Anatomy of Trigeminal nerve Flashcards
What are 3 branches of trigeminal nerve and type of innervation?
Opthalmic nerve V1 - Sensory
Maxillary nerve V2 - Sensory
Mandibular nerve V3 - Sensory + motor
Postganglion parasympathetic fibers join with many branches of trigeminal nerve
What does sensory & motor functions of V nerve include?
Sensation of face, mouth, nasal cavity, dura matter of cranial cavity
Motor - biting & chewing
What is this nerve? Name structure from up to down. Describe
Trigeminal nerve
- Sensory root (large)
- > Contains cell bodies of pseudounipolar neurons
- Motor root (small)
location of trigeminal ganglion
-> MECKEL’S CAVE (TRIGEMINAL CAVE)
4 nuclei of trigeminal nerve
Motor nucleus
- Trigeminal motor nucleus
Sensory nucleus
- Mesencephalic nucleus
- Principal sensory nucleus
- Signal trigeminal nucleus
Name of this sensory nucleus. Describe
Mesencephalic nucleus
- Located in lower midbrain
- Proprioception for masticatory muscles
- Senses deep pressure
- Also receive somatic sensory info from VII, IX, X
Name of this sensory nucleus. Describe
Principal sensory nucleus
- Located in pons
- Tactile information from face and mouth (touch)
- Also receive somatic sensory info from VII, IX, X
Name of this sensory nucleus. Describe
Spinal trigeminal nucleus
- Extends down the medulla & into spinal cord
- Also receive somatic sensory info from VII, IX, X
Identify this nerve.
Where does it come from?
Brain exit?
Ophthalmic nerve V1
- From trigeminal ganglion
- Passes from superior orbital fissure to the orbit
Identify 3 branches of ophthalmic nerve and describe them
(1) Frontal nerve
- Sensory innervation to forehead & scalp
(2) Lacrimal nerve
- Supplies lacrimal gland
(3) Nasociliary nerve
- Supplies eye & nose
the ophthalmic receive sensory fibers from…
- Eyeball
- Skin of upper face & anterior scalp
- Lining of upper part of nasal cavity
- Meninges of anterior cranial fossa
Name these branches from up - down. Describe
Anterior & posterior ethmoidal nerves
+) sensory fibers to meninges of anterior cranial fossa
+) Upper part of nasal cavity to external tip of nose
+) Sphenoid and ethmoid air cells
- Long ciliary nerve
+) supplies eyeball - Short ciliary nerves
+) supplies eyeball
+) carries postganglionic parasympathetic fibers from oculomotor nerve (CN III)
Name of this ganglion
Ciliary ganglion
Name of this nerve. Describe
- Supplies lacrimal gland, adjacent skin
- Carries postganglionic parasympathetic fibers from pterygopalatine ganglion
- > synapse with preganglionic fibers originating from superior salivatory nucleus
- > travel with facial nerve
Maxillary nerve receive sensory fibers from….
- Palpebral fissure & mouth
- Nasal cavity & sinuses
- Maxillary teeth
Course of maxillary nerve (brain exits)
- Trigeminal ganglion
- > foramen rotundum
- > pterygopalatine fossa
- divides into infraorbital nerve & zygomatic nerve
- give branches to nasal nerves, greater palatine nerve, lesser palatine nerve
Name of this nerve.
Describe its course
Infraorbital nerve - From trigeminal nerve -> enter pterygopalatine fossa -> inferior orbital fissure -> infraorbital groove -> orbital floor => gives branches to 3 superior alveolar nerves
What is nervus intermedius?
Root of CN VII that arises between motor root of CN VII and CN VIII
-> Contains special sensory fibers for taste and parasympathetic fibers
Describe special sensory pathway of maxillary nerve
Special sensory information, such as taste, passes from the taste buds on the palate through the palatine nerves
=> pass through the pterygopalatine ganglion without synapsing
=> go through the pterygoid canal,
=> hitchhike with the greater petrosal nerve back to the facial nerve
Describe sensory and motor functions of mandibular nerve V3
Sensory
- Skin over mandible
- Side of cheek and temple
- Oral cavity
- External ear
- Tympanic membrane
- TMJ
Motor - 8 muscles derived from 1st pharyngeal arch
Describe course of mandibular nerve (+ skull exit)
Trigeminal ganglion -> foramen ovale -> infratemporal fossa => gives 4 branches - Auriculotemporal nerve (1) - Buccal nerve (2) - Lingual nerve (3) - Inferior alveolar nerve (4)
Course of lingual nerve?
Lingual nerve (from V3)
- Sensory innervation of anterior 2/3 of tongue
- Preganglionic PNS info from superior salivatory nucleus via chorda tympani (VII) -> SUB
- Post ganglionic PNS info -> submandibular ganglion -> innervate submandibular gland & sublingual gland
Name of this nerve? describe its function
chorda tympani (VII) - Taste info from anterior 2/3 of tongue to solitary nucleus
Name of this nerve? describe its function
Auriculotemporal nerve (V3)
(1) Encircles middle meningeal artery
(2) Supplies
- TMJ
- Parotid fascia
- Skin of temple
- Most skin of external auditory meatus
- Tympanic membrane
(3) Preganglionic PNS info from inferior salivatory nucleus
- Travels with glossopharyngeal nerve IX
- > synapse in otic ganglion
Describe pathway of trigeminal motor nucleus
cerebral cortex ( upper motor neurons)
- > synapse in the trigeminal motor nucleus in the pons of the brainstem to the lower motor neurons.
- > fibers bypass the trigeminal ganglion and merge with the sensory component of the mandibular division.
- > After exiting from the foramen ovale, the mandibular nerve sends off motor branches to the four muscles of mastication. (temporalis, Masseter, medial & lateral pterygoids)
