Risorius

  • The risorius (also risorius muscle, latin: musculus risorius) is a muscle of facial expression located laterally to the mouth opening, which pulls the angle of the mouth laterally.

    Origin

    The risorius originates from the masseteric fascia.

    Insertion

    The risorius inserts into the skin of the angle of the mouth.

    Action

    Upon activation the risorius pulls the angle of the mouth laterally.

    Contractions of the risorius muscle produce facial expression of pleasure and laughter.

    Innervation

    The risorius is innervated by the buccal branch of the facial nerve (CN VII).

    Blood supply

    The risorius is mainly supplied by the superior labial branch of the facial artery.