Podcast
Questions and Answers
Which of these functions is NOT primarily controlled by the brainstem?
Which of these functions is NOT primarily controlled by the brainstem?
- Regulation of heart rate and blood pressure
- Coordination of voluntary movement (correct)
- Control of breathing
- Processing of sensory information from the body
What is the significance of the reticular activating system (RAS) in relation to human movement?
What is the significance of the reticular activating system (RAS) in relation to human movement?
- The RAS is the main pathway for motor commands from the brain to the muscles, facilitating movement execution.
- The RAS directly controls muscle contractions, allowing for voluntary movement.
- The RAS modulates muscle tone and reflexes, influencing movement smoothness and coordination. (correct)
- The RAS transmits sensory information from the body to the motor cortex, enabling the initiation of movement.
Which of these structures is NOT a component of the brainstem?
Which of these structures is NOT a component of the brainstem?
- Medulla
- Pons
- Midbrain
- Thalamus (correct)
What is the primary function of the midbrain?
What is the primary function of the midbrain?
The statement that the brainstem is the oldest part of the brain and shares similar functions with certain reptiles and fish, indicates what important concept in evolution?
The statement that the brainstem is the oldest part of the brain and shares similar functions with certain reptiles and fish, indicates what important concept in evolution?
Which cranial nerve's nucleus lies within the midbrain and primarily controls eye movement?
Which cranial nerve's nucleus lies within the midbrain and primarily controls eye movement?
What is the primary role of the red nucleus, a structure located in the midbrain?
What is the primary role of the red nucleus, a structure located in the midbrain?
What structure is located rostrally to the pons?
What structure is located rostrally to the pons?
Which neurotransmitter is produced by the raphe nuclei, a group of cells within the reticular formation?
Which neurotransmitter is produced by the raphe nuclei, a group of cells within the reticular formation?
Which structure plays a vital role in connecting the third and fourth ventricles, and is often considered a hallmark feature of the midbrain?
Which structure plays a vital role in connecting the third and fourth ventricles, and is often considered a hallmark feature of the midbrain?
What is the characteristic posture associated with damage to the rostral aspect of the midbrain, where the arms are extended and the wrists are flexed, protruding laterally?
What is the characteristic posture associated with damage to the rostral aspect of the midbrain, where the arms are extended and the wrists are flexed, protruding laterally?
Which part of the brainstem is responsible for relaying information to and from the brain and the body, serving as a pivot point for sensory and motor signals?
Which part of the brainstem is responsible for relaying information to and from the brain and the body, serving as a pivot point for sensory and motor signals?
What is the primary function of the corticospinal tract?
What is the primary function of the corticospinal tract?
What is the anatomical relationship between the midbrain and the pons?
What is the anatomical relationship between the midbrain and the pons?
Which of these structures is NOT directly connected to the brainstem?
Which of these structures is NOT directly connected to the brainstem?
Where is the locus coeruleus located, and what neurotransmitter does it produce?
Where is the locus coeruleus located, and what neurotransmitter does it produce?
Which of these structures is involved in the perception of sound?
Which of these structures is involved in the perception of sound?
What is the primary function of the ascending reticular activating system (ARAS)?
What is the primary function of the ascending reticular activating system (ARAS)?
What is the term for the crossing over of neural pathways, typically seen in the medulla oblongata?
What is the term for the crossing over of neural pathways, typically seen in the medulla oblongata?
Which cranial nerve is responsible for controlling the lateral rectus muscle, which helps in moving the eye outward?
Which cranial nerve is responsible for controlling the lateral rectus muscle, which helps in moving the eye outward?
What is the primary function of the substantia nigra, a structure located in the midbrain?
What is the primary function of the substantia nigra, a structure located in the midbrain?
A patient presents with a deviated uvula and difficulty swallowing. What cranial nerve is most likely affected?
A patient presents with a deviated uvula and difficulty swallowing. What cranial nerve is most likely affected?
During a physical examination, a patient is unable to shrug their shoulders against resistance. Which cranial nerve is likely impaired?
During a physical examination, a patient is unable to shrug their shoulders against resistance. Which cranial nerve is likely impaired?
A patient is unable to stick out their tongue straight and it deviates to the right side. What cranial nerve is most likely affected?
A patient is unable to stick out their tongue straight and it deviates to the right side. What cranial nerve is most likely affected?
A patient presents with a loss of taste sensation on the posterior 2/3 of their tongue. Which cranial nerve is likely involved?
A patient presents with a loss of taste sensation on the posterior 2/3 of their tongue. Which cranial nerve is likely involved?
Which of the following is NOT a function of the vagus nerve (CN X)?
Which of the following is NOT a function of the vagus nerve (CN X)?
A patient experiences a sudden loss of hearing in their right ear. Which of the following could be a possible cause based on the information provided?
A patient experiences a sudden loss of hearing in their right ear. Which of the following could be a possible cause based on the information provided?
What does the Weber test assess in relation to hearing?
What does the Weber test assess in relation to hearing?
Which cranial nerve is responsible for providing sensory information from the middle ear?
Which cranial nerve is responsible for providing sensory information from the middle ear?
If a lesion is present on the left medullary pyramids, what would be the expected outcome in terms of motor function?
If a lesion is present on the left medullary pyramids, what would be the expected outcome in terms of motor function?
Which of the following statements accurately describes the function of the stylopharyngeus muscle?
Which of the following statements accurately describes the function of the stylopharyngeus muscle?
What is the primary function of the ossicles in the middle ear?
What is the primary function of the ossicles in the middle ear?
Which of the following is a potential consequence of damage to the cochlear nerve?
Which of the following is a potential consequence of damage to the cochlear nerve?
A patient presents with a drooping of the left palate and a deviated uvula towards the right side. What is the most likely explanation?
A patient presents with a drooping of the left palate and a deviated uvula towards the right side. What is the most likely explanation?
Which cranial nerve is responsible for providing sensory information from the soft palate of the mouth?
Which cranial nerve is responsible for providing sensory information from the soft palate of the mouth?
Which of the following is NOT a function of the glossopharyngeal nerve (CN IX)?
Which of the following is NOT a function of the glossopharyngeal nerve (CN IX)?
How does the Rinne test distinguish between conductive and sensorineural hearing loss?
How does the Rinne test distinguish between conductive and sensorineural hearing loss?
Which function is generally associated with the cranial nerve nuclei that lie more laterally within the brainstem?
Which function is generally associated with the cranial nerve nuclei that lie more laterally within the brainstem?
What major health consequence is typically associated with a quick insult to the brainstem?
What major health consequence is typically associated with a quick insult to the brainstem?
What characteristic distinguishes the cranial nerves from other motor nerves in terms of myelination?
What characteristic distinguishes the cranial nerves from other motor nerves in terms of myelination?
Which cranial nerve is linked with the sense of smell?
Which cranial nerve is linked with the sense of smell?
What type of deficits might occur with a lesion in the optic nerve?
What type of deficits might occur with a lesion in the optic nerve?
What is the primary nuclei associated with the optic nerve?
What is the primary nuclei associated with the optic nerve?
Which artery is primarily responsible for supplying blood to the pons?
Which artery is primarily responsible for supplying blood to the pons?
Which condition exemplifies a minimally conscious state resulting from brainstem injury?
Which condition exemplifies a minimally conscious state resulting from brainstem injury?
What would be the likely visual field loss in a person with bitemporal hemianopsia?
What would be the likely visual field loss in a person with bitemporal hemianopsia?
What defines Bitemporal Hemianopsia?
What defines Bitemporal Hemianopsia?
Which nervous system function does the brainstem primarily regulate?
Which nervous system function does the brainstem primarily regulate?
Which cranial nerve is primarily responsible for most eye movements except abduction?
Which cranial nerve is primarily responsible for most eye movements except abduction?
What is the effect of shining a light in the pupil with respect to the pupillary light reflex?
What is the effect of shining a light in the pupil with respect to the pupillary light reflex?
Which specific muscle does the trochlear nerve primarily innervate?
Which specific muscle does the trochlear nerve primarily innervate?
What consequence would likely arise from a lesion in the trochlear nerve?
What consequence would likely arise from a lesion in the trochlear nerve?
In which location does the oculomotor nerve originate?
In which location does the oculomotor nerve originate?
What effect does damage to the abducens nerve typically have?
What effect does damage to the abducens nerve typically have?
Which cranial nerve crosses the midline before its function?
Which cranial nerve crosses the midline before its function?
What would you expect when testing the pupil during the pupillary light reflex?
What would you expect when testing the pupil during the pupillary light reflex?
What is the primary sensory or motor function of the oculomotor nerve?
What is the primary sensory or motor function of the oculomotor nerve?
Which cranial nerve primarily influences the contralateral side of the body while the others receive input from both sides?
Which cranial nerve primarily influences the contralateral side of the body while the others receive input from both sides?
What is a hallmark sign of individuals experiencing cranial nerve deficits related to blood circulation?
What is a hallmark sign of individuals experiencing cranial nerve deficits related to blood circulation?
What role does the pontine artery play in cranial nerve function?
What role does the pontine artery play in cranial nerve function?
Which cranial nerve is unique for crossing within the brainstem?
Which cranial nerve is unique for crossing within the brainstem?
In terms of cranial nerve lesions, what typically occurs if the injury is before the cranial nerve nuclei?
In terms of cranial nerve lesions, what typically occurs if the injury is before the cranial nerve nuclei?
Which combination of cranial nerves is associated with taste sensation?
Which combination of cranial nerves is associated with taste sensation?
Which symptom is not typically associated with injuries to cranial nerves 5, 7, 9, 10, 11, and 12?
Which symptom is not typically associated with injuries to cranial nerves 5, 7, 9, 10, 11, and 12?
Which nerves are classified as pure motor nerves?
Which nerves are classified as pure motor nerves?
What condition is caused by a lesion affecting cranial nerve pathways before reaching the brainstem?
What condition is caused by a lesion affecting cranial nerve pathways before reaching the brainstem?
Which of the following nerves are considered mixed nerves?
Which of the following nerves are considered mixed nerves?
What is the primary functional role of cranial nerve 3 (Oculomotor nerve)?
What is the primary functional role of cranial nerve 3 (Oculomotor nerve)?
Where does cranial nerve 4 (Trochlear nerve) exit the brainstem?
Where does cranial nerve 4 (Trochlear nerve) exit the brainstem?
What type of information does cranial nerve 5 (Trigeminal nerve) primarily relay?
What type of information does cranial nerve 5 (Trigeminal nerve) primarily relay?
What happens when there is damage to cranial nerve 7 (Facial nerve)?
What happens when there is damage to cranial nerve 7 (Facial nerve)?
Which cranial nerve is primarily involved in the corneal reflex?
Which cranial nerve is primarily involved in the corneal reflex?
What type of deficits should one expect with damage to the vestibulocochlear nerve (CN 8)?
What type of deficits should one expect with damage to the vestibulocochlear nerve (CN 8)?
Which muscle group is primarily innervated by the motor component of cranial nerve 5?
Which muscle group is primarily innervated by the motor component of cranial nerve 5?
Which cranial nerve has a significant autonomic component affecting the lacrimal and salivary glands?
Which cranial nerve has a significant autonomic component affecting the lacrimal and salivary glands?
Which cranial nerves primarily work together to allow tracking of visual stimuli?
Which cranial nerves primarily work together to allow tracking of visual stimuli?
What type of sensory components does the trigeminal nerve include?
What type of sensory components does the trigeminal nerve include?
How would a lesion to the right side of the facial nerve presentation differ from that of a right hemisphere stroke?
How would a lesion to the right side of the facial nerve presentation differ from that of a right hemisphere stroke?
What is the primary testing method for assessing cranial nerve 8 (Vestibulocochlear nerve)?
What is the primary testing method for assessing cranial nerve 8 (Vestibulocochlear nerve)?
Which statement about cranial nerve 6 (Abducens nerve) is accurate?
Which statement about cranial nerve 6 (Abducens nerve) is accurate?
Which cranial nerve is responsible for the sensation of taste in the anterior two-thirds of the tongue?
Which cranial nerve is responsible for the sensation of taste in the anterior two-thirds of the tongue?
Flashcards
Brainstem
Brainstem
The oldest part of the brain, consisting of the midbrain, pons, and medulla.
Midbrain
Midbrain
The uppermost section of the brainstem, involved in vision, hearing, and motor control.
Pons
Pons
The middle section of the brainstem, acting as a bridge for signals between the cerebellum and the cerebrum.
Medulla
Medulla
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Reticular activating system
Reticular activating system
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Brainstem Functions
Brainstem Functions
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Cranial Nerve Nuclei Location
Cranial Nerve Nuclei Location
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Vascular Issues in Brainstem
Vascular Issues in Brainstem
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Cranial Nerve I
Cranial Nerve I
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Cranial Nerve II
Cranial Nerve II
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Staged Consciousness Disorders
Staged Consciousness Disorders
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Blood Supply to Brainstem
Blood Supply to Brainstem
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Olfactory Nerve Testing
Olfactory Nerve Testing
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Visual Deficits and Pituitary Gland
Visual Deficits and Pituitary Gland
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Bitemporal Hemianopsia
Bitemporal Hemianopsia
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Temporal Visual Field
Temporal Visual Field
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Nasal Visual Field
Nasal Visual Field
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Pupillary Light Reflex
Pupillary Light Reflex
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Trochlear Nerve Palsy
Trochlear Nerve Palsy
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Convergence Test
Convergence Test
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Ipsilateral Deficit
Ipsilateral Deficit
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Cerebral Aqueduct
Cerebral Aqueduct
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Substantia Nigra
Substantia Nigra
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Decorticate Posturing
Decorticate Posturing
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Decerebrate Posturing
Decerebrate Posturing
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Medulla Oblongata
Medulla Oblongata
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Corticospinal Tract
Corticospinal Tract
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Reticular Formation
Reticular Formation
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Neuron Transmitters
Neuron Transmitters
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Thalamus
Thalamus
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Crus Cerebri
Crus Cerebri
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Olive Nuclei
Olive Nuclei
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Conductive Hearing Loss
Conductive Hearing Loss
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Weber Test
Weber Test
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Rinne Test
Rinne Test
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Sensorineural Hearing Loss
Sensorineural Hearing Loss
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Cochlear Nerve Activation
Cochlear Nerve Activation
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Glossopharyngeal Nerve (CN 9)
Glossopharyngeal Nerve (CN 9)
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Vagus Nerve (CN 10)
Vagus Nerve (CN 10)
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Palatal Droop
Palatal Droop
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Spinal Accessory Nerve (CN 11)
Spinal Accessory Nerve (CN 11)
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Hypoglossal Nerve (CN 12)
Hypoglossal Nerve (CN 12)
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Ipsilateral Damage Effects
Ipsilateral Damage Effects
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Medullary Pyramids
Medullary Pyramids
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Dysphasia
Dysphasia
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Gag Reflex Test
Gag Reflex Test
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Cranial Nerve Testing
Cranial Nerve Testing
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Double Vision
Double Vision
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Trigeminal Nuclei
Trigeminal Nuclei
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Sensory vs. Motor
Sensory vs. Motor
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Corneal Reflex
Corneal Reflex
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Bell’s Palsy
Bell’s Palsy
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Rinne and Weber Test
Rinne and Weber Test
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Ponto-Medullary Junction
Ponto-Medullary Junction
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Wallenberg Syndrome
Wallenberg Syndrome
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Contralateral Deficits
Contralateral Deficits
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Corticobulbar Tracts
Corticobulbar Tracts
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Extracranial Nerves
Extracranial Nerves
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Pure Sensory Nerves
Pure Sensory Nerves
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Trochlear Nerve
Trochlear Nerve
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Taste Nerves
Taste Nerves
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Parasympathetic Nerves
Parasympathetic Nerves
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Study Notes
Brainstem
- Comprised of the midbrain, pons, and medulla
- Houses vital functions: cardiovascular and respiratory control, sleep regulation, head and neck motor and sensory function
- Damage can be severe or lethal
- Interacts with other CNS structures (thalamus, cerebellum, spinal cord)
- Considered the "oldest" part of the brain, sharing functionalities with reptiles and fish
- Cranial nerves attach to the brainstem
Midbrain
- Located superiorly to the pons
- Contains the cerebral aqueduct (connecting third and fourth ventricles)
- Key structures: crus cerebri (corticospinal tract), basis pedunculi, tegmentum, and tectum (involved in cranial nerve function and eye movement)
- Contains cranial nerves III (oculomotor) and IV (trochlear) nuclei
- Red nucleus: aids in motor coordination (walking)
- Substantia nigra: produces dopamine, crucial for movement; Parkinson's disease involves substantia nigra dopamine loss
- Axial Midbrain Section: superior colliculus, red nucleus, cerebral aqueduct(of Sylvius)
- Decorticate posturing (arms flexed, legs extended) and decerebrate posturing (all limbs extended) occur with midbrain damage
Pons
- Located superior to the medulla, inferior to the midbrain
- Links with the cerebellum.
- Contains vertical tracts and cranial nerve nuclei V, VI, VII, VIII
Medulla Oblongata
- Located superior to the spinal cord, inferior to the pons
- Contains nuclei for cranial nerves IX, X, XI, and XII
- Vertical tracts (decussation) connecting brain and body for coordinating movement and sensation
- Olive nuclei: aid in cerebellar function and sound perception
Major Motor and Sensory Vertical Tracts
- Brain's right side controls body's left side and vice versa
- Corticospinal tract: pathway for movement signals
- Sensory information from one side of the body travels up the vertical tracts to the opposite side (decides and cross over via medulla)
Reticular Formation
- Loose collection of nuclei spanning the brainstem and influencing cortex
- Key Nuclei: Raphe nuclei (serotonin), locus coeruleus & medial reticular area (norepinephrine), longitudinal fasciculus, ventral tegmental area, pedunculopontine nucleus
- Ascending reticular activating system: regulates alertness, sleep, and attention; influences consciousness levels
Blood Supply (Brainstem)
- Internal carotid, posterior communicating, posterior cerebral, superior cerebellar, pontine, basilar, labyrinthine, anterior inferior cerebellar, posterior inferior cerebellar, anterior spinal, and vertebral arteries.
- Vertebral branches (anterior and posterior spinal arteries): medulla
- Basilar and its branches (pontine arteries): pons
- Posterior cerebral and posterior communicating arteries: midbrain
- Vascular issues are a common cause of brainstem lesions.
Cranial Nerves (General)
- Lower motor neurons (except olfactory and optic), some contain motor, sensory or mixed functions
- Lesions can lead to ipsilateral or contralateral deficits, depending on the nerve and location of the lesion.
Cranial Nerve I (Olfactory)
- Sensory; smell detection
- Begins in nasal cavity, passes through cribriform plate to olfactory bulb and tracts to olfactory cortex
- Bilateral function
- Not a lower motor neuron
Cranial Nerve II (Optic)
- Sensory; vision.
- Begins in the retina and goes through optic chasm then lateral geniculate nucleus in thalamus, finally ends in the primary visual cortex.
- Part of upper motor neuron system
- Lesions can cause ipsilateral or contralateral visual field deficits, depending on site
Cranial Nerves III, IV, & VI (Extra-ocular eye movements)
- All motor related to eye movement
- III (Oculomotor): multiple eye muscles, pupil constriction (autonomic)
- IV (Trochlear): superior oblique muscle
- VI (Abducens): lateral rectus muscle
Cranial Nerves V through XII
- All involve complex functions
- V (Trigeminal): sensory (face, sinuses, teeth) and motor (mastication)
- VI (Facial): facial expression, taste (anterior 2/3 of tongue), glands
- VIII (Vestibulocochlear): balance and hearing
- IX (Glossopharyngeal): taste (posterior 2/3 of tongue), pharynx, carotid body
- X (Vagus): pharynx, larynx, thoracic organs (parasympathetic), largest visceral afferent nerve
- XI (Spinal Accessory): trapezius and sternocleidomastoid muscles
- XII (Hypoglossal): tongue movement
Clinical Applications
- Midbrain damage: decorticate and decerebrate posturing
- Cranial nerve lesions: visual deficits, speech difficulties, balance problems, facial paralysis, etc.
- Stroke: various impairments
- Bell's Palsy: facial paralysis
- Wallenberg Syndrome (lateral medullary syndrome): Ipsilateral motor and sensory impairments
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