human_reference_atlas Homo sapiens facial muscle risorius muscle http://upload.wikimedia.org/wikipedia/commons/a/af/Musculusrisorius.png 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. risorius muscle AS Wikipedia:Risorius UBERON:0008598 SCTID:244755003 risorius muscle uberon FMA:46838 musculus risorius risorius MFMO:0000141 muscle of facial expression