Muscles of Facial Expression & Mastication Flashcards
Orbicularis Oculi: Palpebral Part
O/I: courses from the medial palpebral ligament through both lids to insert on lateral palpebral raphe
A: gentle closure of the eyelids (winking, blinking)
Orbicularis Oculi: Orbital Part
O/I: arises from orbital margin & medial palpebral ligament
A: forceful closure of the eyelids
Orbicularis Oculi: Lacrimal Part
O/I: courses posterior to medial palpebral ligament and lacrimal sac
A: draws eyelids and lacrimal sac medially to aid in tear collection
Levator labii superioris alaeque nasi
O: maxilla
I: courses lateral to nose to insert onto skin of upper lip
A: elevates upper lip and dilates nostrils
Levator labii superioris
O: maxilla near the inferior margin of the orbit, deep to orbicularis oculi
I: courses inferiority to insert on the lateral half of the upper lip
A: elevates the upper lip
Zygomaticus minor
O: zygomatic bone medial and anterior to zygomaticus major
I: courses obliquely (medially) to insert on the lateral half of the upper lip
A: elevates the upper lip
Zygomaticus major
O: zygomatic bone
I: courses obliquely to insert on the corner of the mouth
A: pulls the mouth upwards and outwards (smiling and laughing)
Levator anguli oris
O: maxilla deep to levator labii superioris
I: corner of the mouth
A: elevates the corner of the mouth
Risorius
O: parotid facia and buccal skin
I: corner of mouth
A: widens mouth
Depressor anguli oris
O: anterior mandible
I: passes upward to insert onto the angle of mouth
A: depresses corner of the mouth (frowning)
Depressor labii inferioris
O: anterior mandible
I: passes medially to insert onto the lower lip; most medial fibers may cross over one another at the midline
A: depress lower lip and pulls it laterally
Mentalis
O: incisive fossa of mandible
I: onto skin of chin
A: raises and protrudes lower lip
Orbicularis oris
O/I: A circular muscle lying within the upper and lower lips; formed from interlacing fibers of the oral group muscles, plus the buccinator me, and fibers within the lips
A: oral sphincter; closes the mouth and also contributes to pursing and protrusion of the lips
Buccinator
O: pterygomandibular raphe, maxilla, and mandible
I: fibers pass anteriorly to insert onto the mouth, some decussate (crisscross) and form the substance of the cheek
A: aids in mastication by compressing the cheek to keep food between the molars; involved in cheek expansion (whistling or blowing)
Note: Is pierced by the parotid duct; buccal fat pad lies superior to the muscle and is prominent in infants to aid in suckling
Auricular muscles
O/I: radiate around ears
A: mostly rudimentary; moves auricles in some
Platysma
O: superficial fascia of the skin of the thorax
I: courses upward through the neck to insert on the lower part of the face
A: wrinkles the the skin over the neck and he face; may also be active in deep inspiration
Occipitofrontalis
Frontalis m. and the Occipitalis m. bellies are untied by epicranial aponeurosis
Frontalis
O: epicranial aponeurosis
I: skin of forehead
A: wrinkles skin of forehead and raises eyebrows
Occipitalis
O: occipital bone
I: epicranial aponeurosis
A: pulls scalp posteriorly and wrinkles skin over posterior aspect of cranium
Masseter
O: zygomatic arch
I: angle and lateral surface of mandibular ramus
A: elevates mandibke( superficial head also assists in protraction of mandible
Temporalis
O: floor of temporal fascia and inferior temporal line on lateral surface of temporal fascia
I: muscle fibers converge inferiority to form tendon inserting on the coronoid process of the mandible
A: VERTICALLY oriented fibers elevate the mandible; HORIZONTALLY oriented fibers retract the mandible
Medial pterygoid
O: two-heads arise from medial surface of lateral pterygoid plate and tuberosity of maxilla
I: medial surface of mandibular ramus
A: acts with mass enter to elevate mandible; aids in protrusion; alternate unilateral activity produces small grinding movements
Lateral pterygoid
O: two- heads arise from infratemporal surface, crest of great wing if sphenoid, and lateral surface of lateral pterygoid plate
I: joint capsule and articular disc of TMJ and the condylar neck of the mandible
A: bilaterally protracts mandible and depresses chin; unilaterally swings jaw to opposite side; alternate unilateral contraction produces larger lateral chewing movements
