Gross Anatomy of the Trigeminal Nerve

what do the somatosensory/general somatic afferent fibers of CN V carry?

general sensations from the face like pain, temperature, touch, and proprioception

what do the brachiomotor/special visceral efferent fibers of CN V do?

innervate muscle of the first pharyngeal arch

what do the special sensory/special afferent fibers of CN V carry?

taste

what do the visceral motor/general visceral efferent fibers of CN V carry?

parasympathetic fibers to smooth muscles and glands

what is the general pathway of CN V?

it emerges into the posterior cranial fossa and courses anteriorly to reach the middle cranial fossa

where is the trigeminal ganglion located

in the trigeminal impression/trigeminal cave (aka meckel’s cave), which is formed by dura

what is the trigeminal ganglion also known as?

semilunar ganglion or gasserian ganglion

where do V1, V2, and V3 emerge from, and what is their pathway from there?

they all emerge from trigeminal ganglion

V1 and V2 pass in the lateral wall of the cavernous sinus to reach the superior orbital fissure and foramen rotundum (respectively)

V3 takes an inferior course to reach the foramen ovale (does not pass through the cavernous sinus)

how does V1 exit the cranial cavity?

through the superior orbital fissure

how does V2 exit the cranial cavity?

through the foramen rotundum

how does V3 exit the cranial cavity?

through foramen ovale

what are the immediate branches of the mandibular nerve?

meningeal branch (nervus spinosus) and nerve to the medial pterygoid

what are the anterior division branches of the mandibular nerve?

nerve to the lateral pterygoid, deep temporal nerves (anterior and posterior), massenteric nerve, long buccal nerve

what are the posterior branches of the mandibular nerve?

auriculotemporal nerve, lingual nerve, inferior alveolar nerve

what is special about the lingual nerve branch of the mandibular nerve?

it receives the chorda tympani nerve from CN VII

what is special about the inferior alveolar nerve branch of the mandibular nerve?

gives off nerve to mylohyoid, terminates as the mental nerve and incisive nerve

nervous spinosus

a recurrent meningeal branch, re-enters the cranial cavity via the foramen spinosum (travels with the middle meningeal artery) and carries somatosensory from the meninges

nerve to the medial pterygoid

carries motor to the medial pterygoid muscle, tensor tympani muscle, and tensor veli palatini muscle, also carries proprioceptive fibers to the medial pterygoid muscle

which two nerve branches have a somewhat parallel course as they pass through the infratemporal fossa, and how can you tell them apart?

lingual and inferior alveolar nerves

lingual nerve is relatively anterior, medial, and inferior

inferior alveolar nerve is relatively posterior and lateral

auriculotemporal nerve

goes around the middle meningeal artery

lingual nerve

receives chorda tympani (CN VII) branch, has communicating fibers with the submandibular ganglion located on the floor of the oral cavity

what is the cutaneous distribution of the mental nerve of V3?

chin and inferior lip

what is the cutaneous distribution of the long buccal nerve of V3?

cheek

what is the cutaneous distribution of the auriculotemporal nerve of V3?

anterior portion of auricule, temporal region immediately anterior to auricle

what two parasympathetic ganglia is V3 associated with, and where are they located?

submandibular ganglion- on the floor of the oral cavity, suspended from the lingual nerve

otic ganglion- in the intertemporal fossa

the infratemporal fossa is located medial to the…

ramus of the mandible

what are the branchiomotor resident fibers of V3, and what do they innervate?

nerve to medial pterygoid- motor to medial pterygoid muscle, tensor veli palatini muscle and tensor tympani muscle

nerve to lateral pterygoid- motor to lateral pterygoid muscle

deep temporal nerves- motor to temporalis muscle

masseteric nerve- motor to masseter muscle

nerve to mylohyoid- motor to mylohyoid and anterior belly digastric

what does the somatosensory fiber of the nerve to medial pterygoid receive?

proprioception form medial pterygoid muscle, tensor veli palatini muscle, and tensor tympani muscle

what does the somatosensory fiber of the nerve to lateral pterygoid receive?

proprioception from lateral pterygoid muscle

what do the somatosensory fibers of the deep temporal nerves receive?

proprioception from temporalis muscle

what does the somatosensory fiber of the masseteric nerve receive?

proprioception from masster muscle and TMJ

what does the somatosensory fiber of the long buccal nerve receive?

sensory innervation from skin of cheek, buccal mucosa, buccal gingival tissue adjacent to mandibular molars

what does the somatosensory fiber of the lingual nerve receive?

sensory information from anterior 2/3 of tongue, floor of oral cavity, lingual gingival tissue adjacent to all mandibular teeth

what does the somatosensory fiber of the incisive nerve receive?

sensory innervation from 1st mandibular premolar, canine, and incisors, adjacent PDL, and bone

what does the somatosensory fiber of the mental nerve receive?

sensory innervation from the skin of the chin and lower lip, labial mucosa, gingival tissue adjacent to mandibular premolars, canine, and incisors

what does the somatosensory fiber of the nerve to mylohyoid receive?

sensory innervation from mylohyoid and anterior belly of the digastric

what does the somatosensory fiber of the inferior alveolar nerve receive?

sensory innervation from mandibular molars and 2nd premolar teeth, adjacent PDL, bone, and few gingival branches

what does the somatosensory fiber of the auriculotemporal nerve receive?

sensory innervation from skin anterior auricle, external auditory canal, temporal region, and TMJ

t/f the long buccal nerve is anesthetized with an inferior alveolar nerve block

false

what is the pathway of the lesser petrosal nerve as it relates to V3?

lesser petrosal nerve from CN IX to otic ganglion, to auriculotemporal nerve, to parotid gland

what is the pathway of the chorda tympani as it relates to V3?

chorda tympani from CN VII to submandibular ganglion, to lingual nerve OR submandibular gland, from lingual nerve to sublingual gland

postganglionic sympathetic fibers that will be distributed to the major salivary glands travel into the head via the…

external carotid plexus

most sympathetic fibers reach the parotid gland via the…

external carotid artery and its branches

most sympathetic fibers reach the submandibular and sublingual glands via the…

facial artery and its branches

where do preganglionic sympathetic fibers exit the spinal cord, and where do they go from there?

exit from T1-T5 and pass into and ascend the sympathetic chain to the superior cervical ganglion which is the location of sympathetic ganglion cells

where do postganglionic sympathetic fibers that exit the superior cervical ganglion head?

they can form the internal carotid plexus, travel into the cranial cavity and possible be distributed along cranial nerves, including V1 and V2

or

form the external carotid plexus and stay external to the skull and possibly be distributed along cranial nerves, including V3

if the lingual nerve had a lesion in the ITF, proximal to the lingual nerve being joined by the chorda tympani, what would hte clinical findings be?

limited somatosensory innervation on the anterior 2/3 of the tongue

if the lingual nerve had a lesion in the ITF, distal to the lingual nerve being joined by the chorda tympani, what would the clinical findings be?

limited taste on the anterior 2/3 of the tongue, limited salivary gland saliva production, and limited somatosensory innervation on the tongue

which branch of V2 branches prior to traversing the foramen rotundum?

meningeal branch

which branches of V2 are in the PPF?

zygomatic nerve (zygomaticofacial nerve and zygomaticofacial nerve), communicative branches with pterygopalatine ganglion, posterior superior alveolar nerve, and infraorbital nerve (middle superior alveolar, anterior superior alveolar, and terminal branches)

what nerves emerge from the pterygopalatine ganglion?

orbital branches, nasopalatine nerve, pharyngeal nerve, greater palatine nerve, lesser palatine nerve

in the middle cranial fossa, ___ gives rise to a ____ branch before it courses through foramen ____ to enter the PPF

V2, meningeal, rotundum

what is the pathway and branches of the zygomatic nerve?

courses anteriorly and enters the orbit via the inferior orbital fissure, gives rise to the zygomaticofacial and zygomaticotemporal nerves which leave the orbit and emerge on the face via the same named foramina

communicating branch

connects zygomaticotemporal nerve to a branch of V1 (lacrimal nerve)

the PPG is suspended from ___ by two ______, these _____ fibers pass through the PPG ___ interruption and pass into the following branches…

V2, communicating branches, somatosensory, without, orbital branches, nasopalatine nerve, pharyngeal nerve, greater palatine nerve, and lesser palatine nerve

what are the anterior branches from the PPG, and where do they pass?

orbital branches pass anteriorly and traverse the inferior orbital fissure to reach the orbit

what are the inferior branches from the PPG, and where do they pass?

greater/anterior palatine and lesser/posterior palatine nerves pass inferiorly in the (greater) palatine canal to reach the palate

what are the medial branches from the PPG, and where do they pass?

nasopalatine nerve passes medially and transverses the sphenopalatine foramen to enter the nasal cavity

what are the posterior branches from the PPG, and where do they pass?

pharyngeal nerve passes posteriorly through the pharyngeal canal (palatovaginal canal) to reach the nasopharynx

what does the nerve of the pterygoid canal carry as it enters the PPG?

visceral motor fibers (parasympathetic from CN VII and sympathetic) and special sensory fibers (taste from CN VII)

what is the pathway of the posterior superior alveolar nerve?

courses anterolateral from its origin and leaves the PPF through the pterygomaxillary fissure, then descends and enters the maxilla via the alveolar foramen/foramina

what is the pathway of the infraorbital nerve?

courses anteriorly, continuation of the maxillary nerve, the name change occurs as V2 traverses the inferior orbital fissure to the floor of the orbit, courses in the infraorbital groove and canal before emerging on the face via the infraorbital foramen

along its course, what does the infraorbital nerve give rise to, and what does it terminate as?

middle superior alveolar nerve and anterior superior alveolar nerve

terminates as palpebral, nasal, and superior labial branches

what is the superior dental plexus formed by?

nerves that carry sensory information from the maxillary teeth and adjacent periodontal tissues

posterior superior alveolar nerve (branch off maxillary nerve), middle superior alveolar nerve (branch off infraorbital nerve), and anterior superior alveolar nerve (branch off infraorbital nerve)

is the middle superior alveolar nerve a consistent one?

no- when absent, its territory is most often supplied by the anterior superior alveolar nerve

what is the dental pulp innervated by?

somatosensory A delta and C fibers from CN V and postganglionic sympathetic nerve fibers from the superior cervical ganglion (visceral motor)

the nerves enter the root canal along with ____ and ramify as a ____, nerve fibers continue into the _____ layer and enter the _____

blood vessels, plexus, odontoblast layer, dentinal tubules

when doing an inferior alveolar nerve block, can you make your patient blind accidentally? and is it permanent?

yes, if the needle approaches the inferior orbital fissure, then ocular complications can occur like…

temporary diplopia- anesthetic diffuses to CN III, IV, and/or VI, causes paralysis of extraocular muscles

temporary blindness- anesthetic diffuses to CN II, occurs in 1 of 3 patients

Both are temporary, as the anesthetics used by dentists are temporary

what is postulated to be the mechanism by which anesthetic agent reaches the orbit or cavernous sinus to cause temporary visual defects?

inadvertent needle penetration into the orbit or venous injection

what is the cutaneous distribution of the infraorbital nerve of V2?

inferior eyelid, cheek, lateral nose, superior lip

what is the cutaneous distribution of the zygomaticofacial nerve of V2?

prominence of cheek

what is the cutaneous distribution of the zygomaticotemporal nerve of V2?

hairless temporal region (superolateral to eye and anterior to auricle)

what does the somatosensory fiber of the zygomaticotemporal nerve receive?

sensory innervation of the temporal area

what does the somatosensory fiber of the zygomaticotemporal nerve receive?

sensory innervation of the skin over the zygomatic arch

where do the somatosensory fibers of the orbital branches pass to?

paranasal sinus

what does the somatosensory fiber of the palpebral branch receive?

sensory innervation of the skin of the lower eyelid

what does the somatosensory fiber of the nasal branch receive?

sensory innervation of the lateral nose

what does the somatosensory fiber of the superior labial branch receive?

sensory innervation of the cheek and upper lip, labial mucosa, contributes to sensory innervation to the gingival tissue adjacent to the maxillary incisor, canine, and premolar teeth

what does the somatosensory fiber of the anterior superior alveolar nerve receive?

sensory innervation of the canine and incisor teeth, adjacent PDL, bone, and labial gingival tissue, and maxillary sinus

what does the somatosensory fiber of the nasopalatine nerve receive?

sensory innervation of the nasal septum, anterior hard palate, palatal gingival tissue adjacent to maxillary canine and incisor teeth

what does the somatosensory fiber of the middle superior alveolar nerve receive?

sensory innervation from the mesial buccal root of 1st molar and premolars, adjacent PDL, bone, buccal gingival tissue, and maxillary sinus

what does the somatosensory fiber of the posterior superior alveolar nerve receive?

sensory innervation of molars (excluding mesial buccal root of 1st molar), adjacent PDL, bone, and buccal gingival tissue, and maxillary sinus

what does the somatosensory fiber of the greater/anterior palatine nerve receive?

sensory innervation of hard palate, palatal gingival tissue adjacent to maxillary premolars and molars

what does the somatosensory fiber of the lesser/posterior palatine nerve receive?

sensory innervation of the soft palate

what does the somatosensory fiber of the pharyngeal nerve receive?

sensory innervation of nasopharynx

what does the somatosensory fiber of the meningeal nerve receive?

sensory innervation of meninges

what is the pathway of the preganglionic parasympathetic fibers of CN VII as they relate to V2?

preganglionic parasympathetic fibers of CN VII (greater petrosal nerve) to nerve of the pterygoid canal to the PPG

postganglionic parasympathetic fibers are distributed to their targets (_____) via branches of ____

glands in the region of their distribution, V2

how do postganglionic sympathetic fibers reach the cranial cavity and V2 branches?

they travel from the superior cervical ganglion (location of cell bodies) into the cranial cavity via the internal carotid plexus, some postganglionic sympathetic fibers leave the internal carotid plexus as the deep petrosal nerve through the nerve of pterygoid canal to PPG (no synapse) and are distributed along V2 branches

where is there taste along the V2 route?

nerve of the pterygoid canal in the pterygoid canal (from CN VII) to the PPG to the lesser palatine nerve where there is taste on the soft palate

when a greater/anterior palatine nerve block is successfully performed, what is anesthetized?

hard palate, adjacent to the maxillary premolar and molar teeth

in preparing for a posterior superior alveolar nerve block, you review that the posterior superior alveolar nerve supplies…

the maxillary molars, except the mesial buccal root of the 1st molar

what are the branches of the ophthalmic nerve?

meningeal branch, lacrimal nerve, frontal nerve (supraorbital nerve and supratrochlear nerve), and nasociliary nerve (lots of branches)

meningeal branch of V1

sensory branch that emerges from V1 before it transverse the superior orbital fissure

the ophthalmic nerve branches into the ____, ____, and ____ branches before traversing the _____ fissure to enter the orbit

lacrimal, frontal, nasociliary, superior orbital

lacrimal nerve branch of V1

travels along the lateral border of the orbit to reach the lacrimal gland and lateral eye

frontal nerve branch of V1

branches into the supraorbital and supratrochlear nerves within the orbit, both branches course anteriorly through the orbit and emerge superior to the eye

nasociliary nerve of V1

travels in a plane deep/inferior to the lacrimal and frontal nerve

what are the branches of the nasociliary nerve?

sensory root to ciliary ganglion to short ciliary nerve, long ciliary nerves, posterior ethmoidal nerve, anterior ethmoidal nerve, infratrochlear nerve

posterior ethmoidal nerve exits the…

orbit via the posterior ethmoidal foramen