Cranial Nerve Review Flashcards
What are the parasympathetic targets in the head?
- Constrictor Pupillae m.
- Ciliary Smooth m.
- Salivary Glands (submandibular, parotid, sublingual, minor salivary)
- Lacrimal Glands
- Mucous glands (nasal cavity and hard palate)
What 3 cranial nn. carry parasympathetic fibers destined for the head?
3, 7, 10 (Vagus does parasympathetic below the head)
What are the 4 terminal motor ganglia of the head?
- Nerves associated?
C3 - Ciliary
O9 - Otic
P7 - Pterygopalatine
S7 - Submandibular
How do parasympathetic postganglionics in the head generally reach their targets?
- Hitchhike on one of the 3 divisions of trigeminal n.
note: In V3, lingual has both pre and post ganglionic fibers riding along
CN III:
Preganglionic - Cell Bodies, Fibers?
Postgaglionic - Cell Bodies, Fibers?
Preganglionic:
- Cell bodies = Midbrain
- Fibers = CN III (lower?)
Postganglionic:
- Cell bodies = Ciliary Ganglia
- Fibers = Ciliary Nn. (short?)
What are the targets of CN III?
Eyeball:
- Ciliary mm.
- Contrictor pupillae
CN VII:
Preganglionic - Cell Bodies, Fibers?
Postgaglionic - Cell Bodies, Fibers?
Preganglionic:
- Cell bodies (1) = Pons
- Fibers (1) = Greater Petrosal n.
- Cell bodies (2) = Pons
- Fibers (2) = Chorda Tympani n., Lingual n. (V3)
Postganglionic:
- Cell bodies (1) = Pterygopalatine ganglion
- Fibers (1) = Travel with V2 branches
- Cell bodies (2) = Submandibular ganglion
- Fibers (2) = Lingual n. (V3)
CN VII main targets?
Greater Petrosal = Lacrimal Gland
Chorda Tympani = Submandibular and Salivary Glands
CN IX:
Preganglionic - Cell Bodies, Fibers?
Postgaglionic - Cell Bodies, Fibers?
Preganglionic:
- Cell bodies = Medulla
- Fibers = Tympanic n. –> Lesser petrosal n.
Postganglionic:
- Cell bodies = Otic Ganglion
- Fibers = Auriculotemporal n. (V3)
CN IX main parasympathetic target?
Parotid Gland
What fiber types are carried by the chorda tympani n.?
- GVE: PREganglionic PARAsympathetic
- SA: Taste fibers
Where do Chorda Tympani Taste fibers go?
- Anterior 2/3 of the tongue
In what space does Chorda Tympani join the lingual n.?
- Infratemporal Fossa
Describe the path of Chorda Tympani GVE fibers
GVE:
- Bypass Geniculate in Facial Canal (btwn IAM and EAM)
- Pass out into middle ear:
Medial side of Tympanic membrane over malleous
- Exits via Petrotympanic Fissure
Where are the POSTganglionic sympathetics found that complement the parasympathetic functions of Chorda Tympani (CN VII)?
Hitchhike via Facial a., Lingual a.
Path of tympanic n.?
- Continuous with?
- Through Jugular Foramen
- Back up through Tympanic Canaliculis (btwn JF and CC)
- Leaves middle ear to become the lesser petrosal n.
Path of Lesser Petrosal n.?
- Terminates where?
- out of HLPN
- along GLPN
- THROUGH Forament Ovale
- Terminates in Otic Ganglion
What is the major functional different between the tympanic n. and the lesser petrosal n.?
Tympanic = GSA AND GVE
Lesser Petrosal = GVE ONLY
What preganglionic fiber innervates the lacrimal gland?
- Greater Petrosal n. (CN VII)
T or F: all branches of CN VII must enter through IAM
True
Describe the path of the greater petrosal n.
- Exits Facial Cavity via HGPN
- Travels in GGPN
- Join Deep PN
- Enters Pterygoid Canal
- Terminates in PP ganglion
What fibers do Postganglionics of the greater petrosal n. (CN VII) travel on to get to their targets?
- Be specific
- Zygomatic (V2, GSA)
- Lacrimal (V1, GSA)
T or F: the greater petrosal n. only carries preganglionic GVE fibers.
FALSE, carries SA taste fibers to the soft palate too
What is the major functional difference between the greater petrosal n. and the nerve of the pterygoid canal?
- Greater Petrosal = GVE (parasymp, Pregang.) and SA (taste)
- N. of Pterygoid Canal = GVE (SYMPATHETIC POSTgang.; parasymp, Pregang.) and SA (taste)
Most Postganglionic Sympathetic fibers reach targets in the head via branches of the carotid, what are 2 exceptions to this rule?
- Sympathetics in Deep PN and N. of Pterygoid Canal
2. Short and Long ciliary nn.
Where do Preganglionic Fibers traveling to the Ciliary Ganglia exit the skull?
- Superior Orbital Fissure
What branch from CN III conducts ONLY parasympathetic fibers to the ciliary ganglia?
- Parasympathetic Motor Root of CN III
What POSTganglionic Fibers carry info to the Globe?
- Are Parasympathetic fibers the only fibers?
Short Ciliary n.
Fiber Types:
- POSTganglionic sympathetic and parasympathetic
- GSA fibers
What are the SYMPATHETIC targets in the head?
Sweat Glands Vascular Smooth mm. 2 Smooth mm. of the eye: 1. Superior Tarsal m. 2. Dilator Pupillae m.
Where are the PRE and POST ganglionic cell bodies for the parasympathetics in the head?
PREganglionic Cell bodies:
- Lateral Horn of Spinal Cord Gray Matter (T1 and T2)
POSTganglionic Cell bodies:
- Superior Cervical Ganglion
What cranial nn. are purely sensory?
1, 2, and 8
CN I:
- ganglion
- Exits Skull via??
- function
NO associated ganglion
Exits via:
- Cribiform Foramina
Function:
- SA (olfaction)
CN II:
- ganglion
- Exits Skull via??
- function
NO associated ganglion
Exits via:
- Optic Canal
Function:
- Sight
CN VIII:
- ganglion
- Exits Skull via??
- Function
Spiral and Vesibular Ganglia
Exits via:
- External Acoustic Meatus
Function:
- Audition/Equilbrium
What cranial n are purely motor?
3, 4, 6, 11, 12
CN IV:
- Exits skull via?
- Muscle Innervated?
Superior Orbital Fissue
Innervates Superior Oblique
CN IV lesion:
- symptoms?
- Test?
Weakness in:
- Depression
- Adduction??
- Intorsion
Test:
- Look Medially and Down
CN VI:
- Exits skull via?
- Muscle Innervated?
Superior Orbital Fissure
Muscle: Lateral Rectus
CN VI Lesion:
- Syptoms?
- test?
Weakness:
- Abduction
Test:
- Look laterally
You encounter a patient whose eye do not dilate in the absence of light. What nerve is responsible for this finding?
- Cell body location?
This is a loss of sympathetic tone
- Postganglionic cell bodies = Superior Cervical Ganglion
- Preganglionic cell bodies = T1 and T2 lateral Horn
NOTE: Sympathetics travel to dilator pupillae muscle via long and short ciliary nn.
You tell a patient to keep their eyes closed while you try to pull it open. What cranial nn. are you testing?
- Motor Branches of Facial n. (VII)
Note: Closing the eye/keeping the eye closed is a facial n. function
You test a patient for the gag reflex and it is absent, what two nerves could possibly be at fault?
- how to differentiate
No Gag Reflex:
- Glossopharyngeal (IX) = afferent
- Vagus (X) = Efferent
Differentiate with Uvula Deviation Test (say Ahh)
What are the contents of the cavernous sinus?
Lateral Wall:
CNs: III, IV, V1, V2
Middle of Cavernous:
CN VI
Opthalmic Artery
In what area would a tumor result in BOTH loss of Balance AND Facial expression?
Internal Acoustic Meatus
What structures are located medially and superiorly to the cavernous sinus?
- Optic Chiasm
- Pituitary
CN XI:
- How does it get to and exit the skull
- What is its function
- Fiber type
Fiber Type = GSE ONLY
Function - SCM and Trapezuis
Enters Skull via Foramen Magnum
Exits Skull via Jugular Foramen
How would a lesion in CN XI present?
- test
- Shoulder Drooping or Inability to Flex or Rotate the Neck ON AFFECTED SIDE
Test: Have the patient elevate shoulders against force
Where could you find CN XI in the body?
- Deep to upper ~1/3 of SCM
- Deep to Trapezius
Describe the path of CN XII relative to:
- Digastric m.
- Hyoglossus m.
Digastric:
- Deep to the digastric near its inferior tendon
Hyoglossus:
Enters submandibular triangle on the external surface of hyoglossus
What is innervated by CN XII?
- how to test for lesion?
ALL of intrinsic tongue mm.
3/4 Extrinsic tongue mm. (except palatoglossus - X)
Ask patient to stick tongue out in order to test
CN III
- Fiber types
- 2 branches
- Function
Fiber type: GSE, GVE
Superior and Inferior
Function:
Superior - Levator Palpebrae, Superior Rectus
Inferior - Lower Rectus, Medial Rectus, Inferior Oblique
CN III
- Symptoms
- tests
GVE symptoms:
- Dilated pupil
GSE:
- SEVERE Ptosis
- Diplopia (double vision)
- External Stabismus (eye moves down and laterally)
Test:
Most commonly = pupillary Light Reflex
V1 (ophthalmic)
- Associated foramen/fissure
- Main Branches (3)
- Function (GSA, GVE etc.)
- GSA, etc?
Superior Orbital Fissure
Branches:
- Nasociliary
- Frontal
- Lacrimal
Function (GSA):
- Skin on Forehead and Scalp
V2 (maxillary)
- Associated foramen/fissure
- Main Branches (8)
- Function
- GSA, etc?
Foramen Rotundum
Branches:
- Zygomatic
- Infraorbital
- Posterior Superior Alveolar
- Greater Palatine
- Lesser Palatine
- Nasopalatine
- Lateral Nasal Branches
- Pharyngeal
Function (GSA):
- Maxilla Skin
- Maxillary Teeth
V3
- Associated foramen/fissure
- Main Branches (8)
- Function
- GSA, etc?
Foramen Ovale
Branches:
- MAST-MATT = motor
- Auriculotemporal, Inferior Alveolar, Lingual, Buccal = sensory
Function (GSA, BE):
- MAST-MATT = BE
- GSA - mandible, mandibular teeth and gingiva, parotid capsule, floor of the mouth
V1 lesion
-symptoms
General Loss of Sensation on Forehead and Scalp
V2 lesion
-symptoms
Loss of Sensation to the maxilla and maxillary teeth
V3 lesion
- symptoms
GSA:
- Mandible, Parotid Capsule, Lower Teeth, Gingiva
BE:
- weakness in Chewing
- Jaw Deviation TO SIDE OF LESION
CN III
- symptoms
- test
symptoms:
- Dilated pupil
- Ptosis (levator palpebrae sup.)
- Diploia (double vision)
- External Stabismus (eye looks down and out)
Test:
- Light Reflex test is most common
What are the mixed cranial nn.?
V, VII, IX , X
CN VII
- Functions (4)
- What does each function do?
BE, GVE, GSA, SA
BE: Facial mm., Stapedius, Stylohyoid, Post. Digastric
GVE: Submandibular, Sublingual, Lacrimal
GSA: External Ear
SA: Taste anterior 2/3 Tongue, SOFT PALATE
Why is external Stabimus a symptom of CN III lesion?
- Superior Oblique (IV) and Lateral Rectus (VI) pull on the eye unopposed
What part of CN VII carries taste (SA) fibers to the soft palate?
Greater Petrosal (NOT chorda tymp.)
What type of cell bodies can be found in the geniculate ganglion?
GSA and SA cell bodies
What fibers exit the Stylomastiod Foramen?
GSA:
- To external Ear
BE:
- To all mm. of VII except Stapedius
NOTE: NO SA and NO GVE
CN VII lesion
- symptoms
- Facial Paralysis on affected side
- Taste loss on anterior 2/3 tongue
- Dry eye
- Dry Mouth
CN VII Tests
- Ask patient to smile or raise their eyebrows
CN IX:
- Function
- Where?
BE, GVE, GSA, GVA, SA
BE - Stylopharngeus GVE - Parotid GSA - Posterior Tongue, Palatine Tonsils, Oropharynx, Mucosa of middle ear, Auditory Tube GVA- Carotid Body and Sinus SA - Posterior 1/3 of tongue
Specifically what nerve innervates Stylopharyngeus?
N. to Stylopharyngeus
CN IX lesion
- Symptoms
Symptoms
- No gag reflex (IX or X)
- Dry Mouth (no parotid)
What would Dry mouth in addition to gag reflex confirm?
- A lesion in CN IX NOT CN X
CN X
- functions
BE, GVE, GSA, GVA, SA
BE and GVE component of CN X.
BE:
mm. of Arches 4-6
- mm. of larynx
- mm. of pharynx (except stylopharyngeus)
- mm. of Palate (except Tensor Veli Palatini)
GVE:
Smooth mm. and glands trachea and esophagus
GSA, GVA, SA component of CN X.
GSA:
- Posterior ear
- EAM
- Lower 1/3 of Pharyngeal mucosa
- Esophagus
- laryngeal mucosa
- root of the tongue
GVA:
- Carotid Body
SA:
- Base of the tongue and Epiglottis
Ganglia associated with CN X?
Superior and Inferior Ganglia of X
Fiber type and function of the following CN X branches:
- Auricular n.
- Meningeal n.
- Sinus n.
Auricular n. (GSA) - External Ear
Meningeal n. (GSA) - Dura in POSTERIOR cranial fossa
Sinus n. (GVA) - carotid body
What CNs are responsible for innervation of the dura?
- CN V3 (meningeal b.)
- CN X (meningeal b.)
Fiber Type and Function of the following CN X branches:
- Internal Branch of Superior Laryngeal
- Ext. Branch of Superior Laryngeal
IBSL (GSA/GVE):
- mucosa laryngopharynx to vocal folds - GSA
- Root of Epiglottis - GSA
- Glands of the pharynx - GVE
- Root of Tongue and Epiglottis = SA
EBSL (BE):
- Cricothyroid m.
Fiber Type and Function of the following CN X branches:
- Pharyngeal Branch
- Recurrent (inferior) Laryngeal n.
Pharygeal Branch (BE):
- Palatoglossus
- All mm. of Pharynx (except stylopharygeus)
- All soft palate mm. (except tensor Veli Palatini)
Recurrent Laryg (BE/GSA): - Mucosal Lining of Larynx Below Vocal Folds
CN X lesion
- symptoms
- Dysphagia
- Hoarsness
- No Gag Reflex
- No Cough Reflex
- Drooping Palate
CN X tests
- Say Ahh - Uvula deviates to side opposite of lesion
- Listen to Speech
- Evaluate Swallowing and Gag Reflex
