orbicularis oris (muscle)

or·bic·u·la·ris o·ris (mus·cle)

[TA] facial muscle of mouth; origin, by nasolabial band from septum of the nose, by superior incisive bundle from incisor fossa of maxilla, by inferior incisive bundle from lower jaw each side of symphysis; insertion, fibers surround mouth between skin and mucous membrane of lips and cheeks, and are blended with other muscles; action, closes lips; nerve supply, facial. Synonym(s): musculus orbicularis oris [TA], musculus sphincter oris, orbicular muscle of mouth, sphincter oris