Infratemporal Fossa Pt. 2 Flashcards
The nervous structures of the infratemporal fossa include the
Mandibular nerve (CN V3), Chorda tympani nerve (CN VII), and Lesser petrosal nerve (CN XI)
-and octic ganglion
The main nerve for general sensory innervation in the head and motor innervation to skeletal muscle derivatives of the 1st pharyngeal arch with its third division
Trigeminal nerve (more specifically mandibular nerve V3)
Sensory pseudounipolar neurons make up the
trigeminal ganglion of the
Middle cranial fossa
Each of the trigeminal’s 3 divisions exits through foramina in the
Middle cranial fossa
CN V itself does not contain
Autonomic neurons
However, all 4 parasympathetic cranial ganglia are associated with
-Travel on its branches
CN V
The general sensory fibers of CN V1 (opthalmic nerve) are distributed to skin, mucosa, and conjunctiva of the
Front of the head and nose
As the opthalmic nerve exits the cranium and enters the orbit via the superior orbital fissure, it branches into the
Nasociliary, frontal, and lacrimal nerves
In the orbit, CN V1 is associated with the parasympathetic ciliary ganglion whose axons extend to supply the
Pupillary constrictor and Ciliary muscles
How do you test the function of CN V1?
Corneal reflex
-touch the cornea and evoke a reflexive blink
Provides sensation from cornea
CN V1
Provides motor control to orbicularis oculi
CN VII
Conveys sensation for skin and mucosa associated with the upper jaw
CN V2 (maxillary nerve)
In the pterygopalatine fossa, CN V2 is associated with the parasympathetic pterygopalatine ganglion whose axons extend along branches of CN V2 and CN V1 to innervate the
Lacrimal gland in the orbit
CN V! and CN V2 are purely
Sensory
Serves are both sensory for the LOWER jaw region and motor for some skeletal muscles of the head
CN V3 (mandibular nerve)
CN V3 leaves the middle cranial fossa via the
Foramen ovale
All branches of the infratemporal nerve originate in the
Infratemporal fossa
The sensory buccal branch is from
CN V3
The motor innervation to the buccinator is from
CN VII
A sensory branch of CN V3 that encircles the middle meningeal artery and wraps around the neck of the mandible
Auriculotemporal nerve
Distributed to the TMJ, parotid sheath, external ear, tympanic membrane, and skin over the temple
Auriculotemporal nerve
Carries parasympathetic postganglionic fibers from the octic ganglion to the parotid gland
Auriculotemporal nerve
Conveys general sensation from the anterior ⅔ of the tongue, oral mucosa on floor of oral cavity, lingual gingiva of mandibular teeth
Lingual nerve of V3
Special gustatory/taste sensation from the anterior
⅔ of the tongue is carried by sensory fibers in the
Chorda Tympani (CN VII)
Joins the lingual nerve in the infratemporal fossa and travels along the lingual nerve to the tongue in the oral cavity
Chorda Tympani (from CN VII)
Cross the lateral surface of the medial pterygoid into the oral cavity inferior to the LAST molar tooth
Lingual nerve and Chorda tympani
The lingual nerve and sensory fibers of chorda tympani pass into the
Tongue
Presynaptic parasympathetic fibers in the chorda tympani pass into and synapse on the
Submandibular ganglion (on the floor of the oral cavity)
-for secremotor activation
Presynaptic parasympathetic fibers in the chorda tympani pass into and synapse on the submandibular ganglion (on the floor of the oral cavity) for secremotro activation of the
Submandibular and Sublingual glands
Lingual nerve injury proximal to where chorda tympani joins in the infratemporal fossa produces
Ipsilateral loss of general sensation to the anterior 2/3 of the tongue, oral mucosa, and gingivae
Injury distal to the union of the chorda tympani and lingual nerve in the infratemporal fossa results in
Ipsilateral general sensory loss PLUS loss of secretion from submandibular-sublingual salivary glands
-and loss of taste from anterior 2/3 of tongue
Mostly msensory nerve that gives off a motor branch right before it enters the mandibular foramen through the mandibular canal
Inferior alveolar nerve
The inferior alveolar nerve gives off a motor branch to the
Mylohyoid and anterior belly of digastric
In the mandibular canal, branches of the inferior alveolar nerve supply the sensation for the
Mandibular teeth
The inferior alveolar nerve then pierces the mandibles anterior aspect via the mental foramen to supply sensation for the
Chin
Anesthetizes all mandibular teeth to the median plane and skin-mucosa of the chin and lower lip
An inferior alveolar nerve block
Accidental deep injection into the medial pterygoid during an inferior alveolar nerve block would temporarily affect the ability to
Open the mouth (due to pterygoid trismus)
Supply most of the muscles of f the first pharyngeal arch: muscles that move the mandible (muscles of mastication and some suprahyoids) and tensor
muscles (tensor tympani in the middle ear and tensor veli palatini of the soft palate)
Motor branches of the mandibular nerve (CN V3)
Both the middle ear (tympanic cavity) and infratemporal fossa are associated with components of the autonomic motor supply to the
Major salivary glands
To reach the parotid gland with parasympathetic innervation, Presynaptic neuron cell bodies originate in salivary nuclei of the brainstem with axons extending through
CN IX
As CN IX exits the cranium via the jugular foramen, its tympanic nerve branches through a small canaliculus to enter the
Middle ear in the petrous parts of temporal bone
In the middle ear, the tympanic nerve forms the tympanic plexus, which gives rise to the
Lesser petrosal nerve
The lesser petrosal nerve (of CN IX) penetrates the roof of the tympanic cavity to enter the
Middle cranial fossa
The lesser petrosal nerve then leaves the MCF with the mandibular enrve via the foramen ovale to enter the infratemporal fossa where it synapses in the
Octic ganglion
Axons from neuron cell bodies in the octic ganglion travel along the
Auriculotemporal nerve to the parotid gland
Located in the external carotid nerve plexus and the
activity of these fibers may REDUCE secretion from the gland
-apparent as dry mouth when nervous
Sympathetic post synaptic fibers (from cell bodies in cervical ganglia)
To reach the submandibular and sublingual glands with parasympathetic innervation, Presynaptic neuron cell bodies originate in the brainstem salivary nuclei with axons extending through
CN VII
As CN VII travels through the internal acoustic meatus and facial canal, the chorda tympani branches through the middle ear MEDIAL to
The handle of the malleus (attached to tympanic membrane)
The chorda tympani then leaves the middle ear via the Petrotympanic fissure (between tympanic and petrous parts of temporal bone) to enter the
Infratemporal fossa
Once in the infratemporal fossa, the chorda tympani decends to join the
Lingual nerve
Contains both special sensory taste fibers conveying taste from the ANTERIOR 2/3 of the tongue and parasympathetic presynaptic fibers
Chorda tympani
Parasympathetic presynaptic fibers of the chorda tympani (CN VII) synapse in the
-hanging off the lingual nerve in the floor of theoral cavity
Submandibular ganglion
Post synaptic parasympathetic axons then extend to activate secretion of
Submandibular-sublingual glands
The superior boundary of infratemporal fossa is the greater wing of the sphenoid, which contains the
Foramen Ovale and Foramen Spinosum
Permits passage of the mandibular nerve and lesser petrosal nerve from the middle cranial fossa into the infratemporal fossa
Foramen Ovale
Permits passage of the middle meningeal artery from the infratemporal fossa to the middle cranial fossa
Foramen spinosum
The parietal, frontal, greater wing of sphenoid, squamous part of temporal meet at a weak area of
the skull called the
Pterion
Located two fingers breadth superior to the zygomatic arch and one fingers beadth posterior to the frontal process of zygomatic bone
Pterion
Fracture of the pterion may rupture the underlying
Frontal branch of middle meningeal artery
Inferiorly, the medial pterygoid muscle attaches to the
Medial aspect of the mandible ramus (near its angle)
The lateral boundary of the infrtemporal fossa is the
Medial surface of the ramus of mandible
The medial surface of the ramus of the mandible contains the mandibular foramen that transmits the
Inferior alveolar nerve and artery (of maxillary artery)
The medial surface of the ramus of the mandible,
which contains the mandibular foramen that transmits the inferior alveolar nerve (of CN V3) and artery (of maxillary artery) out of the infratemporal fossa and through the mandible to eventually exit through
the mental foramen as the
Mental nerve and artery of the chin
The medial wall of the infratemporal fossa is the
Lateral pterygoid plate of the sphenoid
The anterior wall of the infratemporal fossa is the
Posterior surface of the maxilla
Lies between the medial and anterior walls of the infratemporal fossa and it allows for communication between the infratemporal fossa and the deeper, more medial pterygopalatine fossa
Pterygomaxillary fissure
Passes from the infratemporal fossa to the pterygopalatine fossa via the pterygomaxillary fissure
The third (most distal) part of the maxillary artery
The posterior wall of the infratemporal fossa is formed by the
Tympanic plate, styloid process, and the mastoid process of the temporal bone
