Head: Cranial Nerves VI-XII Flashcards
Cranial nerve VI
- Abducent nerve
Abducent nerve (CN VI)
- Pass through cavernous sinus
- Exits cranium through superior orbital fissure
Abducent nerve (CN VI) function
- Innervates lateral rectus (eye abductor)
Cranial nerve VII
- Facial nerve
Facial nerve (CN VII) is formed by
- Facial nerve proper
- Nervus intermedius
Facial nerve proper innervation
- Muscle of facial expression
Nervus intermedius innervation
- Parasympathetic
- Taste (special sensory)
- Somatic sensory
Facial nerve (CN VII) pathway
- Posterior cranial fossa
- Internal acoustic meatus
- Facial canal (temporal bone)
- Exits skull through stylomastoid foramen
Facial nerve (CN VII) is the
- Longest intraossesous course of any cranial nerve
Branches of Facial nerve (CN VII) in the facial canal
- Greater petrosal
- Nerve to stapedius
- Chorda tympani nerve
Portion of Facial nerve (CN VII) that exits stylomastoid foramen innervates
- Muscles of facial expression
Sensory innervation of Facial nerve (CN VII)
- Special (taste)
- Somatic
Facial nerve (CN VII) cell bodies are located in the
- Geniculate ganglion
Special (taste) innervation of Facial nerve (CN VII)
- Anterior 2/3 of tongue
- Travels in chorda tympani
Somatic sensory innervation of Facial nerve (CN VII)
- Small portion of external ear (concha)
- External acoustic meatus/tympanic membrane
Motor innervation of Facial nerve (CN VII)
- Somatic
- Parasympathetic (visceral)
Somatic motor innervation of Facial nerve (CN VII)
- Muscle of facial expression (and some others)
- Efferent limb of corneal reflex
Parasympathetic (visceral) motor innervation of Facial nerve (CN VII) delivers
- Presynaptic parasympathetics to greater petrosal nerve
- Presynaptic parasympathetics to chorda tympani
Greater petrosal nerve pathway
- Greater petrosal nerve
- Pterygopalatine ganglion
- Lacrimal gland (and other glands)
Chorda tympani pathway
- Chorda tympani
- Submandibular ganglion
- Sublingual & submandibular salivary glands
Lesions to Facial nerve (CN VII) can result in a loss of/altered
- Lacrimation
- Taste anterior 2/3 tongue
- Salivation
Lesions to Facial nerve (CN VII) symptoms
- Depend on location of injury
- Paralysis of facial muscles
- Hyperacusis
- Loss of corneal reflex
Bell’s Palsy
- Idiopathic facial paralysis
- Cause is unknown exactly
Bell’s Palsy symptoms
- Compression,cischemia, demyelination of facial nerve in facial canal
- Can see other symptoms depending on location
Cranial nerve VIII
- Vestibulocochlear nerve
Vestibulocochlear nerve (CN VIII)
- Passes through internal acoustic meatus
- Innervates inner ear structures
Vestibulocochlear nerve (CN VIII) separates into
- Vestibular nerve
- Cochlear nerve
Vestibular nerve (branch of Vestibulocochlear nerve/CN VIII) regulates
- Head positon
- Linear and angular acceleration
Cochlear nerve (branch of Vestibulocochlear nerve/CN VIII) regulates
- Hearing
Cranial nerve IX
- Glossopharyngeal nerve
Glossopharyngeal nerve (CN IX) exits cranium through
- Jugular foramen
Glossopharyngeal nerve (CN IX) is
- Sensory
- Somatic
- Special
- Visceral
Sensory innervation of Glossopharyngeal nerve (CN IX)
- Superior & inferior ganglia of glossopharyngeal
Somatic innervation of Glossopharyngeal nerve (CN IX)
- Tympanic cavity
- Pharynx
- Palatine tonsil
- Posterior 1/3 tongue
- Afferent limb of gag reflex
Special innervation of Glossopharyngeal nerve (CN IX)
- Taste posterior 1/3 of tongue
Visceral innervation of Glossopharyngeal nerve (CN IX)
- Carotid sinus (baroreceptor)
- Carotid body (chemoreceptor)
- Carotid branch
Cranial nerve X
- Vagus nerve
Vagus nerve (CN X) is
- Both sensory and motor
Sensory innervation of Vagus nerve (CN X)
- Superior vagal ganglion
- Inferior vagal ganglion (nodose ganglion)
Motor innervation of Vagus nerve (CN X)
- Somatic
- Visceral (parasympathetic)
Superior vagal ganglion of Vagus nerve (CN X) contains
- Cell bodies of general sensory sensory neurons
Superior vagal ganglion of Vagus nerve (CN X) innervation
- Portion of external ear
- External auditory meatus
- Tympanic membrane
- Larynx (and a portion of laryngopharynx)
Inferior vagal ganglion (nodose ganglion) of Vagus nerve (CN X) contains
- Cell bodies of visceral sensory
- Taste neurons
Inferior vagal ganglion (nodose ganglion) of Vagus nerve (CN X) innervates
- Aortic chemoreceptors
- Baroreceptors
- Thoracic and abdominal organs
- Taste from tongue root, epiglottis
Lesion of Vagus nerve (CN X) effects
- Gag reflex or saying “ahhh”
- Laryngeal paralysis
- Difficulty swallowing (dysphagia)
The gag reflex in Vagus nerve (CN X) lesion results in
- Uvula deviates away from affected side (bad side)
Laryngeal paralysis from the lesion of Vagus nerve (CN X) causes
- Change in voice (hoarseness)
Somatic motor innervation of Vagus nerve (CN X)
- Soft palate (except tensor veli palatine)
- Pharynx (except stylopharyngeus)
- All Laryngeal muscles
- Palatoglossus
Pharynx (except stylopharyngeus) from Vagus nerve (CN X) innervation is the
- Efferent limb of gag reflex
Visceral (parasympathetic) innervation of Vagus nerve (CN X)
- Presynaptic parasympathetic to thoracic and most abdominal viscera up to left colic flexure
Cranial nerve XI
- Spinal accessory nerve
Spinal accessory nerve (CN XI) arises from
- Cervical spinal cord
Spinal accessory nerve (CN XI) enters cranium through the
- Foramen magnum
Spinal accessory nerve (CN XI) exits cranium through the
- Jugular foramen
Spinal accessory nerve (CN XI) innervates
- Sternocleidomastoid muscle
- Trapezius muscle
Lesion to CN XI may cause
- Weakness in SCM/trapezius
- Shoulder shrug
- Cervical rotation to opposite side
Cranial nerve XII
- Hypoglossal nerve
Hypoglossal nerve (CN XII) exits cranium through
- Hypoglossal canal
Hypoglossal nerve (CN XII) is joined by
- Branches of the cervical plexus
Hypoglossal nerve (CN XII) is
- Both sensory and motor
Sensory innervation of Hypoglossal nerve (CN XII)
- None really
- Fibers from cervical plexus travel hitchhike with CN XII
Motor innervation of Hypoglossal nerve (CN XII)
- Intrinsic tongue muscles
- Extrinsic tongue muscles (except palatoglossus)
Hypoglossal nerve lesion may cause
- Dysarthria
- Tongue atrophy
- Deviation to injured side during tongue protrusion