Cranial Nerves Flashcards
Cranial nerves
1 - Olfactory n. 2 - Optic n. 3 - Oculomotor n. 4 - Trochlear n. 5 - Trigeminal n. 6 - Abducens n. 7 - Facial n. 8 - Vestibulocochlear n. 9 - Glossopharyngeal n. 10 - Vagus n. 11 - Spinal accessory n. 12 - Hypoglossal n.
GSE
General somatic efferent
Somatic muscle.
GVE
General visceral efferent
ANS to smooth and cardiac muscle and glands.
SVE
Special visceral efferent
Supplies muscles derived from pharyngeal arches.
GSA
General somatic afferent
Sensory in skin, joints, tendons, muscles (ectoderm).
GVA
General visceral affarent
Sensory to visceral structures (endoderm)
SSA
Special somatic afferent
Hearing, balance and sight.
SVA
Special visceral afferent
Taste and smell.
CN I SS Fibers S/M/B Exits via
Olfactory n. SS - nasal cavity Fibers - SVA S/M/B - Sensory Exits via - olfactory foramina of cribiform plate to olfactory bulb.
Fx of the cribiform plate can cause:
CSF rhinorrhea
How is CN I tested?
With several different odors.
CN II SS Fibers S/M/B Exits via
SS - retina
Fibers - SSA
S/M/B - Sensory
Exits via - Optic canal
Where does CN II terminate?
Geniculate bodies of thalamus
Testing CN II
Light and dark testing Finger counting Snellen's test (80/20) Visual field test Peripheral vision test Pupillary light reflex Blink reflex
CN III SS Fibers S/M/B Exits via
SS - motor to 4 extra-ocular ms. and PSNS to pupil and ciliary ms.
Fibers - GSE and GVE.
S/M/B - Motor
Exits via - Superior orbital fissure
CN IV SS Fibers S/M/B Exits via
SS - motor to superior oblique m.
Fibers - GSE
S/M/B - Motor
Exits via - Superior orbital fissure
CN VI SS Fibers S/M/B Exits via
SS - motor to lateral rectus m.
Fibers - GSE
S/M/B - Motor
Exits via - Superior orbital fissure
Testing Levator palpebrae superioris m. (CN III)
Levator palpebrae superioris m. - hold forehead down and eyelid and have pt try to open.
Testing superior rectus m. (CN III)
Abduct eye, then look up.
Testing inferior rectus m. (CN III)
Abduct eye, then look down.
Testing inferior oblique m. (CN III)
Adduct eye, then look up.
Testing medial rectus m. (CN III)
Adduct eye.
Check which muscle when testing CN IV
Superior oblique m.
Check which muscle when testing CN VI
Lateral rectus m.
CN V SS Fibers S/M/B Exits via
SS - sensation everywhere and motor to muscles of mastication.
Fibers - GSA and SVE
S/M/B - Both
Exits via - V1 ophthalmic n. (S.O.F.), V2 maxillary n. (foramen rotundum) and V3 mandibular n. (foramen ovale)
CN VII SS Fibers S/M/B Exits via
SS - motor to ms. of facial expression, PSNS to lacrimal, nasal and palatine glands, taste of anterior 2/3 of tongue and sensation to external acoustic meatus.
Fibers - SVE, GVE, SVA, GSA
S/M/B - Both
Exits via - internal acoustic meatus and stylomastoid foramen.
Testing of Facial n.
Sensation of tongue.
Wrinkle forehead, blow whistle, smile, suck straw.
Blink reflex
Corneal reflex
CN VIII SS Fibers S/M/B Exits via Divsions
SS - sense of hearing and equilibrium. Fibers - SSA S/M/B - Sensory Exits via - internal acoustic meatus Vestibular and cochlear division.
Testing CN VIII - vestibular division (3)
Romberg’s sign - balance, feet together, extend arms at sides, close eyes.
Past pointing - finger to nose, w/ and w/o eyes open.
Nystagmus - abnormal movement when eye scans the room.
Testing CN VII - cochlear division (4)
Conduction deafness (wax, obstruction).
Whispering/rubbing fingers.
Rinne test
Weber’s test
CN IX SS Fibers S/M/B Exits via
SS - sensation of ear and post 1/3 of tongue, sensory from oropharynx and carotid body, taste of post 1/3 of tongue, PSNS to post 1/3 of tongue, motor to stylopharyngeus ms.
Fibers - GSA, GVA, SVA, GVE, SVE
S/M/B - Both
Exits via - jugular foramen
CN IX is tested at same time as:
CN X
CN X SS - tons Fibers S/M/B Exits via
SS - tons of stuff
Fibers - SVA, GVA, GSA, GVE, SVA
S/M/B - Both
Exits via - jugular foramen
CN XI SS Fibers S/M/B Exits via
SS - SCM m. and Trapezius m.
Fibers - GSE
S/M/B - Motor only
Exits via - jugular foramen
CN XII SS Fibers S/M/B Exits via
SS - tongue ms.
Fibers - GSE
S/M/B - Motor
Exits via - hypoglossal canal
Which nerves have GSE fibers?
CNs 3, 4, 6, 12
Which nerves have GSA fibers?
CNs 3, 7, 9, 10
Which nerves have SVE fibers?
CNs 5, 7, 9, 10
Which nerves have SSA fibers?
CNs 2, 8
