Mastication Flashcards
describe skeletal components of chewing apparatus - main
mandible - bottom
maxilla - top
temporal bone = where mandible sits and articulates with cranium
describe skeletal components of chewing apparatus - chewing muscle attachments
other bones that serve as sites of chewing muscle attachment = zygomatic, parietal and sphenoid
what is ramus of mandible
branch
root part of mandible
Articulates with skul
what is angle of mandible
where ramus becomes corpus
what is mental foramen of mandible
hole on body
what is chin of mandible
mental protuberance
what is coronoid process of mandible
site of muscle attachment
what is mandibular notch of mandible
notch between head and coronoid process
what is condyle of mandible
head
Important for chewing
joint head, knuckle shaped, elliptical surface for mandible
what is mandibular foramen of mandible
nerves and structures enter here and run across mandible (corpus) and comes out a hole
describe tmj - gen
Mandible articulates with temporal at tmj
what is articular tubercle - tmj
Ridge
sits just anteriorly, stopper
what does mandibular fossa of temporal bone do
mandibular fossa of temporal bone = accommodates head of mandible
what is articular disk - tmj
fibrocartilage
chunk - sits between temporal and mandible
helps with gliding, matching surfaces
also allows some movement
what is lateral ligament - tmj
reinforce joints with ligaments = increase stability, prevent dislocation, runs from zygomatic process of temporal to neck
describe joint - tmj
modified synovial hinge joint = primarily a hinge - opens and closes
name what motions does tmj do
protraction
retraction
depression
elevation
side to side - minimal
describe protraction - tmj
anterior translation of mandible
describe retraction - tmj
posterior translation of mandible
describe depression - tmj
abduction
inferior rotation around transverse axis = opening mouth (increase angle between top and bottom)
describe elevation - tmj
adduction
Superior rotation around transverse axis= closing mouth
describe main vs minimal movements of tmj
minimal = side to side translation motion
main = protraction, retraction. Depression, elevation * mostly linear movement
how do we only chew on one side
motion of retraction and protraction essential for aligning teeth
describe tmj/motions during depression of mandible
head glides anteriorly over articular tubercle
head moves within joint and rests on tubercle (abducted and protracted)
describe temporal fossa
superior to zygomatic arch
with floor formed by bones that contribute to pterion = frontal, parietal, temporal and sphenoid
describe infratemporal fossa - gen
deep to zygomatic arch and mandibular ramus
inferior to temporal
describe infratemporal fossa - bony boundaries
mandibular ramus = lateral
Sphenoid = superior and medial (a bit)
maxilla = anterior
Temporal = posterior
NO FLOOR THOOOO
describe infratemporal fossa - occupied by what
muscles of mastication and neurovascular structures
name muscles of mastication
temporalis
masseter
medial and lateral pterygoids
describe temporalis - muscles of mastication - gen
from temporal fossa to coronoid process of mandible
fan shaped muscle -attached to all of temporal fossa
all fibers converge on coronoid process of mandible
describe temporalis - muscles of mastication - function
elevation (anterior fibers) and retraction (posterior fibers) of mandible at tmj
describe temporalis - muscles of mastication - shorten anterior fibers
bring mandible up
pure adduction –> rotate tmj, bring coronoid process superiorly
describe temporalis - muscles of mastication - shorten posterior fibers
pulling mandibular head back into mandibular fossa (when mouth open)
describe masseter - muscles of mastication - gen
from zygomatic arch to lateral surface of ramus and angle of mandible (zygomatic arch supports attachment of masseter)
describe masseter - muscles of mastication - function
elevation and protraction of mandible at tmj
adduction and bring mandible out of socket = open mouth or rotate side to sided -
down to angle of mandible = shorten adduct, only slight protraction
describe masseter - muscles of mastication - relationship with parotid
parotid pierces buccinator
passes around anterior end of masseter
describe medial pterygoid - muscles of mastication - gen
from maxilla/palatine (a bit) to medial surface of ramus and angle of mandible = superficial head
medial surface of lateral pterygoid plate to medial surface of ramus and angle of mandible = deep head
heads run side by side and deep head = bigger
describe medial pterygoid - muscles of mastication - function
elevation of mandible at tmj
masseter and medial pterygoid are mirror images = (oriented same way) on either side of mandibular ramus (runs from ramus to opposite side tmj), creates a v shaped sling for forceful elevation
both muscles = provide very forceful adduction = pulls up mandible
describe lateral pterygoid - muscles of mastication - gen
from sphenoid greater wing to articular disk and condyle of tmj (to mandibular head)= superior head
from lateral surface of lateral pterygoid plate to articular disk and condyle of tmj (to mandibular head) = inferior head
describe lateral pterygoid - muscles of mastication - function bilateral
mandible protraction
initiation of mouth opening
Shorten = mandible out towards other attachment
describe lateral pterygoid - muscles of mastication - function unilateral
translate mandible towards opposite side - moves articular head over to articular tubercle (protraction of mandible)
move ipsilateral mandible head medially - chew on one side only (one side only - head goes on to articular tubercle, move ipsilateral mandible head out so can chew on contralateral side)
describe features of lateral pterygoid muscle of mastication
not involved in chewing - just opens/aligns mouth
lateral to medial pterygoid = more superficial
perpendicular to medial pterygoid (fibers)
describe motor innervation of muscles of mastication - gen
trigeminal - v3 mandibular nerve = through foramen ovale (right into infratemporal fossa)
describe motor innervation of muscles of mastication - branches
lateral pterygoid nerve
medial pterygoid nerve
deep temporal nerves
masseteric nerve (must go over mandibular notch to back or deep side of masseter)
buccal nerve - sensory to cheek
describe buccal nerve - muscles of mastication
big branch of mandibular
inside and outside
Close to buccinator (motor from facial nerve - muscle of facial expression)
describe general sensory innervation to skin of mastication - gen
general sensory innervation to skin and soft tissues around chewing apparatus from CN V (mainly v2 and v3)
describe maxillary teeth
inferior view =
incisors, canines, premolars, molars
describe mandibular teeth
superior view = molars, premolars, canines, incisors
describe types of teeth and functions
incisors = allows us to bite
canines = pierces and threat (secondary feature)
premolars and molars = chewing surfaces
3rd molar = wisdom teeth
describe dental formula for teeth
I = 2
C =1
P = 2
M = 3
4 quadrants = 8x4 = 32 teeth in most adults
describe teeth roots
anchors teeth via roots
describe teeth crowns
exposed, covered in enamel, hard, helps chew
name nerves of teeth
lingual
inferior alveolar nerve
mental nerve
Superior alveolar nerve
infraorbital nerve
what are teeth sockets called
teeth roots = alveoli
describe lingual nerve - teeth
v3 - sensory and general sensation to gums and ant 2/3 tongue
describe inferior alveolar nerve - teeth
v3 - enters via mandibular foramen and runs in mandible
innervation of mandibular teeth and gums of lower jaw —> terminal branch = mental nerve
(sensory to lower lips, and chin, exits via mental foramen)
describe mental nerve - teeth
Sensory to chin
terminal branch of inferior alveolar nerve -v3
describe superior alveolar nerves - teeth
runs partially in maxillary sinus - sensory innervation to maxillary teeth and gums of upper jaw
describe infraorbital nerve - teeth
sphenopalatine splits and sends branch to floor of orbit
v2 (foramen rotundum)
onto face
sends branches to sockets (alveolar) and maxillary teeth
name ateries/veins of teeth
maxillary - branch eca
infraorbital a/v
superior alveolar a/v - another branch
inferior alveolar a/v - run with nerve through mandible
venous plexus
what passes through mandibular foramen
inferior alveolar nerve, artery and vein
describe teeth arteries - pathway
eca –> maxillary –>infraorbital and another branch = sup alveolar and another branch = inf alveolar
what is venous plexus - for teeth
collects all blood - venous from everywhere in head
including surface
describe contents of infratemporal fossa
pterygoid muscles occupy most of infratemporal fossa (lateral pterygoid more superficial)
major neurovascular structures related to chewing apparatus travel in infratemporal fossa, between pterygoid muscles (deep to lateral but superficial to medial pterygoid)
name all components of infratemporal fossa
muscular branches of v3
chorda tympani - cnVII
Maxillary artery
inferior alveolar nerve
sphenopalatine artery
infraorbital nerve
descending palatine artery
buccal nerve - v3
lingual nerve - v3
describe muscular branches of v3 - IFT
go to muscles
describe chorda tymapni CNVII - IFT
Branch of facial nerve to ant 2/3 of tongue (taste), hitchhikes with lingual
describe maxillary artery - IFT
traverses infratemporal fossa diagonally (post to ant)
ends in important branches
describe inferior alveolar nerve - IFT
v3
travels with inferior alveolar a/v
describe sphenopalatine artery - IFT
runs down septum and down incisive canal - back into anterior hard palate
describe infraorbital artery - IFT
enters orbit through infraorbital fissure
describe descending palatine artery - IFT
down into groove (tunnel)= greater and lesser palatine arteries = blood to hard and soft palate
describe buccal nerve - IFT
Sensory - v3
describe lingual nerve - IFT
to tongue
