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82 Cards in this Set
- Front
- Back
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How many cranial nerves are there? |
XII |
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Name the cranial nerves, IN ORDER |
Olfactory Optic Occulomotor Trochlear Trigeminal Abducens Facial nerve Vestibulocochlear Glossopharyngeal Vagus Accessory Hypoglossal nerve |
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What is the cranial exit of CN I? |
Cribriform Plate |
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What is the cranial exit of CN II? |
Optic Canal |
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What is the cranial exit of CN III? |
Superior orbital fissure |
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What is the cranial exit of CN IV? |
Superior orbital fissue |
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What is the cranial exit of CN V? |
V1: Superior Orbital Fissure V2: Foramen rotundum V3: Foramen ovale |
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What is the cranial exit of CN VI? |
Superior Orbital fissure |
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What is the cranial exit of CN VII? |
Internal auditory meatus Stylomastoid foramen |
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What is the cranial exit of CN VIII? |
Internal auditory meatus Does not leave |
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What is the cranial exit of CN X? |
Jugular Foramen |
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What is the cranial exit of CN XI? |
Jugular Foramen |
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What is the cranial exit of CN XII? |
Hypoglossal canal/foramen |
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What is the cranial exit of IX? |
Jugular foramen |
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Which nerves leave through the superior orbital fissure? |
III, IV, VI, V1 |
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Which nerves leave through the cribriform plate? |
I |
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Which nerves leave through the optic foramen? |
II |
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Which nerves leave through the foramen rotundum? |
V2 |
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Which nerves leave through the foramen ovale? |
V3 |
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Which nerves leave through the internal auditory meatus? |
VII, VIII |
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Which nerves leave through the hypoglossal foramen? |
XII |
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Which nerves leave through the jugular foramen? |
IX, X, XI |
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Which nerves run through the stylomastoid foramen? |
VII |
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Which nerves run through the carotid canal? |
IX, X, XI |
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Which cranial nerves are sensory? |
I, II, VIII |
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Which cranial nerves are muscular? |
III, IV, VI, XI, XII |
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Which nerves are mixed motor/sensory? |
V, VII, IX, X |
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GSE cell bodies are found where? |
Brainstem or spinal cord, innervate skeletal muscle |
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Which nerves are GSEs? |
III, IV, VI, spinal root of XI, XII
Also, all 31 spinal nerves have GSE fibers |
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The skeletal muscles supplied by GSEs arise from what embryonic structure? |
Somites |
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The skeletal muscles supplied by SVEs arise from what? |
Branchial arches, not somites |
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Which cranial nerves are SVEs? |
CN V, VII, IX, X, XI (cranial root) |
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Parasympathetic GVEs travel with which cranial nerves? |
III, VII, IX, X |
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GSA fiber cell bodies are found where? |
Outside the CNS, in the dorsal root sensory ganglion or sensory ganglia of cranial nerves |
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GSAs are responsible for which sensations? |
Pain, temperature, touch, pressure, proprioception, etc |
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Which nerves carry GSA fibers? |
CN V, VII, IX,X |
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Which sensations are GVAs responsible for? |
Burning, fullness, pain (poorly localized), thirst, hunger, chemoreception
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Which cranial nerves carry GVAs? |
CN IX, X |
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What are SSAs? |
Special Somatic afferent nerves Fibers associated with special senses of vision and hearing and balance Associated with highly specialized somatic receptiors stimulated by non-chemical changes like light or mechanical movements, ie, retina in eye and auditory receptors in the ear. |
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Which cranial nerves carry SSAs? |
CN II, VIII |
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What are SVAs? |
Special Visceral Afferent nerves Fibers associated with special senses of taste and smell Receptors are highly modified special receptors which detect chemical changes |
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Which nerves carry SVAs? |
CN I, VII, IX, X |
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What is the loss of smell called? |
Anosmia |
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Oculomotor nerve palsy |
Ptosis of the ey lid, paralysis of levator palpebrae superioris and unopposed action of the orbicularis oculi innervated by CN VII Lateral stabismus (down and out) unopposed action of LR and SO Dilation of pupil (paralysis of sphincter innervated by parasympathetics traveling with CNIII resulting in unopposed action of the sympathetics) Loss of accomodation to light Protosis- prominence of the globe Diplopia- double vision |
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What are the special characteristics of the trochlear nerve? |
IV Smallest yet running the longest in its subarachnoid course Only nerve to emerge from the dorsal surface of the brain stem Embedded in the lateral wall of the cavernous sinus (along with III and V1, V2) Enters the superior orbital fissure to supply the superior oblique muscle |
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What are the symptoms and causes of trochlear nerve injury? |
Impairs the ability to depress, abduct, and intort (medially rotate) the affected globe Torn in severe head injuries Vertical diplopia (double vision) when attempting to go down stairs due to unopposed action of inferior oblique. Patient compensates by tucking chin in. Patient looks dejected, hence 'pathetic nerve palsy' Patient also compensates toritonal diplopia by inclining th ehead laterally towards the side of the normal eye in order to keep images level. |
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What are some special characteristics of the abducens nerve? |
VI abducens nerve Longest intradural course within the cranial cavity Makes sharp bend over the crest of the petrous part of the temporal bone and is therefore subject to stretch Parallels internal carotid artery which is also located within the cavernous sinus |
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What are the symptoms and causes of abducens nerve injury? |
Abducens nerve VI Complete paralysis by a space occupying lesion causes medial deviation of affected eye Fully adducted due to unopposed action of medial rectus producing medial strabismus Diplopia in all ranges of movement except on gazing to the side opposite the lesion Injury can result from: -Aneurysm in the circle of Willis -Pressure in the cavernous sinus -Fractures of the cranial base |
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What are the three divisions and nerve types for the trigeminal nerve? |
Cranial nerve V V1- Opthalmic -sensory V2- Maxillary- Sensory V3- Mandibular- Mixed
Standing Room Only -Superior Orbital fissure -Foramen rotundum -Foramen Ovale |
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What are some special characteristics of the V3 branch of the trigeminal nerve? |
V3- Mandibular Arises from the union of the pseudounipolar fibers from the semilunar (trigeminal) ganglion and unites with its motor root fibers originating in the floor of the fourth ventricle.
Exits the skull through foramen ovale in the greater wing of the sphenoid bone
Only division of the trigeminal nerve to innervate the skeletal muscle |
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Trigeminal Neuralgia Etiology |
Tic Douloureaux Etiology: Primary cause is neurovascular compression at the root entry zone as the nerve travels through the prepontine cistern to enter the pons This junctional area is vulnerable to continued pulsatile pressure, can result in focal demyelination and ephatic impulses Majority of the cases, compression is caused by an elongated superior cerebellar artery and to a lesser degree by an elongated anterior inferior cerebellar artery |
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Trigeminal Neuralgia Symptoms |
Severe, electric shock-like stabs lasting several seconds Each attack may be followed by a refractory period lasting minutes or hours Burst of pain can be spontaneous or triggered by stimulating a specific area, usually over the V2 and to a lesser degree the V3 dermatome areas Pain may occur daily for months or weeks and disappear, only to return years later Onset after 50 usually Women 2x as likely to be affected Usually no sensory loss |
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Herpes Zoster Opthalmicus |
Shingles Occurs when the varicellar-zoster virus is reactivated in the trigeminal ganglia of V1 Represents 1/4 of all VZV cases More common in the elderly, immunosuppressed patients Pain (burning, aching, gnawing) is unilateral, steady and sustained. Paroxysmal shooting, stabbing, or radiating pain produced by light mechanical stimuli may persist. Initial onset reveals erythema and typical herpiform lesions of skin, associated with parasthesia Posttherpetic neuralgia- pain persisting more than 4-6 weeks after rash resolves, most frequent neurologcal complication of VZV |
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Facial nerve CN VII has how many roots? |
Two SVE (Branchia motor root to muscles of facial expression) and GSA from skin of ear is the larger root SVA and GVE are smaller root (nervus intermedius) |
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What does the SVE component of the facial nerve do? GVE? SVA? GSA? |
SVE- Supplies the muscles of facial expression, posterior belly of digastric muscle, stylohyoideus, stapedius, platysma, and occipitofrontalis GVE- Parasympathetic innervation of the lacrimal, submandibular, and sublingual glands, as well as mucosal glands of nasopharynx and palate SVA- Taste sensation from anterior 2/3 of tongue and palate GSA- General sensation from the skin of the external ear |
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Branches of the facial nerve before it enters the parotid gland: |
Posterior auricular branch- sensory branch to ear (GSA) and motor to occipital part of occipitofrontalis (SVE) Motor branches to vestigeal muscles of ear (SVE) Motor branches to stylohyoideus and posterior belly of digastric (SVE) |
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Branches of the facial nerve within and exiting the parotid gland |
ALL SVE Temporal Zygomatic Buccal Mandibular Cervical |
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Nerve to Stapedius |
Supplies stapedius muscle Action of stapedius is to prevent hte excessive vibration to be transmitted to the internal ear by pulling on the stapes bone So every time there is loud sound, stapedius contracts to prevent large vibration from damaging inner ear If stapedius is paralyzed due to nerve damage, hyperacusis (sounds sound louder than normal) |
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Chorda Tympani |
SVA Taste to anterior 2/3 of tongue and palate |
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Name and define the two types of facial nerve damage |
Supranuclear facial palsy: Contralateral facial paralysis with sparing of forehead muscles, damage is superior to the facial nucleus in pons Infranuclear facial palsy: ipsilateral facial paralysis. Will have different addition sign/symptoms depending on exact site of the lesion |
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What if the facial nerve had a lesion before the geniculate ganglion? |
Most commonly in the IAM Complete same side facial paralysis Hyperacusis, loss of lacrimation and salivation Loss of taste from anterior 2/3rds of tongue and palate
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What if the facial nerve had a lesion just after geniculate ganglion? |
Complete same side facial paralysis Hyperacusis Loss of taste of anterior 2/3rds of tongue BUT taste over palate and lacrimation is not lost due to preservation of greater superficial petrosal nerve |
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What if the facial nerve had a lesion after the chorda typmpani leaves facial nerve (most commonly at or around the stylomastoid foramen)? |
Bell's Palsy (complete same side facial paralysis) But no taste loss, no hyperacusis, no loss of lacrimation, no loss of salivation |
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Bells Palsy |
A lesion of CN VII which occurs at or below the stylomastoid foramen is commonly referred to as a Bell's Palsy Characteristics of Bell's Palsy include the following on the affected side: Marked facial asymmetry, atrophy of facial muscles, eyebrow droop, eyes remain open, difficulty in tightly closing eyes Smoothing of forehead and nasolabial folds Drooping of the corner of the mouth, yielding inavailability to smile or whistle Loss of efferent limb of conjunctival reflex (can't close eye) Lips can't be tightly held together, or pursed Difficulty keeping food in mouth while chewing on affected side |
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CN VIII name, fiber type, etc? |
CN VIII Special Somatic Afferents It is the nerve of the inner ear Leaves the posterior cranial fossa through the internal acoustic meatus in the petrous part of the temporal bone SSA consisting of a lateral cochlear root for audition and a medial vestibular root for orientation in a 3D space
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Name and define the two types of hearing loss |
Conductive: External ear, tympanic membrane or bony ossicles are issue. Patients with this type of hearing loss speak softly because they hear their voice as louder than background sounds
Sensorineural- Problem in the cochlea, cochlear nerve component or auditory pathway in brain |
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Tinnitus |
Constant ringing sound or buzzing in ear Mostly due to cochlear duct damage |
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High Tone Deafness |
Auoustic trauma disease Continued exposure to loud sounds without protection causes degenerative changes in the spiral organ of the cochlea
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Otic barotrauma |
An imbalance int he pressure between ambient air and the air in the middle ear |
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Aucoustic neruoma |
A slowly progressing benign Schwann cell tumor
Tumor initiates in the vestibular ganglion while in the internal acoustic meatus Early symptom? Hearing loss Dysequilibration and tinnitus in 70% of patients |
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Injuries to CN IX? |
Effect of Injury: Loss of taste from posterior 1/3 of tongue and loss of sensation from the affected side of the soft palate Testing: Suppression of the gag reflex due to the initiating sensory component caried in the afferents to pharynx Jugular foramen syndrome: Tumors in this region produce multiple cranial nerve palsies because CNs IX, X, and XI pass through this foramen Glossopharyngeal Neuralgia (tic): Paroxysmal burning, stabbing pain initiated by swallowing, protruding the tongue or eating |
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CNX- Vagus components |
SVE: Muscles of pharynx (except stylopharyngeus- CN IX ) larynx, soft palate, palatoglossus, and cricothyroideus GVE: Parasympathetic to smooth muscles and glands (of thoracic and abdominal organs) GSA: Cutaneus sensory from auricle/ear and eternal auditory meatus and part of the tympanic membrane SVA: Taste from epiglottis and root of the tongue GVA: Some general ill defined sensation from root of tongue, sensory from lower pharynx, larynx, aortic body and aortic sinus, thoracic and abdominal organs |
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What are the possible results of a CN X lesion? |
1. Hoarseness and dysphonia, due to vocal cord paralysis (laryngeal recurrent n.) 2. Aphonia and inspiratory stridor if both recurrents are damaged, due to cancer, surgery complications 3. Weakness of voice, anesthesia of the upper larynx, paralysis of the cricothyroideus if superior laryngeal damaged 4. Dysphagia (trouble swallowing), injury to pharyngeal branches |
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How do you clinically test for a CNX injury? |
Sagging of affected side of palate. Arch of palate doesn't elevate when patient says "aha". Uvula deviates to unaffected side.
Loss of gag reflex, which affects the motor component of the pharyngeal muscles
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CN XI- Spinal Accessory Nerve components |
Cranial root, joins vagus, and innervates muscles of pharynx, larynx, and palate, (branchiomeric)
Spinal root: Innervates SCM and trapezius (GSE only) |
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Describe the course of cranial nerve XI |
The cranial root emerges from the medulla as a series of rootlets caudal to CNX Spinal root emerges from C1-C6 spinal roots and ascends through foramen magnum. Two roots join inside the cranial cavity, and exit via the jugular foramen The roots separate , cranial root joins CNX and the spinal root descends, enters, and passes through SCM, terminates in the trapezius |
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What are the possible results of injury to CNXI? |
The spinal part is subcutaneous in the posterior cervical triangle, susceptible to injury in nodal biopsy which could cause SCM paralysis and trapezius paralysis
Tested in contralateral turning of head, patient presents with drooping of affected shoulder |
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Describe the components of CN XII |
Hypoglossal nerve GSE Innervates intrinsic and extrinsic muscles of the tongue
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Describe the course of the hypoglosssal nerve |
CNXII Emerges from the upper medulla between the medullary pyramid and the olive Leaes the skull through the hypoglossal canal Passes downward and forward int he neck between the ICA and IJV Crosses the loop of the lingual artery (BRance of ECA) Passes DEEP TO MYELOHYOID MUSCLE Sends branches to the muscles of the tongue |
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What are the muscles supplied by the hypoglossal nerve CNXII? |
Extrinsic muscles of the tongue: genioglossus, hyoglossus, styloglossus, NOT PALATOGLOSSUS Intrinsic muscles of the tongue. |
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Which nerve acts as a carrier for the superior fibers of C1 to supply the geniohyoid, thyrohyoid and the infrahyoid muscles via the ansa cervicalis? |
Hypoglossus muscle |
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What are the effects and testing for seeing if there is an injury to CN XII? |
Effect: Difficulty in speech/articulation of words (moderate dysarthria). Atrophy of the ipsilateral side of the tongue (appears shrunken and wrinkled).
Testing: When a patient is asked to stick out their tongue, it moves to the affected side due to the unopposed action of the genioglossus on the normal side. |
