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129 Cards in this Set

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List 3 functions of cranial nerves:
1. To provide motor/sense innervation to head/neck
2. To innervate special sense organs
3. To carry ANS fibers
What are the 3 sensory modalities of cranial nerves?
1. Special sense
2. Somatic sense
3. Visceral sense
What information is obtained by special sensory nerves?
-Smell (CN I)
-Vision (CN II)
-Taste (CNs VII, IX, X)
-Hearing/Balance (CN VIII)
What info is obtained by somatic sensory nerves?
Proprioception, pain, temp, vibration, touch, from the skin and body wall.
What info is obtained by visceral sensation?
Info re: glands and organs in thoracic/abdominal/pelvic cavities
What is visceral motor innervation responsible for?
Innervation of cardiac muscle, smooth muscle, and glands.
What is branchial motor innervation responsible for?
Innervation of muscles derived from branchial arches
What 4 types of muscles are branchially derived?
-Mastication
-Face expression
-Pharynx
-Larynx
What is somatic motor innervation responsible for?
Innervation of skeletal muscles from myotomes
What muscles in the head are considered somatic?
Extraocular
Tongue
What nerves are purely special sensory?
I - olfactory
II - optic
VIII - acoustic
CAPOLO in reverse
What nerves are purely somatic motor?
IV - Trochlear
VI - Abducens
XII - Hypoglossal
HAT
What cranial nerves are special sensory?
One, Two, and 7-10
What cranial nerves are somatic sensory?
5, 7, 9, 10
the store and one more
What cranial nerves are visceral sensory?
9 and 10
What cranial nerves are visceral motor?
3, 7, 9, 10
What cranial nerves are branchial motor?
5, 7, 9, 10, 11
the store and two more
What cranial nerves are somatic motor?
3, 4, 6, 12
Purely sensory cranial nerves:
1, 2, 8
CN 1 - Olfactory:
-Function
-Neuron cell body locations
-Skull passage
-Injury
-Possible cause of injury
Function = smell
NCB = olfactory epithelium
Skull hole = cribiform plate
Injury = anosmia
Cause = fracture of crib plate
CN II - optic
-Function
-Neuron cell body locations
-Skull passage
-Injury
-Possible cause of injury
-Function = vision
NCB = back of retina
-Skull passage = optic canal
-Injury = anopsias
-Cause = eyeball trauma
CN VIII - Vestibulocochlear
-Function
-Neuron cell body locations
-Skull passage
-Injury
-Possible cause of injury
Function = hearing and balance
NCB = Cochlea (spiral ganglion) and Semicircular canals (vestibular ganglion)
Skull hole = internal acoustic meatus
Injury: hearing impaired or loss, tinnitus, vertigo
Cause: tumor
Purely MOTOR nerves:
3, 4, 6, 11, 12
CN III - Oculomotor
-Function
-Neuron cell body locations
-Skull passage
Function = eye movement
NCB: upper midbrain oculomotor nucleus
Hole: superior orbital fissure
What is the route of the oculomotor nerve (4 points)
1. Emerges near median plane at midbrain/pons junction
2. Passes between posterior cerebral & superior cerebellar arteries
3. Passes through cavernous sinus & Superior orbital fissure
4. Passes within common tendinous ring of rectus muscles
What 5 muscles does CN III innervate?
1. Levator palpebrae
2. Superior rectus
3. Inferior rectus
4. Medial rectus
5. Inferior oblique
What are 3 types of CN 3 injuries?
1. Ptosis
2. Lateral stabismus
3. Diplopia
what is ptosis?
When the eyelid droops due to paralysis of levator palpebrae
What is lateral strabismus?
When the eye turns down and laterally due to unopposed action of superior oblique and lateral rectus
What is diplopia?
double vision due to lateral strabismus
What are 2 possible causes of oculomotor nerve injuries?
1. Cavernous sinus injury
2. Aneurysms of posterior cerebral or superior cerebellar arteries.
CN IV - Trochlear
-Function
-Neuron cell body locations
-Skull passage
-Structure innervated
Function: eye movement
NCB: lower midbrain trochlear nucleus
Skull hole: superior orbital fissure
Innervates Superior oblique m
Descrie the route of the trochlear (CN IV) nerve (3 points):
1. Emerges from dorsal midbrain
2. Passes thru cavernous sinus and superior orbital fissure
3. Passes outside common tendinous ring from which rectus muscles originate
What is special about the trochlear nerve route?
It is the only cranial nerve to emerge from the dorsal aspect of the brain.
How is the eye impaired when CN IV is injured?
Unable to look down when eye is adducted -> results in diplopia
What is a possible cause of CN IV injury?
Cavernous sinus injury
CN VI - Abducent
-Function
-Neuron cell body locations
-Skull passage
-Innervated structure
Function = eye movement
NCB = pons abducent bodies
Skull hole = sup. orbital fiss.
Innervates lateral rectus m.
Describe the route of CN VI (3 points):
1. Emerges near median plane at junction of pons/medulla
2. Passes thru cavernous sinus and superior orbital fissure
3. Passes within common tendinous ring from which rectus muscles originate
2 types of abducent nerve injuries:
Medial strabismus
Diplopia
What is medial strabismus?
Eye turns medially due to unopposed action of medial rectus m.
What is diplopia again?
double vision due to medial strabismus
What are 2 possible causes of abducent nerve injuries?
1. Cavernous sinus injury
2. Fracture of skull base
CN XI - Spinal accessory
-Function
-Neuron cell body locations
-Skull passage
-Injury
-Possible cause of injury
Function: head/neck movement
NCB: spinal cord - anterior horn of cervical region
How on earth does the spinal accessory nerve enter the skull?
Through foramen magnum; then it exits through the jugular foramen; how weird...
hello
hello
what does cN XI innervate?
-Trapezius
-Sternocleidomastoid
what are 2 types of injuries to the spinal accessory nerve?
1. Weak turning head to opposite side
2. Weak shugging shoulders
What could cause injury to CN XI?
Well a neck laceration; like what if you got into a knife fight, that could do it.. what else?
So CN XI emerges from the spinal cord; what might be confused with its roots?
CN X (vagus) also arises from cranial roots, but these are medulla roots; only CN XI arises from spinal cord roots, and it doesn't arise from the medulla at all.
CN XII - Hypoglossal:
-Function
-Neuron cell body locations
-Skull passage
-Injury
-Possible cause of injury
Function = swallow/suck/chew/
stick tongue out.
NCB: medulla - hypoglossal nucleus
Skull hole: hypoglossal canal
Innervates: all tongue muscles iexcept one extrinsic
Injury: unilateral lesion
Cause: neck laceration
What is the route of the hypoglossal nerve? (2 points)
1. Emerge from side of medulla (anterior to olives..)
2. pass through hypoglossal canal; curve forward near mandibular angle to "ansa cervicalis" to enter tongue.
What extrinsic tongue muscle does the hypoglossal n NOT innervate? What does innerv. it?
Palatoglossus - CN X
What results from a unilateral lesion of the hypoglossal nerve?
Protruded tongue deviates to one side.
3 divisions of CN V:
-Ophthalmic
-Maxillary
-Mandibular
What kind fo nerve is each division of CN V?
Opthalmic = purely sensory
Maxillary = purely sensory
Mandibular = mixed motor/sensory
Opthalmic CN V1:
-Function
-NCB location
-Skull hole
-Injury
-Cause of injury
Function: senssory from skin of forehead, scalp, nasal mucous membranes.
NCB: trigeminal ganglion
Skull hole: Sup orb fissure
Injury: Anesthesia
Cause: inflammation
Maxillary - CN V2
-Function
-NCB location
-Skull hole
-Injury
-Cause of injury
Function: Sensory from skin of upper lip, cheek prominence, palate, maxillary sinus.
NCB: Trigeminal ganglion
Skull hole: Forament rotundum
Injury: Anesthesia and Trigeminal neuralgia
Cause: inflammation
What is trigeminal neuralgia, and another name for it?
Intermittent excruciating pain; aka Tic douloureux
Mandibular - CN V3; SENSORY
-Function
-NCB location
-Skull hole
-Injury
-Cause of injury
Function: sensory from skin of lower jaw, ant 2/3 tongue
NCB: trigeminal ganglion
Skull hole: foramen ovale
Injury: Anesthesia/Trigeminal neuralgia
Cause: inflammation
Mandibular - CN V3; MOTOR
-Function
-NCB location
-Skull hole
-Injury
-Cause of injury
Function: branchial motor - swallowing and chewing
NCB: pons - motor nucleus of V
Skull hole: Foramen ovale
Injury: difficulty chewing
Cause: inflammation
8 muscles innervated by CN V3 - MOTOR:
-Temporalis
-Medial/Lateral Pterygoids
-Masseter
-Tensor veli palatini
-Tensor tympani
-Mylohyoid
-Digastric (anterior belly)
What cranial nerves have both sensory and motor functions?
V, VII, IX, X
5, 7, 9, 10 (store + 1 more)
The facial nerve has 3 modalities of functions; what are they?
-Somatic sensory
-Special sensory
-Branchial motor
-What is the specific somatic sensory function of CN VII?
-What is its specific special sensory function?
-What is its motor function?
Somatic sense: skin behind ear, external acoustic meatus, tympanic membrane.
Special sense: taste from anterior 2/3 tongue & palate.
Motor: facial expression
What is the location of CN VII's
-Sensory NCBs?
-Motor NCBs?
Sensory = geniculate ganglion
Motor = pons
Through what specific BONE does CN VII enter/exit the skull, and at what parts?
TEMPORAL BONE:
Entrance: internal acoustic meatus
Exit: stylomastoid foramen
What will injury to CN VII's somatic sensory component result in?
Anesthesia
What will injury to CN VII's SPECIAL sensory component result in?
Loss of taste sensation in the tongue's anterior 2/3rds.
What could cause injury to the special sense component of CN VII?
Injury to the chorda tympani n.
What are the 5 terminal branches of the facial motor nerve?
-Temporal
-Zygomatic
-Buccal
-Mandibular
-Cervical
What 4 structures are innervated by CN VII?
-Facial expression muscles
-Stapedius
-Stylohyoid
-Digastric (posterior belly)
What innervates the digastric
-Anterior belly?
-Posterior belly?
Ant = V3 - mandibular n.

Post = CN VII
What are the muscles of facial expression?
-Orbicularis oculi/oris
-Platysma
-Buccinator
-Frontalis
-Occipitalis
What does an injury to the CN VII result in, and what could cause it?
Bell's palsy - caused by injury in region of parotid gland.
What are 4 symptoms of bell's palsy?
1. Facial muscle paralysis
2. Inability to close eyes (paralyzed orbicularis oculi)
3. Angle of mouth droops
4. Inability to wrinkle forehead
What type of lesion of CN VII will cause inability to wrinkle forehead, and why?
Only PERIPHERAL - b/c frontalis is bilaterally innervated.
Glossopharyngeal CN IX has four functional modalities; what are they?
1. Somatic sensory
2. Visceral sensory
3. Special sensory
4. Branchial motor
CN IX - somatic sensory from 7 places:
PSTPAMM
-Posterior 1/3rd tongue
-Tonsils
-Soft palate
-Pharynx
-Auditory tube
-Middle ear
-Mastoid air cells
Where are CN IX's NCBs
-for sensory components?
-for motor components?
Sensory: Superior ganglion of IX
Motor: nucleus ambiguus in medulla
What path does the glossopharyngeal n. take to get out of the brain?
Runs along the temporal bone and occipital bone to exit via the jugular foramen.
What will injury to CN IX do to its somatic sensory abilities?
Cause dysphagia (difficulty swallowing) and/or dysarthria (speech difficulty)
What is a possible cause of injury to the glossopharyngeal nerve?
Neck laceration
What is the 2 functions of CN IX's visceral sensory ability?
1. Detectn of O2 tension in the carotid BODY via chemoreceptors
2. Detectn of blood pressure in carotid SINUS via baroreceptors
How will injury to visceral sensation of glossopharygneal n. manifest?
As changes in blood pressure
What is the special sensory function of CN IX?
Taste from the posterior 1/3rd of tongue.
What is the branchial motor function of CN IX?
Phonation - elevation of the pharynx.
What muscle does CN IX specifically innervate?
Stylopharyngeus
What will injury to the motor function of CN IX result in?
Dysphagia (difficulty swallowing) and/or dysarthria
CN X - the Vagus nerve - has 4 functional modalities; they are?
1. Somatic sensory
2. Visceral sensory
3. Special sensory
4. Branchial motor
From where does CN X receive somatic sensation? (6 places)
PLEETME: Pharynx, larynx, external ear, external auditory canal, tympanic membrane, and meningies in posterior cranial fossa.
Where are the somatic sensory NCB's of CN X located?
In the superior ganglion of CN X
Where are the special sensory NCB's of CN X located?
Inferior ganglion of CN X
Where are the visceral sensory NCB's of CN X located?
Inferior ganglion of CN X
Through what bones/hole does the vagus nerve pass thru/exit the skull?
-Temporal/occipital bones
-Jugular foramen
What special sensory function does CN X have?
Taste from the epiglottis
What are the 3 visceral sensory functions of CN X?
1. Sensation in muscles/mucous membranes in pharynx/larynx and thoracid/abdominal viscera
2. Chemoreceptors in AORTIC BODY adjacent to aortic arch
3. Stretch receptors in aortic arch walls
What is the branchial motor functino of CN X?
Speech
Where are the motor NCBs of CN X located?
In the nucleus ambiguus of the medulla
What branchial muscles are innervated by CN X? (6)
-Soft palate skeletal muscles - EXCEPT 2!!
-Pharyngeal constrictor mm
-Levator palati
-Salpingopharyngeus
-Palatopharyngeus
-Palatoglossus
What are the 2 EXCEPTIONS to soft palate muscles innervated by CN X? What are they innervated by?
Stylopharyngeus - CN IX
Tensor veli palatini - CN V3
What are 3 results of injury to the branchial component of the vagus nerve?
1. Sagging soft palate
2. Difficulty coughing, swallowing, clearing throat, etc
3. Dysphagia
What does the autonomic nervous system innervate?
-Smooth muscle
-Cardiac muscle
-Glands
What are the divisions of ANS?
-Sympathetic
-Parasympathetic
What is the format of the ANS?
1. Preganglionic NCBs in a brain nucleus OR sp. cd. gray matter.
2. Preganglionic fibers travel WITH CRANIAL NERVES.
3. Preganglionic fibers SYNPSE on postganglnic fiber's cell body in a peripheral ganglion.
4. Postganglnc fibers travel with CRANIAL NERVES
5. Postgnglnc fibers innervate target organs, they respond.
What cranial nerves have autonomic function?
3, 7, 9, 10
CN III - oculomotor
CN VII - facial
CN IX - Glossopharyngeal
CN X - Vagus
CN III:
-Preganglionic NCB location
-Route
-Postganglionic NCB location
-Route
-Target
Pre NCB: Edinger westphal nuceus in upper midbrain
Pre Route: with CN III
Post NCB: Ciliary ganglion (V1)
Post route: w/ short ciliary n
Target: Sphincter pupillae and Cilary muscles
Loss of CN III autonomic function results in:
1. Myodiasis - unopposed dilation of pupils
2. Inability to read up close
CN VII has what 2 autonomic functions?
-Lacrimal innervation
-Salivatory innervation
CN VII - lacrimal:
-Preganglionic NCB location
-Route
-Postganglionic NCB location
-Route
-Target
Pre NCB: superior salivatory nucleus in pons
Route: thru nervous intermedius and geniculate ganglion (both CN VII); via Greater petrosal n. to Nerve of Pterygoid canal
Post NCB: Pterygopalatine ganglion (attchd to V2)
Post route: Via zygomaticotemporal n (v2) and lacrimal nerve (v1)
Target: Lacrimal gland and mucosa of nasal cavity, nasopharynx, and palate.
What will injury to CN VII lacrimal function result in?
Dry corneas
CN VII - salivary
-Preganglionic NCB location
-Route
-Postganglionic NCB location
-Route
-Target
Pre NCB: superior salivatory nucleus
-Pre Route: thru nervous intermedius and geniculate ganglion (both VII); via Chorda tympani to join Lingual n. (v3)
-Post NCB: Submandibular ganglion (attached to v3)
-Post route: already there
-Target: submandibular and sublingual glands
Injury to salivary function of CN VII results in:
failure to salivate at those glands.
CN IX
-Preganglionic NCB location
-Route
-Postganglionic NCB location
-Route
-Target
Pre NCB: inferior salivatory nucleus
Route: exit brain w/ CN IX fibers, pass thru tympanic n and lesser petrosal n.
Post NCB: otic ganglion (attchd to V3)
Post route: runs w/ auriculotemporal n (of V3)
Target: parotid gland
Injury to salivary function of CN IX results in:
failure to salivate at parotid gland.
CN X
-Preganglionic NCB location
-Route
-Postganglionic NCB location
-Route
-Target
Pre NCB: Dorsal motor nucleus of CN X in medulla
Route: run with CN X
Post NCB: autonomic ganglia near or w/in target organ walls
Target smooth muscle and glands of GI tract, pulmonary, and cardiovascular systems
Purely sensory nerves: (3)
1, 2, 8
Olfactory
Optic
Vestibulocochlear
Sensory + motor nerves: (4)
5, 7, 9, 10
Trigeminal
Facial
Glossopharyngeal
Vagus
Purely motor nerves: (5)
3, 4, 6, 11, 12
Oculomotor
Trochlear
Abducent
Spinal accessory
Hypoglossal
Nerves associated w/ Special Senses: (6)
1, 2, 7, 8, 9, 10
I = olfactory = smell
II = optic = vision
VII = facial = taste (ant 2/3)
VIII = vestibulocochlear = balance and hearing
IX = glossopharyngeal = taste (post 1/3)
X = vagus = taste (epiglottis)
Cranial nerves passing thru cavernous sinus:
3, 4, 5 (1/2), 6
Cranial nerves innervating extraocular muscles:
3, 4, 6
Cranial nerves carrying preganglionic parasympathetic fibers:
3 (sphincter pupillae and ciliary muscles)
7 (lacrimal, submandibular and sublingual glands)
9 (parotid)
10 (smooth muscle of thorax and abdominal viscera)
Cranial nerves to which parasympathetic ganglia are attached:
V1 = ophthalmic - ciliary ganglion
V2 = maxillary - pterygopalatine ganglion
V3 = mandibular - otic and submandibular ganglia
Which cranial nerves pass thru the ethmoid bone?
only one; olfactory CN I
Which cranial nerves pass thru the sphenoid bone?
2,3,4,5,6
Which nerves pass thru what holes in the sphenoid bone?
2 = optic canal
3, 4, V1, 6 = sup orb fissure
V2 = foramen rotundum
V3 = foramen ovale
Which cranial nerves pass thru the Temporal bone?
7, 8, 9, 10, 11
Which nerves pass thru what holes in the temporal bone?
7 & 8 = internal acoustic meatus
9-11 = jugular foramen
11 = also thru foramen magnum
Which cranial nerves pass thru the occipital bone?
only one; hypoglossal CN XII passes thru hypoglossal canal.