Cranial Nerves and Clinical Testing Flashcards
The Facial nerve arises from the _____ as a ________
pontomedullary junction
sensory and motor rootlet
The 2 roots of the facial nerve travel through the __________ where they are in close proximity to the inner ear
internal acoustic meatus
From the internal acoustic meatus the facial nerve enters the ______
facial canal
What is the facial canal?
Canal that runs between the internal acoustic meatus and the stylomastoid foramen
What 3 events occur to the facial nerve in the facial canal?
1) the two roots fuse to form the facial nerve, 2) the nerve forms the geniculate ganglion
3) the nerve gives rise to the greater petrosal nerve, nerve to stapedius and the chorda tympani
What does the greater petrosal nerve supply?
parasympathetics fibres to the mucous and lacrimal glands
What does the nerve to stapedius supply?
motor fibres to stapedius
What does the chorda tympani supply?
special sensory fibres (taste) to the anterior 2/3 of tongue, parasympathetics to submandibular and sublingual glands
The facial nerve exits the facial canal via the ________
stylomastoid foramen
The glossopharyngeal nerve originates in the ___1___ and leaves the cranium via the ___2_____
1) medulla oblongata
2) jugular foramen
The glossopharyngeal nerve descends _______ to the internal carotid artery and several branches arise
Anterolateral
Describe sensory innervation via the glossopharyngeal nerve?
Tympanic nerve provides sensation to middle ear, internal surface of tympanic membrane and eustachian tube
Innervation to the carotid sinus
Pharyngeal branch innervation to the mucosa of the oropharynx
Lingual nerve provides posterior 1/3 of tongue with general taste and sensation
Tonsillar branch innervates the palatine tonsils
Somatic motor provided by glossopharyngeal?
Stylopharyngeus
Parasympathetic provided by glossopharyngeal?
Parotid gland secretomotor
Sensory part of gag reflex is provided by?
Glossopharyngeal
What nerve provides sensation to the middle ear, internal surface of tympanic membrane and eustachian tube?
Glossopharyngeal via the tympanic nerve
What nerve provides posterior 1/3 of the tongue with general sensation and taste?
Glossopharyngeal nerve
Palatine tonsils are innervated by the?
Glossopharyngeal nerve
Parotid gland secretomotor function is by?
Glossopharyngeal nerve
Glossopharyngeal nerve is associated with derivatives of the ______ pharyngeal arch
3rd
The vagus nerve is associated with derivatives of the _____ pharyngeal arches
4th and 6th
The vagus nerve originates from the ___1__ exiting the cranium via the ___2_____
1) medulla oblongata of the brainstem
2) jugular foramen
In the neck the vagus nerve travels in the _____ with ______
carotid sheath
IJV and common carotid artery
The left recurrent laryngeal nerve recurs under ___1__
The right recurrent laryngeal nerve recurs under ___2__
1) aortic arch
2) subclavian artery
The vagus nerve supples somatic sensation to
posterior part of external auditory canal and external ear
The vagus nerve provides visceral sensation to
laryngopharynx
superior aspect of larynx
heart
GI tract up to splenic flexure
Motor functions of the vagus nerve?
Majority of muscles of pharynx and larynx as well as palatoglossus of tongue and majority of muscles of soft palate
Parasympathetic functions of vagus nerve?
Heart, Lungs and GI Tract
What nerve provides parasympathetics to the heart and GI tract?
Vagus
What nerve provides majority of muscles of pharynx and larynx as well as palatoglossus of tongue and majority of muscles of soft palate?
Vagus
What nerve provides visceral sensation to the laryngopharynx, superior part of the larynx, heart and GI tract up to the splenic flexure?
Vagus
Special sensation supplied by the facial nerve? Via what nerve?
special sensory fibres for taste to anterior 2/3 of tongue via chorda tympani (GENERAL SENSATION IS SUPPLIED BY THE TRIGEMINAL)
Parasympathetics supplied by the facial nerve?
Mucous glands and lacrimal glands
Submandibular and sublingual salivary glands
What nerve supplies motor innervation to some of the muscles surrounding the ear?
Facial via the posterior auricular nerve
Facial nerve gives motor innervation to?
Muscles of facial expression
The hypoglossal nerve arises from the ___1_____ and exits the cranium via the __2____ It then travels down to enter the ___3____
1) medulla oblongata
2) hypoglossal canal
3) tongue
What is the function of hypoglossal nerve?
MOTOR FUNCTION
Innervates all the muscles of the tongue except palatoglossus
genioglossus, hyoglossus, styloglossus, superior longitudinal, inferior longitudinal, transverse and vertical
What nerve innervates all the extrinsic and intrinsic muscles of tongue EXCEPT palatoglossus?
Hypoglossal
The trigeminal nerve is associated with derivatives of the ________
1st pharyngeal arch
Trigeminal nerve originates off the __1____ CNV1 exits the cranium via __2__ CNV2 exits the cranium via ___3__ CNV3 exits the cranium via ___4____
1) Pons
2) the superior orbital fissure
3) Foramen rotundum
4) Foramen ovale
CNV1, 2 and 3 sensory innervations?
CNV1 roughly upper 1/3 of face skin and mucous membranes
CNV2 roughly middle 1/3 including nasal cavity, maxillary sinus, teeth and gingiva in super 1/2
CNV3 Bottom 1/3 of face, also floor of oral cavity, ant 2/3 of tongue general sensation, lower teeth and gingiva
CNV3 motor function?
Motor to the muscles of mastication, some supra hyoid muscles, tensor veil palatini in the soft palate, tensor tympani in the ear
What nerve provides motor innervation to tensor tympani?
CNV3
The vestibulocochlear nerve originates at the __1___ and exits the cranium via the _2____
1) pontomedullary junction
2) internal acoustic meatus
Function of vestibulocochlear nerve?
Vestibular nerve innervates the vestibular system responsible for balance
The cochlear nerve travels to the cochlea forming the spiral ganglia which serve the sense of hearing
The spinal accessory nerve has a spinal component arising from ___1___ and cranial component arising from __2__ It leaves the cranium via the ____3____
1) C1-C5/C6
2) Medulla
3) Jugular foramen
Spinal accessory nerve provides motor innervation to?
Sternocleidomastoid and trapezius
What nerves leaves the cranium via the foramina in the cribriform plate of the ethmoid bone?
Olfactory
What nerves leave the cranium via the optic canal?
Optic
What nerves leave the cranium via the superior orbital fissure?
Oculomotor, Trochlear and CNV1, Abducent
What nerves leave the cranium via the foramen rotundum?
CNV2
What nerves leave the cranium via the foramen ovale?
CNV3
What nerves leave the cranium via the internal acoustic meatus?
Facial and Vestibulocochlear
What nerves leave the cranium via the jugular foramen? What else runs through here?
Glossopharyngeal, vagus and spinal accessory
The internal jugular vein
What nerves leave the cranium via the hypoglossal canal?
Hypoglossal
What modalities does the olfactory nerve have?
special sensory
What modalities does the optic nerve have?
special sensory
What modalities does the oculomotor nerve have?
motor and parasympathetic
What modalities does the trochlear nerve have?
motor
What modalities does the trigeminal nerve have?
CN V1 & V2: sensory only; V3 is sensory & motor
What modalities does the abducent nerve have?
motor
What modalities does the facial nerve have?
special sensory; motor & parasympathetic
What modalities does the vestibulocochlear nerve have?
special sensory
What modalities does the glossopharyngeal nerve have?
special sensory; sensory; motor & parasympathetic
What modalities does the vagus nerve have?
sensory; motor; parasympathetic
What modalities does the spinal accessory nerve have?
motor
What modalities does the hypoglossal nerve have?
motor
Describe how you would clinically test the sensory portion of the trigeminal nerve?
Sensory:
Key points for clinical testing are
Ophthalmic (CNV1):
forehead, upper eyelid & tip of nose
Maxillary (CNV2):
mid-cheek, lower eyelid, upper lip & nostril of nose
Mandibular (CNV3):
mid-cheek, lower lip & chin
Ask the patient to close their eyes
Gently brush the skin in each dermatome with a fine tip of cotton wool
Ask the patient to tell you when they feel their skin being touched
Compare the 2 sides
Describe how you would clinically test the motor portion of the trigeminal nerve?
Palpate the strength of contraction of the masseter & temporalis by asking patient to clench their teeth
Ask the patient to open their jaw against resistance
Describe how you would clinically test the motor function of the facial nerve?
Can clinically test motor function of CN VII by asking patient to: Frown (frontalis) close eyes tightly (orbicularis oculi) Smile (elevators of lips) puff out cheeks (buccinator)
Describe a few ways in which you can clinically test the vagus nerve?
ask patient to say ‘ah’
uvula should lift straight up in midline
unilateral pathology will pull uvula away from the non-functioning side
ask patient to swallow small amount of water
watch larynx movement
splutter may suggest abnormal swallow
listen to speech
hoarseness may suggest abnormal function of muscles of larynx
ask patient to cough
remember also requires diaphragm
Cause have to adduct the vocal chords
Describe how you would clinically test the spinal accessory nerve?
ask patient to shrug shoulders
ask them to turn head to look up towards the opposite side
Describe how you would clinically test the hypoglossal nerve?
ask patient to stick tongue straight out
if both CNXII’s are functioning normally the tongue tip remains in the midline on protrusion
if there is unilateral CN XII pathology the tongue tip will point towards the side of the injured nerve
Describe how you would clinically test the optic nerve?
Light Reflexes; Visual Field Testing; Snellen Chart
Describe how you would clinically test the oculomotor nerve?
Extraocular eye movements
Describe how you would clinically test the trochlear nerve?
Extraocular eye movements (“down & in”)
Describe how you would clinically test the abducent nerve?
Extraocular eye movements (lateral gaze)
Describe how you would clinically test the vestibulocochlear nerve?
Rhinne’s & Weber’s hearing tests
What is the only cranial nerve to attach to the Pons?
trigeminal
What is the largest of all cranial nerves?
trigeminal
All the forimanae the divisions of the trigeminal nerve pass through are found in what bone?
sphenoid
Once facial nerve emerges from stylomastoid foramen it only contains _____________
somatic motor fibres
After exiting the stylomastoid foramen the facial nerve gives off _____________
branches to go around the ear as well as stylohyoid muscle and the posterior belly of digastric
The facial nerve goes into the parotid (although doesn’t supply it) and it then gives off its five terminal branches which are _________
- To Zanzibar by Motor Car
* Temporal, Zygomatic, Buccal, Mandibular, Cervical
The muscles of facial expression originate on bone but insert onto __________
superficial fascia
List some of the muscles of facial expression
Frontalis, occipitalis, Orbicularis oculi, Elevators of the lips, Orbicularis oris
What is the vermillion border and what is the clinical significance?
border where thin skinned and hairless beginning of the lip itself, lacerations crossing the border need very careful suturing
The vagus nerve passes _________ to the root of the lung
posterior
The vagus nerve passes through diaphragm with oesophagus at _________
T10 vertebral level
What happens to the vagus nerve once it passes through the diaphragm?
The nerves become trunk like again and then referred to as anterior and posterior vagal trunks as opposed to left and right
This is because they turn on themselves and emerge anterior and posterior to the stomach
