Trigeminal nerve
The trigeminal nerve is the fifth cranial nerve and its primary role is relaying sensory information from the face and head, although it does provide motor control to the muscles of mastication. It is both large and complicated and has multiple brainstem nuclei (sensory and motor) as well as many interconnections with other cranial nerves. It swaps parasympathetic fibers and taste fibers somewhat haphazardly and divides into numerous terminal branches.
Gross anatomy
Nuclei
There are four cranial nerve nuclei: three sensory and one motor.
The sensory nuclei are arranged in a column which spans from the midbrain through the pons and medulla and into the upper cervical cord.
- mesencephalic nucleus: proprioceptive fibers for muscles of the face, orbit, mastication, and tongue; extends through the whole length of the midbrain, lateral to the cerebral aqueduct
- main sensory nucleus: located in the upper pons, lateral to the motor nucleus, is responsible for touch sensation for all three trigeminal divisions
- spinal nucleus: lower pons to upper cervical cord (as far as the third cervical segment), is responsible for pain and temperature; additionally it receives afferent fibers from the glossopharyngeal nerve and vagus nerve.
The motor nucleus is located in the upper pons and gives off the smaller motor root which bypasses the trigeminal ganglion and innervates the muscles of mastication as well as mylohyoid, the anterior belly of digastric, tensor tympani and tensor palatini.
Intracranial component
The trigeminal nerve exits at the mid pons anteriorly, courses through the prepontine cistern (cisternal portion), and crosses the porus trigeminus to enter a prolongation of dura at the apex of the petrous temporal bone known as the Meckel cave (cavernous portion) where its fibers form the trigeminal ganglion, which is also known as the Gasserian or semilunar ganglion. It then divides into three main branches known as divisions:
Ophthalmic division / nerve (V1 or Va)
Courses anteriorly in the lateral wall of the cavernous sinus inferior to the trochlear nerve and is crossed medially by the oculomotor nerve. Just before entering the orbit, the tentorial nerve arises and ascends to supply a large portion of the falx and supratentorial dura. The ophthalmic division then divides into 3 terminal branches before each passes through the superior orbital fissure separately:
- frontal nerve (superior orbital fissure outside the tendinous ring)
- lacrimal nerve (superior orbital fissure outside the tendinous ring)
- nasociliary nerve (superior orbital fissure through the tendinous ring)
Maxillary division / nerve (V2 or Vb)
Courses anteriorly low in the lateral wall of the cavernous sinus inferior to the ophthalmic division. Just before exiting the skull it runs along the floor of the middle cranial fossa and gives off the middle meningeal nerve which ascends to supply the anterior dura of the middle cranial fossa. It then passes through the foramen rotundum in the greater wing of the sphenoid bone to exit the skull and enter the superior aspect of the pterygopalatine fossa. It gives branches to the pterygopalatine ganglion but also receives parasympathetic nerves from the ganglion via the greater petrosal nerve. It then divides into the:
- zygomatic nerve (inferior orbital fissure)
- infraorbital nerve (inferior orbital fissure then infraorbital foramen)
- nasopalatine nerve (sphenopalatine foramen)
- posterior superior nasal nerves (sphenopalatine foramen)
-
greater palatine nerve (greater palatine foramen)
- lateral posterior inferior nasal nerve (un-named foramina)
- lesser palatine nerve (lesser palatine foramen)
- pharyngeal nerve (palatovaginal canal)
Mandibular division / nerve (V3 or Vc)
Courses inferiorly through the foramen ovale to enter the infratemporal fossa, hence it does not pass through the cavernous sinus. It consists of a sensory root and a smaller motor root, the latter which bypasses the trigeminal ganglion inferiorly. These roots pass through the foramen ovale separately and then unite just below the foramen. It immediately gives off nervus spinosus and nerve to medial pterygoid from the main trunk. It then descends in the infratemporal fossa passing between the tensor veli palatini and lateral pterygoid muscles before dividing into anterior and posterior divisions:
- anterior division (4 branches, all motor except one)
- posterior division (3 branches, all sensory except one)
Related pathology
Related Radiopaedia articles
Anatomy: Brain
-
brain
- grey matter
- white matter
-
cerebrum
-
cerebral hemisphere (telencephalon)
- cerebral lobes and gyri
- frontal lobe
- parietal lobe
-
occipital lobe
- occipital pole
- lingual gyrus
- fusiform gyrus (Brodmann area 37)
- calcarine (visual) cortex
- cuneus
- temporal lobe
- basal forebrain
- limbic system
- insula
-
cerebral sulci and fissures (A-Z)
- calcarine fissure
- callosal sulcus
- central (Rolandic) sulcus
- cingulate sulcus
- collateral sulcus
- inferior frontal sulcus
- inferior occipital sulcus
- inferior temporal sulcus
- interhemispheric fissure
- intraparietal sulcus
- lateral (Sylvian) sulcus
- lateral occipital sulcus
- marginal sulcus
- occipitotemporal sulcus
- olfactory sulcus
- paracentral sulcus
- paraolfactory sulcus
- parieto-occipital fissure
- posterior parolfactory sulcus
- precentral sulcus
- preoccipital notch
- postcentral sulcus
- rhinal sulcus
- rostral sulcus
- subparietal sulcus
- superior frontal sulcus
- superior occipital sulcus
- superior temporal sulcus
- cortical histology
- cerebral lobes and gyri
- white matter tracts
- deep grey matter
-
pituitary gland
- posterior pituitary and stalk (part of diencephalon)
- anterior pituitary
- inferior hypophyseal arterial circle
- diencephalon
-
cerebral hemisphere (telencephalon)
-
brainstem
- midbrain (mesencephalon)
- pons (part of metencephalon)
- medulla oblongata (myelencephalon)
- white matter
-
grey matter
- non-cranial nerve
-
cranial nerve nuclei
- oculomotor nucleus
- Edinger-Westphal nucleus
- trochlear nucleus
- motor nucleus of CN V
- mesencephalic nucleus of CN V
- main sensory nucleus of CN V
- spinal nucleus of CN V
- abducent nucleus
- facial nucleus
- superior salivatory nucleus
- cochlear nuclei
- vestibular nuclei
- inferior salivatory nucleus
- solitary tract nucleus
- ambiguus nucleus
- dorsal vagal motor nucleus
- hypoglossal nucleus
-
cerebellum (part of metencephalon)
- vermis
- cerebellar hemisphere
- cerebellar peduncles
- cranial meninges (meninx primitiva)
- CSF spaces
-
cranial nerves (mnemonic)
- olfactory nerve (CN I)
- optic nerve (CN II)
- oculomotor nerve (CN III)
- trochlear nerve (CN IV)
- trigeminal nerve (CN V) (mnemonic)
- abducens nerve (CN VI)
- facial nerve (CN VII) (segments mnemonic | branches mnemonic)
-
vestibulocochlear nerve (CN VIII)
- vestibular ganglion (Scarpa's ganglion)
- glossopharyngeal nerve (CN IX)
- vagus nerve (CN X)
- spinal accessory nerve (CN XI)
- hypoglossal nerve (CN XII)
- functional neuroanatomy
- CNS development
- cerebral vascular supply
- arteries
- vascular territories
-
circle of Willis
- internal carotid artery (ICA) (segments)
- vertebral artery
-
normal variants
- intracranial arterial fenestration
- internal carotid artery (ICA)
- anterior cerebral artery (ACA)
- middle cerebral artery (MCA)
- posterior cerebral artery (PCA)
- basilar artery
- persistent carotid-vertebrobasilar artery anastomoses (mnemonic)
-
cerebral venous system
-
dural venous sinuses
- basilar venous plexus
- cavernous sinus (mnemonic)
- clival diploic veins
- inferior petro-occipital vein
- inferior petrosal sinus
- inferior sagittal sinus
- intercavernous sinus
- internal carotid artery venous plexus of Rektorzik
- jugular bulb
- marginal sinus
- occipital sinus
- sigmoid sinus
- sphenoparietal sinus
- straight sinus
- superior petrosal sinus
- superior sagittal sinus
- torcula herophili
- transverse sinus
-
cerebral veins
-
superficial veins of the brain
- superior cerebral veins (superficial cerebral veins)
- inferior cerebral veins
- superficial middle cerebral vein
- superior anastomotic vein (of Trolard)
- inferior anastomotic vein (of Labbe)
-
superficial veins of the brain
- deep veins of the brain
- normal variants
-
dural venous sinuses
- arteries
- glymphatic pathway
Anatomy: Head and neck
- skeleton of the head and neck
-
cranial vault
- scalp (mnemonic)
- fontanelle
-
sutures
- calvarial
- facial
- frontozygomatic suture
- frontomaxillary suture
- frontolacrimal suture
- frontonasal suture
- temporozygomatic suture
- zygomaticomaxillary suture
- parietotemporal suture (parietomastoid suture)
- occipitotemporal suture (occipitomastoid suture)
- sphenofrontal suture
- sphenozygomatic suture
- spheno-occipital suture (not a true suture)
- lacrimomaxillary suture
- nasomaxillary suture
- internasal suture
- basal/internal
- skull landmarks
- frontal bone
- temporal bone
- parietal bone
- occipital bone
- skull base (foramina)
-
facial bones
- midline single bones
- paired bilateral bones
- cervical spine
- hyoid bone
- laryngeal cartilages
-
cranial vault
- muscles of the head and neck
- muscles of the tongue (mnemonic)
- muscles of mastication
-
muscles of facial expression
- occipitalis muscle
- circumorbital and palpebral muscles
- nasal muscles
- buccolabial muscles
- elevators, retractors and evertors of the upper lip
- levator labii superioris alaeque nasalis muscle
- levator labii superioris muscle
- zygomaticus major muscle
- zygomaticus minor muscle
- malaris muscle
- levator anguli oris muscle
- risorius muscle
- depressors, retractors and evertors of the lower lip
- depressor labii inferioris muscle
- depressor anguli oris muscle
- mentalis muscle
- compound sphincter
- orbicularis oris muscle
- incisivus superior muscle
- incisivus inferior muscle
- muscle of mastication:
- elevators, retractors and evertors of the upper lip
- muscles of the middle ear
- orbital muscles
- muscles of the soft palate
- pharyngeal muscles
- suprahyoid muscles
- infrahyoid muscles
- intrinsic muscles of the larynx
- muscles of the neck
- accessory muscles of the neck
- deep cervical fascia
-
deep spaces of the neck
- anterior cervical space
- buccal space
- carotid space
- danger space
- deep cervical fascia
- infratemporal fossa
- masticator space
- parapharyngeal space
- stylomandibular tunnel
- parotid space
- pharyngeal (superficial) mucosal space
- perivertebral space
- posterior cervical space
- pterygopalatine fossa
- retropharyngeal space
- suprasternal space (of Burns)
- visceral space
- surgical triangles of the neck
- orbit
- ear
- paranasal sinuses
- nose
- oral cavity
- pharynx
- larynx
- viscera of the neck
- blood supply of the head and neck
-
arterial supply
-
common carotid artery
- carotid body
- carotid bifurcation
- subclavian artery
- variants
-
common carotid artery
- venous drainage
-
arterial supply
- innervation of the head and neck
-
cranial nerves
- olfactory nerve (CN I)
- optic nerve (CN II)
- oculomotor nerve (CN III)
- trochlear nerve (CN IV)
-
trigeminal nerve (CN V) (mnemonic)
- trigeminal ganglion
- ophthalmic division
- maxillary division
- mandibular division
- abducens nerve (CN VI)
- facial nerve (CN VII)
-
vestibulocochlear nerve (CN VIII)
- vestibular ganglion (Scarpa's ganglion)
- glossopharyngeal nerve (CN IX)
-
vagus nerve (CN X)
- superior laryngeal nerve
- recurrent laryngeal nerve (inferior laryngeal nerve)
- (spinal) accessory nerve (CN XI)
- hypoglossal nerve (CN XII)
- parasympathetic ganglia of the head and neck
- greater occipital nerve
- third occipital nerve
-
cervical plexus
- muscular branches
- longus capitis
- longus colli
- scalenes
- geniohyoid
- thyrohyoid
-
ansa cervicalis
- omohyoid (superior and inferior bellies separately)
- sternothyroid
- sternohyoid
- phrenic nerve
- contribution to the accessory nerve (CN XI)
- cutaneous branches
- muscular branches
- brachial plexus
- pharyngeal plexus
-
cranial nerves
- lymphatic drainage of the head and neck
- embryological development of the head and neck