Cranial Nerves

A 40-year-old man was admitted to the neurology service for evaluation of persistent numbness over his left jaw and lower face. MRI reveals a schwannoma, which is compressing a cranial nerve as the nerve exits the skull. The cranial nerve involved in this case exits the skull through which of the following foramina? (A) Foramen ovale (B) Foramen rotundum (C) Foramen spinosum (D) Jugular foramen (E) Superior orbital fissure

(A) Foramen ovale Standing: Superior orbital fissure: V1 Room: Foramen Rotundum: V2 Only: Foramen Ovale: V3

Ansa Cervicalias

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Cough Reflex

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Nervus Intermedius

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Lacrimation Reflex

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Superior Orbital Fissure Syndrome

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Hypoglossal Nerve Lesion UMN vs LMN

* * * * * * *http://library.med.utah.edu/kw/hyperbrain/syllabus/syllabus10.html

Alternating Hemiplegia

* * * * * * *use the quizlet search feature

Facial Nerve Lesion UMN vs LMN

* * * * * *https://www.youtube.com/watch?v=5T4G27xkckE

Match the four parasympathetic CNs with their corresponding parasympathetic ganglia in the head *3 *7 *9 *10 *Otic Ganglion *Ciliary Ganglion *Pterygopalatine Ganglion *Submandibular Ganglion

*3: Ciliary Ganglion *7: Submandibular and Pterygopalatine Ganglion *9: Otic Ganglion *10: The parasympathetic ganglia of 10 are thoracoabdominal and are not in the head!

Match the four parasympathetic CNs with their corresponding brainstem nuclei *3 *7 *9 *10 *Dorsal Motor Nucleus of Vagus *Superior Salivatory Nucleus *Edinger Westphal Nucleus *Inferior Salivatory Nucleus *Lacrimal Nucleus

*3: Edinger Westphal Nucleus *7: Superior Salivatory Nucleus & Lacrimal Nucleus (Some sources include the salivatory and lacrimal nucleus as one entity, others as separate) *9: Inferior Salivatory Nucleus *10: Dorsal Motor Nucleus of Vagus

Match the Cranial Nerve with its corresponding General Somatic Efferent Nucleus *3 *4 *6 *12 *Trochlear Nucleus *Abducent Nucleus *Oculomotor nucleus *Hypoglossal Nucleus

*3: Oculomotor Nucleus *4: Trochlear Nucleus *6: Abducent Nucleus *12: Hypoglossal Nucleus

Match the Cranial Nerve with its corresponding Branchial Motor Nucleus *5 *7 *9 *10 *11 *Nucleus Ambiguus *Motor Nucleus of the Facial Nerve *Motor Nucleus of the Trigeminal Nerve *Nucleus of Spinal Accessory

*5: Motor Nucleus of the Trigeminal Nerve *7: Motor Nucleus of the Facial Nerve *9: Nucleus Ambiguus *10: Nucleus Ambiguus *11: Nucleus of Spinal Accessory

Ramsay Hunt Syndrome

*AKA Herpes Zoster Ot *Associated with reactivation of Herpes Zoster in the geniculate ganglion *Involves CN 7, but cn 8 and 9 can be involved as well *Triad of unilateral facial paralysis, lesions/vesicles in the external auditory canal, ear pain *Can also have hearing deficits, tinnitus, and vertigo *Unlike Bell's Palsy, it presents with hearing loss * *Tx: Acyclovir

Gag Reflex

*Afferent: Glossopharyngeal Nerve (CN 9) *Efferent: Vagus Nerve (CN 10) *Sensation in the oropharynx is relayed via CN 9 to the Nucleus Solitarius. *From the Nucleus Solitarius, fibers synapse with efferents in the Nucleus Ambiguus *Carried by CN 10, which causes elevation of soft palate, and constriction of pharyngeal muscles **CN 9 damage causes no gag reflex to occur upon touching ipsilateral side* **CN 10 damage causes uvula to deviate to opposite side*

Bell's Palsy and Crocodile Tears

*An uncommon consequence of recovery (Synkinesis) from Bell's palsy where faulty regeneration of the facial nerve occurs *Synkinesis = the result from miswiring of nerves after trauma *Efferents "mis-sprout" from the Superior Salivatory Nucleus and instead of innervating the salivary glands, they are misdirected to the Lacrimal glands **Excessive lacrimation induced by eating* *Can also possibly cause eye closure when the mouth is moved

Sensory Trigeminal Tracts

*Dorsal Trigeminal Tract: Chief Trigeminal Sensory Nucleus to Ipsilateral VPM (without crossing): Contain somatosensory information from inside of mouth *Trigeminal Lemniscus: Fine touch and Dental Pressure neurons synapse in Chief Trigeminal Sensory Nucleus and then crosses midline and travels next to medial lemniscus to contralateral VPM *Spinal Trigeminal Tract/ Spinal Tract of V: Carries first order neurons from the Trigeminal Ganglion to the Spinal Trigeminal Nucleus *Important to note that in addition to CN 5, 7, 9, and 10 also convey pain information from their corresponding ganglion to the spinal trigeminal nucleus. *Ventral Trigeminal Tract: From the spinal trigeminal nucleus, second-order neurons cross the midline and join the fibers from the Trigeminal Lemniscus and terminate in contralateral VPM *Mesencephalic Trigeminal Tract:

Jaw Jerk Reflex

*Elicited by placing index finger over the middle of the patient's chin with the mouth slightly open *The index finger is then tapped with a reflex hammer *Afferent: Sensory portion of V3 *Efferent: Motor portion of V3 *The afferent limb travels via V3 to the mesencephalic nucleus of the trigeminal nerve. (in Midbrain) *The mesencephalic nucleus sends axons to the trigeminal motor nucleus (in Pons) *The efferent limb arises from the trigeminal motor nucleus and also travels via V3, to the masseter. *The jaw-jerk is usually absent or weakly present *in individuals with UMN lesions, reflex can be quite pronounced (hyperactive or repeating)

CN 6 Lesion

*Eye is slightly adducted when looking straight *Double vision is greatest when looking in the direction of the affected eye (looking left when left eye is affected viceversa) *Often associated with increased ICP * * * *

Trigeminal Nerve

*GSA * * * *SVE *Originates from trigeminal motor nucleus located in pons *The branchial motor root of the trigeminal nerve joins V3 to exit in the foramen ovale and supplies the muscles of mastication + tensor tympani, tensor veli palatini, mylohyoid, and anterior belly of digastric *

Hypoglossal Nerve

*GSE *Originates from the Hypoglossal Nucleus in the medulla oblongata *Exit cranial cavity via Hypoglossal Canal/Foramen *Supply the intrinsic muscles and three of the four extrinsic muscles of the tongue (except palatoglossus; CN X) *The superior root of the ansa cervicalis accompanies the hypoglossal nerve before branching off and joining the inferior root * * * * *

Facial Nerve

*GVE (parasympathetic) component begins in the Superior Salivatory Nucleus (& Lacrimal Nucleus) *The parasympathetic nerves are carried as a small branch called the Nervus Intermedius *The SVE (branchial motor) component begins in the Motor Nucleus of Facial Nerve *The two roots travel through the internal acoustic meatus and enter the facial canal of the temporal bone *Within the canal, the two roots fuse to form the facial nerve *At the genu/bend, the Geniculate Ganglion is formed *The Greater Petrosal Nerve is given off at the genu and reaches the Pterygopalatine Ganglion *The Chorda Tympani is given off right before the stylomastoid foramen and courses upward to join the lingual nerve and reaches the Submandibular Ganglion * * * * * * * *

CN 10 Lesion

*Ipsilateral paralysis of the soft palate, pharynx, and larynx leading to dysphonia(hoarseness)/fixed vocal cord *Nasal speech, nasal regurgitation (liquid enters trachea) *Dysphagia and palate droop *Loss of the gag reflex (efferent limb) *Anesthesia of the pharynx and larynx, leading to unilateral loss of the cough reflex *Uvula pointing away from side of lesion **********Aortic aneurysms and tumors of the neck and thorax **frequently compress the vagal nerve.

CN 4 Lesion

*MCC is congenital *MCC acquired cause is trauma *Remember that the trochlear nerve decussates just caudal to the inferior colliculus *Lesion prior to decussation => dysfunction of contralateral superior oblique => tilting of head towards side of lesion **Lesion after decussation => dysfunction of ipsilateral superior oblique => tilting of head away from lesion* **Nasal Upshoot (eye turns upward when looking towards he nose) occurs when patients try to look medially (i.e when reading/walking down stairs)* *

Match each of the three Trigeminal Sensory Nuclei, with it's position in the Brainstem (Midbrain, Pons, Medulla) *Mesencephalic Trigeminal Nucleus *Chief Trigeminal Sensory Nucleus *Spinal Trigeminal Nucleus

*Mesencephalic Trigeminal Nucleus: Midbrain *Chief Trigeminal Sensory Nucleus: Pons *Spinal Trigeminal Nucleus: Medulla

For each of the three Trigeminal Sensory Nuclei, provide the sensory modality that it serves *Mesencephalic Trigeminal Nucleus *Chief Trigeminal Sensory Nucleus *Spinal Trigeminal Nucleus

*Mesencephalic Trigeminal Nucleus: Proprioception (From Jaw Muscles) *Chief Trigeminal Sensory Nucleus: Fine Touch, Dental Pressure *Spinal Trigeminal Nucleus: Crude Touch, Pain, Temperature

Bell's Palsy

*Most common cause of unilateral facial paralysis *Most commonly idiopathic *May also be viral: Lyme disease, Herpes simplex, Herpes Zoster, CMV *Other causes include sarcoidosis, tumors, Diabetes/hypertension *Usually acute in presentation *Usually due to inflammation of the Facial nerve lying within the facial canal (therefore LMN) *Ipsilateral paralysis of both upper and lower muscles of facial expression *Paralysis of the stapedius muscle results in hyperacusis *Loss of taste sensation to anterior tongue *Bilateral Bell palsy is unusual; however, it is commonly associated with Lyme disease. *Corneal reflex may be absent *70-80% of patients recover spontaneously within 2-12 weeks *Tx: Steroids, Artificial tears/taping eye shut, antiviral drugs if necessary

Cavernous Sinus Thrombosis

*Most common initial presenting symptom is Headache * * *Causitive organisms is most commonly Staphylococcus aureus (70%) * * *Tx: Antibiotics with or without surgical drainage

Cavernous Sinus

*Paired venous sinus found on each side of the sella turcica *Lateral Wall: CN III, IV, V1, V2 *Centrally: CN VI, ICA *CN VI is most susceptible to injury **Postganglionic sympathetic pupillary fibers are also carried alongside the ICA and damage may result in a Horner's Syndrome*

Vagus Nerve

*SVE *Arises from the nucleus ambiguus *Innervates the pharyngeal arch muscles of the larynx and pharynx, striated muscle of the upper esophagus, musculus uvalae, and levator palati and palatoglossus *Provides the efferent limb of the gag reflex *GVE *Arises from the Dorsal Motor Nucleus of Vagus *Some sources say that cardiac preganglionics arise from the nucleus ambiguus *These preganglionic axons innervate terminal ganglia in the pharynx, larynx, abdomen, heart, lungs (notice that the vagus does not have any parasympathetic ganglia in the head and neck region) *

Glossopharyngeal Nerve

*SVE *Originates from the nucleus ambiguus *Innervates the Stylopharyngeus Muscle which elevates the pharynx during talking and swallowing and contributes to the Gag Reflex *GVE *Originates from the Inferior Salivatory Nucleus *Projects via the tympanic nerve and lesser petrosal nerve to the Otic Ganglion *Postganglionic fibers from the otic ganglion project to the parotid gland via the auriculotemporal nerve (CN V3). * * * * * * *

Spinal Accessory Nerve

*SVE (Branchiomotor) *Traditionally, the accessory nerve is divided into spinal and cranial parts. *The spinal part originates from the Nucleus of Spinal Accessory located in C1-C5/C6 (Unique in that it does not originate from the brainstem unlike the other CNs) *The cranial part originates from the nucleus ambiguus *Enter the cranial cavity via the Foramen Magnum *Exit cranial cavity via Jugular Foramen *The Cranial part rejoins the vagus nerve and distributes to the same targets as the vagus (considered to be functionally part of the vagus) *The Spinal part innervates the SCM and Trapezius *Fxn: *Deficit:

Miscellaneous Facts about CNs *What is the only nerve to exit the brainstem dorsally? *Which nerve is the largest? *Which nerve has the longest intracranial course? * * *

*What is the only nerve to exit the brainstem dorsally? 4 *Which nerve is the largest? 5 *Which nerve has the longest intracranial course? 4

A 53-year-old woman has a paralysis of the right side of her face that produces an expressionless and drooping appearance. She is unable to close her right eye, has difficulty chewing and drinking, perceives sounds as annoyingly intense in her right ear, and experiences some pain in her right external auditory meatus. Physical examination reveals loss of the blink reflex in the right eye on stimulation of either cornea and loss of taste from the anterior two-thirds of the tongue on the right. Lacrimation appears normal in the right eye, the jaw-jerk reflex is normal, and there appears to be no problem with balance. Question 1 of 2 The inability to close the right eye is the result of involvement of which of the following? A. Zygomatic branch of the facial nerve B. Buccal branch of the trigeminal nerve C. Levator palpebrae superioris muscle D. Superior tarsal muscle (of Müller) E. Orbital portion of the orbicularis oculi muscle Question 2 of 2 Which of the following is the branch of the facial nerve that conveys secretomotor neurons involved in lacrimation? A. Chorda tympani B. Deep petrosal nerve C. Greater superficial petrosal nerve D. Lacrimal nerve E. Lesser superficial petrosal nerve

1. A. Zygomatic branch of the facial nerve 2. C. Greater superficial petrosal nerve The greater superficial petrosal nerve leaves the facial nerve (CN VII) at the geniculate ganglion. It carries secretomotor neurons from the superior salivatory nucleus to the pterygopalatine ganglion and joins along the way with the sympathetic deep petrosal nerve to become the nerve of the pterygoid canal

A 67-year-old male with a past medical history of lung cancer and chronic sinusitis presents to the emergency room with left-sided eye pain. He also reports a moderate headache, for which he has taken ibuprofen without relief. On exam, he is noted to have left-sided proptosis (Figure A) and decreased occular range of motion. An MRI is performed, and he is found to have a cavernous sinus thrombosis (Figure B). Which of the following group of nerves run through the cavernous sinus? 1. III, IV, V-1, V-2, and VI 2. III, IV, V-2, V-3, and VI 3. IV, V-1, V-3, VI, and IX 4. V-1, V-2, V-3, VII, and VIII 5. VII, VIII, IX, XI, and XII

1. III, IV, V-1, V-2, and VI

What cranial nerves exit the skull through the superior orbital fissure?

3,4,6 and V1

Which of the four Cranial Nerves have General Somatic Efferent Functions (GSE)?

3,4,6, and 12

What are the four CNs that carry parasympathetic fibers?

3,7,9,10

Which of the Cranial Nerves have Branchial Motor Function? (SVE)

5, 7, 9, 10, 11

What 4 CNs use the Spinal trigeminal nucleus? What kinds of fibers are found in this nucleus?

5,7,9,10 Pain

What cranial nerves exit the skull through the Internal Auditory Meatus?

7,8

What 3 CNs use the Solitary nucleus? What kind of fibers are found in this nucleus?

7,9,10 Visceral Sensory information (eg, taste, baroreceptors, gut distention)

There are 12 pairs of cranial nerves; how many of them have their nuclei within the brainstem? Which are the exceptions?

9 of the cranial nerves have their nuclei within the brainstem Exceptions: CN 1,2,11

What 3 CNs use Nucleus Ambiguus? What kinds of fibers are found in this nucleus?

9,10,11

What cranial nerves exit the skull through the jugular foramen?

9,10,11

In "Jaw jerk Reflex" afferent limb carries impulses to the "nucleus" located in ? A-Mid brain B-Pons C-Medulla E-Cervical spinal cord

A)

A physician is performing a cranial nerve examination on a patient. While testing the gag reflex, it is noted that when the right side of the pharyngeal mucosa is touched, the patient's uvula deviates to the right. When the left side of the pharyngeal mucosa is touched, the patient does not gag. Which of the following is the most likely location of his lesion? A. Left glossopharyngeal nerve and left vagus nerve B. Left glossopharyngeal nerve only C. Left vagus nerve only D. Right glossopharyngeal nerve and right vagus nerve E. Right glossopharyngeal nerve only F. Right vagus nerve only

A. Left glossopharyngeal nerve and left vagus nerve Touching the right side => uvula deviates to right Means CN 9 on right side is intact Means CN 10 on left side is damaged Touching the left side => no gag Means CN 9 on left side is damaged

72-year-old male with a history of a previous stroke comes to the physician for an annual exam. When the patient sticks out his tongue, you note that it deviates to the left. In addition, when the left posterior pharynx is stimulated with a cotton swab, the uvula deviates to the right. Which cranial nerves are involved? A. Left hypoglossal nerve; Left vagus nerve B. Left hypoglossal nerve; Right vagus nerve C. Right hypoglossal nerve; Left vagus nerve D. Right hypoglossal nerve; Right vagus nerve E. Left hypoglossal nerve; Left glossopharyngeal nerve. F. Left hypoglossal nerve; Right glossopharyngeal nerve.

A. Left hypoglossal nerve; Left vagus nerve 12: Typically LMN lesion. Tongue deviates toward side of lesion 10: Uvula deviates away from side of lesion *Mnemonic: Tongue, towards lesion, Uvula, Uway from lesion*

Fibers of the facial nerve loop around the _____________ before exiting the brainstem

Abducens Nuclei

CN __________ provides touch sensation for the anterior 2/3 of the tongue CN __________ provides touch sensation for the posterior 1/3 of the tongue CN __________ provides taste for the anterior 2/3 of the tongue CN __________ provides taste for the posterior 1/3 of the tongue

Anterior 2/3 Touch Sensation: 5 Taste: 7 Posterior 1/3 Touch Sensation & Taste: 9

The Nervus Intermedius contain(s): (Pick all that apply) A. Motor Fibers B. Sensory Fibers C. Secretory Fibers D. Parasympathetic Fibers E. Sympathetic Fibers

B,D

Bulbar Palsy vs PseudoBulbar Palsy

Bulbar *Typically involves CN 9,10,11, and 12 **LMN Lesion* *Gag reflex - absent *Tongue - wasted, wrinkled, fasciculations *Palatal movement - absent. *Jaw jerk - absent or normal *Speech - nasal "indistinct (flaccid dysarthria), lacks modulation and has a nasal twang" *Emotions - normal *Other - signs of the underlying cause, e.g. limb fasciculations. Pseudobulbar *Typically involves CN 5,7,9,10,11, and 12 **UMN Lesion (usually bilateral degeneration of corticobulbar tract)* *Gag reflex - increased or normal *Tongue - spastic, small, and tight *Palatal movement - absent. **Jaw jerk - increased* *Speech - spastic: "a monotonous, slurred, high-pitched, 'Donald Duck' dysarthria" that "sounds as if the patient is trying to squeeze out words from tight lips". *Emotions - labile (inappropriate crying/laughing) *Examination may reveal upper motor neuron lesion of the limbs

What is bulbar palsy? What is pseudobulbar palsy?

Bulbar palsy refers to impairment of CN 9,10,11, and 12 Occurs due to impairment of the cranial nerve nuclei or distally (LMN lesion) Pseudobulbar palsy refers to impairment of the same cranial nerves but occurs due to impairment of the Corticobulbar pathways that arise from the cortex and innervate the cranial nerve nuclei (UMN lesion). For clinically evident dysfunction to occur, such lesions must be bilateral as these cranial nerve nuclei receive bilateral innervation. Two exceptions to this are the muscles of the lower face and the genioglossus muscle (responsible for sticking out tongue) which only receive contralateral innervation

Bulbar Palsy is a ____________ (UMN/LMN) disorder PseudoBulbar Palsy is a ____________ (UMN/LMN) disorder

Bulbar: LMN PseudoBulbar: UMN

A 42-year-old male presents to the emergency room with a one day history of facial weakness, vertigo, and ataxia. Physical examination reveals an erythematous left external ear canal with vesicular eruptions. There is left facial weakness with left forehead involvement. When asked to walk the patient is unable to do so because of severe vertigo. What is the most likely diagnosis? A. Bell's palsy B. Left acoustic neuroma C. Ramsay Hunt syndrome D. Multiple sclerosis E. Shy-Drager syndrome

C. Ramsay Hunt syndrome Ramsay Hunt syndrome is characterized by ear pain, tinnitus, ipsilateral facial palsy, vertigo and ataxia. It is caused by varicella virus infection of the ear canal with involvement of the seventh and eighth cranial nerves. Examination of the ear canal may show erythema with vesicular eruptions. Treatment is with acyclovir. The other choices are incorrect.

A patient is observed to suffer from an alternating hypoglossal hemiplegia. There is atrophy of the tongue on one side and deviation of the tongue toward the right on protrusion. In addition, the patient exhibits upper motor neuron paralysis of the left side of the body. Deviation of the tongue toward the right involves which of the following? A. Left nucleus ambiguus B. Left pyramidal tract caudal to the decussation C. Right hypoglossal nerve D. Right nucleus ambiguus E. Right pyramidal tract rostral to the decussation

C. Right hypoglossal nerve Alternating Hemiplegia = Ipsilateral lower motor neuron paralysis of cranial nerve Contralateral upper motor neuron paralysis of arm and leg This patient has UMN paralysis of left side of body (contralateral) LMN paralysis of hypoglossal = deviates towards side of lesion Deviating towards right means that right hypoglossal nerve is damaged

Which of the following statements about the corticobulbar tracts is correct? A. They arise along with the corticospinal tracts from both sensory and motor areas of the cortex. B. They travel primarily in the posterior limb of the internal capsule. C. They provide bilateral innervation to most of the motor nuclei they serve. D. They contact circuit neurons to coordinate motor activity of the entire limb that they innervate. E. They innervate both somatic and visceral motor nuclei in the brainstem

C. They provide bilateral innervation to most of the motor nuclei they serve

The primary sensory neuron cell bodies for the afferent trigeminal fibers (V1-V3) are located within? A.Cerebral cortex B.Chief Trigeminal Sensory Nucleus: C.Trigeminal ganglion D.Spinal Trigeminal Nucleus

C. Trigeminal Ganglion The trigeminal ganglion is analogous to the dorsal root ganglia of the spinal cord, which contain the cell bodies of incoming sensory fibers from the rest of the body

Which of the Cranial nerves running through the Cavernous Sinus is most susceptible to injury?

CN 6 Only cranial nerve 6 runs centrally within the cavernous sinus and as such is the most likely nerve to be affected by cavernous sinus pathology

What are the Cranial Nerves that receive unilateral UMN innervation?

CN 7 and 12 The corticobulbar tracts provide bilateral innervation to most of the motor nuclei they serve Two exceptions: muscles of the lower face and the genioglossus muscle (responsible for sticking out tongue) which only receive contralateral innervation

What 2 Nuclei of the Trigeminal Nerve send ascending branches?

Chief Trigeminal Sensory Nucleus and Spinal Trigeminal Nucleus

What are the four parasympathetic ganglia in the head?

Ciliary Ganglion Pterygopalatine Ganglion Submandibular Ganglion Otic Ganglion

A 16-year-old girl with much facial acne has continued to pick at and squeeze her 'pimples.' One day facial bacteria from one of her open sores enters her facial veins and travels to the right cavernous sinus of her brain, causing a cavernous sinus thrombosis. Which two structures in the cavernous sinus of the brain will be most affected? A Cranial nerves II and III B Cranial nerves V1 and V2 C Sphenoid bone and internal carotid artery D Cranial nerve VI and internal carotid artery E Cranial nerves IX and IV

D Cranial nerve VI and internal carotid artery

Intracranial Hemorrhage because of an epidural hematoma is due to the rupture of a vessel that enters the cranium through which cranial foramen ? A-Foramen lacerum B-Foramen ovale C-Foramen rotundum D-Foramen spinosum E-Foramen magnum F-Jugular foramen

D-Foramen spinosum Epidural Hematoma = rupture of middle meningeal artery

Lesions of the glossopharyngeal nerve would A. Affect the sympathetic innervation to the parotid gland B. Affect the parasympathetic innervation to the submandibular gland C. Affect taste to the anterior 1/3 of the tongue D. Result in general sensory deficit to the pharynx E. Result in loss of motor innervation to the risorius muscle

D. Result in general sensory deficit to the pharynx

A 45-year-old man with a history of vertigo is brought to the emergency department because of loss of consciousness after a fall. He appears mildly confused but is not in any acute distress. Physical examination of the head shows blood behind the tympanic membrane. A CT scan of the head shows a basilar skull fracture, with a fracture fragment compromising the foramen rotundum. Which of the following will most likely result from the patient's foramen rotundum injury? A. Bleeding from the carotid artery B. Bleeding with epidural hematoma formation C. Ipsilateral deviation of the tongue D. Sensory defects in the midface E. Sensory defects of the forehead

D. Sensory defects in the midface Standing: Superior orbital fissure: V1 Room: Foramen Rotundum: V2 Only: Foramen Ovale: V3

Corticobulbar Tract

Descending pathway that arises from the lateral aspect of the primary motor cortex and synapses with motor cranial nerves for voluntary control of the muscles of facial expression, eye movements, jaw opening and closing, and movements of the tongue *Fxn: Voluntary control of head and neck *Origin: Lateral aspect of primary motor cortex *Distribution: Bilateral to most CN nuclei of the brainstem except contralateral to 7 (lower face) *Contained within the Genu of the internal capsule *Travels parallel to the Corticospinal tract *For clinical dysfunction to occur, most require bilateral damage (Two exceptions: CN 7 lower face, CN 12 genioglossus muscle)

Which of the following cranial nerves does NOT carry preganglionic fibers in the head? A) III B) V C) VII D) IX E) XI

E)

During an experiment on the cough reflex in humans, a subject inhales air containing different amounts of particles that will impact and adhere to mucus primarily in the trachea. Blockade of which of the following afferent pathways would most likely prevent this subject's reflex to initiate a cough? A) Glossopharyngeal B) Laryngeal C) Olfactory D) Trigeminal E) Vagal

E) Vagal

A 55-year-old banker develops paralysis on the right side of the face, which produces an expressionless and drooping appearance. He is unable to close the right eye and also has difficulty chewing and drinking. Examination shows loss of blink reflex in the right eye to stimulation of either right or left conjunctiva. Lacrimation appears normal on the right side, but salivation is diminished and taste is absent on the anterior right side of the tongue. There is no complaint of hyperacusis. Audition and balance appear to be normal. Which of the following is the most likely location of the lesion? A. In the brain and involves the nucleus of the facial nerve and superior salivatory nucleus B. Within the internal auditory meatus C. At the geniculate ganglion D. In the facial canal just distal to the genu of the facial nerve E. Just proximal to the stylomastoid foramen

E. Just proximal to the stylomastoid foramen The patient has facial paralysis, which indicates injury to the facial nerve. A problem in the internal auditory meatus usually affects hearing and balance. That the superior salivatory nucleus is normal is indicated by normal lacrimation. Hence, the lesion must be distal to the origin of the greater superficial nerve at the genu of the facial nerve. However, absence of hyperacusis indicates that the branch to the stapedius muscle is functioning normally, and this fact suggests that the lesion is close to the stylomastoid foramen. Loss of taste and diminished salivation locate the lesion proximal to the origin of the chorda tympani nerve. If the lesion were distal to the stylomastoid foramen, taste and salivation would have been normal with facial paralysis as the only sign.

All of the motor innervation of the tongue is provided by hypoglossal (CN XII) T/F?

F! All except for the Palatoglossus muscle which is provided by vagus CN X

Which thalamic nuclei is involved in relaying somatosensory information from face to cortex? from rest of body?

Face: VPM (Make up on face; vpM) Rest of Body: VPL

Which structures are located in the lateral wall of the Cavernous Sinus? Which structures are located centrally in the Cavernous Sinus?

Lateral Wall: CN III, IV, V1, V2 (superior to inferior) Centrally: ICA, CN VI FIND A PIC

The Trigeminal Sensory System is composed of three nuclei. What are they?

Mesencephalic Trigeminal Nucleus Chief Trigeminal Sensory Nucleus Spinal Trigeminal Nucleus

Which vessels and nerves pass through the superior orbital fissure

NERVES V1 -lacrimal -frontal -nasociliary nerve III (superior and inferior division) VI IV VESSELS superior and inferior ophthalmic vein

The Superior Salivatory nucleus gives preganglionic axons which are carried by the ____________________ nerve and terminates in the ____________________ ganglion The Lacrimal nucleus gives preganglionic axons which are carried by the ____________________ nerve and terminates in the ____________________ ganglion

Superior Salivatory -> Chorda Tympani -> Submandibular Lacrimal -> Greater Petrosal -> Pterygopalatine

Why may the corneal reflex be absent in patients with Bell's Palsy?

The corneal reflex causes blinking of the eye when the cornea is touched. Afferent division carried by the V1 of the trigeminal nerve and the efferent part is carried by the facial nerve and causes contraction of orbicularis oculi. Because the facial nerve is paralyzed, eyelid closure may be impaired. It is important to lubricate the eye with artif cial tears and to tape the eye shut during the night in order to prevent damage to the cornea

What is unique about the Mesencephalic Nucleus?

The neurons of the mesencephalic nucleus are the only case in which the cell bodies of primary sensory neurons lie within the CNS, rather than a peripheral ganglia. Therefore there are no synapses within it! (Most synapse in the Motor Nucleus)

A UMN Lesion of the Hypoglossal Nerve => The tongue deviates ________________ (ipsilateral/contralateral) to the side of the lesion A LMN Lesion of the Hypoglossal Nerve => The tongue deviates ________________ (ipsilateral/contralateral) to the side of the lesion

UMN: Contralateral LMN: Ipsilateral

The upper half of the Motor Nucleus of Facial nerve receives stimulation from ______________ (ipsilateral,contralateral, both) corticobulbar tract/s The lower half of the Motor Nucleus of Facial nerve receives stimulation from ______________ (ipsilateral,contralateral, both) corticobulbar tract/s

Upper Half: Both Contralateral and Ipsilateral Lower Half: Contralateral

Where does each division of the Trigeminal Nerve exit the skull?

V1: *S*uperior Orbital Fissure V2: Foramen *R*otundum V3: Foramen *O*vale Mnemonic: Standing Room Only

As a physician you are seeing a patient who presents to you with weakness, hyper-reflexes and persistent spasms of the muscle. On lower extremities exam you strike the patients sole with an instrument that reveals a reflex causing the big toe of the patient to extend upwards. With the clinical presentation of this patient, which of the following below is also a possible pathological finding? a) Corneal reflex b) Lacrimation reflex c) Jaw jerk reflex d) Pupillary reflex e) Gag reflex

c) Jaw jerk reflex The patient is presenting with a UMN Lesion. The jaw jerk reflex is usually absent except in patients with UMN Lesions

During what appeared to be routine surgery for a torn ligament, a middle-aged man suffered a stroke. After a few days, the patient showed some recovery because he was able to walk with some difficulty, and, in addition, sensory functions seemed normal. However, a neurologic evaluation revealed a weakness in muscles that regulate breathing, speech, swallowing, and facial expression. A subsequent magnetic resonance imaging scan indicated that the stroke was limited but primarily affected the: a. Premotor cortex b. Medullary pyramids c. Posterior limb of internal capsule d. Genu of internal capsule e. Anterior limb of internal capsule

d. Genu of internal capsule The symptoms described in this case reflect pseudobulbar palsy , which is characterized by weakness in the muscles of the head and face. It involves corticobulbar pathways that innervate, in part, cranial nerve motor nuclei. These fibers are contained in the genu of the internal capsule.

Clinical presentation of Cavernous Sinus Syndrome

decreased corneal and maxilllary sensation not mandibular

CN 3 Lesion

https://www.youtube.com/watch?v=fMAIYqPNiYY