Cranial Nerves Flashcards
CN IX name & function
Glossopharyngeal nerve
- taste from posterior 1/3 of tongue
- motor to stylopharyngeus muscle
- parasympathetic to parotid salivary glands
- visceral sensory from carotid sinus & body
- sensory to tympanic cavity, auditory tubes, upper pharynx, soft palate, posterior 1/3x of tongue
Lesion of CN IX
- loss of sensation (or intense pain) of upper pharynx
- reduced/absent gag reflex
- difficulty adjusting BP/HR to postural changes
CN IX nuclei
- solitary nucleus (taste, visceral afferents)
- nucleus ambiguus (motor & parasympathetic)
- inferior salivatory nucleus (parasympathetic)
CN X function
Vagus nerve:
- parasympathetic to thoracic & abdominal viscera (lungs heart, GI)
- motor to pharyngeal constrictors, intrinsic laryngeal, palatal muscles for phonation & swallowing
- taste from larynx & epiglottis
- sensory to larynx, small portion of external ear, meninges in posterior cranial fossa and foramen magnum
CN X name
Vagus nerve
CN IX name
Glossopharyngeal nerve
CN X nuclei
- Dorsal motor nucleus of vagus (parasympathetic)
- nucleus ambiguus (motor)
- solitary nucleus (taste, visceral afferents)
CN X lesion
- loss of parasympathetics to thorax & abdomen (^HR, dec digestion)
- dysphonia (hoarse voice), dysphagia (difficulty swallowing)
CN XI name
Accessory nerve
CN XI function
Accessory
- cranial: motor to pharyngeal, laryngeal, palatal muscles (runs with CN X)
- spinal: motor to trapezius & sternocleidomastoid muscles
CN XI lesion
Paralysis of ipsilateral trapezius & sternocleidomastoid muscles
CN XI nuclei
Nucleus ambiguus (motor)
Disperse cell bodies in medulla & cervical spinal cord
CN XII name
Hypoglossal nerve
CN XII nuclei
Hypoglossal nucleus
CN XII function
Motor to muscles of tongue (except palatoglossus)
CN XII lesion
Ipsilateral tongue paralysis & atrophy
CN V name
Trigeminal nerve
CN V nuclei
- Nucleus of spinal tract of trigeminal (pain & temp)
- mesencephalic nucleus (proprioception)
- motor nucleus (mastication muscles)
Peripheral branches of CN V
V1: ophthalamic (sensory)
V2: maxillary (sensory)
V3: mandibular (mixed)
CN V function
Trigeminal
- sensory to face, scalp, teeth, most tongue, oral & nasal mucosa, dura mater & cerebral BVs
- motor to mastication muscles (masseter, temporalis, medial & lateral pterygoid muscles)
CN V lesion
Trigeminal neuralgia (tic douloureux)
facial anesthesia/numbness
Inability/difficulty biting down with jaw deviation to same side
Examination of CN V lesion
Touch by cotton swab
Pain by pinprick
Temperature
Corneal reflex
Jaw reflex
Masticatory movements
CN VI name
Abducens
CN VI nucleus
Abducent nucleus
CN VI function
Extraocular movements (lateral rectus muscle)
Examination of CN VI
Lateral eye movements (abduction)
CN VI lesion
Diplopia (double vision), medial strabismus
Levels of CN V
- Nucleus of spinal tract of trigeminal - midpons-C5
- Chief sensory nucleus - midpons
- Mesencephalic nucleus - midpons-midbrain
- Motor nucleus - midpons
Where does CN V exit?
Trigeminal nerve: Midpons
Level of CN VI
Abducens: tegmentum of lower pons at level of facial colliculus
Where does CN VI exit?
Pontemedullary junction between basilar pons & pyramid
CN VII name
Facial
CN VII nuclei
Facial nucleus (motor)
Nucleus of solitary tract (taste & parasympathetic)
Superior salivatory nucleus (parasympathetic)
Levels of CN VII
Facial nucleus: Lower pons at level of facial colliculus
Where does CN VII exit?
Cerebellopontine angle
CN VII peripheral branches
Temporal
Zygomatic
Buccal
Marginal
Mandibular
Cervical
(The Zebra Bit My Cat)
CN VII function
Facial:
- motor to muscles of facial expression
- taste from anterior 2/3 of tongue via chorda tympani
- parasympathetic to lacrimal, serous & mucous glands of nasopharynx, and submandibular & sublingual glands via chorda tympani
Examination of CN VII
Facial expression movements & taste
CN VII lesion
Bell’s Palsy:
LMN type facial paralysis
(hyperacpusis, unilateral facial paralysis with inability to wrinkle forehead, raise eyebrow, shut Ike, tear flow over sagging lower eyelid, loss of lost from anterior 2/3 of tongue
CN VIII name
Vestibulocochlear
CN VIII nuclei
- vestibular nuclei (4)
- cochlear nuclei
CN VIII function
Balance & equilibrium
Hearing
CN VIII lesion
Vertigo, nystagmus, vomiting
Loss of hearing
CN IV name
Trochlear
Nucleus of CN IV
Anterior part of periaqueductal gray at level of inferior colliculus
Where does CN IV exit?
Inferior to inferior colliculi after nerve fibers decussation in superior medullary velum
CN IV function
Innervation of superior oblique muscle
Examination of CN IV
Turn Eyeball into down & in position
CN IV lesion
Inability and double vision when looking down & in
CN III Name
Oculomotor
CN III nuclei
Anterior portion of periaqueductal gray at level of superior colliculus
- motor
- edinger-westphal (parasympathetic)
where does CN III exit?
Interpeduncular fossa
CN III function
- Motor to all extraocular muscles except lateral rectus & superior oblique (Medial rectus, superior rectus, inferior rectus, inferior oblique & levator palpebrae superioris)
- parasympathetics to sphincter pupillae (constriction) & ciliaris (accomodation)
CN III lesion
Ptosis
Lateral strabismus
Mydriasis (enlarged, unresponsive to light pupil)
Cycloplegia (enlarged, unresponsive to accommodation pupil)
