Infratemporal fossa + TMJ Flashcards
what is the infratemporal fossa?
‘Space’ beneath the base of the skull - between the skull and the ramus of the mandible
what opens into the infratemporal fossa?
foramen ovale opens into = allows mandibular branch of trigeminal nerve to exit the skull.
middle meningeal artery pathway?
Middle meningeal artery passes from the infratemporal fossa into the foramen spinosum to gain entry into the skull
boundaries infratemporal fossa
Anterior = posterior surface of the maxilla Posterior = styloid process Superior = infratemporal surface of the greater wing of sphenoid Medial = lateral pterygoid plate Lateral = ramus of the mandible
whats this?
what passes through here?
pterygomaxillary fissure
Terminal branches of the maxillary artery pass through the pterygomaxillary fissure to exit the infratemporal fossa
contents of infratemporal fossa?
Lateral + medial pterygoid Mandibular division of trigeminal (+ branches) Maxillary artery (+ branches) Pterygoid venous plexus Chorda tympani Otic ganglion
lie deeper than masseter + temporalis
mandibular division of trigeminal nerve pathway?
The mandibular division of the trigeminal nerve passes through the foramen ovale and into the infratemporal fossa, where it forms branches that supply the muscles of mastication and sensory nerves to the teeth and oral cavity
divisions of mandibular division of trigeminal nerve?
Anterior division = x2 deep temporal, masseteric, n. to lateral pterygoid, buccal (buccal = sensory)
Posterior division = lingual (joined by chorda tympani), inferior alveolar, mylohyoid, auriculotemporal
Pre-division = meningeal branch, nerve to medial pterygoid and communicating branch (tensor tympani and tensor veli palatini)
inferior alveolar nerve branches from?
Function?
auricolotemporal branch?
The inferior alveolar branch = branch of posterior division of mandibular division of trigeminal
supplies the lower teeth and then passes out onto the face to supply cutaneous innervation to the skin over the mandible
Auriculotemporal branch also branch of posterior division of mandbular
supplies cutaneous innervation to the skin anterior to the auricle
The inferior alveolar and lingual nerves are the largest branches of the mandibular division of trigeminal
maxillary artery?
pathway?
important to note
Maxillary artery is a terminal branch of the external carotid artery
It passes through the infratemporal fossa where it branches to form arteries that supply the muscles of mastication, the dura, lower teeth + cheek.
It then passes between the heads of lateral pterygoid to enter pterygomaxillary fissure and give off posterior superior alvolar branch to the upper teeth
Note that it does not form a lingual artery – this is the second branch of the anterior division of the external carotid artery.
label branches of maxillary artery
label arteries
branch from?
branch from maxillary artery
parts of maxillary artery?
branches of last part?
3 parts = mandibular, pterygoid and pterygopalatine
Pterygopalatine branches=
Posterior superior alveolar (upper molar and premolar)
Infraorbital (canal in floor of orbit, foramen)
Anterior superior alveolar branches (upper incisor and canine)
what surrounds lateral pterygoid?
contains?
communicates with?
drains into?
pterygoid venous plexus
contains = veins from orbit, nasal and oral cavities
Communicates with cavernous sinus and facial vein (bacteria from cuts on face can enter meninges)
Drained by maxillary vein
pterygoid venous plexus
parasympathetic secretomotor nerves that supply submandibular + sublingual salivary glands?
pathway of this nerve?
The parasympathetic secretomotor nerves that suppliy the submandibular and sublingual salivary glands are from the facial nerve
Main part of the facial nerve passes through stylomastoid foramen and through the parotid gland to the muscles of facial expression.
The lingual branch of the mandibular division of the trigeminal nerve passes from the infratemporal fossa into the oral cavity (ideal candidate to carry parasympathetic nerve fibres to mouth)
The facial nerve forms a branch called the chorda tympani as it passes through the temporal bone.
Chorda tympani crosses the handle of the malleus (ossicle in the middle ear) then passes through a bony canal to reach the infratemporal fossa
in infratemporal fossa joins the lingual nerve to supply parasymp + taste to oral cavity
…
otic ganglion found?
revise pathway
infratemporal fossa at the opening of the foramen ovale
what pass through otic ganglion without synapsing?
sympathetic fibres
motor nerves to tensor tympani + tensor veli palatini
TMJ?
articular surfaces?
surrounded by?
innervation?
Synovial joint between head of mandible and mandibular fossa & articular tubercle on the squamous part of the temporal bone
Articular surfaces = fibrocartilage
surrounded by fibrous capsule
innervation = auriculotemporal + masseteric nerves
capsule of TMJ reinforced by?
Capsule reinforced by lateral (temporomandibular) ligament
Sphenomandibular and stylomandibular ligaments (medially)
which muscle attaches to articular disc of TMJ?
Lateral pterygoid attaches to the articular disc and capsule
joint cavity of TMJ divided by?
divisions of joint cavity movements
Cavity divided by fibrous articular disc
Head of mandible and disc = elevation and depression (hinge)
Disc and mandibular fossa & articular process = protrusion and retraction (gliding)
TMJ movements to close both?
open mouth?
chew?
To close mouth = elevation and retraction pull condyle backwards
To open mouth = both sides depression and protrusion to slide disc and condyle forwards towards tubercle
Asynchronous gliding = chewing
articular tubercle
Movements of the mandible + muscles
Elevation = head of mandible and disc move backward and head rotates on lower surface of disc – temporalis, masseter and medial pterygoid
Depression = head of mandible rotates on undersurface of articular disc and mandible is pulled forward - lateral pterygoid, digastric, geniohyoid, mylohyoid, gravity
Protrusion = articular disc and head of mandible move forward. Movement in upper part of cavity - lateral pterygoid (medial pterygoid assists)
Retrusion = articular disc and head of mandible pulled backward into mandibular fossa – posterior fibres of temporalis
Lateral chewing = protrusion and retrusion combined - pterygoids
Photograph A shows some of the fat removed from the infratemporal fossa to reveal the maxillary artery and the mandibular division of the trigeminal nerve. Medial and lateral pterygoid muscles can be seen – they are muscles of mastication that act to elevate the mandible (medial pterygoid) and protrude the mandible (lateral pterygoid).
Photograph B shows vessels originating from the superior surface of the maxillary artery – the masseteric and deep temporal arteries that supply the muscles of mastication.
hotograph A shows the first part of the maxillary artery, prior to dissection (the area inside the white dotted box). Photograph B shows the same area with the fat and fascia removed to show further branches of the maxillary artery. The deep auricular and anterior tympanic arteries supply the ear. The middle meningeal artery passes through the foramen spinosum to enter the skull and supply the dura. The inferior alveolar artery branches from the inferior surface of the maxillary artery and passes into the mandibular foramen to supply the lower teeth and gums. Photograph C shows the inferior alveolar artery and nerve passing into the mandibular foramen (the mandible has been cut and reflected in this image).
Photograph A shows a deep dissection of the infratemporal fossa. The maxillary artery can be seen crossing the fossa from lateral to medial (a transverse pathway). The branches of the mandibular division of the trigeminal nerve run in the opposite direction – from superior to inferior as they pass away from the foramen ovale and towards the structures of the mouth. The chorda tympani carries parasympathetic fibres from the facial nerve, this can be seen joining the posterior surface of the lingual branch of the mandibular division of the trigeminal nerve. This allows the parasympathetic innervation to be carried to the oral cavity to supply the submandibular and sublingual salivary glands. The inferior alveolar nerve supplies the lower teeth with sensory innervation and also ends as the mental nerve on the skin of the mandible. The buccal nerve carries sensory innervation to the cheek and the 2nd and third molar teeth.
Photograph B shows the mandibular division close to the foramen ovale – the approximate position of the foramen is shown by a white arrow.
Photograph A shows the approximate position of the temporomandibular joint (within the blue circle). Photograph B shows the joint partially disarticulated to show the disc lying close to the articular tubercle. Photograph C shows the disc and the joint cavity (shown by the white arrow) above the disc. The disc divides the joint cavity into two, movements may occur between the head of the mandible and the disc, and also between the disc and the articular tubercle.
