THE TRIGEMINAL NERVE

classification of functional columns

general & special

general

have the same functions as those for spinal nerves

all over the body

examples: sense of touch, sense of pain

special

are specific only to cranial nerves

found in your brain

examples: CN 1, CN II, CN VIII

2 subdivisions of general & special function columns

afferent & efferent

somatic & visceral

afferent

sensory

it receives the information / stimulus

then sends off the brain

efferent

motor / action

response sa muscles

fibers are being used

somatic

general tissues

muscles & bones

visceral

internal organs

cranial nerves

12 pairs of nerves that connect your brain to different parts of your head, neck & trunk

named according to function and structure

numbered based off their location from front to back

has 7 functional components / functional columns

a given cranial nerve may have 1-5 functional columns

sensory & motor

categorization of cranial nerves

5 functional columns

general somatic afferent — GSA

special somatic afferent — SSA

general visceral afferent — GVA

special visceral afferent — SVA

general visceral efferent — GVE

general somatic afferent — GSA

exteroceptors & proprioceptors

these are the same as in spinal nerves

example:

pain / touch & temperature / within tendons & joints

special somatic afferent — SSA

special senses in the eye & ear

examples:

hearing & equilibrium

general visceral afferent — GVA

sensory from viscera

these are the same as in spinal nerves

example:

gut / temperature

special visceral afferent — SVA

olfaction & taste

general visceral efferent — GVE

autonomic nervous system / involuntary

example:

cardiac muscles / smooth muscles / glands

general somatic efferent — GSE

skeletal (somatic) muscle

the same as in spinal nerves

special visceral efferent — SVE

skeletal muscles

which develops from the pharyngeal (branchial) arches

sometimes used in gut / homologous to GSE

examples of receptors

somatic sensory receptors

visceral sensory receptors

somatic sensory receptors

monitor the outside world & body position

visceral sensory receptors

monitor internal conditions & organ systems

examples of effectors

skeletal muscle

smooth muscle / cardiac muscle / glands

gastrointestinal smooth muscle

general organization of the nervous system

skin —> spinal cord —> thalamus → sensory signals within afferent division —> brain —> CNS processing —> sends off a response within efferent division —> somatic nervous system (voluntary) or autonomic nervous system (involuntary)

if in somatic nervous system —> skeletal muscles

if in autonomic nervous system —> para or sympathetic division —> smooth muscle / cardiac muscle / glands

if in enteric nervous system —> gastrointestinal smooth muscle

cranial nerve V — trigeminal nerve

main sensory nerve of the head

largest cranial nerve

contains both sensory & motor fibers; mainly sensory

transmits information to the brain about touch, pain, temperature and proprioception from face & head

controls muscles of mastication (chewing)

4 muscles supplies by the mandibular nerve

tensor tympani

tensor veli palatini

mylohyoid

anterior belly of the digastric

tensor tympani

small muscle within the middle ear

dampens the sounds of chewing

tensor veli palatini

a small muscle found in the soft palate

prevents the food from being placed upward

makes the food go down

mylohyoid

the floor of the mouth

anterior belly of the digastric

major muscle for mouth opening

4 muscles of mastication

masseter

temporalis

medial / internal pterygoid

lateral / external pterygoid

3 muscles of mastication primarily responsible for jaw closing (elevating the mandible)

masseter

temporalis

medial pterygoid

masseter

located at the angle of the jaw

responsible for elevating the mandible (closing the jaw)

temporalis

fan-shaped muscle

located on the side of the head

helps in elevating & retracting

medial / internal pterygoid

located on the inside of the mandible

helps in elevating the mandible & moving it

lateral / external pterygoid

responsible for protrusion & moving the mandible from side to side & lateral excursion

has 2 heads (superior & inferior)

proprioception

the awareness of the positions of your muscles & joints

3 divisions / branches of trigeminal nerve

ophthalmic V1 — sensory

maxillary V2 — sensory

mandibular V3 — sensory & motor

supraorbital fissure

this is where ophthalmic nerve passes through

foramen rotundum

this is where maxillary nerve passes through

foramen ovale

this is where mandibular nerve passes through

gasserian & semilunar

other names for ganglion

sensory root of trigeminal nerve

they arise from the semilunar ganglion (neural crest) — cresent shaped

enter the brain stem through the pons

motor root of trigeminal nerve

have fibers that have their origin in the motor nucleus located in the upper pons, along the medial side of the ganglion

passes below to the foramen ovale

posterior view of brainstem of the trigeminal root (from behind)

3 sensory nuclei & a motor nucleus associated with the trigeminal nerve

3 sensory of nuclei

main sensory nucleus

spinal trigeminal nucleus

mesencephalic nucleus

main sensory nucleus

processes tactile (touch) sensation from the face, head, mouth

spinal trigeminal nucleus

it is responsible for pain & temperature sensations (hot & cold)

mesencephalic nucleus

it is responsible in proprioception from the jaw & teeth to prevent from over mastication

ganglion

found outside of the brain

nuclei

found inside of the brain

meckel’s cave or cavity

where the trigeminal ganglion lies

thinnest branch of the largest cranial nerve

ophthalmic branch

thickest branch of the largest cranial nerve

mandibular branch

3 major branches of ophthalmic nerve

frontal nerve

lacrimal nerve

nasocilliary nerve

nasocilliary nerve

the most complex branch of the thinnest branch of the largest cranial nerve

lacrimal nerve

smallest or the thinnest branch of the thinnest branch of the largest branch of the cranial nerve

frontal nerve

largest branch of the thinnest branch of the largest cranial nerve

2 divisions of frontal nerve

supraorbital nerve

supratrochlear nerve

supraorbital nerve

thicker branch of the largest branch of the thinnest branch of the largest cranial nerve

more on the lateral

supplies the upper eyelid & skin scalp up to the cortex of the head

supratrochlear nerve

supplies the upper eyelid & skin forehead; more on the medial & lower

lacrimal nerve

it supplies the lacrimal gland & upper eyelid

lacrimal gland

responsible for producing tears

major branches of nasocilliary nerve

cilliary ganglion

long & short cilliary nerves

infratrochlear nerve

anterior ethmoidal nerve

post ethmoidal nerve

post ethmoidal nerve

supplies the post ethmoidal sinus & sphenoid sinus

anterior ethmoidal nerve

supplies the ant. ethmoidal sinuses / wall of nasal cavity / tip of nose

infratrochlear nerve

supplies the bridge of nose

long & short cilliary nerves

supplies the eye (iris, cornea)

cilliary ganglion

nerve to cilliary ganglion

branches within the middle cranial fossa

meningeal nerve

meningeal nerve

supplies the meninges

branches within the middle cranial fossa

posterior superior alveolar nerve

zygomatic nerve

ganglionic branches nerve

infraorbital nerve

posterior superior alveolar nerve

supplies the maxillary sinus & the maxillary molars

passes through the pterygomaxillary fissure to enter the infratemporal fossa

zygomatic nerve

passes through the inferior orbital fissure to enter the orbit

ganglionic branches nerve

contain sensory fibers & postganglionic autonomic fibers

infraorbital nerve

considered the continuation of the maxillary division of the trigeminal nerve

passes through the orbital fissure to enter the orbit

branches associated with the pterygopalatine ganglion

pharyngeal nerve

posterior superior nasal nerve

posterior medial superior nasad

greater palatine nerve

posterior inferior nasal branch of the greater palatine nerve

lesser palatine nerve

nasopalatine nerve

pharyngeal nerve

passes through the pharyngeal canal to enter & supply the nasopharynx

posterior superior nasal nerve

passes through the sphenopalatine foramen to enter the nasal cavity

posterior medial superior nasal

this nerve supplies the posterior portion of the nasal septum

greater palatine nerve

supplies the palatal gingiva & mucosa from the area in the premolar region to the posterior border of the hard palate to the midline

posterior inferior nasal branch of the greater palatine nerve

this supplies the posterior part of the lateral wall of the nasal cavity in the region of the middle meatus

lesser palatine nerve

this supplies the uvula, tonsils & soft palate via the lesser palatine foramen

nasopalatine nerve

this supplies the gingiva & mucosa of the hard palate from central incisor to canine

branches within the infraorbital canal

middle superior alveolar nerve

anterior superior alveolar nerve

middle superior alveolar nerve

a variable nerve

it innervates part of the maxillary sinus, the premolars, and the mesiobuccal root of the 1st molar

anterior superior alveolar nerve

it innervates the maxillary central incisors, lateral & canine teeth, and some part of the maxillary sinus

branches after infraorbital nerve emerges from the infraorbital foramen

superior labial branch of the infraorbital nerve

nasal branch of the infraorbital nerve

inferior palpebral branch of the infraorbital nerve

superior labial branch of the infraorbital nerve

this nerve supplies the skin of the upper lip

nasal branch of the infraorbital nerve

this nerve supplies the ala of the nose

inferior palpebral branch of the infraorbital nerve

this nerve supplies the skin of the lower eyelid

a result of trigeminal nerve damage

decreased sensation

trigeminal neuralgia

increased pain sensation

weakening and/or paralysis of muscles of mastication (chewing)

2 divisions of the mandibular branch of the trigeminal nerve

anterior — smaller / mainly motor with 1 sensory brach (buccal)

posterior — larger / mainly sensory with 1 motor branch (nerve to the mylohyoid)

anterior divisions of the mandibular nerve

masseteric nerve

anterior & posterior deep temporal

medial pterygoid

lateral pterygoid

buccinator nerve

masseteric nerve

this innervate the masseter muscles

also provides a small branch to the TMJ

passes laterally superior to the lateral pterygoid muscle

anterior & posterior deep temporal nerve

pass superior to the lateral pterygoid muscle

between the skull & temporalis muscle while passing deep to the muscle to innervate it

medial pterygoid

enters the deep surface of the muscle

lateral pterygoid

passes into the deep surface of the muscle

often arises from the buccal nerve

buccinator nerve

this supplies the skin over the buccinator muscle / mucous membrane lining its inner surface / the gingiva along the mandibular molars

posterior division of the mandibular nerve

auriculotemporal

lingual nerve

inferior alveolar

mylohyoid

auriculotemporal

runs posteriorly just inferior to the lateral pterygoid

continues the medial side of the neck of the mandible