Sievert: Infratemporal fossa Flashcards
What is the only division of the trigeminal nerve that carries both motor and sensory information?
V3 is the only division
**V1 and V2 are only sensory
Where is the infratemporal fossa located?
deep to the mandible
inferior to the zygomatic arch
What are the boundaries of the infratemporal fossa? Anterior? Medial? Lateral? Posterior?
ant - maxillary bone
medial - lateral pterygoid plate
lateral - ramus of mandible
posterior - parts of the temporal bone
What is significant about the following features of the mandible?
Condyle and coronoid process
Mandibular notch
Condyle and coronoid process are for the attachment of muscles
Mandibular notch allows for small nerves to pass thru
What is the opening between the styloid process and the mastroid process? What nerve passes through here?
stylomastoid foramen; cranial nerve 7 passes through here **it is almost entirely motor as it passes through and gives off its 5 terminal branches
What is located between the pterygoid plate and the maxillary bone? Why is this important?
pterygomaxillary fissure; it is a way for things to get into and out of the pterygopalatine fossa
What does the foramen ovale allow for?
the passage of V3 into infratemporal fossa from the cranial cavity
What does the foramen spinosum allow for?
passage of middle meningeal artery from infratemporal fossa to cranial cavity
Where do blood vessels and nerves to the mandible (lower teeth) enter?
mandibular foramen
The temporomandibular joint has two joint cavities - a superior joint cavity, a disc, and an inferior joint cavity. It has a ligamentous capsule surrounding the whole thing. What muscle of this joint attaches to both the condyle and the disc, and pulls both of these structures anteriorly to aid in mastication?
lateral pterygoid muscle
When the jaw opens, what happens to the condyle?
It moves anteriorly on the mandibular fossa and rides forward
How do you get wide opening of the TMJ?
protraction of the condyle in the mandibular fossa and on top of the articular tubercle
What does extreme protraction cause the muscles of mastication to do?
Causes these muscles to contract forcefully
What must occur for the jaw to open widely?
protraction
This muscle attaches to the condyle and also has one head that goes to the disc. When this muscle contracts, it pulls from posterior to anterior, and the condyle slides down onto the articular tubercle.
Lateral pterygoid
Which movements of the TMJ occur in the lower joint cavity?
elevation and depression
Which movements of the TMJ occur in the upper joint cavity?
protraction and retraction
**both the disc and the condyle are being pulled forward by the lateral pterygoid muscle
How do you get a grinding motion of the jaw?
Use a combination of protraction/retraction and elevation/depression to create side-to-side movements of the jaw.
**use alternating sides
What are two important ligaments of the TMJ?
sphenomandibular
stylomandibular
What muscle is the main protractor that pulls the condyle toward the pterygoid plates?
lateral pterygoid
The lateral pterygoid muscle has two heads? Where do they insert?
one head goes to the disc, one head goes to the condyle.
(blank) cartilage covers the articular surfaces of the temporomandibular joint. A joint (blank) connects the bones. Synovial membranes line non-weight bearing surfaces.
hyaline; capsule
Does the TMJ have a high range of motion?
Yes, compared to other joint types
**due to its gliding motion
Elevation and depression of the jaw are (blank) movements, while protraction and retraction are (blank) movements
hinge; gliding
What kind of dislocation is the TMJ most prone to?
anterior dislocation when jaw is open wide
**head of mandible displaced anterior to articular tubercle
What 3 things are found in the infratemporal fossa?
muscles of mastication
branches of the mandibular nerve **V3 which has various branches
branches of the maxillary artery **4 branches
What type of fibers are necessary for muscles of mastication?
branchiomotor!
Where do all muscles of mastication come from? What are they innervated by?
the first branchial arch;
the mandibular division of the trigeminal nerve **only division with motor in addition to sensory
What does the masseter muscle do? What is it not good at?
it is a powerful elevator of the mandible **closer of the jaw, brings the mandible up toward the zygomatic arch
The temporalis muscle has both anterior and posterior fibers. How are the anterior fibers oriented? What do they do? How are the posterior fibers oriented? What do they do?
anterior fibers are vertically oriented and contribute to elevation of the mandible; posterior fibers are horizontally oriented and contribute to retraction of the mandible
What nerve supplies the temporalis and masseter muscles?
motor fibers of V3
What are the two pterygoid muscles? Where do they both arise from? What are they innervated by?
medial and lateral pterygoid muscles; they both arise from the lateral pterygoid plate; they are innervated by motor fibers of V3
The lateral pterygoid muscle goes from the lateral pterygoid plate to what two things?
the condyle and the disc
What are the actions of the masseter muscle?
elevation
protraction
What are the actions of the temporalis muscle?
elevation
retraction
rotation
What are the actions of the lateral pterygoid muscle?
depression
protraction
rotation
What are the actions of the medial pterygoid muscle?
elevation
protraction
rotation