Muscles of Mastication and Infratemporal Fossa Flashcards
Where does the temporalis muscle insert
cornonoid process of the mandible
The muscles of mastication develop from which branchial arch
what nerve innervates that arch
what artery supplies the muscles of mastication
1st branchial arch
trigeminal nerve (mandibular division V3) - named according to hte corresponding muscle
second part of maxillary artery (named according to corresponding muscle)
What covers the medial surface of the medial pterygoid and splits around the lateral pterygoid
pterygoid fascia
what is the pterygospinous ligament
may be formed by pterygoid fascia between the medial and lateral pterygoid muscles
the pterygoid fascia is continuous with the _______, ________, and the _______
stylomandibular ligament, deep parotid fascia, and the superficial fascia of the neck
In fracture dislocations of the mandible anterior to the angle of the mandible, what causes the proximal portion of the mandible to displace upward and forward?
the masseter muscle
What nerve innervates the buccinator muscle
CN VII
what is the buccinator’s role in mastication
pushes food onto chewing portion of the teeth,
if paralyzed, food is pushed between teeth and cheeks
what structures pass between the two heads of the lateral pterygoid
maxillary artery
long buccal nerve
what structures pass between the medial and lateral pterygoids
the inferior alveolar and lingual nerves
Describe the jaw jerk (masseteric) reflex mechanism
one synapse only
rapid depression of the chin
stretching neuromuscular spindle in masseter
maseteric nerve to mesencephalic nucleus of V (sensory nucleus)
motor nucleus of V
masseteric nerve to neuromuscular endplates in the masseter muscle
contraction of masseter muscle
what is the jaw jerk reflex
rapid depression of the chin results in a closing of the mouth
What is responsible for action of normal opening of the mouth
gravity,
lateral pterygoid
what muscles are responsible for wide opening of the mouth
lateral pterygoid,
suprahyoid
what muscles are responsible for closing the mouth
temporalis
masseter
medial pterygoid
How many different joint cavities make up the TMJ. What are they separated by?
to separate disks subdivided by an articular disk
What type of joint is the superior joint of the TMJ
gliding joint
between mandibular fossa and articular tubercle, and the articular disk
capsule is thin and loose to permit extensive sliding movement
MOBILE
what type of joint is the inferior joint of the TMJ
hinge type joint between the articular disk and the mandibular condyle
lower capsule is strong and tight
What is the articular disk of the TMJ attached to
the sphenomeniscus muscle and the strong lateral (collateral) ligament
What ligament makes it much easier to open the mouth
stylomandibular ligament
from the apex of the syloid process to the inner surface of the angle of the mandible
biomechanically changes the transverse axis of rotation from a line between the mandibular condyles to a line between the lingulae
What are two critical developments in the skull
development of dentition
development of paranasal sinuses
Newborn has a mental angle of
why
175 degrees, because the alveolar bone is only a shell and the basilar bone is thin
four year old child has a mental angle of
140 degrees
adult has a mental angle of
why
110-120 degrees
due to the development of dentition
