IT Fossa Flashcards
What are the boundaries of the IT Fossa?
Lateral: ramus of mandible
Medial: lateral plate of pterygoid process (sphenoid bone)
Anterior: Infratemporal surface of maxilla
Roof: greater wing of sphenoid
Superior: Zygomatic arch (superficial), IT crest on sphenoid (deep)
What artery is in the IT fossa? what are its branches?
1. Maxillary Artery (MID B PIGS) M: middle meningeal (to dura) I: Inferior Alveolar (gives off mylohyoidal branch) to jaw/gums.. lower teeth D: Deep Temporal (to temporalis) B: Buccal: To buccinator
P: Posterior Superior Alveolar (to gums/molars .. upper teeth)
I: Infraorbital (through infraorbital foramen) to
G: greater and Lesser palatine artery: Greater = hard palate, lesser = soft palate
S: sphenopalatine: in nose.. frequent cause of nosebleeds
what nerve innervates most of the structures in the IT fossa? It also runs in the IT fossa
V3 (mandibular) also thhttp://www.med.umich.edu/lrc/coursepages/m1/anatomy2010/html/index.htmle chorda tympanii of VII
what muscles are included in the IT fossa?
2/4 of the muscles of mastication (medial and lateral pterygoids)
the parotid duct goes through which muscle?
buccinator
which cranial foramen are found in the IT fossa
ovale (V3), spinosum (middle meningeal), external acoustic meatus, zygomaticofacial/temporal, alveolar (for inferior alveolar nerve/artery
what is the track of the inferior alveolar nerve??
it exits off of V3. Then it travels to lower teeth/gums through the mandibular foramen, and exits out of the mental foramen as the mental nerve
what does the mylohoid nerve branch off of? what does it innervate? What groove does it run through?
branches off of inferior alveolar nerve (V3), innervates the mylohyoid and anterior belly of the digastric (posterior belly is innervated by VII); runs through the mylohyoid groove in the inner mandible
what does the facial nerve innervate MOTOR? what are its branches? what are the facial artery branches?
innervates the muscles of facial expression (motor), stapedius, posterior belly of the digastric, stylohyoid + visceral motor to submandib, sublingual, lacrimal glands,
nerve branches: TZBMC (M = meningeal)
artery branches: inf. labia, sup. labia, lat. nasal, angular
where is the pterygoid plexus located?
between the medial and lateral plexus, and between the temporalis muscle and laterial pterygoid muscle
what runs between the tensor veli palatini muscle and levator veli palatini muscle?
superior pharyngeal constrictor
what is the clinical significance of the pterygoid plexus?
its connected to the cavernous sinus via emissary veins; thus infections from face, nasal, oral cavities and orbit can spread into the cranial cavity directly via the pterygoid plexus
where does the maxillary arter airse from?
the external carotid; posterior to the neck of the mandible
what is the course of the middle meningeal artery?
off of the maxillary art. medial to neck of mandible, courses superficially, goes through auriculotemporal circle/split, and then goes through the foramen spinosum (middle cranial fossa), to supply the dura
what is the course of the inferior alveloar artery?
follows inferior alveolar nerve path; goes through the mandibular foramen into the ramus and exits via mental foramen
where is the buccal artery located with respect to the buccinator muscle?
anterior
is the maxillary artery found anterior or posterior to the lateral pterygoid muscle?
can be either! 66% = superficial, 33% deep
what is the function of the anterior trunk of V3?
Motor EXCEPT the buccal nerve branch (sensory to cheek skin and second/third molar)
what is the function of the buccal branch off facial vs. V3?
Facial: MOTOR to buccinator
V3: SENSORY: to cheek skin and second/third molar
what is the function of the posterior trunk of V3?
Sensory EXCEPT nerve to mylohyoid (motor to mylohyoid + anterior belly of digastric)
what are the sensory branches of V3?
BAIL: Buccal Auricolotemporal I: inferior Alvelolar L: Lingual
what is the course of the lingual nerve? what cranial nerve does it come from? what division (ant/post) of V3 does it come from?
V3 POSTERIOR;
runs parallel and ANTERIOR to the inferior alveloar nerve (DOES NOT ENTER THE MANDIBULAR FORAMEN OR MANDIBLE IN GENERAL)
Enters the mouth next to the ramus of the mandible and runs parallel to the flood of mouth
PASSES UNDER MUCOSA BELOW THE THIRD MOLAR
what is the function of the lingual nerve?
general somatic sensory to anterior 2/3 of tongue, floor of mouth, lower gingiva
what is the course of the inferior alveolar nerve? what cranial nerve does it come from? what division (ant/post) of V3 does it come from?
V3 POSTERIOR;runs parallel and POSTERIOR to the lingual nerve. It goes inside the mandibular foramen and enters the ramus of the mandible. it sends branches to the lower teeth and then emerges from the mental foramen as the mental nerve to the chin region
what is the function of the inferior alveolar nerve?
sensory to lower teeth, chin, and lower lip
what is the course of the buccal nerve (of V3)? what division (ant/post) of V3 does it come from?
V3, ANTERIOR
starts between the two heads of the pterygoid, emerges through the lateral pterygoid muscle and runs superfically to cheek
what is the function of the buccal nerve?
sensory to the skin of the cheek and lower gums
what is the course of the auricolotemporal nerve? what division (ant/post) of V3 does it come from?
V3, POSTERIOR encircles the middle meningeal artery
what is the function of the auricolotemporal nerve?
general sensory to auricle and TM joint and is a highway for parasympathetic post-ganglionic (for parotid gland stimulation)
what muscles are innervated by V3?
MAMTT M: mylohyoid A: anterior belly of digastric M: muscles of mastication (lat/med pterygoid, masseter, temporalis) T: tensor veli palatini T: tensor tympani
what is the course of chorda tympani? what cranial nerve does it come from?
VII; after leaving the faical canal, it passes through the middle ear cavity and enters the IT fossa, and joins the lingual nerve
what is the function of the chorda tympani?
- taste sensation to anterior to 2/3 tongue
2. preganglionic parasympathetic fibers to submandibular ganglia (salivary secretions)
what nerves give sensation (general and special) to the anterior tongue? posterior 1/3?
anterior 2/3: general = lingual (V3),; special = chorda tympani (VII)
posterior 1/3: glossopharyngeal
what nerve does chorda tympani join?
lingual (V3)
where are the cell bodies for taste to anterior 2/3 of tongue found?
in genticulate ganglion
where are cell bodies of submandibular/sublingual parasympathetic found?
in brain stem (at superior salivatroy nucleus)
where are cell bodies of general sensation to the anterior 2/3 of the tongue found?
trigeminal ganglion
what are the attachments of the temporalis muscle?
temproal fossa and coronoid process of mandible
what are the attachments of the masseter?
zygomatic arch and ramus of mandible (lateral surface)
what are the attachments of the lateral pterygoids?
2 heads; on the lateral pterygoid plate (of sphenoid) and neck of the mandible
what passes between the two heads of the inferior border of the medial/lateral pterygoids?
inferior alveolar nerve and lingual nerve
which is attached more superficially on the lateral pterygoid plate, the medial or lateral pterygoid muscle?
the lateral pterygoid
what are the attachments of the medial pterygoid muscle?
2 heads; on the lateral pterygoid plate (of sphenoid) and mandible angle (medial surface)
what is the function of the temporalis muscle?
elevates mandible, some retraction
what is the function of the masseter?
elevates mandible, some retraction
what is the function of the lateral pterygoid?
protrusion, side to side moevement
what is the function of the medial pterygoid?
protrusion, side-to-side movement elevates mandible
what bones/articulations form the TM joint?
head of the mandible via mandibular fossa with the articular tubercle of the temporal bone
is there an articular disc in the tmj? what’s its function?
yes; divides the joint into upper and lower compartments
what are the ligaments that help strengthen the TM joint?
**latreral (temporomandibular) ligament, and the stylomandibular and sphenomandibular ligaments
what are the two movements of the TM joint?
- hinge-like
2. forward gliding
describe what happens when the mouth is open/closed with respect to the TM joint
Closed: head of mandible is vertically aligned with the mandibular fossa (the disc fits properly in the socket)
Opened: the mandible becomes depressed via the HINGE rotation (first) then as the mouth continus to open wider, the mandibular head and articular disc GLIDE FORWARD on the temporal bones until the MANDIBULAR HEAD IS VERTICALLY ALIGNED TO THE ARTICULAR TUBERCLE
if the jaw is closed, where is the head of the mandible found? where is it when the jaw is open?
closed: in line with mandibular fossa
open: in line with articular tubercle (frontal border of the fossa)
what muscles protrude the TMJ during opening of the mouth ?
pterygoid muscles
what usually prevents the TMJ from gliding too anterior?
the articular tubercle
when does TMJ dislocation occur?
when the mandibular head passes anterior to the articular tubercle
what happens to the mouth (symptoms) during TMJ dislocation?
the mouth cannot close completely because contact with the upper and lower molars; pain is due to sensory innervation of the TM joint by the auriculotemporal nerve
what nerve is responsible for the pain sensed during TMJ dislocation?
auriculotemporal
