Risorius

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	Buccal branch of the facial nerve
Action	draw back angle of mouth

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.

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.

Innervation

Like all muscles of facial expression, the risorius is innervated by the facial nerve (CN VII).

External links

LUC ris
-1160773552 at GPnotebook
Risorius+muscle at eMedicine Dictionary
PTCentral

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 As such, some of the information contained herein may be outdated.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.

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v • d • e

List of muscles of head and neck: the head

Extraocular (CN III, IV, VI)

oblique (inferior, superior) - rectus (superior, inferior, medial, lateral) - levator palpebrae superioris (superior tarsal)

Mastication (CN V3)

masseter - temporalis - pterygoid (lateral, medial)

Facial (CN VII)

Ear	auriculares (anterior, superior, posterior) - temporoparietalis

Scalp/eyelid	occipitofrontalis (occipitalis, frontalis) - orbicularis oculi (depressor supercilii) - corrugator supercilii

Nose	procerus - nasalis (dilatator naris) - depressor septi nasi - levator labii superioris alaeque nasi

Mouth	levator anguli oris - levator labii superioris - zygomaticus (major, minor) orbicularis oris - risorius - buccinator depressor anguli oris - depressor labii inferioris - mentalis

Mouth/throat (CN IX, X, XI)
(except TVP=V3)

Soft palate	veli palatini (tensor, levator) - musculus uvulae - palatopharyngeus (to pharnyx) - palatoglossus (to tongue)

Pharynx	pharyngeal constrictor (superior, middle, inferior) - longitudinal (stylopharyngeus, salpingopharyngeus)

Larynx	cricothyroid - cricoarytenoid (posterior, lateral) - arytenoid (oblique arytenoid/aryepiglottic, transverse arytenoid) - thyroarytenoid (vocal, thyroepiglottic)

Tongue (CN XII)

extrinsic (genioglossus, hyoglossus/chondroglossus, styloglossus) - intrinsic (superior longitudinal, inferior longitudinal, transverse, vertical)

Categories: Muscle stubs | Muscles of the head and neck

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