Muscles of the Lips and Facial Expression

What are the five angular muscles?

1) levator labii superioris alaeque asi muscle 2) levator labii superioris muscle 3) zygomaticus minor muscle 4) zygomaticus major muscle 5) depressor labii inferioris muscle

mentalis muscle function

elevates, protrudes, and everts the lower lip and may crease the chin

depressor labii inferioris muscle origin

from external oblique line of the mandible; travels superiorly and medially to insert into the modiolus and the inferior orbicularis oris muscle;

origin of risorius muscle

from fascia above parotid gland and the aponeurosis of the master muscle and inserts into the modiolus

zygomaticus minor muscle origin

from zygomatic bone lateral to the levator labii superioris and tracks inferiorly and medially to insert into the superior portion of the oribicularis oris muscle

What are the sections of the tongue?

body, root, dorsum, blade, apex

apex of the tongue

tip or most anterior portion of the tongue

Platysma muscle

very thin, flat, and large; covers the majority of the anterior and lateral surfaces of the neck; extension is very variable;

What are the three vertical muscles?

1) mentalis muscle 2) levator anguli oris muscle (caninus) 3) depressor anguli oris muscle

extrinsic muscles of the tongue

1) palatoglossus muscle 2) styloglossus muscle 3) hyoglossus muscle 4) genioglossus muscle

intrinsic muscles of the tongue

1) superior longitudinal muscle 2) inferior longitudinal muscle 3) transverse muscle 4) vertical muscle allow for precise adjustments in tongue form and position

blade of the tongue

anterior part of the tongue, just behind the apex and beneath the alveolar ridge of the maxilla

mentalis muscle origin

anterior surface of the body of the mandible to insert on the skin of the chin and on the inferior portion of the orbicularis oris muscle and the modiolus

Why are exactly determinations of muscle function difficult?

because of the considerable complexity of facial and lip musculature combined with variability in location and morphology across individuals (which may be due to differences in facial size and shape)

zygomaticus major muscle innervation

buccal and zygomatic branches of the facial nerve (cranial nerve VII)

The orbicularis oris muscle is innervated by the _____

buccal branch of the facial nerve (cranial nerve VII)

buccinator muscle is innervated by ____

buccal branch of the facial nerve (cranial nerve VII)

What are the two transverse muscles of the face?

buccinator muscle and risorius muscle

depressor labii inferioris muscle innervation

by the mandibular branch of the facial nerve (cranial nerve VII)

levator labii superioris alaeque nasi muscle innveration

by zygomatic and buccal branches of the facial nerve

levator labii superioris (superior ) muscle innervation

by zygomatic and buccal branches of the facial nerve (cranial nerve VII)

risorius muscle innervation

by zygomatic and buccal branches of the facial nerve (cranial nerve VII)

levator anguli oris muscle (caninus) origin

canine fossa to insert into the modiolus and the superior portion of the orbicularis oris superior muscle

platysma muscle innervation

cervical branch of the facial nerve (cranial nerve VII)

orbicularis oris muscle

composed of primarily horizontally oriented muscle fibers that encircle the mouth in four quadrants: left, right, superior, and inferior, with each quadrant fanning out from the modiolus to the facial midline

body of the tongue

constitutes the major mass of the tongue

buccinator muscle

deep facial muscle and a primary muscle of the cheeks; to obtain a good view, remove master, which is an important jaw-closing muscle

platysma muscle location

deep to the depressor anguli oris muscle; in most individuals, it extends to the cheeks and the muscles of the mouth and the modiolus; however, for some, it can spread even farther up to the muscles surrounding the eyes;

depressor anguli oris muscle origin function

depresses the angle of the mouth, as indicated by its name, such as in an expression of sadness

dorm of the tongue

dorsal surface of the tongue

what is the function of the levator labii superioris muscle?

elevates and everts the upper lip and contributes to deepening the nasolabial furrow

levator anguli oris muscle (caninus) function

elevates the angle of the mouth and, together with zygomaticus major muscle, pulls lips superiorly and laterally and deepens the nasolabial fold, as in smiling or laughing

zygomaticus minor muscle function

elevates the upper lip and contributes to deepening the nasolabial fold, as in smiling

zygomaticus major muscle origin

from zygomatic bone, lateral to the zygomaticus minor muscle; courses inferiorly and medially to insert into the superior portion of the orbicularis oris muscle and the modiolus; often composed of superficial and deep portions

levator labii superioris alaeque nasi muscle origin

frontal process of the maxilla and divides into medial and lateral muscular portions; the medial portion inserts into alar cartilage and acts to dilate the nostril; the lateral portion inserts into the lateral portion of the superior orbicularis muscle, elevates and everts (turns inside out) the upper lip, and contributes to deepening the nasolabial sulcus

What are the two groups of tongue muscles?

intrinsic muscles (origins and insertions inside tongue) extrinsic muscles (origins outside tongue and insertion in the tongue)

levator labii superior muscle origin

lateral to the levator labii superioris alaeque nasi muscle from the inferior surface of the orbit to course inferiorly and medially to insert into the superior orbicularis oris muscle;

What is the orbicularis oris muscle involved in?

lip compression for mastication, swallowing, and speech sound production

depressor anguli oris muscle origin innervation

mandibular and buccal branches of the facial nerve (cranial nerve VII)

mentalis muscle innervation

mandibular branch of the facial nerve (cranial nerve VII)

Muscle fibers in each quadrant of the orbicularis oris muscle

marginal portions (pars marginalis), deep to the vermilion, and peripheral portions (pars peripheralis), around the lips

buccinator muscle function

muscle contraction pulls the lips laterally (retraction), compresses the cheeks, and assists in manipulation the food bolus during mastication and swallowing

risorius muscle function

muscular contraction pulls the lips laterally, as in laughing or smiling

where is the risorius muscle?

parallel and superficial to buccinator muscle

depressor anguli oris muscle origin

partially covers and is lateral to the depressor labii inferioris muscle and is superficial to the platysma muscle; originates from external oblique line of the mandible and courses superiorly to the modiolus and inferior portion of orbicularis oris; superiorly it is continuous with elevator angluli oris muscle and inferiorly with platysma muscle

root of the tongue

posterior portion that forms the anterior boundary of the pharyngeal cavity

zygomaticus major muscle function

pulls the lips superiorly and laterally such as when smiling or laughing

depressor labii inferioris muscle function

pulls the lower lip down during mastication and may contribute to facial expressions such as sadness or sorrow

origin of buccinator muscle

quadrilateral muscle that originates from the pterygomandibular raphe (ligament) and the molar alveolar processes of the mandible and maxilla; muscle fibers course anteriorly (horizontally) to insert into the modiolus and the superior and inferior portions of the orbicularis oris muscle (crossed and uncrossed fibers) at the angle of the mouth

risorius muscle

shows considerable individual variability and is often absent

platysma muscle function

when it contracts, expands the neck and pulls the skin of the neck upward, which may also facilitate the drainage of nearby blood vessels; also may play a role in the downward movements of the lower lip and jaw

zygomaticus minor muscle innervation

zygomatic and buccal branches of facial nerve