risorius


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ri·so·ri·us (mus·cle)

[TA]
facial muscle of mouth; origin, from platysma and fascia of masseter; insertion, orbicularis oris and skin at corner of mouth; action, draws angle of mouth laterally, lenghthening rima oris; nerve supply, facial.
Farlex Partner Medical Dictionary © Farlex 2012

risorius

(rī-sŏ′rē-ŭs) [L., laughing]
The muscular fibrous band arising over the masseter muscle and inserted into the tissues at the corner of the mouth.
Medical Dictionary, © 2009 Farlex and Partners
References in periodicals archive ?
Inasmuch as the risorius muscles often (but not in sad human expression) are frequently cooperative with the zygomatics, old adages such as "sing with a pleasant expression," "breathe as though inhaling the fragrance of a rose," etc., clearly are meant to affect the shape of the resonance chamber.
Denervation of the orbicularis oculi muscle results in the inability of the patient to close the eye lids effectively, while denervation of the risorius muscle results in the limited retraction of the angle of mouth.
Istemsiz kasilmalar orbicularis oculi, frontalis, zygomaticus major, zygomaticus minor, levator labi superioris, risorius, orbicularis oris, mentalis ve platysma kaslarinda gozlenebilir (6,8).
"Fleeting facial expressions are expressed by minute and unconscious movements of facial muscles like the frontalis, corregator, and risorius," Frank explains.
When the labial elevator muscles (i.e., levator labii superior, levator anguli oris and risorius) are stretched downward throughout the entire muscle, the upper lip can become more active.
* the marginal mandibular branch to the risorius muscle and the muscles of the lower lip and chin
* the mandibular lamina (the depressor labii inferioris, the mentalis, the risorius, the depressor anguli oris, the inferior part of the orbicularis oris, and perhaps the buccinator and the levator anguli otis)
Rama Against The Demons, Theatre Du Risorius, 10.30am-11.30am, Garage Theatre, Grindlay Street, pounds 6.
It was used macroscopic dissection and direct observation of the orbicular muscles of the lips, depressor of angle of mouth, risorius and elevator of upper lip and wing of nose.
The toxin is typically injected into the zygomaticus major and minor, the levator anguli oris, and the risorius. Improvement has been reported to occur in 92 to 100% of patients.