Head&Neck Trigeminal N

Trigeminal nerve
• Largest cranial nerve

• Sensory supply to: Face
greater part of scalp
teeth
Oral and nasal cavities
dura mater
• Motor supply to: Muscles of mastication
anterior belly of diagastric
mylohyoid
Origin
• Principal sensory nucleus
• Spinal trigeminal nucleus
• Motor nucleus
Ventral surface of pons by two roots- motor &
sensory
Trigeminal ganglion
Three divisions: ophthalmic
maxillary
mandibular
Maxillary nerve
• Wholly sensory
• Course: Traverse foramen rotundum
post. wall of pterygopalatine fossa
enters the inferior orbital fissure
enter infra orbital canal
emerges on face as infraorbital nerve
Maxillary nerve-Branches
In the cranial cavity:
• Meningeal (to dura mater)
In pterygopalatine fossa:
• Ganglionic- connected to PP ganglion; contain lacrimal secretomotor &
sensory fibres from orbital periosteum and mucosa
of nose, palate and pharynx.
• Zygomatic- enters orbit; divides in to zygomaticotemporal and
zygomaticofacial branches.
• Superior alveolar nerves- Posterior
In the infraorbital canal:
• Middle
• Anterior
On face:
• palpebral
• nasal
• superior labial
Pterygopalatine ganglion
• In the Pterygopalatine fossa
• Motor: Preganglionic fibres are from:
Nerve of pterygoid canal
Special lacrimatory nucleus– sensory root of facial
nerve– greater petrosal nerve+ deep petrosal
nerve – synapse in PP ganglion—
(postganglionic fibres)—join maxillary nerve–
Zygomatic nerve—lacrimal nerve.
In addition: secretomotor fibres to
palatine/pharyngeal/nasal glands via
palatine/nasal branches.
• Sympathetic: same as motor root
• Branches:
Orbital: to orbital periosteum; orbitalis;sphenoid and
ethmoid sinuses.
Palatine: greater-runs in greater palatine canal to
hard palate; supplies gums, mucosa and glands.
lesser palatine- runs in greater palatine canal to hard
palate; supplies uvula, tonsil, soft palate
Nasal: Lateral post. Sup. nasal branches(6)
supply post. Parts of sup. & middle nasal
concha, post. Ethmoidal sinuses.
Medial post. Sup. nasal branches(2-3)-
nasopalatine; supply nasal septum and hard palate.
Pharyngeal: supply mucosa of nasopharynx.
Mandibular nerve
• Supplies: Teeth and gums; skin in
temporal region; part of auricle; external
auditory meatus; tympanic membrane;
lower lip, part of face; muscle of
mastication; mucosa of ant.2/3 of tongue;
mucosa of floor of oral cavity.
• Large sensory root
• Small motor root
Mandibular nerve (contd.)
• Emerges from foramen ovale
• Gives two branches before dividing
meningeal
nerve to medial pterygoid
• Divides in to- small anterior
large posterior
• Branches:
1. Meningeal (nervus spinosus): reenters cranium thru’
foramen spinosum; supply dura mater in the middle
cranial fossa.
2. N. to medial pterygoid: supplies medial pterygoid; 1 or
2 filaments pass through otic ganglion and supply
tensor tympani and tensor palati.
• Anterior Trunk:
1. Buccal
2. Masseteric
3. Deep temporal
4. Nerve to lateral pterygoid
• Posterior Trunk:
1. Auriculotemporal
Communicates with otic ganglion and facial nerve.
i) Auricular, ii) Articular, iii) Parotid,
iv) Temporal & v) to External auditory meatus
2. Lingual:
Joined by chorda tympani.
Sensory to mucosa of anterior 2/3rd of
tongue, floor of mouth and gums.
3. Inferior alveolar:
Nerve to mylohyoid; Branches to lower
teeth and Mental branch.
Submandibular ganglion
• Small, fusiform, on upper part of hyoglossus
• Superficial to deep part of submand. Gland
• Connected functionally to facial nerve
• Motor root: sup. salivatory N.– facial nerve– chorda
tympani– lingual nerve– synapse in ganglion– postgang.
Secretomotor fibres to salivary glands.
• Sympathetic root: from plexus around facial artery– do
not synapse—vasomotor to blood vessels.
• Sensory root: from lingual nerve- do not synapse.
• Branches: to submandibular and sublingual glands.
Otic ganglion
• Small, fusiform, between mandibular nerve and tensor tympani.
• Peripheral parasympathetic ganglion
• Connected functionally with glossopharyngeal nerve
• Motor root: Inf. salivatory N.– IX nerve– Lesser petrosal– synapse
in ganglion– postgang. Secretomotor fibres to parotid gland via
auriculotemporal nerve.
• Sympathetic root: from plexus around Middle men. artery– do not
synapse—vasomotor to blood vessels.
• Sensory root: from auriculotemporal nerve-- do not synapse.
• Branches: communicating branch to auriculotemporal nerve for
parotid gland
communicating branch to chorda tympani
communicating branch to nerve of pterygoid canal
Motor branch to tensor tympani and tensor palati
Applied anatomy
• Trauma, tumors, aneurysms or meningeal infections will
cause:
Paralysis of muscles of mastication with deviation of mandible
towards the site of lesion.
Loss of soft tactile, thermal or painful sensations on the face
Loss of corneal reflex and sneezing reflex
• Trigeminal neuralgia: excruciating pain in the area of
distribution; females more affected.
• Referred pain
• Mandibular nerve block
• Dental anesthesia (Inf. Alveolar nerve block)
• Lingual nerve injury

Head&Neck Trigeminal N

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Trigeminal nerve

• Largest cranial nerve

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