of the muscle.
Details
OriginParotid fascia
InsertionModiolus
ArteryFacial artery
NerveBuccal branch of the facial nerve
ActionsDraws back angle of mouth
Identifiers
Latinmusculus risorius
TA98A04.1.03.028
TA22078
FMA46838
Anatomical terms of muscle

The risorius muscle is a highly variable muscle of facial expression. It has numerous and very variable origins, and inserts into the angle of the mouth. It receives motor innervation from branches of facial nerve (CN VII). It may be absent or asymmetrical in some people. It pulls the angle of the mouth sidewise, such as during smiling.