Cranial nerves Flashcards
cranial nerve nuclei - located in
tegmentum portion of brain stem (between dorsal and ventral portion)
cranial nerve nuclei in midbrain
CN III, CN IV (3-4)
cranial nerve nuclei in pons
CN V, CN VI, CN VII, CN VIII (5-8)
cranial nerve nuclei in medulla
CN IX, X, XII (9,10,12)
cranial nerve nuclei in spinal cord
CN XI (11)
sulcus limitans - anatomical function
seperate lateral cranial nuclei (sensory) from medial cranial nuclei (motor)
medial cranial nuclei - function
motor
lateral cranial nuclei - function
sensory
CN I passing through
many openings of the cribriform plate of the ethmoid bone (anterior cranial fossa)
cranial nerves that enter into the middle cranial fossa through sphenoid bone
CN II - CN VI (2-6)
CN II enter into ….. cranial fossa via ….
middle cranial fossa
via optic canal
…. pass through optic canal
CN II
ophthalmic artery
… pass through superior orbital fissure into medial cranial fossa
CN III, IV, V1, VI, ophthalmic vein, sympathetic fibers
superior orbital fissure - bone?
sphenoid bone
optic canal - bone?
sphenoid bone
CN V2 enter into …. via …
middle cranial fossa
Foramen Rotundum
CN V3 enter into …. via …
middle cranial fossa
Foramen Ovale
… pass through Foramen spinosum into
middle meningeal artery
middle cranial fossa
pathways to anterior middle cranial fossa through sphenoid bone and what passes through
- optic canal (CN II, ophatlmic artery, central retinal vein)
- superior orbital fissure (CN III, IV, V1, VI, ophthalmic vein, sympathetic fibers)
- foramen Rotundum (CN V2)
- foramen ovale (CN V3)
- foramen spinosum (middle meningeal artery)
cranial nerve V enter into middle cranial fossa through
V1 - superior orbital fissure
V2 - foramen Rotundum
V3 - foramen ovale
cranial nerves? that passes into posterior nerves through … bone
CN VII-XII (7-12)
temporal or occipital bone
….passes through internal auditory meatus
CN VII
CN VIII
….passes through jugular foramen
CN IX
CN X
CN XI
jugular vein
….passes through hyoglossal canal (area of hypoglossal canal)
CN XII
between foramen magnum (medial) and jugular foramen (lateral)
….passes through foramen magnum
spinal roots of CN XI
brain stem
vertebral arteries
pathways to posterior cranial fossa through temporal or occipital bone and what passes through
- internal auditory meatus (CN VII, VIII)
- Jugular foramen (CN IX, X, XI, jugular vein)
- hypoglossal canal (CN XII)
- foramen magnum (spinal roots of CN XI, brain stem, vertebral arteries
pathways into cranial
- cribriform plate
- optic canal
- superior orbital fissure
- foramen Rotundum
- foramen ovale
- foramen spinosum
7 internal auditory meatus - Jugular foramen
- hypoglossal canal
- foramen magnum
cranial nerves
CN I – Olfactory CN II – Optic CN III – Oculomotor CN IV – Trochlear CN V – Trigeminal CN VI – Abducens CN VII – Facial CN VIII – Vestibulocochlear CN IX – Glossopharyngeal CN X – Vagus CN XI – Accessory CN XII – Hypoglossal
CN IX
glossopharyngeal
CN XII
hypoglossal
cranial nerves - only sensory?
I, II, VIII
cranial nerves - only motor?
III, IV, VI, XI, XII
cranial nerves - BOTH sensory and motor?
V, VII, IX, X
CN I - function
smell
CN II - function
optic
CN III - function
- eye movement
- pupillary constriction
- accommodation
- eyelid opening
CN III - eye movements by
innervation of:
- superior rectus
- medial rectus
- inferior rectus
- inferior oblique
CN III- eyelid opening by
innervation of
LEVATOR PALPEBRAE
CN IV - function
eye movement
CN IV - eye movement by
innervation of superior oblique
CN V - function
- mastication
- facial sensation
- somatosensation from anterior 2/3 of tongue
CN V - facial sensation - divisions
- ophthalmic
- maxillary
- mandibular
CN VI - function
eye movement
CN VI - eye movement by
innervation of lateral rectus
CN VII - function
- facial movements
- taste from anterior 2/3 of tongue
- lacrimation
- salivation
- eyelid closing
- stapedius muscle of the ear
CN VII - salivation via
submandibular and sublingual glands
CN VII - eyelids closing via
orbicularis oculi
CN VII - ear
innervates stapedius muscle of the ear
CN VII vs parotid gland
nerve courses through the parotid gland, but does not innervate it
CN VIII - function
- hearing
2. balance
CN IX - function
- taste and somatosensation from posterior 1/3 of tongue
- swallowing
- salivation
- monitoring carotid body and sinus chemo and baroreceptors
- elevates pharynx and larynx
CN IX - salivation
innervates parotid gland
CN IX - elevates pharynx and larynx
innervates stylopharyngeus
CN X - function
- taste from epiglottic region
- swallowing
- soft palate elevation
- midline uvula
- talking
- coughing
- parasympathetics to thoracoabdominal viscera
- monitoring aortic arch body and chemo and baroreceptors
- tongue movement
CN XI?
accessory
CN XI - function
head turning
shoulder shrugging
CN XI innervates
- sternocleidomastoid muscle
2. trapezius
CN XII - function
tongue movement
innervation of salivation
- parotid gland (IX)
2. submandibular and sublingual glands (VII)
tongue - main muscles (and innervation)
- hyoglossus (XII)
- genioglossus (XII)
- styloglossus (XII)
- palatoglossus (X)
vagal nuclei
- nucleus solitarius
- nucleus ambiguus
- dorsal motor nucleus
nucleus solitarius - function and composed of
visceral sensory information (taste, baroreceptors, gut distention)
VII, IX, X
nucleus ambiguus - function and composed of
motor innervation of pharynxm larynx, upper esophagus (swallowing, palate elevation)
IX, X, XI (cranial portion)
dorsal motor nucleus - function and composed of
sends autonomic (parasympathetic) fibers to heart, lung, upper GI X
vagal nuclei and compsed of
- nucleus solitarius - VII, IX, X
- nucleus ambiguus - IX, X, XI (cranial portion)
- dorsal motor nucleus - X
cranial nerve reflex?
- corneal 2. lacrimation 3. jaw jerk
4. pupillary 5. Gag
corneal nerve reflex - afferent and efferent
afferent - V1 opthalmic (nasociliary branch)
effernt - VII (temporal branch - orbicullaris oculi)
Gag reflex - afferent and efferent (only CN)
afferent - IX
effernt - X
pupillary reflex - afferent and efferent (only CN)
afferent - II
effernt - III
Lacrimation reflex - afferent and efferent (only CN)
afferent - V1
effernt - VII
loss of lacrimation reflex vs tears
does not preclude emotional tears
jaw jerk reflex - afferent and efferent (only CN)
afferent - V3 (sensory - muscle spindle from masseter)
effernt - V3 (motor - maseter)
CN X lesion - appearance
uvula deviates AWAY from side of lesion. Weak side collapses and uvula points away
CN XII lesion - appearance
tongue deviates toward side of lesion (“lick your wounds”) due to weakened tongue muscles on affected side (LMN lesion)
CN XI lesion - appearance
weakness turning head to contralateral side of lesion (Sternocleidomastoid muscle)
Shoulder droop on side of lesion (trapezius)
CN V motor lesion - appearance
jaw deviates TORWARD side of lesion due to unopposed force from the opposite pterygoid muscle
cranial nerve without thalamic relaty to cortex
oflactory
vagal nuclei that sends autonomic fibers to heart, lung, upper GI
dorsal motor nucleus
jaw jerk - muscle?
masseter
V lesion - jaw deviates toward the site of lesion due to (muscle)
opposite pterygoid muscle
gag reflex is depressed by
opioids