Cranial Nerves: Trigeminal Nerve Flashcards
Which cranial nerve is the trigeminal nerve?
five
The trigeminal nerve is innervated by what kind of fibers (non specific)?
large sensory and small motor component
Where is the nerve trunk of the trigeminal attached?
at the junction of the trapezoid body and the pons
Through what does the trigeminal nerve pass through?
the trigeminal canal in the petrous part of the temporal bone
What is located in the trigeminal canal?
the trigeminal ganglia
What do the trigeminal ganglia contain?
general somatic afferent neurons which receive sensory information from the vast area of the head
What are the three branches of the trigeminal nerve?
opthalmic branch, mandibular branch, maxillary branch
What type of fibers does the opthalmic branch contain?
sensory
What do the sensory fibers of the opthalmic branch supply?
the eyelid, eyeball, skin covering the nose, the mucosa covering nasal cavity
What structure does the opthalmic branch go through to leave the cranial cavity?
the orbital fissure
What does the opthalmic branch do after it exits the orbital fissure?
it divides into three branches
What are the three branches of the opthalmic branch?
the frontal, lacrimal, and nasociliary
Which is the most dorsally located branch of the opthalmic branch?
the frontal nerve
What is the course of the frontal nerve of the opthalmic branch?
it courses above the dorsal oblique and dorsal rectus muscles of the eyeball and then reaches the orbital ligament
What does the frontal nerve of the opthalmic branch do when it reaches the orbital ligament?
it divides into the supratrochlear nerve and supraorbital nerve
What do the supratrochlear and supraorbital nerve supply?
the skin on the medial 2/3 of the upper eyelid up to the dorsal midline
Which is the smallest branch of the opthalmic branch?
the lacrimal
What does the lacrimal nerve supply?
the lacrimal gland
What type of axons does the lacrimal nerve contain?
sympathetic post-ganglionic axons
What is the largest of the three branches of the opthalmic branch?
the nasociliary
Where is the nasociliary of the opthalmic branch located?
deep inside the periorbita over the retractor bulbi muscle
What are the branches of the nasociliary branch of the opthalmic?
a communicating branch to the ciliary ganglion, long ciliary nerves, the ethmoidal nerve, and the infratrochlear nerve
What type of fibers does the communicating branch of the nasociliary branch of the opthalmic carry?
GVE
What type of axons does the communicating branch of the nasociliary branch of the opthalmic contain?
postganglionic sympathetic axons
Where do the postganglionic sympathetic axons in the communicating branch to the ciliary ganglion go?
they pass the ciiliary ganglion to join the short ciliary branches of the oculomotor nerve
Where are the neurons of the communicating branch of the nasociliary nerve located?
in the cranial cervical ganglion
How does the communicating branch of the nasociliary nerve reach the opthalmic nerve?
via the internal carotid plexus formed at the origin at the internal carotid artery
What does the communicating branch of the nasociliary supply?
the smooth muscle cells within the periorbita, the eyelids, and the dilator of the pupil
What type of fibers does the long ciliary nerve of the nasociliary branch carry?
GVA, SVA, and SSA
Where do the long ciliary nerves of the nasociliary branch enter the eyeball?
dorsomedial to the optic nerve
Where do the GVA fibers of the long ciliary nerves of the nasociliary branch go and do the other fibers follow it?
ONLY the GVA branches go to the eyeball including the corneal epitherlium and bulbular conjunctiva
Where does the ethmoidal nerve of the nasociliary branch go and how does it get there?
it goes into the nasal cavity through the ethmoidal foramina
What does the ethmoidal nerve of the nasociliary branch supply?
the nasal mucosa and courses cranially to supply the external nostrils
Where is the infratrochlear nerve of the nasociliary branch located and how does it course?
located ventral to the trochlea of the tendon of the dorsal oblique muscle and becomes subcutaneous at the medial canthus of the eye
What type of fibers does the maxillary branch contain?
sensory and autonomic
What do the sensory fibers of the maxillary branch supply?
the upper eyelid, nasal mucosa, upper teeth, upper lip and nose
What do the autonomic fibers of the maxillary branch supply?
the lacrimal, nasal, and palatine glands
What structure does the maxillary branch go through to exit the cranial cavity?
the round foramen
What structure does the maxillary nerve follow after it leaves the cranial cavity?
the maxillary artery
What are the branches of the maxillary nerve?
the zygomatic nerve, the pterygopalatine nerve, and the infraorbital nerve
Where does the zygomatic nerve detach from the maxillary?
at the rostral alar foramen
When the zygomatic nerve detaches from the maxillary, what does it do?
divides into the zygomaticotemporal nerve and the zygomaticofacial nerve
What is the course of the zygomaticotemporal of the zygomatic nerve?
it courses between the dorsal rectus and the dorsal oblique muscles
Lateral to the orbital ligament, what does the zygomaticotemporal of the zygomatic nerve do?
it becomes subcutaneous and innervates the skin of the upper eyelid
What overlaps the zygomaticotemporal of the zygomatic nerve?
the frontal nerve and infratrochlear nerve
What type of axons does the zygomaticotemporal nerve of the zygomatic carry and where do they go?
postganglionic parasympathetic axons from the pterygopalatine ganglia to the lacrimal gland
What is the course of the zygomaticofacial nerve of the zygomatic?
it runs rostrally in the orbit deep to the periorbita and emerges medial ligament
What does the zygomaticofacial nerve of the zygomatic supply?
the skin dorsal to the zygomatic arch up to the external ear
What area does the zygomaticofacial nerve of the zygomatic overlap?
the area innervated by the branches of the opthalmic nerve
When does the pterygopalatine nerve detach from the maxillary?
during its course within the orbit lateral to the pterygoideus muscle
Where is the pterygopalatine ganglion located?
dorsal to the pterygopalatine nerve of the maxillary
What are the branches of the pterygopalatine nerve of the maxillary?
minor palatine nerve, major palatine nerve, caudal nasal nerve
What does the minor palatine nerve of the ptergopalatine nerve supply?
the soft palate
What type of axons/fibers does the minor palatine nerve of the pterygopalatine have?
GVA, postganglionic parasympathetic axons, and SVA axons
What do the GVA fibers of the minor palatine do?
provide sensation to the soft palate
What do the postganglionic parasympathetic axons of the minor palatine go to?
the palatine glands within the soft palate
Where are the neurons for the SVA fibers of the minor palatine located?
in the geniculate ganglion
What do the SVA fibers of the minor palatine for?
taste
Where does the major palatine nerve detach from the pterygopalatine nerve?
distal to the minor palatine nerve
What does the major palatine of the pterygopalatine supply?
the hard palate
The major palatine of the pterygopalatine nerve has what type of fibers (nonspecific)?
sensory
What is the caudal nasal nerve a continuation of?
the pterygopalatine nerve in the pterygopalatine fossa
What is the course of the caudal nasal nerve?
it moves from the pterygopalatine fossa and enters the nasal cavity through the sphenopalatine foramen
What does the caudal nasal nerve supply?
sensory innervation to the nasal mucosa of the ventral nasal meatus
What type of axons does the caudal nasal nerve contain and what do they supply?
postganglionic sympathetic axons; nasal glands
What is the infraorbital nerve a continuation of?
the maxillary after it gives off the pterygopalatine
What does the infraorbital nerve do in the pterygopalatine fossa?
gives off the caudal superior alveolar branches
What do the caudal superior alveolar branches of the infraorbital supply?
the caudal upper cheek teeth
After giving off the caudal superior alveolar branches, what does the infraorbital nerve do?
enters the maxillary foramen and gives off the middle superior alveolar branches
What do the middle superior alveolar branches supply?
the remaining upper cheek teeth
Just before leaving the infraorbital canal, what does the infraorbital nerve do?
it gives off the rostral superior alveolar branches
What do the rostral superior alveolar branches supply?
the upper canine and incisors
What does the infraorbital nerve do after it leaves the infraorbital foramen?
it divides into a number of branches to supply the skin below the orbit and the upper lip
What does damage to the zygomaticotemporal and zygomaticofacial of the zygomatic branch cause?
lack of a blink response upon touch to this region
What does damage to the nasal sensory branches of the maxillary nerve cause?
a lack of response to tickling the interior of he nose with a cotton swab or object - the dog should pull their head back
What happens if the GVE fibers of the maxillary nerve are affected?
they may cause dry eye or a dry nasal cavity
What type of fibers does the mandibular nerve have (non specific)?
sensory and motor
What do the motor components of the mandibular nerve supply?
the muscles of mastication
What do the sensory components of the mandibular nerve supply?
cheek, lower lip, part of the tongue, lower teeth, the floor of the oral cavity, the interosseous part of the external ear canal, the skin of the lower jaw, the skin covering the temporalis and the masseter, the tactile hairs of the cheek, and the external ear
What structure does the mandibular nerve go through to exit the cranial cavity?
the oval foramen
What branches does the mandibular nerve give off after exiting through the oval foramen?
the masticator nerve, lateral and medial pterygoid nerve, tensor tympani nerve, tensor veli palatini, buccal nerve, auriculotemporal nerve, inferior alveolar nerve, and lingual nerve
What type of fibers does the masticator nerve of the mandibular nerve have (nonspecific)?
motor fibers
What does the masticator nerve of the mandibular supply?
rostral belly of the digastricus muscle to open the mouth
The masticator nerve of the mandibular has two branches, what are they?
masseteric nerve branch and deep temporal nerve
What does the masseteric nerve branch of the masticator nerve supply?
the masseter
What does the deep temporal nerve of the masticator nerve supply?
the temporalis muscle to close the mouth
What type of fibers does the lateral and medial pterygoid nerve have (nonspecific)?
motor
What do the lateral and medial pterygoid nerves of the mandibular supply?
the pterygoideus
What type of fibers does the tensor tympani nerve have (nonspecific)?
motor
What does the tensor tympani nerve of the mandibular supply?
the tensor tympani muscle of the malleus
How does the tensor tympani muscle respond to loud noises?
it contracts to tighten the tympanic membrane and prevents a big bang from the malleus
What type of fibers does the tensor veli palatini of the mandibular have (nonspecific)?
motor
What do the tensor veli palatini of the mandibular nerve supply?
the thin muscle of the soft palate
What does the tensor veli palatini muscle do?
controls the nasopharyngeal opening of the auditory tube to maintain air pressure in the middle ear cavity
What type of fibers does the buccal nerve of the mandibular have (nonspecific)?
sensory
What does the buccal nerve of the mandibular innervate?
the mucosa of the cheek
What is the course of the buccal nerve of the mandibular?
it crosses the pterygoid, then crosses the rostral border of the masseter, it then enters the cheek lateral to the zygomatic salivary gland
Where can the buccal nerve of the mandibular be seen?
where the deep and facial veins meet
Where is the auriculotemporal nerve (sensory) branch off from the mandibular?
at the level of the oval foramen
What is the course of the auriculotemporal nerve of the mandibular?
it passes caudal to the temporomandiular joint, and emerges between the auricular cartilage of the ear and the masseter
What does the auriculotemporal nerve of the mandibular do when it is between the auricular cartilage of the ear and the masseter?
it gives off the external acoustic meatus nerve, postganglionic parasympathetic axons, rostral auricular nerves, and transverse facial branch
What does the external acoustic meatus nerve of the auriculotemporal nerve supply?
sensory fibers to the skin of the external acoustic meatus close to the tympanic membrane and the membrane itself
What does the postganglionic parasympathetic axons of the auriculotemporal nerve supply?
the parotid salivary gland
What do the rostral auricular nerves of the auriculotemporal nerve supply?
the external ear, the skin over the temporalis and the zygomatic arch
What does the transverse facial branch of the auriculotemporal nerve supply?
sensory innervation to the to the tactile hairs of the cheeks and the skin over the masseter
Where does the inferior alveolar nerve arise?
on the lateral aspect of the medial pterygoid muscle
What does the inferior alveolar nerve do before it enters the mandibular foramen?
it gives off the mylohyoid nerve
What does the mylohyoid nerve of the inferior alveolar nerve supply?
the mylohyoid muscle
What does the inferior alveolar nerve of the mandibular do after it enters the mandibular foramen?
it passes through the mandibular canal and supplies the lower cheek
What does the inferior alveolar nerve do after it exits the mental foramina?
it exits as the mental nerves (sensory) to the lower lip and to the rostral intermandibular region
What does the lingual nerve of the mandibular supply?
sensory fibers to the rostral 2/3 of the mucous membrane of the tongue
What sensations do the sensory fibers of the lingual nerve convey?
tactile, noxious, and thermal sensations
What does the lingual nerve of the mandibular receive?
the chorda tympani nerve
What type of fibers does the chorda tympani nerve contain?
SVA, GVE (preganglionic parasympathetic axons)
What do the SVA fibers of the chorda tympani nerve do?
convey taste impulses from the fungiform papillae
What do the GVE fibers of the chorda tympani nerve do?
they go to the salivary gland
What does the lingual nerve do after it receives the chorda tympani nerve?
it crosses the pterygoid muscles and gives off branches to the buccal mucosa and then passes between the styloglossus and mylohyoideus muscles
What does the lingual nerve of the mandibular do when it passes between the styloglossus and mylohyoideus muscles?
gives off GVE fibers to the mandibular ganglion
What does the lingual nerve of the mandibular do at the base of the tongue?
it gives off the sublingual nerve
What does the sublingual nerve innervate?
the sublingual mucosa and gives off GVE fibers to the sublingual salivary glands
What does damage to the motor fibers of the masticatory muscles cause?
atrophy of the affected muscles, prominent temporal fossa and zygomatic arch; if bilateral injury it will cause a dropped lower jaw
What does damage to the mandibular nerve cause? (secondary)
sunken eyeballs
What does damage to the sensory components of the mandibular nerve cause?
skin over and below the zygomatic arch, the mandible and mucosa lose sensory components and no tooth ache
