Review of Suprahyoid Region, Facial Muscles and Parotid Gland Flashcards
mylohyoid muscles
attachment innervation
attachment suprahyoid muscle
mylohyoid line of the mandible to the hyoid bone
innervated by the nerve to the mylohyoid
geniohyoid
attachment innervation
attachment deep to the mylohyoid and attaches at the mental spine of the mandible –> to the hyoid
innervation - C1 via the hypoglossal nerve
Digastric
attachment innervation
+ regions
attachment of anterior: digastric fossa of the mandible
posterior: mastoid notch (temporal bone? i think)
MEET AT THE INTERMEDIATE TENDON TO ATTACH ON THE HYOID
innervation is different for anterior and posterior
anterior = nerve to mylohyoid
posterior innervation = facial nerve
stylohyoid
attachment innervation
attachment : styloid process of temporal bone to the hyoid
innervation : facial nerve
function of the suprahyoid muscles
collectively, the suprahyoids make up a significant part of the floor of the mouth and elevate the hyoid and larynx
hypoglossal nerve
course
CN XII
leaves the skull through the hypoglossal canal and descends almost vertically in the neck to a level just below the angle of the mandible
here (just below angle of mandible) angles sharply forward and crosses the external carotid artery
it continues forward and crosses the lingual artery
the hypoglossal travels DEEP to the mylohyoid muscle to reach the tongue
hypoglossal location in relation to the mylohyoid muscle
can be found DEEP to this muscle
location of muscles of facial expression
facial muscles - are in the subcutaneous tissue of the anterior and posterior scalp, face, and neck
most muscles of facial expression attach where
to bone or fascia and produce their effects by pulling the skin
development of muscles of facial expression
all develop from the mesoderm in the SECOND PHARYNGEAL ARCHES
CLINICAL NOTE; FACIAL SWELLING
The face has no distinct deep fascia and the subcutaneous tissue between the cutaneous attachments of the facial muscles is loose
the looseness of the subcutaneous tissue ENABLES FLUID AND BLOOD TO ACCUMULATE IN THE LOOSE CONNECTIVE TISSUE
- swelling is evident after removal of wisdom teeth
occipitofrontalis
Attachment
Action
Innervation
occipitofrontals is a flat digastric muscle, with occipital and frontal bellies that share a common tendon, the epicranial aponeurosis
occipital belly attaches to the superior nuchal line
the frontal belly inserts into the skin and subcutaneous tissue of eyebrows and forehead
Action: independent contraction of the occipital belly retracts the scalp and contraction of the frontal belly protracts it
innervation:
occipital belly - posterior auricular branch of facial nerve
frontal belly - temporal branches of facial nerve
epicranial aponeurosis
common tendon of the occipital and the frontal bellies of the occipitofrontalis muscle
(facial expression muscle)
- broad, strong, tendinous sheet that serves as the attachment for the occipitofrontalis
this is avascular and considered LAYER 3 of the scalp (5 total layers)
there is a lot of tension here so if laceration occurs on the skull –> will have a pretty big gap
5 layers of the scalp
- skin
- connective tissue
- epicranial aponeurosis (remember avascular)
- loose areolar tissue
- pericranium
literally spells scalp if use (a) for epicranial aponeurosis
skin layer of scalp
thin, except in the occipital region, containing many sweat and subaceous glands and hair follicles
connective tissue layer of the scalp
forms the thick, dense, richly vascularized subcutaneous ;ayer that is well supplied with cutaneous nerves
epicranial aponeurosis layer/role in scalp
LAYER 3
This broad, strong, tendinous sheet that serves as the attachment for the occipitofrontalis muscle
loose aerolar tissue layer of scalp
4th layer
this allows the movement/gliding along of the epicranial aponeurosis
Pericranium
layer 5 of the scalp - part of the periosteum
dense layer of connective tissue that forms the external periosteum of the neurocranium
muscles of the mouth, lips, and cheeks
Orbicularis oris –> spincter around the mouth
Buccinator in the cheeck
elevators, retractors, and evertors (rotating upwards) of the upper lip
depressors, retractors, and evertors of lower lip
Orbicularis Oris Attachments Action Innervation Description
Attachments: Medial maxilla and mandible, and angle of the mouth –> INSERTS within the mucous membrane of the lips
Action: Tonic (resting state of muscle) is closing the mouth/ closes mouth
PHASIC: compresses tand protrudes lips (kissing face)
Innervation : Buccal and marginal mandibular branches of facial nerve
Description : encircles the mouth within the lips, controlling entry and exit through the oral fissure
also important in speech /articulation
Buccinator Description Attachments Action Innervation
Description : thin, flat rectangular muscle and within a plane that is DEEPER than the other muscles –> because it occupies a deeper, more medially placed plane than the other facial muscles, it passes deep to the mandible so that it is more closely related to the buccal mucosa than the skin of the face (makes sense because in cheek)
Attachments: laterally to the alveolar processes of the maxillae and mandible OPPOSITE THE MOLAR TEETH and to the pterygomandibular raphe
Action : active in smiling, keeps cheek taught –> PREVENTING IT FROM BEING FOLDED OR INJURED IN CHEWING AND KEEPS FOOD BETWEEN TEETH (not looking like a chipmunk when eating) so controlling tension in the lateral cheeks/side of mouth
COMPRESSES CHEECKS AGAINST TEETH AND GUMS
Innervation: BUCCAL BRANCH OF FACIAL NERVE
Buccinator and pterygomandibular raphe
oral cavity is CONTINOUS with space = pharynx behind it –> the anterior of pharynx and the posterior of the oral cavity we have this pterygomandibular raphe AT THE JUNCITON
a tendinous thickening of the buccopharyngeal fascia
anteriorly, its fibers blend with the orbicularis oris muscle fibers meet with eachother
buccinator
anterior muscle fibers of the buccinator
they ‘mingle’ medially with those of the orbicularis oris, and the tonus of the two muscles COMPRESS CHEECK AND LIPS AGAINST TEETH AND GUMS
BUCCINATOR IMPLICATION IN DENTISTRY
this muscle (more anterior fibers) along with the orbicularis oris and tongue KEEP FOOD BETWEEN THE OCCLUSAL SURFACES OF THE TEETH during mastication to prevent food from accumulating in the oral vestibule
muscle that resists the forces generated by whisteling and sucking
buccintor
bell’s palsy
more dental implications with paralysis to CN VII –> cannot keep food between teeth on one side so more prone to decay
Mobius syndrome
rare birth defect caused by the absence or underdevelopment of CN 6 and 7
ASSYMETRICAL OF FACIAL EXPRESSION AND SEVERE TOOTH DECAY
- food is touching outer surface of the teeth and not staying between the occlusal surfaces
Platysma Description and where is it located? Attachments Action Innervation
Description - broad, thin sheet like / apron of muscle fibers that drape over the upper portion of neck
IN SUBCUTANEOUS TISSUE OF THE NECK
Attachments : Subcutaneous tissue of supra and infraclavicular regions –> to the base of the mandible, skin of the cheek, angle of the mouth and orbicularis oris
Action : From superior attachment - tenses the skin, producing vertical skin ridges
Inferior attachment –> helps depress the mandible and draw corners of the mouth inferiorly, as in a grimace
Innervation: Cervical branch of facial nerve
Levator anguli oris muscle Description Attachments Action Innervation
Description
Attachments: ORIGINATES from the canine fossa of the maxilla immediatley INFERIOR to the infraorbital foramen and INSERTS into the angle of the mouth, blending with the fibers of the orbicularis muscle
Action - lifts the angles of the mouth
Innervation : Buccal branch of facial nerve
Depressor anguli oris Description Attachments Action Innervation
Description - triangular muscle
Attachments : FROM the external oblique line of the mandible –> ascending fibers converge at the apex to insert into the angle of the mouth from BELOW AND BLEND with the fibers of the orbicularis oris muscle
Action - pulls on angle of the mouth downward
Innervation - marginal mandibular branch of facial nerve
*levators and depressor - if have levator - likely will have depressor opposing the action of the other
Zygomaticus major Description Attachments Action Innervation
Description - snaring facial expression
Attachments ARISES from LATERAL aspect of the zygomatic bone –> fibers angle downward and medially to insert into the angle of the mouth and blend with the orbicularis oris muscle
Action - draws the angle of the mouth upward and backward
Innervation - Bucal branch of the facial nerve + some fibers from zygomatic branch
Zygomaticus minor Description Attachments Action Innervation
Description
Attachments: ARISES from the ANTERIOR aspect of the zygomatic bone –> fibers angle donward and medially to inser into the skin of the UPPER LIP
Action - assists in elevation of the upper lip (since more anterior than the major - not as much into the angle so not bringing lip back as much as it is bringing it up - elavating)
Innervation - buccal branch of the facial nerve
Risorius Description Attachments Action Innervation
Description - thin muscle - more straight and bringing the lips back mainly directly posterior
Attachments: ARISES from parotid and masseteric fascia, and buccal skin –> INSERTS traversely into the angle of the mouth
Action: Retracts the angle of the mouth posteriorly
Innervation: Mandibular and/or buccal branch of the facial nerve
*highly variable
Levator labii superioris Description Attachments Action Innervation
Description
Attachments: originates from the the inferior orbital margin (higher up than the levator anguli oris) –> inserts into UPPER LIP
Action- raise the upper lip
Innervation: Buccal branch of facial nerve
Depressor labii inferioris Description Attachments Action Innervation
Description
Attachments: ARISES from the lowest portion of the oblique line of the mandible –> inserts into the SKIN OF LOWER LIP
Action: depresses the lower lip
Innervation: marginal mandibular branch of facial nerve
Orbicularis oculi Description Attachments Action Innervation
Description - TWO PORTIONS - Palpebral and Orbital
Attachments ORGINATES from medial orbital margin and lacrimal bone INSERTS into skin around orbit
Action - palpebral portion is BLINKING and Orbital portion is FORCEFUL closing of the eye
Innervation - temporal and zygomatic branches of facial nerve
Corrugator Supercilli Description Attachments Action Innervation
Description -
Attachments: Medial end of supercilliary arch (ridge superior to the supraorbital margin) –> SKIN overlying the supercilliary arch and supraorbital margin
Action - draw the eyebrows medially and inferiorly
Innervation - temporal branch of facial nerve
Mentalis Description Attachments Action Innervation
Description
Attachments: Body of mandible anterior to roots of inferior incisors –> skin of chin
Action - elevates and protrudes lower lip (pouting)
Innervation: Marginal mandibular branch of facial nerve
class II malocclusion
there is a small mandible in relation to the maxilla - so the MENTALIS MUSCLE ARE HYPERACTIVE WHEN THE LIPS ARE CLOSED
the dimpling of the chin indicates hyperactive mentalis muscle
- have to bring lower lip up and forward - almost constant contraction of the mentalis muscle
components of nasalis muscle
Alar part
Transverse part
Levator labi superioris alaeque nasii and alar part of nasalis Description Attachments Action Innervation
Description
Attachments: Frontal process of maxilla –> alar cartilage
Action: Depress ala laterally –> DIALATES nasal aperture
Innervation: Buccal branch of facial nerve
Procerus and transverse part of nasalis Description Attachments Action Innervation
Description
Attachments: Fascia on dorsum of nose and lateral nasal cartilage –> skin of inferior forehead between brows
Action: depresses medial end of brow, wrinkles skin on dorsum of nose
Innervation: buccal branch of faccial nerve
procerus - wrinkles?
clinical correlation with nasal muscles (diagnostic value)
true NASAL breathers can flare their nostrils distinctly
MOUTH BREATHERS - caused by chronic nasal obstruction, for example, DIMINISHES and sometimes eliminates the ability to flare the nostrils (due to atrophy and disuse of the muscles)
children who are chronic mouth breathers?
often develop dental MALOCCLUSION (improper bite) because the alignment of the teeth is maintained to a large degree by normal periods of occlusion and labial closure
Parotid Gland enclosed in?
tough fascial capsule –> PAROTID SHEATH derived from the INVESTING LAYER OF DEEP CERVICAL FASCIA
embedded in the parotid gland superficial to deep?
Parotid plexus of the facial nerve (CN VII) and its branches
Retromandibular vein
External Carotid Artery
*surgery to this area is risky due to all of the stuff passing through the duct
nerve artery and vein similar to the carotid sheath we talked about before
parotid gland shape and details
parotid gland has an irregular shape because the area is occupied by the gland, the PAROTID BED, is ANTERIOINFERIOR TO THE EXTERNAL ACOUSTIC MEATUS –> where it is wedged between the ramus of the mandible and the mastoid process (of temporal bone) (most is superficial but kind of cups posterior aspect
Fatty tissue between the lobes of the gland assures the flexibility the gland must have to accomodate the motion of the mandible
the apex of the parotid gland is posterior to the angle of the mandible and its base is related to the zygomatic arch
the parotid duct passes…
passes horizontally from the anterior edge of the gland and the anterior border of the masseter–> turns medially–> PIERCES THE BUCCINATOR and enters the oral cavity through a small orifice OPPOSITE THE SECOND MAXILLARY MOLAR
T/F parotid lymph nodes are on the parotid sheath and within the gland
TRUE
opening of the parotid duct into oral cavity
long duct connecting to the epithelial surface in the oral cavity
opening is OPPOSITE second maxillary molar
trunks of the facial nerve that give rise to the parotid plexus
temporofacial and cervicofacial trunks of the facial nerve give rise to the parotid plexus
five terminal branches of parotid plexus TYPICALLY emerge as ….
*variations exist
Temporofacial trunk—> gives rise to temporal, zygomatic, and buccal branches
Cervicofacial trunk –> gives rise to buccal, mandibular, and cervical branches
discrepancy seen most in buccal branch fibers origin
