risorius muscle

Facial muscle that attaches to the fascia of the masseter muscle and the facia of the skin in the region of the corner (angle) of the mouth. Even in species in which this muscle is present, it is highly variable. A true risorius muscle may only be present in Hominins (humans and great apes). See Diogo 2008; Diogo et al., 2009; Burrows et al.., 2011., also DuBrul, 1980. Every claim on this page comes from the Leumas anatomy graph and carries its source.

What the risorius muscle is

Facial muscle that attaches to the fascia of the masseter muscle and the facia of the skin in the region of the corner (angle) of the mouth. Even in species in which this muscle is present, it is highly variable. A true risorius muscle may only be present in Hominins (humans and great apes). See Diogo 2008; Diogo et al., 2009; Burrows et al.., 2011., also DuBrul, 1980. The atlas records it as a muscle at the organ scale in the human body.

Where the risorius muscle is

It sits in the head, within the muscular system. Not positioned individually, and containment is not asserted either. Drawn near structures of the same kind, which is a weak claim about location.

What the risorius muscle connects to

The atlas records 5 typed relationships for it, across 4 kinds of connection. a kind of facial muscle.

Supply and innervation

Innervation: facial nerve.

Also called

Also recorded as musculus risorius and risorius. Searching any of those names reaches this page.

Source

Uberon multi-species anatomy ontology (Mungall et al.), CC BY 4.0. Term UBERON:0008598, version 2026-06-19, retrieved 2026-08-24. Licence: CC-BY-4.0.

• A kind of: facial muscle.
• Attaches to: masseter muscle and skin of body.
• Innervated by: facial nerve.
• inserts into: facial modiolus.

Questions

Where is the risorius muscle?

It sits in the head, within the muscular system. Not positioned individually, and containment is not asserted either. Drawn near structures of the same kind, which is a weak claim about location.

What does the risorius muscle connect to?

A kind of: facial muscle.

Is the risorius muscle the same in other species?

Leumas holds the same relationship vocabulary for every species it carries, so where another dataset records this structure you can put the two side by side on /compare.