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WorksheetsNeuro Week #8
Total questions: 104
Worksheet time: 3hrs 28mins
What are the four functions of cranial nerves?
Participates in the regulation of autonomic and endocrine functions, decision-making and adaptations of instinctive and motivational behaviors to changes in the environment through implicit associative learning, changes in short- and long-term synaptic plasticity, and activation of the fight-or-flight response via efferent projections from its central nucleus to cortical and subcortical structures.
Supply motor innervation to muscles of the face, eyes, tongue, jaw, and two other superficial neck muscles, sternocleidomastoid, and trapezius.
Transmit somatosensory information from the skin and muscles to the face and temporomandibular joint.
Transmit special sensory information related to visual, auditory, vestibular, taste, olfactory, and visceral sensations.
Provide parasympathetic regulation of the pupil size, curvature of the lens of the eye, heart rate, blood pressure, breathing, and digestions.
Where do signals from the olfactory bulb travel to in the olfactory nerve?
- Signals travel in the olfactory tract directly to the cerebellum in the brainstem and to the cerebral cortex and parahippocampal gyrus in the posterior temporal lobe.
- Signals travel in the olfactory tract indirectly to the primary cerebral cortex in the amygdala and to the brainstem and parahippocampal gyrus in the lateral temporal lobe.
- Signals travel in the olfactory tract directly to the primary olfactory cortex in the insula and to the amygdala and parahippocampal gyrus in the medial temporal lobe.
What region of the brainstem does the trigeminal nerve emerge from?
Emerges from the frontalis in the buccinator between the medulla and the cerebellar peduncles.
Emerges from the lateral pons in the cerebral cortex between the amygdala and the cerebellar peduncles.
Emerges from the mid pons in the brainstem between the pons and the cerebellar peduncles.
What areas of the head and face does the trigeminal nerve provide somatosensory innervation to?
- Eyeballs including cornea.
- Anterosuperior external ear
- Anterior ear canal
- Tongue
- Temporomandibular joint
- Masseter
- Temporalis
- Lateral and medial pterygoids
- Frontalis
- Orbicularis oculi
- Orbicularis oris
- Buccinator
Which 3 sensory nuclei receive facial somatosensory information via the branches of the trigeminal nerve (specify the type of somatosensory information for the different sensory nuclei)?
- Proprioceptive via medulla
- Hard touch via posterior sensory
- Moderate nociception and temperature via spinal
- Proprioceptive via brainstem
- Physical touch via lateral sensory
- Slow nociception and temperature via sympathetic fibers
- Proprioceptive via mesencephalic
- Light touch via main sensory
- Fast nociception and temperature via spinal
What muscles does the trigeminal nerve innervate?
- Frontalis
- Orbicularis oculi
- Orbicularis oris
- Buccinator
- Masseter
- Temporalis
- Lateral and medial pterygoids
- Palatoglossus
- Palatopharyngeus
- Muscles of the larynx
- Sternocleidomastoid
- Trapezius
What reflex is mediated by the trigeminal nerve and facial nerve? Describe the underlying mechanism.
- Trigeminal nerve: afferent limb corneal reflex.
- Facial Nerve: efferent limb of corneal reflex.
Touching of the cornea elicits closing of the eyelids.
- Trigeminal nerve: efferent limb grasp reflex.
- Facial Nerve: afferent limb of grasp reflex.
Blowing on the cornea elicits opening of the eyelids.
- Trigeminal nerve: efferent limb stepping reflex.
- Facial Nerve: efferent limb of stepping reflex.
Putting water on the cornea elicits closing of the eyelids.
Where does the facial nerve emerge from the brainstem?
Base of the pons
Base of the medulla
Base of the brainstem
Base of the cerebellar peduncles
Which muscles does the facial nerve innervate?
- Sternocleidomastoid
- Trapezius
- Palatoglossus
- Palatopharyngeus
- Muscles of the larynx
- Masseter
- Temporalis
- Lateral and medial pterygoids
- Frontalis
- Orbicularis oculi
- Orbicularis oris
- Buccinator
Which part of the tongue does the facial nerve provide special sensory for taste?
Posterior 2/3 of the tongue
Anterior 2/3 of the tongue
Tip of the tongue
Lateral side of the tongue
Which cranial nerve innervates most of the glands in the head except the parotid salivary glands?
Trigeminal nerve
Oculomotor nerve
Facial nerve
Hypoglossal nerve
Can you describe the cortical control of the muscles in the upper and lower face?
Cortical control of muscles in the upper face in unilateral and in the lower face is ipsilateral.
Cortical control of muscles in the upper face in bilateral and in the lower face is contralateral.
Where does the glossopharyngeal nerve emerge from the brainstem?
Rostral medulla posterior to the olive.
Midbrain to the olive.
Pons to the olive.
Medulla oblongata to the olive.
Which part of the tongue does the glossopharyngeal nerve provide special sensory for taste?
Posterior 1/3 of the tongue
Anterior 2/3 of the tongue
Posterior 2/3 of the tongue
Tip of the tongue
Which muscle does the glossopharyngeal nerve innervate?
Lateral ptreygoid
Medial pterygoid
Stylopharyngeus
Masseter
Which reflexes are mediated by the glossopharyngeal and vagus nerve? Describe the underlying mechanism.
- Glossopharyngeal Nerve: afferent limb of the gag and swallowing reflex
- Vagus Nerve: efferent limb of the gag and swallowing reflex
Gag reflex: touching of pharynx elicits contraction of pharyngeal muscles.
Swallowing reflex: food touching entrance of pharynx elicits movement of the soft palate and contraction of pharyngeal muscles.
- Glossopharyngeal Nerve: efferent limb of the autonomic and chewing reflex
- Vagus Nerve: afferent limb of the tonic neck and sneezing reflex
Gag reflex: touching of pharynx elicits relaxation of pharyngeal muscles.
Swallowing reflex: liquids touching the entrance of pharynx elicits no movement of the hard palate and relaxation of pharyngeal muscles.
Where does the vagus nerve emerge from the brainstem?
Rostral medulla anterior to the olive and lateral to cranial nerve XII.
Rostral medulla posterior to the olive and inferior to cranial nerve XI.
Ventral medulla anterior to the olive and superior to cranial nerve X.
Which muscles does the vagus nerve innervate?
- Sternocleidomastoid
- Trapezius
- Palatoglossus
- Palatopharyngeus
- Muscles of the larynx
- Frontalis
- Orbicularis oculi
- Orbicularis oris
- Buccinator
What autonomic afferent and parasympathetic innervation does the vagus nerve supply and what are some of the parasympathetic functions?
- Autonomic afferent: from the pharynx, larynx, thorax, and abdomen
- Parasympathetic: efferents to smooth muscles and glands in the pharynx, larynx, thorax, and abdomen.
Functions:
o Reduction of heart rate
o Constrict the bronchi.
o Affect speech production.
o Increase digestive activity.
- Autonomic afferent: from the tongue, lips, thorax, and stomach
- Parasympathetic: afferents to skeletal muscles and glands in the tongue, lips, thorax, and stomach.
Functions:
o Increase of heart rate
o Vasodilate the bronchi.
o Affect hearing production.
o Decrease digestive activity.
Which cranial nerves provide autonomic innervation (specific the structures they innervate)?
- Abducens nerve
Efferents to ciliary muscle (changes shape of lens to focus on a near object)
Pupillary sphincter
- Hypoglossal nerve
Efferents to lacrimal, sublingual, and submandibular glands
- Trigeminal nerve
Efferent to parotid gland
Afferents from carotid sinus and carotid body
- Trochlear nerve
Afferents and efferents:
Heart, lungs, trachea, bronchi, larynx, pharynx, gastrointestinal system, liver, and pancreas.
- Oculomotor nerve
Efferents to ciliary muscle (changes shape of lens to focus on a near object)
Pupillary sphincter
- Facial nerve
Efferents to lacrimal, sublingual, and submandibular glands
- Glossopharyngeal nerve
Efferent to parotid gland
Afferents from carotid sinus and carotid body
- Vagus nerve
Afferents and efferents:
Heart, lungs, trachea, bronchi, larynx, pharynx, gastrointestinal system, liver, and pancreas.
What muscles does the accessory nerve innervate?
- Frontalis
- Orbicularis oculi
- Orbicularis oris
- Buccinator
- Sternocleidomastoid
- Trapezius
- Stylopharyngeus
- Masseter
- Temporalis
- Lateral and medial pterygoids
What muscles does the hypoglossal nerve innervate?
- Intrinsic muscles of the tongue
Superior longitudinal muscle
Inferior longitudinal muscle
Transverse muscle
Vertical muscle
- Extrinsic muscles of the tongue
Genioglossus
Hyoglossus
Styloglossus
- Palatoglossus
- Palatopharyngeus
- Muscles of the larynx
- Frontalis
- Orbicularis oculi
- Orbicularis oris
- Buccinator
Which cranial nerves are involved in eating?
- Olfactory nerve (CN I)
- Facial nerve (CN VII)
- Optic nerve (CN II)
- Trochlear nerve (CN IV)
- Vestibulocochlear nerve (CN VIII)
- Trigeminal nerve (CN V)
- Facial nerve (CN VII)
- Glossopharyngeal nerve (CN IX)
- Vagus nerve (CN X)
- Hypoglossal nerve (CN XII)
Which cranial nerves are involved in speaking? Discuss each one’s role in speech production.
- Trigeminal nerve: controls jaw movements.
- Facial nerve: coordinates lip movements.
- Glossopharyngeal nerve
- Vagus nerve: sounds generated by the larynx.
- Hypoglossal nerve: innervates the tongue.
- Trochlear nerve: controls jaw movements.
- Accessory nerve: coordinates lip movements.
- Optic nerve
- Oculomotor nerve: sounds generated by the larynx.
- Vagus nerve: innervates the tongue.
- Trigeminal nerve: coordinates lip movements.
- Facial nerve: cotrols jaw movements.
- Glossopharyngeal nerve
- Vagus nerve: innervates the tongue.
- Hypoglossal nerve: sounds generated by the larynx.
Which cranial nerves receive descending control by the corticobrainstem tracts and the emotion system?
- Oculomotor nerve (3)
- Trochlear nerve (4)
- Trigeminal nerve (5)
- Glossopharyngeal nerve (9)
- Vagus nerve (10)
- Accessory nerve (11)
- Hypoglossal nerve (12)
- Vestibulocochlear nerve (8)
- Optic nerve (2)
- Trigeminal nerve (5)
- Glossopharyngeal nerve (9)
- Vagus nerve (10)
- Accessory nerve (11)
- Olfactory nerve (1)
What is the big picture role of the brainstem in the CNS?
An essential crossroads of neural communication and regulation.
Integration center for pathways.
Major processing center for emotions. It also links your emotions to many other brain abilities, especially memories, learning and your senses.
When it doesn't work as it should, it can cause or contribute to disruptive feelings and symptoms.
It deals with the autonomic functions of breathing, heart rate, blood pressure, and sleep-wake cycle.
Which region of the brainstem are the cerebral peduncles located and what major descending motor tract do they contain?
Located in the medulla.
Descending spinothalamic tracts that mediate voluntary motor activity.
Located in the pons.
Ascending corticobrainstem tracts that mediate involuntary motor activity.
Located in the midbrain.
Descending corticospinal tracts that mediate voluntary motor activity.
Which cranial nerve emerges from the interpeduncular fossa?
Trigeminal nerve
Optic nerve
Oculomotor nerve
Facial nerve
What are the primary functions of the nuclei contained in the pons?
Manages heart, circulation and breathing.
Sleep, respiration, swallowing, bladder, control, hearing, equilibrium, taste, eye movement, facial expressions, facial sensation, & posture.
Anger, fear, and sadness, as well as the controlling of aggression.
Breathing, consciousness, blood pressure, heart rate, and sleep.
Which descending motor tract is located in the medullary pyramids and what happens to this tract in this region?
Descending corticospinal fibers which cross forming the decussation of the pyramids in the caudal medulla.
Descending corticobrainstem fibers which cross forming the decussation of the pyramids in the caudal medulla.
Descending spinothalamic fibers which cross forming the decussation of the pyramids in the caudal medulla.
Descending reticulospinal fibers which cross forming the decussation of the pyramids in the caudal medulla.
Where are the olives located?
Postolateral surface of the rostral medulla.
Anterior surface of the rostral medulla.
Lateral surface of the rostral medulla.
Anterolateral surface of the rostral medulla.
Where is the superior colliculus located in the brainstem and what is its function?
- Part of the tectum of the midbrain.
- Integrates various sensory inputs and influences eye movement, head and body orientation, and postural adjustments.
- Part of the tectum of the medulla.
- Integrates various motor outputs and influences mouth movement, limb orientation, and trunk adjustments.
Where is the inferior colliculus located in the brainstem and what is its function?
- Located just below the superior colliculus in the midbrain tectum.
- Integrates auditory info from both ears to detect the location of sounds.
- Located just above the inferior colliculus in the medulla tectum.
- Integrates auditory info from both ears to detect the location of sounds.
Where is the basilar section of the midbrain located and what structures does it primarily contain?
Located laterally.
Corticospinal, corticobrainstem, corticopontine, and corticoreticular tracts, substantia nigra, pontine nuclei, and inferior olive, and the pontocerebellar axons.
Located posteriorly.
Spinothalamic, corticobrainstem, corticopontine, and corticoreticular tracts, substantia nigra, pontine nuclei, and superior olive, and the pontocerebellar axons.
Located anteriorly.
Corticospinal, corticobrainstem, corticopontine, and corticoreticular tracts, substantia nigra, pontine nuclei, and inferior olive, and the pontocerebellar axons.
Where is the tegmentum located and what roles does it play?
Located laterally.
Involved in adjusting the general level of neural activity via the reticular formation, integrating sensory info via sensory nuclei and the ascending sensory tracts, and cranial nerve functions via the cranial nerve nuclei.
Located posteriorly.
Involved in adjusting the general level of neural activity via the reticular formation, integrating sensory info via sensory nuclei and the ascending sensory tracts, and cranial nerve functions via the cranial nerve nuclei.
Located anteriorly.
Corticospinal, corticobrainstem, corticopontine, and corticoreticular tracts, substantia nigra, pontine nuclei, and inferior olive, and the pontocerebellar axons.
Where is the tectum located and what are the functions of the structures it contains?
Longitudinal section, posterior to the tegmentum.
Contains structures involved in the reflexive control of intrinsic and extrinsic eye muscles and in movements of the head.
Located posteriorly.
Involved in adjusting the general level of neural activity via the reticular formation, integrating sensory info via sensory nuclei and the ascending sensory tracts, and cranial nerve functions via the cranial nerve nuclei.
Located anteriorly.
Corticospinal, corticobrainstem, corticopontine, and corticoreticular tracts, substantia nigra, pontine nuclei, and inferior olive, and the pontocerebellar axons.
Which descending motor tracts are contained in the basis pedunculi in the midbrain?
Spinothalamic, corticobrainstem, and reticulospinal tracts.
Corticopontine, corticospinal, and corticobrainstem tracts.
Corticospinal
Corticobrainstem
Corticopontine axons
Pontine nuclei
Pontocerebellar axons
Which nuclei in the basal ganglia circuit is located in the basis pedunculi in the upper/rostral midbrain?
Tegmentum
Pons
Substantia Nigra
Medulla
Where is the red nucleus located and what circuit is it part of?
- In the tectum.
- Part of a cognitive-emotion circuit.
- In the tegmentum.
- Part of a cognitive-motor circuit.
- In the pons.
- Part of a behavioral-motor circuit.
What structures are located anterior to the cerebral aqueduct in the midbrain tegmentum?
Olfactory complex, the nuclei of cranial nerve VII (facial nerve) and the nucleus of the vestibulocochlear nerve, cranial nerve III.
Optic complex, the nuclei of cranial nerve V (trigeminal nerve) and the nucleus of the hypoglossal nerve, cranial nerve II.
Oculomotor complex, the nuclei of cranial nerve III (oculomotor nerve) and the nucleus of the trochlear nerve, cranial nerve IV.
What structure surrounds the cerebral aqueduct in the midbrain tegmentum and what are some of the functions it is involved in?
Tegmentum.
Coordinates somatic and autonomic reactions to nociception, threats, and emotions. Also, elicits the freeze-fight-flight reaction and vocalization during laughing and crying.
Periaqueductal gray.
Coordinates somatic and autonomic reactions to nociception, threats, and emotions. Also, elicits the freeze-fight-flight reaction and vocalization during laughing and crying.
Cerebral peduncles.
Coordinates somatic and autonomic reactions to nociception, threats, and emotions. Also, elicits the freeze-fight-flight reaction and vocalization during laughing and crying.
Which descending motor tracts synapse in the pons?
- Vestibulospinal
- Spinobrainstem
- Spinopontine axons
- Pontine nuclei
- Anterior cerebellar axons
- Reticulospinal
- Corticobrainstem
- Corticopontine axons
- Pons
- Spinocerebellar axons
- Corticospinal
- Corticobrainstem
- Corticopontine axons
- Pontine nuclei
- Pontocerebellar axons
Which cranial nerve nuclei and their function are located in the tegmentum of the pons?
- Trigeminal (CN V)
Function: chewing.
- Abducens (CN VI)
Function: lateral movement of the eye.
- Facial (CN VII)
Function: in facial expressions.
- Vestibulocochlear (CN VIII)
Function: sound; head position and head movement.
- Facial (CN VII)
Function: chewing.
- Vestibulocochlear (CN VIII)
Function: lateral movement of the eye.
- Trigeminal (CN V)
Function: in facial expressions.
- Abducens (CN VI)
Function: sound; head position and head movement.
- Trigeminal (CN V)
Function: in facial expressions.
- Abducens (CN VI)
Function: medial movement of the eye.
- Facial (CN VII)
Function: chewing.
- Vestibulocochlear (CN VIII)
Function: sound; limb position and limb movement.
What functions do the medullary neuronal networks coordinate?
- Emotion control
- Coughing
- Head and eye movements.
- Swallowing
- Behavioral control
- Sneezing
- Limb and trunk movements.
- Chewing
- Cardiovascular control
- Breathing
- Head and eye movements.
- Swallowing
Which cranial nerve nuclei are located in the dorsal section of the upper medulla?
- Medial to lateral
Hypoglossal nucleus of CN XII
Dorsal motor nucleus of the Vagus, CN X
The solitary nucleus which processes taste from CN VII and IX
Autonomic afferents from CN IX and X
Vestibular nuclei for CN VIII
- Lateral to medial
Olfactory nucleus of CN I
Dorsal motor nucleus of the facial, CN VII
The solitary nucleus which processes taste from CN VI and X
Autonomic efferents from CN II and IX
Vestibular nuclei for CN VIII
Which cranial nerve nuclei are located in the lateral medulla and what are their functions?
- Spinal trigeminal nucleus
Process nociceptive and temperature information from the ipsilateral face.
- Nucleus ambiguous
Contributes motor fibers to striated muscles in the pharynx, larynx, and upper esophagus via CN IX and X.
- Spinal vestibulocochlear nucleus
Process nociceptive and sensation information from the contralateral face.
- Nucleus ambiguous
Contributes sensory fibers to striated muscles in the pharynx, tongue, and upper esophagus via CN X and VII.
Which cranial nerve structures are in the caudal medulla and what are their function?
- Glossopharyngeal nerve (CN IX)
Function: controls movements of the tongue essential for speech articulation, swallowing, and manipulation of food.
- Trigeminal Nerve (CN V)
Function: controlling heart rate, respiratory digestions, and maintaining homeostasis.
- Vestibulocochlear Nerve (CN XI)
Function: controlling head rotation, shoulder elevation, and posture.
- Hypoglossal nerve (CN XII)
Function: controls movements of the tongue essential for speech articulation, swallowing, and manipulation of food.
- Vagus Nerve (CN X)
Function: controlling heart rate, respiratory digestions, and maintaining homeostasis.
- Spinal Accessory (CN XI)
Function: controlling head rotation, shoulder elevation, and posture.
What are the overall functions of the reticular formation?
- Integrate sensory and cortical information.
- Regulates somatic motor activity.
- Autonomic function
- Consciousness
- Modulates nociceptive information.
- Integrate motor and cortical information.
- Regulates autonomic motor activity.
- Somatic function
- Unconsciousness
- Modulates nociceptive information.
What are the major reticular nuclei in the brainstem?
- Dorsal tectum area
- Pedunculopontine nucleus
- Pons olive
- Locus coeruleus
- Lateral reticular area
- Ventral tegmental area
- Pedunculopontine nucleus
- Raphe nuclei
- Locus coeruleus
- Medial reticular area
Where does the midbrain receive its entire blood supply from?
Posterior cerebral artery
Anterior cerebral artery
Anterior choroidal artery
Middle cerebral artery
Where does the pons receive its blood supply from?
Carotid artery and its branches
Basilar artery and its branches
Cerebellar artery and its branches
Vertebral artery and its branches
Which arteries supply the medulla?
- Anterior spinal arteries supply the dorsal columns in the caudal medulla.
- Posterior spinal artery supplies the paramedian area of the medulla along with the lateral areas of the rostral medulla.
- Vertebral inferior arteries supply the posterolateral area of the medulla.
- Posterior arteries supply the paramedian area of the caudal medulla, the paramedian and the lateral areas of the rostral medulla.
- Posterior spinal arteries supply the dorsal columns in the caudal medulla.
- Anterior spinal artery supplies the paramedian area of the medulla along with the lateral areas of the rostral medulla.
- Posterior inferior arteries supply the posterolateral area of the medulla.
- Vertebral arteries supply the paramedian area of the caudal medulla, the paramedian and the lateral areas of the rostral medulla.
When would a lesion in the brainstem cause ipsilateral corticospinal and dorsal column medial lemniscus impairments?
When the spinothalamic tract or ventral column nuclei are in the inferior medulla.
When the corticospinal tract or dorsal column nuclei are in the inferior medulla.
When the corticospinal tract or ventral column nuclei are in the superior medulla.
When the reticulospinal tract or dorsal column nuclei are in the superior medulla.
Will lesions to the spinothalamic tract in the brainstem cause ipsilateral or contralateral impairments?
Ipsilateral impairments
Contralateral impairments
Do lesions in the brainstem cause ipsilateral or contralateral signs?
A combination of ipsilateral and contralateral signs.
Ipsilateral signs
Contralateral signs
What is the effect on fast nociceptive and temperature sensation in the face and the body when a lesion occurs in the lower pons and/or medulla interrupting spinal trigeminal and spinothalamic axons?
- Axons that convey fast nociceptive information from the face descend ipsilaterally near the spinothalamic tract, which are carrying nociception info from the contralateral body.
- Contralateral loss from the face would occur if the trigeminal lemniscus axons were interrupted.
- If the lesion was in the cerebrum, midbrain, or upper pons contralateral loss would occur for the face and the body.
- Axons that convey slow nociceptive information from the face descend contralaterally near the corticospinal tract, which are carrying nociception info from the ipsilateral body.
- Ipsilateral loss from the face would occur if the trigeminal lemniscus axons were stopped.
- If the lesion was in the cerebrum, midbrain, or upper pons ipsilateral loss would occur for the face and the body.
What is Rule 1 of the brainstem rule of 4?
- There are 4 tracts to the side that begin with S.
- Sympathetic tract: synapses with sympathetic neurons that innervate the superior tarsal muscle which assists in raising the eyelid and the pupillary dilator muscle.
- Spinothalamic tract: fast nociception and temperature from the body.
- Spinal trigeminal tract: fast nociception and temperature from the face.
- Spinocerebellar tract: unconscious proprioception.
- There are 2 cranial nerves in the midbrain, 4 in the pons, and 4 in the medulla.
- Midbrain: CN III, IV
- Pons: CN V, VI, VII, VIII
- Medulla: CN VIII, IX, X, XII
- CN V extends into the medulla.
- CN VIII extend into both the pons and medulla.
- The nucleus of CN XI is in the spinal cord.
- CN XI is not affected by brainstem lesions.
What is Rule 2 of the brainstem rule of 4?
- The four motor medially located nuclei in the brainstem are numbers that divide equally into 12.
- CN III, IV, VI, XII.
- Oculomotor nucleus
- Nucleus of trochlear nerve
- Abducens nucleus
- Hypoglossal nucleus
- There are 4 tracts to the side that begin with S.
- Sympathetic tract: synapses with sympathetic neurons that innervate the superior tarsal muscle which assists in raising the eyelid and the pupillary dilator muscle.
- Spinothalamic tract: fast nociception and temperature from the body.
- Spinal trigeminal tract: fast nociception and temperature from the face.
- Spinocerebellar tract: unconscious proprioception.
What is Rule 3 of the brainstem rule of 4?
- There 4 structures near the midline that begin with M.
- Motor nuclei of CNs that innervate muscles that move the eyes (CN III, IV, VI) or move the tongue (CN XII).
- Motor tract: corticospinal tract.
- Medial longitudinal fasciculus: neurons within the brainstem that coordinate eye and head movements.
- Medial lemniscus: part of the dorsal column medial lemniscus pathway.
- The four motor medially located nuclei in the brainstem are numbers that divide equally into 12.
- CN III, IV, VI, XII.
- Oculomotor nucleus
- Nucleus of trochlear nerve
- Abducens nucleus
- Hypoglossal nucleus
What is Rule 4 of the brainstem rule of 4?
- There 4 structures near the midline that begin with M.
- Motor nuclei of CNs that innervate muscles that move the eyes (CN III, IV, VI) or move the tongue (CN XII).
- Motor tract: corticospinal tract.
- Medial longitudinal fasciculus: neurons within the brainstem that coordinate eye and head movements.
- Medial lemniscus: part of the dorsal column medial lemniscus pathway.
- The four motor medially located nuclei in the brainstem are numbers that divide equally into 12.
- CN III, IV, VI, XII.
- Oculomotor nucleus
- Nucleus of trochlear nerve
- Abducens nucleus
- Hypoglossal nucleus
What structures may be damaged in a person who has a lateral brainstem lesion in the pons? Would these signs be ipsilateral or contralateral?
- Affects cranial nerves V (trigeminal), VIII (vestibulocochlear), IX (glossopharyngeal) & X (vagus).
- Spinothalamic tract: contralateral loss of nociceptive and temperature sensation from the body.
- Spinal trigeminal tract: loss of nociception and temperature from ipsilateral face.
- Spinocerebellar tract: ipsilateral ataxia of the limbs.
- Sympathetic pathway: ipsilateral Horner’s syndrome.
- Affects cranial nerves V (trigeminal), VII (facial) & VIII (vestibulocochlear).
- Affects the 4 S’s: spinocerebellar tract, spinothalamic tract, spinal trigeminal tract & sympathetic pathway.
- Spinothalamic tract: contralateral loss of nociceptive and temperature sensation from the body.
- Spinal trigeminal tract: loss of nociception and temperature from ipsilateral face.
- Spinocerebellar tract: ipsilateral ataxia of the limbs.
- Sympathetic pathway: ipsilateral Horner’s syndrome.
What structures may be damaged in a person who has a lateral brainstem lesion in the medulla? Would these signs be ipsilateral or contralateral?
- Affects cranial nerves V (trigeminal), VIII (vestibulocochlear), IX (glossopharyngeal) & X (vagus).
- Spinothalamic tract: contralateral loss of nociceptive and temperature sensation from the body.
- Spinal trigeminal tract: loss of nociception and temperature from ipsilateral face.
- Spinocerebellar tract: ipsilateral ataxia of the limbs.
- Sympathetic pathway: ipsilateral Horner’s syndrome.
- Affects cranial nerves V (trigeminal), VII (facial) & VIII (vestibulocochlear).
- Affects the 4 S’s: spinocerebellar tract, spinothalamic tract, spinal trigeminal tract & sympathetic pathway.
- Spinothalamic tract: contralateral loss of nociceptive and temperature sensation from the body.
- Spinal trigeminal tract: loss of nociception and temperature from ipsilateral face.
- Spinocerebellar tract: ipsilateral ataxia of the limbs.
- Sympathetic pathway: ipsilateral Horner’s syndrome.
What are the signs and symptoms of lateral medullary syndrome (Wallenberg’s syndrome)?
- CN 5 (spinal trigeminal nucleus): Loss of nociception & temperature from the ipsilateral face.
- CN 8 (vestibular nuclei): Vertigo, nausea, vomiting, nystagmus, tilted head position & balance problems.
- CN 10 (efferents from dorsal motor nucleus of vagus): problems with digestion & decreased ability to slow heart rate.
- CN 10 (afferents to solitary nucleus): increased heart rate.
- CN 9 & 10 (nucleus ambiguus): problems with swallowing, speaking, loss of gag reflex & hoarseness.
- CN 5(spinal trigeminal nucleus): loss of nociception and temperature from the ipsilateral face
- CN 7(facial nucleus): ipsilateral paralysis muscles of face, loss of efferent limb of corneal reflex and stapedial reflex (causes sounds to be louder due to loss of stapes bone movement damping)
- CN 7(salivatory nucleus): lack of tears in the eyes and decreased salivation
- CN 8(cochlear nucleus): unilateral deafness
- CN 8 (vestibular nuclei): vertigo, nausea, vomiting, nystagmus
What artery is occluded in lateral medullary syndrome?
Anterior inferior cerebellar artery
Posterior inferior cerebellar artery
Basilar artery
What are the signs and symptoms of lateral inferior pontine stroke?
- CN 5 (spinal trigeminal nucleus): Loss of nociception & temperature from the ipsilateral face.
- CN 8 (vestibular nuclei): Vertigo, nausea, vomiting, nystagmus, tilted head position & balance problems.
- CN 10 (efferents from dorsal motor nucleus of vagus): problems with digestion & decreased ability to slow heart rate.
- CN 10 (afferents to solitary nucleus): increased heart rate.
- CN 9, 10, 12 (nucleus ambiguus): problems with swallowing, speaking, loss of gag reflex & hoarseness.
- CN 5(spinal trigeminal nucleus): loss of nociception and temperature from the ipsilateral face
- CN 7(facial nucleus): ipsilateral paralysis muscles of face, loss of efferent limb of corneal reflex and stapedial reflex (causes sounds to be louder due to loss of stapes bone movement damping)
- CN 7(salivatory nucleus): lack of tears in the eyes and decreased salivation
- CN 8(cochlear nucleus): unilateral deafness
- CN 8 (vestibular nuclei): vertigo, nausea, vomiting, nystagmus
What artery is occluded in a lateral inferior pontine stroke?
Cerebellar artery
Posterior inferior cerebellar artery
Anterior inferior cerebellar artery
Basilar artery
What structures may be damaged in a person who has a medial brainstem lesion in the midbrain? Would these signs be ipsilateral or contralateral?
- Cranial nerve III (oculomotor) or IV (trochlear).
- Motor (corticospinal tract): contralateral weakness.
- Medial lemniscus: contralateral loss fine touch and conscious proprioception.
- Medial longitudinal fasciculus: ipsilateral internuclear ophthalmoplegia.
- Medial motor nucleus in medulla: ipsilateral deviation of the tongue.
- Cranial nerve VI (abducens)
- Motor (corticospinal tract): contralateral weakness.
- Medial lemniscus: contralateral loss fine touch and conscious proprioception.
- Medial longitudinal fasciculus: ipsilateral internuclear ophthalmoplegia.
- Medial motor nucleus in medulla: ipsilateral deviation of the tongue.
- Cranial nerve XII (hypoglossal)
- Motor (corticospinal tract): contralateral weakness.
- Medial lemniscus: contralateral loss fine touch and conscious proprioception.
- Medial longitudinal fasciculus: ipsilateral internuclear ophthalmoplegia.
- Medial motor nucleus in medulla: ipsilateral deviation of the tongue.
What structures may be damaged in a person who has a medial brainstem lesion in the pons? Would these signs be ipsilateral or contralateral?
- Cranial nerve III (oculomotor) or IV (trochlear).
- Motor (corticospinal tract): contralateral weakness.
- Medial lemniscus: contralateral loss fine touch and conscious proprioception.
- Medial longitudinal fasciculus: ipsilateral internuclear ophthalmoplegia.
- Medial motor nucleus in medulla: ipsilateral deviation of the tongue.
- Cranial nerve VI (abducens)
- Motor (corticospinal tract): contralateral weakness.
- Medial lemniscus: contralateral loss fine touch and conscious proprioception.
- Medial longitudinal fasciculus: ipsilateral internuclear ophthalmoplegia.
- Medial motor nucleus in medulla: ipsilateral deviation of the tongue.
- Cranial nerve XII (hypoglossal)
- Motor (corticospinal tract): contralateral weakness.
- Medial lemniscus: contralateral loss fine touch and conscious proprioception.
- Medial longitudinal fasciculus: ipsilateral internuclear ophthalmoplegia.
- Medial motor nucleus in medulla: ipsilateral deviation of the tongue.
What structures may be damaged in a person who has a medial brainstem lesion in the medulla? Would these signs be ipsilateral or contralateral?
- Cranial nerve III (oculomotor) or IV (trochlear).
- Motor (corticospinal tract): contralateral weakness.
- Medial lemniscus: contralateral loss fine touch and conscious proprioception.
- Medial longitudinal fasciculus: ipsilateral internuclear ophthalmoplegia.
- Medial motor nucleus in medulla: ipsilateral deviation of the tongue.
- Cranial nerve VI (abducens)
- Motor (corticospinal tract): contralateral weakness.
- Medial lemniscus: contralateral loss fine touch and conscious proprioception.
- Medial longitudinal fasciculus: ipsilateral internuclear ophthalmoplegia.
- Medial motor nucleus in medulla: ipsilateral deviation of the tongue.
- Cranial nerve XII (hypoglossal)
- Motor (corticospinal tract): contralateral weakness.
- Medial lemniscus: contralateral loss fine touch and conscious proprioception.
- Medial longitudinal fasciculus: ipsilateral internuclear ophthalmoplegia.
- Medial motor nucleus in medulla: ipsilateral deviation of the tongue.
What are the symptoms and signs of medial medullary syndrome?
- CN 3 (oculomotor nerve parasympathetic nucleus): dilation of pupil & inability to focus on near objects.
- CN 3 (oculomotor nucleus): unable to move eye up, down & in; drooping of upper eyelid; double vision. Eye abduction & depression are intact because CN 6 innervates the lateral rectus and CN 4 innervates the superior oblique.
- The hypoglossal is lost and tongue deviates to the ipsilateral side.
- Contralateral paresis, contralateral loss of fine touch and conscious proprioception, ipsilateral internuclear ophthalmoplegia (inability to move left eye toward midline, and ipsilateral loss of cranial nerve function affecting CN 3, 4, 6, or 12).
- Because the lesion affects the medulla, the motor nucleus of CN 12 is damaged.
What are the symptoms and signs of a basilar artery stroke in the midbrain?
- CN 3 (oculomotor nerve parasympathetic nucleus): dilation of pupil & inability to focus on near objects.
- CN 3 (oculomotor nucleus): unable to move eye up, down & in; drooping of upper eyelid; double vision. Eye abduction & depression are intact because CN 6 innervates the lateral rectus and CN 4 innervates the superior oblique.
- The hypoglossal is lost and tongue deviates to the ipsilateral side.
- Contralateral paresis, contralateral loss of fine touch and conscious proprioception, ipsilateral internuclear ophthalmoplegia (inability to move left eye toward midline, and ipsilateral loss of cranial nerve function affecting CN 3, 4, 6, or 12).
- Because the lesion affects the medulla, the motor nucleus of CN 12 is damaged.
What vital functions may be disrupted with damage to the medulla or pons?
- Increase heart rate due to loss of vagus nerve input.
- Fluctuating blood pressure.
- Cessation of breathing.
- Decrease heart rate due to loss of trigeminal nerve input.
- Decreased blood pressure.
- Cessation of breathing.
- Increase heart rate due to loss of facial nerve input.
- Increased blood pressure.
- Cessation of breathing.
There are 4 D's of brainstem dysfunction. What causes dysphagia?
- Dysphagia: impaired speaking (difficulty enunciating and phonating; language is not impaired).
o Lesions of CN V, VII, X, XII
- Dysphagia: impaired swallowing.
o Lesions of CN V, VII, IX, X, or XII.
o UMN lesions
- Dysphagia: double vision
o Lesions of CN III, IV, VI
- Dysphagia: impaired ability to control the distance of movements.
o Lesions that interrupt tracts entering or exiting the cerebellum.
There are 4 D's of brainstem dysfunction. What causes dysarthria?
- Dysarthria: impaired ability to control the distance of movements.
o Lesions that interrupt tracts entering or exiting the cerebellum.
- Dysarthria: double vision
o Lesions of CN III, IV, VI
- Dysarthria: impaired swallowing.
o Lesions of CN V, VII, IX, X, or XII.
o UMN lesions
- Dysarthria: impaired speaking (difficulty enunciating and phonating; language is not impaired).
o Lesions of CN V, VII, X, XII
There are 4 D's of brainstem dysfunction. What causes diplopia?
- Diplopia: impaired ability to control the distance of movements.
o Lesions that interrupt tracts entering or exiting the cerebellum.
- Diplopia: double vision
o Lesions of CN III, IV, VI
- Diplopia: impaired speaking (difficulty enunciating and phonating; language is not impaired).
o Lesions of CN V, VII, X, XII
- Diplopia: impaired swallowing.
o Lesions of CN V, VII, IX, X, or XII.
o UMN lesions
There are 4 D's of brainstem dysfunction. What causes dysmetria?
- Dysmetria: impaired speaking (difficulty enunciating and phonating; language is not impaired).
o Lesions of CN V, VII, X, XII
- Dysmetria: double vision
o Lesions of CN III, IV, VI
- Dysmetria: impaired ability to control the distance of movements.
o Lesions that interrupt tracts entering or exiting the cerebellum.
- Dysmetria: impaired swallowing.
o Lesions of CN V, VII, IX, X, or XII.
o UMN lesions
What regions of the brainstem can cause disorders of consciousness?
- The reticular formation and/or the axons of the ascending reticular activating system.
- The medullar formation and/or the axons of the ascending to medulla activating system.
What is locked in syndrome (include symptoms and signs)?
- Mimics impaired consciousness but consciousness is intact.
o Damage to UMN causes complete paralysis.
o Voluntary control of eye movements.
o Spared sensation
Due to basilar artery stroke
- Mimics impaired consciousness but consciousness is NOT intact.
o Damage to UMN causes complete paralysis.
o Voluntary control of eye movements.
o Spared sensation
Due to basilar artery stroke
What is vertebrobasilar insufficiency?
- Produces transient symptoms of brainstem region ischemia when the neck is extended and rotated.
- Produces transient symptoms of medulla region ischemia when the limbs are extended and rotated.
What can a lesion in the olfactory nerve cause?
- Inability to detect sounds.
- Inability to detect threats.
- Inability to detect smells.
What are some symptoms and signs of trigeminal nerve lesions?
- Preventing blinking in response to touch stimulation of the cornea & the jaw will deviate toward the involved side when the mouth is opened.
- One side of the face to droop and prevents the person from being able to completely close the ipsilateral eye.
- Paresis may be accompanied by pain near the ear, partial loss of taste sensation, and sensitivity to sound on the affected side.
What are some symptoms of trigeminal neuralgia?
- Difficulty speaking and swallowing, poor digestion due to decreased digestive enzymes and decreased peristalsis, asymmetric elevation of the palate, hoarseness, and loss of the gag and swallowing reflexes.
- Produces severe, sharp, stabbing pain.
- Pain begins and ends abruptly, lasts less than 2 minutes, and is not associated with sensory loss.
- Many people also have less severe, continuous, dull, throbbing, or aching pain in the same distribution that lasts hours to days.
What are some of the symptoms and signs of facial nerve lesions?
- One side of the face to droop and prevents the person from being able to completely close the ipsilateral eye.
- Paresis may be accompanied by pain near the ear, partial loss of taste sensation, and sensitivity to sound on the affected side.
- Difficulty speaking and swallowing, poor digestion due to decreased digestive enzymes and decreased peristalsis, asymmetric elevation of the palate, hoarseness, and loss of the gag and swallowing reflexes.
Facial Paralysis?
interrupts voluntary control contralateral facial muscles only in the lower half of the face.
completely unable to contract the muscles of facial expression and cannot close the ipsilateral eye.
Lesion in the Corticobrainstem Tract?
completely unable to contract the muscles of facial expression and cannot close the ipsilateral eye.
interrupts voluntary control contralateral facial muscles only in the lower half of the face.
Which cranial nerves may have lesions in a patient that has absent gag and swallowing reflexes?
Trigeminal
Facial
Glossopharyngeal
Hypoglossal
What are some symptoms and signs of a vagus nerve lesion?
- Weakness or paralysis which prevents complete closing of the ipsilateral eye and moving the ipsilateral forehead, cheeks, lips, and chin.
- Audible leaking of air on the puffing the cheeks.
- Difficulty speaking and swallowing, poor digestion due to decreased digestive enzymes and decreased peristalsis, asymmetric elevation of the palate, hoarseness, and loss of the gag and swallowing reflexes.
What side does the uvula deviate toward in a patient who has a lesion in the vagus nerve?
Strong side
Weak side
Both sides
What muscles would have paresis or paralysis with an accessory nerve lesion?
Sternocleidomastoid & trapezius
Rectus capitis & scalenus
Splenius capitis & levator scapulae
Semispinalis capitis & longissimus capitis
What signs would a patient present with who has a complete lesion of the hypoglossal nerve?
- When a person with this lesion is asked to stick out the tongue, the tongue protrudes to the opposite side with the lesioned nerve rather than in the midline.
- Problems with tongue control result in not being able to speak and swallow at all.
- When a person with this lesion is asked to stick out the tongue, the tongue protrudes toward the side with the lesioned nerve rather than in the midline.
- Problems with tongue control result in difficult speaking and swallowing.
Which cranial nerves may have lesions in a person who has dysphagia (frequent aspiration, choking, lack of awareness of food in one side of the mouth)?
V( trigeminal), VII (Facial), IX (glossopharyngeal), X (vagus), or XII (hypoglossal)
Trigeminal Nerve (V), Facial Nerve (VII), Vagus Nerve (X), & Hypoglossal Nerve (XII).
Which cranial nerves may have lesions in a person who has dysarthria?
Trigeminal Nerve (V), Facial Nerve (VII), Vagus Nerve (X), & Hypoglossal Nerve (XII).
V (trigeminal), VII (Facial), IX (glossopharyngeal), X (vagus), or XII (hypoglossal)
What are the abnormal findings on the CN V sensory and motor exam?
- Weakness of the masseter is evident with palpation and when the examiner can overcome the power of the muscles.
- Weakness of pterygoids when jaw deviates towards the ipsilateral side with mouth opening.
- Weakness or paralysis which prevents complete closing of the ipsilateral eye and moving the ipsilateral forehead, cheeks, lips, and chin.
- Audible leaking of air on the puffing the cheeks.
How do you interpret abnormal findings on the CN V exam?
o CN V (trigeminal) lesions cause either anesthesia, loss of general senses of the face, anterior head and corneal sensation and or severe pain on the ipsilateral side.
o Anesthesia occurs if nerve conduction is impaired.
o Lesions affecting the trigeminal sensory nuclei or ascending pathways to the thalamus and the somatosensory cortex also impair facial sensation.
o Unilateral Lesion: jaw deviates toward the weak side because the action of the contralateral pterygoids is unopposed with opening.
o Other causes of masseter weakness: lesions that affect the UMNs that excite LMNs innervating the masseter muscle, or the neuromuscular junction between the LMNs and the masseter, or the muscle.
o A CN VII (facial) lesion causes ipsilateral facial paralysis or paresis, and upper and lower face are equally involved.
o Either the CN 7 cell bodies or the axons may be affected.
o Cortical or corticobrainstem tract lesion results in paresis affecting only the contralateral lower face and spares the upper face.
What are the abnormal findings on the CN Vll motor exam?
- Weakness or paralysis which prevents complete closing of the ipsilateral eye and moving the ipsilateral forehead, cheeks, lips, and chin.
- Audible leaking of air on the puffing the cheeks.
o Either louder in unimpaired ear or affected ear.
How do you interpret abnormal findings on the CN Vll exam?
o CN VII (facial) cochlear branch lesion causes sensorineural hearing loss if air conduction is greater than bone conduction.
o Conductive hearing loss if bone conduction is greater than air conduction.
o A CN VII (facial) lesion causes ipsilateral facial paralysis or paresis, and upper and lower face are equally involved.
o Either the CN 7 cell bodies or the axons may be affected.
o Cortical or corticobrainstem tract lesion results in paresis affecting only the contralateral lower face and spares the upper face.
What cranial nerves are tested with the corneal reflex test?
CN V (trigeminal) & CN VII (facial)
CN I (olfactory) & CN II (optic)
CN VIII (vestibulocochlear) & CN IX (glossopharyngeal)
What are abnormal findings on the Weber test and how do you interpret them?
- Abnormal:
o Either louder in unimpaired ear or affected ear.
- Interpretation:
o CN VII (facial) cochlear branch lesion causes sensorineural hearing loss if sound is louder in the unaffected ear.
o Conductive hearing loss due to middle ear infection, excessive earwax, or punctured eardrum, if sound is louder in the affected ear.
- Abnormal:
o Either air conduction lasts longer than bone conduction or bone conduction lasts longer than air conduction.
- Interpretation:
o CN VII (facial) cochlear branch lesion causes sensorineural hearing loss if air conduction is greater than bone conduction.
o Conductive hearing loss if bone conduction is greater than air conduction.
What are abnormal findings on the Rinne test and how do you interpret them?
- Abnormal:
o Asymmetrical contraction of the pharynx
o Asymmetrical rise of the soft palate with the uvula deviating from midline.
- Interpretation:
o Absence of the gag reflex can occur with either CN IX (glossopharyngeal) or X (vagus) lesion or both.
o CN IX (glossopharyngeal) lesion: lack of gag reflex.
o CN X (vagus) lesion: lack of gag reflex or deviation of the uvula from midline.
- Abnormal:
o Either air conduction lasts longer than bone conduction or bone conduction lasts longer than air conduction.
- Interpretation:
o CN VII (facial) cochlear branch lesion causes sensorineural hearing loss if air conduction is greater than bone conduction.
o Conductive hearing loss if bone conduction is greater than air conduction.
What are abnormal findings on the gag reflex test and how do you interpret them?
- Abnormal:
o Asymmetrical contraction of the pharynx
o Asymmetrical rise of the soft palate with the uvula deviating from midline.
- Interpretation:
o Absence of the gag reflex can occur with either CN IX (glossopharyngeal) or X (vagus) lesion or both.
o CN IX (glossopharyngeal) lesion: lack of gag reflex.
o CN X (vagus) lesion: lack of gag reflex or deviation of the uvula from midline.
- Abnormal:
o Unilateral weakness: the uvula will deviate toward the normal side because that side of the palate is pulled up higher.
o Bilateral weakness: neither side of the palate will elevate and there will be marked nasal air escape.
- Interpretation:
o CN X (vagus) lesion: hoarseness and asymmetric elevation of the soft palate, with the uvula deviating toward the unaffected side.
What are abnormal findings on the palatal and pharynx control exam and how do you interpret them?
- Abnormal:
o When the patient contracts the muscles of the neck left sternocleidomastoid muscle is easily seen but the right absent
- Looking at the back of the patient, the left trapezius muscle is outlined and present, but the right is atrophic and hard to identify.
- Interpretation:
o Lesion on the right 11th (accessory) cranial nerve.
- Abnormal:
o Unilateral weakness: the uvula will deviate toward the normal side because that side of the palate is pulled up higher.
o Bilateral weakness: neither side of the palate will elevate and there will be marked nasal air escape.
- Interpretation:
o CN X (vagus) lesion: hoarseness and asymmetric elevation of the soft palate, with the uvula deviating toward the unaffected side.
What are abnormal findings on the CN Xl test and how do you interpret them?
- Abnormal:
o Either air conduction lasts longer than bone conduction or bone conduction lasts longer than air conduction.
- Interpretation:
o CN VII (facial) cochlear branch lesion causes sensorineural hearing loss if air conduction is greater than bone conduction.
o Conductive hearing loss if bone conduction is greater than air conduction.
- Abnormal:
o When the patient contracts the muscles of the neck left sternocleidomastoid muscle is easily seen but the right absent
- Looking at the back of the patient, the left trapezius muscle is outlined and present, but the right is atrophic and hard to identify.
- Interpretation:
o Lesion on the right 11th (accessory) cranial nerve.
- Abnormal:
o Asymmetrical contraction of the pharynx
o Asymmetrical rise of the soft palate with the uvula deviating from midline.
- Interpretation:
o Absence of the gag reflex can occur with either CN IX (glossopharyngeal) or X (vagus) lesion or both.
o CN IX (glossopharyngeal) lesion: lack of gag reflex.
o CN X (vagus) lesion: lack of gag reflex or deviation of the uvula from midline.
Which cranial nerves contain lower motor neurons?
Cranial Nerves III through VII, & IX through XII
Cranial Nerves II through V, & VII through XI
Cranial Nerves I through V, & X through XII
Where does the middle cerebellar peduncle connect and what kind of information is transmitted?
Connects to the brainstem and carries efferent info into the thalamus and the pontine nuclei.
Connects to the subcortical connections and carries efferent info into the cerebral cortex and the pontine nuclei.
Connects to the pons and carries afferent info into the cerebellum and the pontine nuclei.
