Cranial Nerves

Front 1

CN I
OLFACTORY

Back 1

Origin: Olfactory Mucosa; Upper Nasal Cavity (Nerve ends @ olefactory Bulb
Brain Exit: Ventral Hypothalmus
Skull Exit: Cribiform Plate
Function: Smell; ONLY sense that reaches cortex directly & not via the thalamus
Exam: Odorants applied to nostril w/ eyes closed
Lesion: Anosmia , Cacosmia, Uncinate Fits (olfactory & gustatory hallucinations )

Front 2

CN I
OLFACTORY

Tract

Back 2

Processes cross @ the cribiform plate & synapse in olfactory bulb, through lateral olefactory stria, PROJECTS directly to the primary olfactory cortex.
Which is defined as the Piriform cortex.

Front 3

CN I
OLFACTORY
EXPLAIN PIRIFORM CORTEX

Back 3

It's part of the amygdala ( Ganglia of limbic system adjoining temporal lobe( Fear & Emotion, Aggression ) & Part of the entorhinal cortex
ALL located : Ant. portion of parahippocampal gyrus.
Medial olfactory stria sends fibers via Ant. commissure to CONTR. olfactory bulb.

Front 4

CN II
OPTIC

Back 4

Origin: Ganglia cells in retina
Brain Exit: Ventral to hypothalamus
Skull Exit: Optic canal & Supra orbital fissure
Function: Vision
Exam: Visual acuity , Visual field mapping, Visual reflexes
Lesion: Anopsia

Front 5

CN II
OPTIC
FIBERS from

Back 5

Optic tract also forms Superior brachium :: sends light reflex information to superior colliculus
LGB nucleus : Fibers reach primary visual cortex
(Cuneus & lingual gyri ) via optic radiation, :: so left halves of both eyes visual fields ultimately end in the RIGHT visual cortex & vice versa.

Front 6

CN III
OCULOMOTOR

Back 6

Origin: Motor nucleus
(Parasympathetic) Edinger- Westphall
Nucleus
(B) Nucleus are in PAG @ LVL of Sup. Colliculus
Brain Exit: ABOVE Sup colliculus in front of interpeduncular fossa
Skull Exit: SUP. orbital fissure
Function: (M) INN. eye muscles
(med, sup, & inf oblique, & levator
palpebrae superioris)
(Para) INN. sphincter pupillae (accommodation reflex) and ciliaris ( light reflex)
Exam: (M) eye lid movement, vertical and medial eye mvm.
(Para) Light & accommodation
Lesion: ptosis, lateral strabismus, diplopia, myadriasis, cyclopledgia, loss of light reflex

Front 7

CN III

OCULOMOTOR

Parasympathetic fibers
Post ganglionic sympathetic

Back 7

P.F. synapse w/ the ciliary ganglion
PostGang. sympathetic fibers from internal carotid plexus ( from cervical sympathetic gang.) also use the short ciliary nerves to the dilator pupillae

Front 8

CN IV
TROCHLEAR

Back 8

Origin: Nucleus
Brain Exit: 2 nerves cross in SMV &
EXIT INF to INF colliculi
LEVEL: Midbrain, LVL of INF. Colliculus in Anterior portion of PAG
Skull Exit: SUP. Orbital Fissure
Function: SUP. Oblique eye muscle
( Extraocular mvm )
Exam: "H" Pattern Downward & Inward
Lesion: Weakness of Down & Inward gaze,
Diploplia ( trouble going down steps) head tilt

to opp. side

Front 9

CN V
TRIGEMINAL

Back 9

Origin/ LVL: Nucleus of ST. or Trigeminal ( P&T)

MIDPONS - C5
Chief Sensory Nucleus ( Touch )
MIDPONS
Motor Nucleus ( Muscle of Mastification)
MIDPONS
Brain Exit: Midpons
Function: Sensory to: Face, scalp, teeth, most of tongue, oral & nasal mucosa, dura mater & cerebral blood vessels.
Sensory fibers are Pseudounipolar cell
bodies are in V ( semilunar ganglion)
Mesncephalic nucleus in case of
proprioception
Motor of Mastication ( Masseter, Temporalis, Med & Lat. pterygoid muscle) tensor tympani and tensory veli palatini muscle the mylohyoid & ANT. belly of digastric muscle

Lesion: Deviation of jaw to AFFECTED side, trigeminal neuralgia (tic douloureux), UNI.Lateral severe pain all over face) Herpes Zoster, Headache, Facial Anesthesia

Exam: Touch by cotton swab, pain by pin prick, corneal reflex, jaw reflex, masticatory mvm.

Front 10

CN V
TRIGEMINAL
PERIPHERAL BRANCHES

Back 10

V1: OPTHALMIC ( SENSORY ) Exits Skull SOF
V2: MAXILLARY ( SENSORY ) Exits Skull Foramen Rotundum
V3: MANDIBULAR ( MIXED ) Exits Skull Foramen
Ovale

Front 11

CN V
TRIGEMINAL
PERIPHERAL BRANCHES

Back 11

Meningeal branch of V3 re-enters of the skull w/ middle meningeal artery through foramen spinosum

V2: goes through FR & ENTERS pyerygopalatine fossa
In PFossa RECEIVES POSTGANG Paraympathetic fibers from pyerygopalatine ganglion known as: SPHENOPALATINE GANGLION ( pregang fibers in the facial nerve)

V2: sends POSTGANG fibers via zygomaticotempor branch --- lacrimal branch of V1 & then from there to lacrimal gland.

Maxillary nerve exits in infraorbital foramen

Front 12

CN VI
ABDUCENT

Back 12

Origin: Nucleus
LEVEL: Lower pons @LVL of Facial Colliculus
Brain Exit: Pontomedullary Junc. b/t
Basilar pons & pyramid
Skull Exit: SOF
Function: Extraocular MVM: Lateral Rectus
Muscle
Exam: Lateral Eye MVM "H" pattern
Lesion: Diplopia, Medial Strabismus

Front 13

CN VII
FACIAL

Back 13

Origin/LEVEL: (Motor ) Facial Nucleus
Lower Pons @LVL of Facial Colliculus

(Taste & Parasympathetic)
Nucleus of Solitary Tract

(Parasympathetic)
Superior Salivartory Nucleus

Brain Exit: Cerebellopontine angle
Skull Exit: Styloid mastoid foramen
Function: Taste from 2/3 ANT. portion of tongue
via chorda tympani (peripheral axon
of geniculate ganglion) joins V3
Central axons from GG joins
nervous intermedius on way to
synapse w/ solitary nucleus

MVM of facial muscle (auricular)
stapedius, POS. belly of digastric &
stylohyoid muscle

Exam: Taste, Facial expression
Lesion: Above Nucleus
UMN : CONTRA. lower facial mm 1/4

of face
Below Nucleus
LMN: IPSL UNIL. facial mm 1/2 of face
Bells Palsy
Hyperaccousis (paralysis of stapedius)

Front 14

CN VII
FACIAL
Parasympathetics

Back 14

Parasympathetic to lacrimal & Serous & Mucous Gland of
nasopharnyx
submandibular
sublingual salivary glands ( via chorda tympani)

Front 15

CN VII
FACIAL
Preganglionic parasympathetic

Back 15

Fibers from Nervous intermedius form greater petrosal nerve.
Greater Petrosal Nerve is joined by sympathetic fibers from DEEP petrosal nerve to form the nerve to the pyerygold canal ( VIDIAN NERVE) which synapses in the pterygo (SPHENO) palatine ganglion

Front 16

CN VII
FACIAL
PTERYGOPALANTINE GANGLION

Back 16

sends postgang. fibers to maxillary nerves, for there to the zygomaticotempoal nerve V2 --- ultimately to the lacrimal nerve V1 to supply the lacrimal gland

also sends postgang fibers via the palatine nerves to the serous & mucous glands of the soft & hard palatine & nasopharynx

Front 17

CN VII
FACIAL
Preganglionic parasympathetic Travel w/ Nerve

Back 17

P.P. from nervous intermedius travel with the facial nerve through internal acoustic meatus where they JOIN the chorda tympani

CHORDA TYMPANI:: exits the ear cavity through petrotympanic fissure and joins lingual nerve V3 to supply the submandibular ganglion & sublingual salivary glands

Front 18

CN VIII
VESTIBULOCOCHLEAR

Back 18

Origin: 1.Vestibular Nuclei
2.Chochlear Nuclei
LEVEL: 1. Lateral Aspect of 4th ventricle
2. Acoustic Tubercle
Brain Exit: Cerebellopontine angle
Function: 1. Balance and Equilibrium

2. Hearing
Exam: 1. Caloric test, Barany Chair Test
2. Weber & Rinne test , Audiogram
Lesion: 1. Vertigo, Nystagmus, Dysequilibrium
2. Loss of hearing, tinnitus
Reaches inner ear via the internal acoustic meatus

Front 19

CN IX
GLOSSOPHARYNGEAL

Back 19

Origin/ Level: Nucleus of Solitary Tract
Taste and Autonomic
MEDULLA
Nucleus Ambiguus
Motor
MEDULLA
Inferior Salivatory Nucleus
Parasympathetic
PONS
Nucleus of Spinal Tract of V
Brain Exit: Post- Olivary Sulcus
Function: Motor : Stylopharyngeus muscle
Taste from POST. 1/3 of tongue
Sensory to middle ear, tympanic
cavity, Eustachian tubes, Tonsil,
Nasopharynx, Uvula, Soft palate

Exam: Taste and general sensation of POST 1/3
of tongue, GAG Reflex

Lesion: Loss of sensation to upper pharynx
Absent of GAG
Hypertension
Glossopharyngeal Neuralgia
Loss of sensation in Naso-oro-
pharyngeal

Front 20

CN IX
GLOSSOPHARYNGEAL
Preganglionic Parasympathetic

Back 20

Fibers from IX nerve form the TYMPANIC NERVE--- enters the tympanic plexus & joined by sympathetic fivers from carotid plexus ( SUP. Cervical Ganglion)

Sympathetic and Para. fibers form the ganglion enter the auriculotemporal nerve V3 which WRAPS around middle meningeal artery to SUPPLY parotid salivary gland

Front 21

CN X
VAGUS

Back 21

Origin/ Level: Dorsal Motor Nucleus
Parasympathetic
MEDULLA
Nucleus Ambiguus
Motor
MEDULLA
Nucleus of Solitary Tract
Taste & Parasympathetic
MEDULLA
Nucleus of Spinal Tract of V
Sensory
MEDULLA

Brain Exit: Post- Olivary Nucleus
Skull Exit: Jugular foramen
Function: Parasymapthetic to throax & abdomen
Motor to Pharyngeal Constritor,
Intrinsic laryngeal muscles,
palatine muscles (except tensory veli palatini),
upper esophagus,
phonation and swallowing
Taste fibers form larynx and epiglottis
Sensory to pharynx, larynx,
The concha of external ear,
& meninges of the posterior fossa
Lesion: Hoarsness, dysphagia, loss of GAG, uvular deviation to strong side

Front 22

CN XI
ACCESSORY

Back 22

Origin/ Level: Nucleus Ambiguus & Disperse
cell bodies/ Medulla & cervical seg.
Brain Exit: Post-Olivary Sulcus
Skull Exit: Jugular Foramen
Function: Cranial accessory: Joins X to supply the muscles of pharynx, larynx, & soft palate
Spinal Accessory: motor to sternocleidomastoid & trapezius muscles
Lesion: Inability to rotate head & shrug shoulders

Front 23

CN XII
HYPOGLOSSAL

Back 23

Origin: Nucleus
Level: Medulla
Brain Exit: Pre-Olivary Nucleus
Skull Exit: Hypoglossal Canal
Function: Motor to all tongue muscles ( muscles that end with glossus) EXCEPT palatoglossus which is supplied by the VAGUS like palatine muscles
Lesion: IPSIL tongue paralysis & atrophy

Front 24

Cranial Nerves Exit the skull via Juglar Foramen

Back 24

IX, X, & XI

Front 25

Parasympathetic inn. of body function
Preganglionic cells run w/ CN III

Back 25

Nucleus: Edinger-Westphal
Ganglion: Ciliary

Inn: Sphincter Pupillaae, Ciliary Muscles

Front 26

Parasympathetic inn. of body function
Preganglionic cells run w/ CN VII

Back 26

Nucleus: Superior Salivatory
Ganglion: Pterygopalatine ; Submandibular

Inn: P) lacrimal gland, glands of nasopharynx
S) submandibular, sublingual sallivatory glands

Front 27

Parasympathetic inn. of body function
Preganglionic cells run w/ CN IX

Back 27

Nucleus: Inferior Salivatory
Ganglion: optic

Inn: Parotoid salivatory gland

Front 28

Parasympathetic inn. of body function
Preganglionic cells run w/ CN X

Back 28

Nucleus: Dorsal Motor & Nucleus Ambiggus
Ganglion: Diffuse Thoracic and Abdominal

Inn: Heart, esophagus, lunchs, stomach, liver, gall bladder, pancreas, and foregut and midgut derivatives