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Flashcards in Cranial Nerve Overview Deck (21)
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1
Q

Name the Cranial Nerves (12 pairs)

A
CN I 	Olfactory 					
CN II 	Optic 					
CN III 	Oculomotor			
CN IV 	Trochlear 				
CN V 	Trigeminal 				
CN VI 	Abducent 			
CN VII 	Facial 			
CN VIII 	Vestibulocochlear		
CN IX 	Glossopharyngeal 	
CN X 	Vagus 			
CN XI 	Accessory 		
CN XII 	Hypoglossal
2
Q

Describe the pathway of the Olfactory (CN I)

A
  • Fiber type: Special sensory
  • Cranial exit: Cribriform foramina
  • Pathway: Olfactory bulb Cribriform foramina Olfactory nerves in nasal cavity
  • Target: Olfactory nerves in nasal mucosa (smell)
3
Q

Describe the pathway of the Optic (CN II)

A
  • Fiber type: Special sensory
  • Cranial exit: Optic canal
  • Pathway: Optic chiasm Optic nerve Optic canal
  • Target: retina (sight)
4
Q

Describe the pathway of the Oculomotor (CN III)

A
  • Fiber type: Somatic motor and parasympathetic
  • Cranial exit: Superior orbital fissure

-Pathway:
•Cavernous sinus Superior orbital fissure Muscles located in orbit
•Parasympathetic pathway: Cavernous sinus Superior orbital fissure Ciliary ganglion (synapse)

-Targets:
•Somatic motor targets: levator palpebrae superioris m., extraocular muscles: superior, medial, and inferior rectus, inferior oblique
•Parasympathetic targets: Ciliary muscle and sphincter pupillae muscle

5
Q

Describe the pathway of the Trochlear (CN IV)

A
  • Fiber type: Somatic motor
  • Cranial exit: Superior orbital fissure
  • Pathway: Cavernous sinus -> Superior orbital fissure -> Superior orbit
  • Target: superior oblique muscle
6
Q

Describe the pathway of the Trigeminal (CN V)

A
  • Somatic sensory and somatic motor

- There are three divisions of this nerve: Ophthalmic (CN V1), Maxillary (CN V2), Mandibular (CN V3)

7
Q

Describe the pathway of the Ophthalmic (CN V1)

A
  • Fiber type: Somatic sensory only
  • Cranial exit: Superior orbital fissure

-Pathway: Trigeminal ganglion -> Superior orbital fissure -> Through orbit
Major Targets: Skin of forehead, scalp, upper eyelid, cornea, mucosa of anterior nasal cavity and frontal/ethmoidal sinuses

8
Q

Describe the pathway of the Maxillary (CN V2)

A
  • Fiber type: Somatic sensory only
  • Cranial exit: Foramen rotundum
  • Pathway: Trigeminal ganglion -> Foramen rotundum -> Branches travel through pterygopalatine fossa to either inferior orbital fissure and orbit or inferior targets
  • Major Targets: Skin of face, lower eyelid, upper lip, maxillary teeth and gingivae, scalp, maxillary sinuses, mucosa of posterior nasal cavity and hard & soft palate
9
Q

Describe the pathway of the Mandibular (CN V3)

A
  • Fiber Type: somatic sensory and somatic motor
  • Cranial exit: Foramen ovale
  • Pathway: Trigeminal ganglion -> Foramen ovale -> Branches (lingual nerve, etc) and travels inferior, posterior or anterior to targets
  • Targets:
    1) Somatic sensory targets: portion of scalp near anterior auricle, external tympanic membrane, skin of face, cheek, lower lip, mandibular teeth and gingivae, TMJ, anterior 2/3rds tongue
    2) Somatic motor targets: muscles of mastication (temporalis, masseter, lateral & medial pterygoids), mylohyoid, anterior belly of digastric m, tensor veli palatini and tensor tympani mm.
10
Q

Describe the pathway of the Abducent (CN VI)

A

-Fiber type: Somatic motor only
-Cranial exit: superior orbital fissure
-Pathway: Cavernous sinus -> superior orbital fissure -> lateral orbit
Target: Lateral rectus muscle

11
Q

Describe the pathway of the Facial (CN VII)

A
  • Fiber types: Somatic motor, special sensory, parasympathetic, and sympathetic
  • Cranial exit: Stylomastoid foramen
  • General Pathway: Internal acoustic meatus facial canal gives off three branches (chorda tympani, branch to stapedius muscle, greater petrosal) exits facial canal via stylomastoid foramen travels inferiorly

-Targets: Somatic motor to stapedius, muscles of facial expression (buccinator, occipitofrontalis, orbicularis oris, orbicularis oculi, platysma), stylohoid m., posterior belly of digastric

12
Q

Describe the pathway of the Chorda tympani: Portion of the Facial (CN VII)

A
  • Middle ear -> Hitchhike on lingual nerve (CN V3) -> anterior & posterior to targets OR -> Submandibular ganglion (synapse) -> oral cavity.
  • Special sensory target: anterior 2/3rds of tongue (taste)
  • Parasympathetic target: submandibular and sublingual glands
13
Q

Describe the pathway of the Greater Petrosal: Portion of the Facial (CN VII)

A
  • Exit temporal bone -> joins with deep petrosal nerve (carries sympathetic fibers) -> pterygoid canal -> pterygopalatine ganglion (synapse) -> Hitchhike on CN V2 -> travels anteriorly
  • Parasympathetic/sympathetic target: Lacrimal gland and mucosa of nasal cavity
14
Q

Describe the pathway of the Vestibulocochlear (CN VIII)

A
  • Fiber type: Special sensory only
  • Cranial exit: Internal acoustic meatus
  • Pathway: Internal acoustic meatus -> Divides into vestibular and cochlear nerves -> inner ear
  • Targets:
    1) Vestibular n. targets are vestibule and semicircular canals (balance)
    2) Cochlear n. target is cochlea (hearing)
15
Q

Describe the pathway of the Glossopharyngeal (CN IX)

A
  • Fiber types: Somatic sensory, Visceral sensory, Special sensory, Somatic motor, Parasympathetic (visceral motor)
  • Cranial exit: Jugular foramen
  • Pathway: Jugular foramen -> Gives off tympanic nerve (see below) and then travels inferiorly to most targets
  • Major Targets:
    1) Somatic motor target: stylopharyngeus muscle
    2) Visceral sensory target: carotid body and sinus
    3) Somatic sensory target: mucosa of oropharynx, posterior 1/3 of tongue, soft palate
    4) Special sensory target: posterior 1/3 of tongue (taste)
16
Q

Describe the pathway of the Tympanic nerve: Portion of the Glossopharyngeal (CN IX)

A
  • Re-enters skull through temporal bone -> travels through middle ear -> lesser petrosal branch exits middle ear -> foramen ovale -> otic ganglion -> hitchhikes on auriculotemporal branch of CN V3
  • Tympanic nerve targets:
    1) Somatic sensory target: internal surface of tympanic membrane
    2) Parasympathetic target: parotid gland
17
Q

Describe the pathway of the Vagus (CN X)

A
  • Fiber types: Somatic sensory, special sensory, somatic motor in the head and neck.
  • Remember: provides parasympathetic innervation to targets in thorax and abdomen.
  • Cranial exit: jugular foramen
  • Pathway: Jugular foramen -> Travels inferiorly -> Gives off superior laryngeal branch (see below) near hyoid -> Travels inferiorly -> Branches into recurrent laryngeal nerve (see below) -> Travel around aortic arch and brachiocephalic trunk superiorly to larynx.
  • Targets:
    1) Somatic motor targets: pharyngeal constrictors, muscles of palate (levator veli palatini, palatoglossus, palatopharyngeus, NOT tensor veli palatini), esophagus
    2) Special sensory targets: epiglottis and palate (taste)
18
Q

Describe the pathway of the Superior laryngeal: Portion of Vagus (CN X)

A
  • Branches into internal branch and external branch
  • Targets:
    1) Somatic sensory targets (internal branch): laryngeal mucosa superior to vocal folds
    2) Somatic motor target (external branch): cricothyroid muscle
19
Q

Describe the pathway of the Recurrent laryngeal: Portion of Vagus (CN X)

A
  • After traveling around aortic arch and brachiocephalic trunk, changes names in larynx to inferior laryngeal nerve.
  • Targets:
    1) Somatic motor targets: most intrinsic muscles of larynx (transverse & oblique arytenoid mm., posterior cricoarytenoid, lateral cricoarytenoid, thyroarytenoid)
    2) Somatic sensory targets: laryngeal mucosa inferior to vocal folds.
20
Q

Describe the pathway of the (Spinal) Accessory (CN XI)

A
  • Fiber type: Somatic motor only
  • Cranial exit: Jugular foramen
  • Pathway: Superior spinal cord -> ENTERS skull through foramen magnum -> EXITS skull via jugular foramen -> Neck muscles
  • Targets: Sternocleidomastoid and trapezius muscles
21
Q

Describe the pathway of the Hypoglossal (CN XII)

A
  • Fiber type: Somatic motor only
  • Cranial exit: Hypoglossal canal
  • Pathway: Hypoglossal canal -> Travels inferiorly medial to tongue -> Anteriorly toward intrinsic and extrinsic tongue muscles
  • Targets: Intrinsic tongue muscles and Extrinsic tongue muscles (hyoglossus, genioglossus, styloglossus).