Risorius
From Wikipedia, the free encyclopedia
| Risorius | ||
|---|---|---|
 |
||
| Muscles of the head, face, and neck. | ||
| Latin | musculus risorius | |
| Gray's | subject #108 385 | |
| Origin: | parotid fascia | |
| Insertion: | modiolus | |
| Artery: | facial artery | |
| Nerve: | facial nerve | |
| Action: | draws back angle of mouth | |
| Dorlands/Elsevier | m_22/12550552 | |
The risorius arises in the fascia over the parotid gland and, passing horizontally forward, superficial to the platysma, inserts onto the skin at the angle of the mouth. It is a narrow bundle of fibers, broadest at its origin, but varies much in its size and form.
[edit] Action
The risorius retracts the angle of the mouth to produce a smile, albeit an insincere-looking one that does not involve the skin around the eyes. Compare with a real smile, which raises the lips with the action of zygomaticus major and zygomaticus minor muscles and causes "crow's feet" around the eyes using the orbicularis oculi muscles.
[edit] Innervation
Like all muscles of facial expression, the risorius is innervated by the facial nerve (CN VII).
[edit] External links
This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant.
 |
This muscle article is a stub. You can help Wikipedia by expanding it. |
scalp/eyelid: occipitofrontalis (occipitalis, frontalis) - orbicularis oculi - corrugator supercilii - depressor supercilii
extraocular: levator palpebrae superioris - superior tarsal - rectus (superior, inferior, medial, lateral) - oblique (superior, inferior) - intraocular: ciliary - iris dilator - iris sphincter
ear: auriculares - temporoparietalis - stapedius - tensor tympani
nose: procerus - nasalis (dilatator naris) - depressor septi nasi - levator labii superioris alaeque nasi
mouth: levator anguli oris/depressor anguli oris - levator labii superioris/depressor labii inferioris - zygomaticus (major, minor) - mentalis - buccinator - orbicularis oris - risorius
mastication: masseter - temporalis - pterygoid (lateral, medial)
tongue: extrinsic (genioglossus - hyoglossus - chondroglossus - styloglossus) intrinsic (superior longitudinal - inferior longitudinal - transversus - verticalis)
soft palate: levator veli palatini - tensor veli palatini - musculus uvulae - palatoglossus - palatopharyngeus
pharynx: pharyngeal constrictor (inferior, middle, superior) - stylopharyngeus - salpingopharyngeus
larynx: cricothyroid - posterior cricoarytenoid - lateral cricoarytenoid - arytenoid - thyroarytenoid
