Cranial Nerves/Brain Stem Flashcards
CN I Fiber types, exit
Sensory, cribriform plate
CN II Fiber types, exit
Sensory, optic canal
CN III (fiber types, 4 functions, exit, 2 nuclei)
Motor
Eye movement (SR, IR, MR, IO), pupillary constriction (sphincter pupillae), accomodation, eyelid opening (levator palpebrae)
Superior orbital fissure
Main is in midbrain, also Edinger-Westphal/muscarinic receptors for pupillary constriction
CN IV Fibers, Exit, Nucleus
Motor
Superior orbital fissure
Midbrain
CN V Fibers, 3 Functions, Nucleus, 3 exits
Both Mastication (V3 mandibular), Facial sensation, somatosensation from anterior 2/3 of tongue Pons V1: Superior Orbital Fissure V2: Foramen Rotundum V3: Foramen Ovale
CN VI (fibers, nucleus, exit)
Motor
Pons
Superior orbital fissure
CN VII (Fibers, 6 Functions/Important Course, Nucleus, Exit)
Both
Facial movement/expression, taste from anterior 2/3 of tongue, lacrimation, salivation (submandibular and sublingual glands), eyelid closing (orbicularis oculi), stapedius muscle (passes THROUGH parotid but DOES NOT innervate it)
Pons
Internal auditory meatus
CN VII 5 Branches
Temporal Zygomatic Buccal Marginal mandibular Cervical
CN VIII Fiber types, 2 functions, nucleus, exit
Sensory
Hearing and balance
Pons
Internal auditory meatus
CN IX (Fiber Types, 4 Functions, Nucleus, Exit)
Both
Taste and somatosensation from posterior 1/3 of tongue, swallowing, salivation (parotid gland), monitoring carotid body and sinus chemo/baroreceptors, and stylopharyngeus (elevates pharynx/larynx)
Medulla
Jugular foramen
CN X (Fibers, 8 functions, Nucleus, exit)
Both
Taste from epiglottic region, swallowing, soft palate elevation, midline uvula, talking, coughing, thoracoabdominal viscera, monitoring aortic arch chemo/baroRs
Medulla
Jugular Foramen
CN XI Fibers, Nucleus, Exit
Motor
Spinal cord (come in through foramen magnum)
Jugular foramen
CN XII Fibers, Nucleus, Exit
Motor
Medulla
Hypoglossal canal
Nucleus Solitarius (what it does, 3 CNs)
Visceral Sensory information (taste, baroRs, gut distention)
VII, IX, X
Nucleus aMbiguous (what it does, 3 CNs)
Motor innervation of pharynx, larynx, upper esophagus (swallowing, palate elevation)
IX, X, XI (cranial portion)
Dorsal motor nucleus (what it does, CN)
Sends autonomic (parasympathetic) fibers to heart/lungs/upper GI X
Corneal Reflex
Touch cornea with cotton, should blink
Afferent: V1 ophthalmic (nasociliary branch)
Efferent: VII (temporal branch: orbicularis oculi)
Lacrimation Reflex
Afferent: V1 (loss of reflex does not preclude emotional tears)
Efferent: VII
Jaw Jerk Reflex
Tap chin. Normally shouldn’t respond, if they do, UMN lesion
Afferent: V3 (sensory - muscle spindle from masseter)
Efferent: V3 (motor - masseter)
Pupillary Reflex
Afferent: II
Efferent: III
Gag Reflex
Afferent: IX
Efferent: X
CN V Motor Lesion
Jaw deviates TOWARD side of lesion due to unopposed force from opposite pterygoid muscle
CN X Lesion
Uvula deviates AWAY from side of lesion. Weak side collapses and uvula points away
CN XI Lesion
Weakness turning head to contralateral side of lesion (SCM). Shoulder droop on each side of lesion (Trapezius)
CN XII Lesion
Tongue deviates TOWARD side of lesion due to weakened tongue muscles on affected side
5 Structures of RAS
Reticular Formation Mesencephalic nucleus Thalamic intralaminar nucleus Dorsal hypothalamus Tegmentum
Superior Colliculi
Conjugate vertical gaze center
Inferior colliculi
Information to primary auditory center
3 Jaw Closing Muscles
Masseter, temporalis, medial pterygoid
1 Jaw Opening Muscle
Lateral pterygoid
9 Structures of Cavernous Sinus (& which most susceptible to injury)
CN III, IV, V1, V2, and VI
ICA, pituitary, optic chiasm, sphenoid sinus (mycosis can spread)
VI most suceptible to injury. Motor damage from the ocular ones and hypo/hyperesthesias from V1/V2 damage
Superior Oblique Action/Damage
Causes eye to look down and laterally. So damage, look medially and superiorly
Inferior Oblique Action/Damage
Causes eye to look up/laterally. So damage look down and medially
