Cranial nerves Flashcards
GSA
5, 7, 9, 10
GSE
3, 4, 6, 11, 12
GVA
9,10
GVE
3, 7, 9, 10
SVE
5, 7, 9, 10
SVA
1, 7, 9, 10
SSA
2, 8
Where does CN 1 exit?
Foramina of cribriform plate
Where does CN 2 exit?
Optic canal
WHat exits thru the SOF?
CNs 3, 4, V1, 6
What exits the foramen rotundum?
CN V2
What exits the foramen ovale?
CN V3
What exits the Foramen SpinsouM?
Middle Meningeal a. And v.
Meningeal branch of CN V3
What exits the foramen cecum?
Emissary vein to superior sagittal sinus
What exits the carotid canal?
Internal carotid artery
Internal carotid nerve plexus
What exits the Internal acoustic meatus?
CN 7
CN 8
What exits the Jugular foramen?
CN 9, 10, 11
Inferior petrosal sinus, sigmoid sinus, posterior meningeal a.
Where does CN 12 exit?
Hypoglossal canal
What exits the foramen magnum?
Spinal roots of CN 11
Medulla Oblongata
meninges
Vertebral As.
Meningeal Branches of vertebra arteries
What innervates Tensory Tympani and Tenso Veli palatini?
Trigeminal N. - V3
What are the “rules” for sympathetic fibers in the head?
Post ganglionic (have already synapsed)
From superior cervical ganglion of the sympathetic trunk
Travel on vessels to structures they innervate
What are the “rules” for parasympathetics in the head?
Preganglionic fibers
From nuclei in brain stem
Synapse at 4 ganglia in head
(Otic, ciliary, pterygopalatine, submandibular)
Carried by CN 3, 7, 9, 10
How do the postgalnglionic fibers of the parasympathetic system travel in the head?
Via branches of CN 5
What supplies Lateral Rectus?
CN 6
What supplies Superior oblique m. ?
CN 4
What supplies superior rectus, inferior rectus, medial rectus, inferior oblique, and levator palpabrae superioris?
CN 3
When the ciliary muscle is not innervated,how is the lens; zonular fibers?
What does this allow for?
W/out nerve stimulation, Ciliary m. = relaxed Lens = stretched Refracts light for distant vision Zonular fibers = tensed
How does OCulomotor N. Palsy present?
Down and out
How does trochlear n. Palsy present?
Paralysis of Superior oblique
Unable to move eye down and out
How does Abducent n. Palsy present?
Paralysis of lateral rectus m.
Unable to move eye laterally
What are the branches of V1 (ophthalmic division)?
Lacrimal
Frontal —> Supra- orbital/trochlear
Nasociliary —> Long/short ciliary; infratrochlear; ethmoidals
Meninges branch
What are the branches of V2 (maxillary div.)?
- Zygomatic
- Infraorbital —> ext nasal, superior labial
- Superior alveolar
- Palatine —> greater and lesser palatine
- Meningeal (ant. And middle cranial fossa)
What are the branches from V3 (mandibular div.)?
- Buccal
- Lingual
- Inferior alveolar
- Auriculotemporal
- Meningeal
Also supplies Ms. of Mastication
Wha are the muscles of mastication?
Medial pterygoid
Lateral pterygoid
Temporal
Masseteric
What supplies mylohyoid?
Where does this n. Come from?
N. To mylohyoid From V3 (mandibular div.)
Where does each branch of trigeminal have sensory?
V1: forehead to tip of nose
V2: side of nose and medial cheeks, under eyes, upper lip
V3: lateral cheeks, down to jaw line, lower lip
How are the lacrimal glands innervated?
CN 7 at superior salivatory nucleus
—> greater petrosal n. (At geniculate ganglion)
—> greater + deep petrosal n. (At foramen lacerum) = N. To Pterygoid canal
—> travels thru pterygoid canal, enters pterygopalatine fossa
—> pterygopalatine ganglion
—> travel via zygomatic branch (V2) and Lacrimal n. (V3)
—> innervate lacrimal gland
How are the submandibular and sublingual glands innervated?
CN 7 at superior salivatory nucleus —> Chorda tympani —> goes thru middle ear —> joins lingual n (V3) in infratemporal fossa —> submandibular ganglion —> glands
How are the Ciliary Ms. innervated?
CN 3 at Edinger Westphal nucleus
—> Ciliary ganglion
—> short ciliary n. (V1)
—> Ciliary Ms.
How is the parotid gland innervated?
CN 9 at Inferior salivatory nucleus —> Tympanic n. —> Lesser petrosal n. —> lesser petrosal leaves thru foramen ovale —> otic ganglion —> via auriculotemporal n. (V3) —> parotid gland
What is the main parasympathetic n. In the body?
Vagus n.
What nerves can be compressed due to cavernous sinus?
CNs 3, 4, V1, and 6
6 will be the most affected
What results from a fracture of cribriform plate?
Lesion of CN 1
Anosmia (loss of smell)
CSF rhinorrhea
What results from direct trauma to orbit or eyeball, or a FX involving optic canal?
CN 2 lesion
Loss of pupillary constriction
(Pupillary reflex is first sensed by CN 2, then motor is done by CN 3)
What results from pressure on optic pathway, laceration or intracerebral clot in temporal, parietal, or occipital lobes of brain?
CN 2 lesion
Visual field defects
(Section of R. Optic n. = right monocular blindness)
(Section of optic chiasm = bitemporal hemianopsia)
(Section of R. Optic Tract= left homonymous hemianopsia)
What results from pressure from herniating uncus on CN 3; fracture involving cavernous sinus; or aneurysms?
CN 3 lesion
Dilated pupil; ptosis; eye turns down and out; pupillary reflex on side of lesion lost
What results from stretching of CN 4 during its course around brain stem or a fracture of the orbit?
CN 4 lesion
Inability to load down when eye is adducted
(SO-4; h test will have you Adduct and look down to isolate muscle)
What results from an injury to terminal branches in roof of maxillary sinus; or a pathological process affecting trigeminal ganglion?
CN V lesion
Loss of pain and touch sensation
Paresthesia
Masseter and Temporalis Ms. do not contract
Deviation of mandible to side of lesion when mouth is opened
What results from a lesion to the base of brain or fracture involving cavernous sinus or orbit?
CN 6 lesion
Eye fails to move laterally; diplopia on lateral gaze
What results from a laceration or contusion in parotid region?
(Region is important for this CN**)
CN 7 lesion
Paralysis of facial muscles; eye remains open; angle of mouth droops; forehead does not wrinkle
What results from a fracture of temporal bone?
CN 7 lesion
Paralysis of facial Ms
Eye remains open (orbicularis oculi not innerv.)
Angle of mouth droops
Forehead does not wrinkle
Plus involvement of cochlear n. And Chorda tympani (loss of taste on ant. 2/3s of tongue)
Dry cornea
What results form an intracranial hematoma (“Stroke”)?
Forehead wrinkles bc of bilateral innervation of frontalis m.
Paralysis of contralateral facial muscles
(One side of face paralyzed and droops)
What happens due to a Acoustic Neuroma? (Tumor of nerve)
CN 8 lesion
Progressive unilateral hearing loss
Tinnitus
What results from a brain stem lesion or deep laceration of neck?
CN X lesion
Sagging of soft palate (levator veli palatini)
Deviation of uvula to normal side
Hoarseness owing to paralysis of vocal fold
What results from a laceration of the neck?
CN 11 lesion
paralysis of SCM and Traps
Drooping of shoulder
Winging of scapula
What results from neck laceration or fractures of cranial base involving CN 12?
CN 12 lesion
Protruded tongue deviates toward affected side
Moderate dysarthria (disturbance of articulation)
Why is CN 2 susceptible to effects of demyelinating diseases of CNS?
What would be an example?
Made from retinal ganglion cells from brain so it is myelinated by CNS (i.e. oligodendrocytes)
Multiple Sclerosis
What is Optic Neuritis?
Keim specifically mentioned this
Lesion of CN 2
Causes diminution of visual acuity
Caused by inflammatory, generative, demyelinating, or toxic substances (methyl, ethyl alcohol, tobacco, lead, and mercury)
What could cause compression of the optic pathway?
Pituitary gland tumor
Berry aneurysms of ICA
What is the first sign of CN 3 compressioN?
ipsilateral slowness of pupillary response to light
Pupil is dilated on injured side
How does one compensate for diplopia?
Incline head anteriorly and laterally toward side of normal eye
What will an injury to the trigeminal n. Manifest as?
Paralysis of Ms. of Mastication w/ deviation of mandible toward side of lesion
Loss of ability to sense in face
Loss of corneal reflex and sneezing reflex
what can cause injury to trigeminal n.?
Herpes zoster
Also dental trauma, cranial trauma, head and neck tumor, intracranial tumors, idiopathic trigeminal neuropathy
What is trigeminal neuralgia? (Tic douloureux)
Affects sensory root of CN 5
Produces excruciating episodic pain
How nerves do you anesthesize for dental needs?
CN 5 and inferior alveolar n.
Lesion near origin of CN 7, effects?
Near geniculate ganglion
Loss of motor, taste and autonomic function (no tears, no saliva, no nasal mucous)
Central lesion of CN 7, effects?
Lesion of CNS
Paralysis of Ms. in inferior face on opposite side
(Can still wrinkle forehead bc that is bilateral!!)
lesions to Superifical branches of CN 7, effect?
Stapedius m. Not innervated
Ear more sensitive to low tones
What is Bell’s palsy?
Unilateral facial paralysis of sudden onset
Which part of ear does conductive deafness involve and what does it cause?
Hearing loss
Ext. or middle ear
Which part of ear does sensorineural deafness involve and what does it cause?
Damage to hair cells in the inner ear
Disease in cochlea or in pathway from cochlea to brain
What CN would vertigo involve?
CN 8
What is the most common trauma to the CN 9 (glossopharyngeal n. )?
How does it present?
Iatrogenic (physican caused)
Absent gag reflex
What is jugular foramen syndrome?
Lesion to CN 9.10.11
Diaphragma
Dysarthria
What could injury to recurrent laryngeal n. Cause?
Dysphonia (hoarseness or weakness of voice- due to paralysis of vocal folds)
Paralysis of both recurrent laryngeal n. Causes?
Aphonia - loss of voice
Inspiratory strider - harsh, high ptiched respiratory sound
Injury to CN 12 commonly seen with what?
Tongue that protrudes and deviates toward paralyzed side
What is Strabismus?
Eye not in parallel/deviated improperly
Due to lesion of CN 3 or 4
How does a lesion in the vestibular branch of CN 8 present?
Loss of balance, nausea, vomiting, and dizziness
How does a lesion in the cochlear branch present?
Deafness
What structures does CN 1 supply?
Nasal cavity
What structures does CN 2 supply?
Photoreceptors from rods and cones and ganglion cells
Where does CN 2 originate from?
Retina
What structures does CN 3 supply?
Levator palpabrae superioris Superior rectus Inferior rectus Inferior oblqiue Medial rectus
Constrictor Pupillae (parasym) Ciliary ms.
What structures does CN 4 supply?
Superior oblique m.
Where does CN 1 originate?
Bipolar neurons in olfactory mucosa of nasal cavity
What structures does CN 5 supply?
Sensory to face
Mylohyoid Ant. Belly of Digastric m. Ms. Of mastication Tensory tympani m. Tensor veli palatini m. (V3)
What structures does CN 6 supply?
Lateral rectus m.
What structures does CN 7 supply?
5 motor branches
Ms. Of facial expression
Stapedius
Post. Belly of digastric m.
Stylohyoid
Lacrimal glands
Taste to ant. 2/3 of tongue
Tympanic membrane of ear
What structures does CN 8 supply?
Vestibular branch: vestibule, macula, semicircular canals
Cochlear branch: supplies cochlea
What structures does CN 9 supply?
Stylopharyngeus
Pharynx
Soft palate
Tonsils
Tongue
Ear
Parotid salivary gland
Carotid branch
What structures does CN 10 supply?
Pharynx Larynx Epiglottis Ext. ear and tympanic membr. Soft palate
Heart, thoracic viscera, abdominal viscera, aortic arch and aortic bodies
Glands of heart, lungs, pharynx, larynx, trachea, and abd. Organs
What structures does CN 11 supply?
Scm
Trap
What structures does CN 12 supply?
Extrinsic tongue ms.
Intrinsic tongue ms.
What are the extrinsic tongue ms.?
Hyoglossus
Genioglossus
Styloglossus
All innerv. By CN 12
what is the only CN to exit the dorsal surface of the midbrain?
CN 4- trochlear n.
What CNs originate in the Midbrain?
CN 4
What CNs originate from midbrain pontine junction?
CN 3
What CNs originate from the Pons?
CN 5
What CNs originate from the Ontine-medulla junction?
CN 6, 7, 8
What CNs originate from Medulla Oblongata?
CN 9, 10, 11, 12
What function can CN 9 do bc of its innervation to Carotid branch?
BP, Po2, Pco2, pH via chemoreceptors fibers to carotid body
What do intrinsic ms. Of the tongue do?
Extrinsic Ms?
Extrinsic: move tongue
Intrinsic: change shape of tongue
