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Pyramidal and Extrapyramidal Tracts Anatomy Quiz
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Pyramidal and Extrapyramidal Tracts Anatomy Quiz

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Questions and Answers

What is the anatomical location of the cell body of lower motor neurons in the descending pathway?

  • Brainstem
  • Posterior column of spinal cord gray
  • Anterior column of spinal cord gray (correct)
  • Cerebral cortex

    • Which descending tract is responsible for the primary control of voluntary movement?

  • Hypoglossal nucleus
  • Pyramidal system (correct)
  • Corticobulbar tract
  • Extrapyramidal tracts

    • What is the main function of neurons in the descending pathway?

  • Initiate reflex arcs within the spinal cord
  • Control skeletal muscle activity (correct)
  • Carry sensory information to the brain
  • Coordinate autonomic responses

    • What is the primary role of lower motor neurons in the descending pathway?

    <p>Transmit motor commands to skeletal muscles</p> Signup and view all the answers

    What is the main pathway for voluntary, discrete, skilled movement?

    <p>Corticospinal tract</p> Signup and view all the answers

    Involvement of which area results in a cortical lesion related to motor pathways?

    <p>Paracentral Lobule</p> Signup and view all the answers

    Which lesion type involves damage to the upper motor neuron?

    <p>Cortical Lesion</p> Signup and view all the answers

    Which neuron type is referred to as the 'final common pathway' in the descending pathway?

    <p>1st order neuron</p> Signup and view all the answers

    Where are the origin of the tract fibers for the corticospinal tract located?

    <p>Pons/Medulla</p> Signup and view all the answers

    Which pathway utilizes 3 neurons in controlling skeletal muscle activity?

    <p>Descending pathway</p> Signup and view all the answers

    What is the primary function of the pyramidal and extrapyramidal tracts discussed?

    <p>Controlling voluntary movements</p> Signup and view all the answers

    Which descending tract is NOT part of the primary control of voluntary movement?

    <p>Internal Capsule</p> Signup and view all the answers

    Where do fibers of the pyramidal tract arise from the Primary Motor Cortex?

    <p>Precentral gyrus</p> Signup and view all the answers

    Which area does NOT provide axons directly controlling movement to the pyramidal tract?

    <p>Postcentral gyrus</p> Signup and view all the answers

    Where are the neurons that specifically influence eye movements located?

    <p>Frontal eye fields</p> Signup and view all the answers

    Which area constitutes the sensorimotor cortex giving rise to the pyramidal tract?

    <p>Secondary Motor Cortex</p> Signup and view all the answers

    Where are fibers of the pyramidal tract arising from the Primary Sensory Cortex?

    <p>Postcentral gyrus</p> Signup and view all the answers

    What is the primary function of the pyramidal tract?

    <p>Control of muscles involved in speech and vocalization</p> Signup and view all the answers

    Which reticulospinal tract is almost entirely ipsilateral and facilitates extensor motor neurons?

    <p>Pontine reticulospinal tract</p> Signup and view all the answers

    Which reticulospinal tract has both crossed and uncrossed fibers and is inhibitory to extensor motor neurons?

    <p>Medullary reticulospinal tract</p> Signup and view all the answers

    Which function is attributed to the Medullary Reticulospinal Tract but not to the Pontine Reticulospinal Tract?

    <p>Provides pathway for autonomic functions control</p> Signup and view all the answers

    Which part of the spinal cord primarily carries the Pontine Reticulospinal Tract?

    <p>Anterior funiculus</p> Signup and view all the answers

    What is the primary feature that distinguishes the Medullary Reticulospinal Tract from the Pontine Reticulospinal Tract?

    <p>Uncrossed fibers</p> Signup and view all the answers

    Which nervous system functions can be influenced by the Medullary Reticulospinal Tract?

    <p>Pupillary dilation, sweating, shivering</p> Signup and view all the answers

    What type of motor deficit would a lesion above the pyramidal decussation produce?

    <p>Contralateral loss of motor function</p> Signup and view all the answers

    Which system is responsible for the cross-over of fibers in the medulla?

    <p>Dorsal column-medial lemniscal system</p> Signup and view all the answers

    In the context provided, what would be the result of a lesion below the pyramidal decussation?

    <p>Ipsilateral loss of motor function</p> Signup and view all the answers

    What is the motor strength observed over the right upper extremity in the provided neurological examination?

    <p>1/5</p> Signup and view all the answers

    Where does the decussation occur for fibers related to pain and thermal sensation in the spinal cord?

    <p>Medulla</p> Signup and view all the answers

    Based on the presented case evaluation, what can be concluded about the location of the lesion?

    <p>It is a spinal cord lesion on the right side</p> Signup and view all the answers

    What is the main function of the Corticospinal tract?

    <p>Primary control of voluntary, discrete, skilled movement</p> Signup and view all the answers

    Which part of the brainstem is NOT associated with the origin of the Extrapyramidal tracts?

    <p>Supplementary Motor Area</p> Signup and view all the answers

    What is a characteristic feature of Lower Motor Neuron lesions?

    <p>Muscle atrophy</p> Signup and view all the answers

    Where does the decussation occur for fibers related to voluntary motor control in the Corticospinal tract?

    <p>Pons/Medulla</p> Signup and view all the answers

    Which type of lesion involves damage to Upper Motor Neurons?

    <p>Cortical lesion</p> Signup and view all the answers

    Which anatomical location is associated with Reflex Arc in the motor pathways?

    <p>Facial Motor Nucleus</p> Signup and view all the answers

    What would be the result of a lesion affecting the fibers above the pyramidal decussation?

    <p>Bilateral paralysis</p> Signup and view all the answers

    Which area of the spinal cord would show paralysis following a lesion involving the lateral corticospinal tract?

    <p>Contralateral side</p> Signup and view all the answers

    What motor function is directly impacted by lesions involving the uncrossed fibers of the anterior corticospinal tract?

    <p>Upper limb control</p> Signup and view all the answers

    In cases of spinal cord lesions, why does paralysis occur on the ipsilateral side of the body?

    <p>Due to uncrossed fibers</p> Signup and view all the answers

    How is motor control affected if there is a lesion below the pyramidal decussation?

    <p>Ipsilateral motor deficits</p> Signup and view all the answers

    What distinguishes the fibers of the Lateral Corticospinal Tract from those of the Anterior Corticospinal Tract?

    <p>Crossing over at the medulla</p> Signup and view all the answers

    What is the significance of the feedback information from muscles, joints, skin, and tendons in the movement process?

    <p>It is relayed back to the brainstem centers and cerebellum for fine-tuning of movement</p> Signup and view all the answers

    Which system plays a supporting role in the production of well-coordinated movements?

    <p>Extrapyramidal system</p> Signup and view all the answers

    What is the primary function of the cerebellum in relation to movement?

    <p>Fine-tuning and adjustment of movement</p> Signup and view all the answers

    What type of symptoms would a patient experience if there is an occlusion of vessels supplying the area where CST fibers pass through?

    <p>Paralysis or weakness of arms, trunk, and legs</p> Signup and view all the answers

    Which part of the internal capsule contains fibers controlling the upper limbs?

    <p>Anterior limb</p> Signup and view all the answers

    What is the difference between the anterior (ventral) and lateral CST regarding crossing of fibers?

    <p>Uncrossed fibers for anterior CST, crossed fibers for lateral CST</p> Signup and view all the answers

    Where do CST fibers controlling lower extremities terminate within the spinal cord?

    <p>Primarily at cervical and upper thoracic spinal segments</p> Signup and view all the answers

    What is the significance of pyramidal decussations in the corticospinal tract?

    <p>They facilitate voluntary movement</p> Signup and view all the answers

    Which part of the CST has a somatotopic arrangement with fibers controlling lower extremities located posteriorly?

    <p>Posterior limb</p> Signup and view all the answers

    In a patient where the tongue is both atrophied and deviated to the right, what type of lesion is most likely present?

    <p>Lower Motor Neuron (LMN) lesion to the right hypoglossal nucleus</p> Signup and view all the answers

    If a stroke patient presents with a deviated tongue to the right but without atrophy, what type of lesion is most likely responsible?

    <p>Upper Motor Neuron (UMN) lesion to the right hypoglossal nucleus</p> Signup and view all the answers

    If a resident notices a stroke patient's tongue is deviated to the right but not atrophied, what type of lesion is most likely involved?

    <p>Upper Motor Neuron (UMN) lesion to the right hypoglossal nucleus</p> Signup and view all the answers

    When a patient wakes up unable to move the entire left half of the face, what type of lesion is typically indicated?

    <p>Lower Motor Neuron (LMN) lesion on the left side</p> Signup and view all the answers

    In a scenario where a stroke patient can still wrinkle both eyebrows but cannot move the left lower half of the face, where is the lesion likely located?

    <p>Right side, upper motor neuron (UMN)</p> Signup and view all the answers

    What type of lesion would be suspected in a stroke patient presenting with atrophy and deviation of the tongue to the right?

    <p>Upper Motor Neuron (UMN) lesion to the right hypoglossal nucleus</p> Signup and view all the answers

    What is the primary role of the extrapyramidal system in movement coordination?

    <p>Facilitate fine-tuning and adjustment of movement</p> Signup and view all the answers

    Which brain structure relays information to both the brainstem centers and lower motor neurons for movement coordination?

    <p>Cerebellum</p> Signup and view all the answers

    What type of movement feedback is essential for the fine-tuning and adjustment of movement coordination?

    <p>Feedback from muscles, joints, skin, and tendons</p> Signup and view all the answers

    Where does the cerebellum primarily receive sensory inputs for movement coordination?

    <p>From muscles, joints, skin, and tendons</p> Signup and view all the answers

    Which descending tract plays a significant role in voluntary, discrete, skilled movement coordination?

    <p>Lateral corticospinal tract</p> Signup and view all the answers

    In the coordination of movement, what does the cerebellum relay information to enhance fine-tuning?

    <p>Lower motor neurons and brainstem centers</p> Signup and view all the answers

    What specific movements are controlled by the Supplementary Motor Area according to the text?

    <p>Simultaneous movements on both sides of the body</p> Signup and view all the answers

    Which artery supplies the dorsal and lateral portions of the cerebral hemispheres according to the provided text?

    <p>Middle Cerebral Artery (MCA)</p> Signup and view all the answers

    In case of an occlusion of the Anterior Cerebral Artery (ACA), what symptom is likely to be observed according to the text?

    <p>Weakness in the lower extremities</p> Signup and view all the answers

    What specific area of the brain represents lower limbs in the motor homunculus according to the text?

    <p>Paracentral Lobule</p> Signup and view all the answers

    What feature distinguishes the involvement of the Middle Cerebral Artery (MCA) from that of the Anterior Cerebral Artery (ACA) when occluded according to the text?

    <p>Weakness in face and upper extremities</p> Signup and view all the answers

    What is the primary role of the BA 4 area surrounding the central sulcus as mentioned in the text?

    <p>Fine motor control of hands and fingers</p> Signup and view all the answers

    Where are the perineal muscles, legs, and feet represented on the primary motor and premotor cortex?

    <p>Medial portion</p> Signup and view all the answers

    What is unique about the location of pyramidal cells of Betz within the precentral gyrus?

    <p>Located in the innermost layer of the cortical surface</p> Signup and view all the answers

    Which area of the primary motor and premotor cortex influences and controls the lips and face?

    <p>Ventral portion</p> Signup and view all the answers

    What percentage of the entire corticospinal tract do the pyramidal cells of Betz give rise to?

    <p>3%</p> Signup and view all the answers

    In which area of the primary motor and premotor cortex are the arms and trunk represented?

    <p>Superior portion</p> Signup and view all the answers

    What is distinctive about the axons from pyramidal cells of Betz in relation to spinal cord connections?

    <p>They synapse directly with anterior horn cells in the spinal cord</p> Signup and view all the answers

    What is the significance of occlusion of a vessel supplying the area where CST fibers pass through?

    <p>Dense manifestation of symptoms with paralysis or weakness of arms, trunk, and legs</p> Signup and view all the answers

    Which part of the internal capsule contains fibers controlling the lower extremities according to the somatotopic arrangement?

    <p>Posterior limb</p> Signup and view all the answers

    What is the primary difference between the anterior corticospinal tract and the lateral corticospinal tract?

    <p>Uncrossed vs. crossed fibers</p> Signup and view all the answers

    What is the role of decussations in the corticospinal tract?

    <p>Ensure contralateral control of motor functions</p> Signup and view all the answers

    What would be expected if there is a lesion affecting the CST fibers above the pyramidal decussation?

    <p>Bilateral motor deficits below the lesion</p> Signup and view all the answers

    What can be expected if there is damage to the Upper Motor Neurons in a patient?

    <p>Spasticity and exaggerated deep tendon reflexes</p> Signup and view all the answers

    What is the primary characteristic that distinguishes poliomyelitis from Amyotrophic lateral sclerosis (ALS)?

    <p>Affected neurons in poliomyelitis are in the anterior gray columns, whereas in ALS, they affect the lateral funiculus.</p> Signup and view all the answers

    What distinguishes severe cases of poliomyelitis from Amyotrophic lateral sclerosis (ALS)?

    <p>Severe polio cases result in paralysis of intercostal muscles and diaphragm, leading to ventilator support, while ALS does not affect these muscles.</p> Signup and view all the answers

    Which statement accurately describes the inheritance pattern of Amyotrophic lateral sclerosis (ALS)?

    <p>ALS is inherited in approximately 10% of cases and is rarely familial.</p> Signup and view all the answers

    What is a key difference between the manifestation of upper motor neuron (UMN) and lower motor neuron (LMN) lesions seen in Amyotrophic lateral sclerosis?

    <p>LMN lesions result in muscle atrophy and fasciculations, whereas UMN lesions cause muscle spasticity.</p> Signup and view all the answers

    How do patients with Amyotrophic lateral sclerosis typically present due to damage to both the anterior horn cells and corticospinal tracts?

    <p>Patients will show symptoms of both UMN and LMN lesion manifestations.</p> Signup and view all the answers

    What factor contributed to the re-emergence of polio cases in the Philippines despite being declared polio-free by WHO?

    <p>Despite vaccination efforts, the Dengvaxia scare in September 2019 resulted in a decline in immunization rates against polio.</p> Signup and view all the answers

    Which of the following best describes the primary function of the Corticospinal tract?

    <p>Pathway for voluntary, discrete, skilled movements</p> Signup and view all the answers

    Involvement of which area of the CNS leads to manifestations in patients associated with the motor pathways?

    <p>Supplementary Motor Area</p> Signup and view all the answers

    What distinguishes an Upper Motor Neuron lesion from a Lower Motor Neuron lesion?

    <p>Atrophy in perineal muscles</p> Signup and view all the answers

    Which anatomical location is associated with Reflex Arc in the motor pathways?

    <p>Spinal Cord</p> Signup and view all the answers

    What is distinctive about the manifestation of extrapyramidal tracts compared to pyramidal tracts?

    <p>Descending pathways for involuntary movements</p> Signup and view all the answers

    Which descending tract plays a significant role in voluntary, discrete, skilled movement coordination?

    <p>Corticospinal Tract</p> Signup and view all the answers

    What type of lesion would result in paralysis of the contralateral lower half of the face according to the text?

    <p>Upper motor neuron lesion</p> Signup and view all the answers

    Which part of the face would be unaffected by a supranuclear lesion according to the text?

    <p>Upper half of the face on both sides</p> Signup and view all the answers

    What kind of paralysis is observed in Central Facial Paralysis?

    <p>Unilateral lower facial paralysis</p> Signup and view all the answers

    In Bell's Palsy, what type of paralysis is typically experienced by the patient?

    <p>Peripheral lower facial paralysis</p> Signup and view all the answers

    Which area innervates the lower half of the face only from contralateral sensory motor cortex?

    <p>Ventral portion</p> Signup and view all the answers

    What is the outcome for more than 85% of individuals with Peripheral Facial Paralysis within 1 to 2 months?

    <p>Complete recovery</p> Signup and view all the answers

    What is the primary role of the femoral nerve in the monosynaptic reflex arc?

    <p>Stimulate the quadriceps muscle</p> Signup and view all the answers

    What is the origin of the Rubrospinal Tract?

    <p>Red nucleus</p> Signup and view all the answers

    Where do the fibers of the Rubrospinal Tract terminate within the spinal cord?

    <p>Lamina V, VI, VII</p> Signup and view all the answers

    Where do the motor fibers of the femoral nerve travel to in order to stimulate the quadriceps muscle?

    <p>L2-L4 segments</p> Signup and view all the answers

    What is the function of the internal capsule in the corticospinal tract?

    <p>Separate the lentiform nucleus from the thalamus</p> Signup and view all the answers

    What function is associated with the Rubrospinal Tract?

    <p>Influence muscle tone of extensor groups</p> Signup and view all the answers

    Which decussation do fibers of the Rubrospinal Tract cross immediately after originating?

    <p>Ventral tegmental decussation</p> Signup and view all the answers

    Which region serves as the origin of the 1st order neuron in the corticospinal tract?

    <p>Cerebral cortex</p> Signup and view all the answers

    What is the primary influence of the Rubrospinal Tract on muscle activity?

    <p>Assist in flexor muscle group activity</p> Signup and view all the answers

    In the monosynaptic reflex arc, what is the main effect of stimulating muscle spindles in the quadriceps muscle?

    <p>Facilitation of knee joint extension</p> Signup and view all the answers

    What is the significance of tapping the patellar tendon in relation to the monosynaptic reflex arc?

    <p>Stimulation of muscle spindles</p> Signup and view all the answers

    Which tract is functionally similar to the Rubrospinal Tract and assists in its activities?

    <p>Corticospinal Tract</p> Signup and view all the answers

    What is the primary function of the Pontine (Medial) Reticulospinal Tract?

    <p>Facilitatory to extensor motor neurons</p> Signup and view all the answers

    Which manifestation is likely to be observed in a patient with a lesion involving the Medullary (Lateral) Reticulospinal Tract?

    <p>Contraction of gastrointestinal sphincter muscles</p> Signup and view all the answers

    What is a characteristic feature of the Rubrospinal Tracts?

    <p>Facilitatory to flexor motor neurons</p> Signup and view all the answers

    In the context provided, what would be expected if there is damage to the Medullary (Lateral) Reticulospinal Tract?

    <p>Decreased respiratory rate</p> Signup and view all the answers

    Which statement accurately describes the function of the Vestibulospinal Tracts?

    <p>Facilitatory to extensor motor neurons</p> Signup and view all the answers

    What is the main role of the Rubrospinal Tracts in movement coordination?

    <p>Control voluntary, discrete, skilled movements</p> Signup and view all the answers

    What would be the expected motor deficit if a lesion occurs above the pyramidal decussation?

    <p>Contralateral motor deficit</p> Signup and view all the answers

    In a patient with right-sided manifestations, why can a spinal cord lesion on the right side be ruled out?

    <p>Pyramidal tract lesion</p> Signup and view all the answers

    Where do fibers cross in the medulla for pain and thermal sensation?

    <p>Lateral funiculus</p> Signup and view all the answers

    Which tract carries fibers that primarily control voluntary, discrete, skilled movements?

    <p>Rubrospinal tract</p> Signup and view all the answers

    In a patient with contralateral loss of pain and thermal sensation below the lesion level, where is the site of the lesion most likely located?

    <p>Above the pyramidal decussation</p> Signup and view all the answers

    What type of motor deficit would be expected in a patient with a lesion below the pyramidal decussation?

    <p>Ipsilateral motor deficit</p> Signup and view all the answers

    What type of fibers make up 75-90% of the lateral corticospinal tract?

    <p>Crossing of fibers</p> Signup and view all the answers

    What is the consequence of an occlusion of vessels supplying the area where CST fibers pass through?

    <p>Patient experiences paralysis or weakness</p> Signup and view all the answers

    What would be the expected outcome if the vessel supplying the area where CST fibers pass through becomes occluded?

    <p>Paralysis or weakness in arms, trunk, and legs</p> Signup and view all the answers

    Which tract controls arms, trunk, and lower limbs located at the posterior limb of the internal capsule?

    <p>Lateral Corticospinal Tract</p> Signup and view all the answers

    What distinguishes the anterior corticospinal tract from the lateral corticospinal tract regarding fiber crossing?

    <p>Uncrossed fibers</p> Signup and view all the answers

    Where do CST fibers controlling the upper limbs traverse within the internal capsule?

    <p>Anterior limb</p> Signup and view all the answers

    Where do fibers of the Corticobulbar Tract originate from?

    <p>Primary motor cortex</p> Signup and view all the answers

    What is the primary function of the Pons/Medulla Lateral Vestibulospinal Tract?

    <p>Maintenance of upright posture and balance</p> Signup and view all the answers

    Which region do fibers of the Corticobulbar Tract project to, apart from motor nuclei of certain Cranial Nerves?

    <p>Reticular formation</p> Signup and view all the answers

    Which type of fibers does the Medial Vestibulospinal Tract contain?

    <p>Both crossed and uncrossed fibers</p> Signup and view all the answers

    Where does the Medial Vestibulospinal Tract terminate within the spinal cord?

    <p>Rexed Laminae VII &amp; VIII</p> Signup and view all the answers

    Which area is essential for controlling facial muscles involved in emotional expressions, receiving projections from the Corticobulbar Tract?

    <p>Reticular formation</p> Signup and view all the answers

    In addition to motor nuclei of certain Cranial Nerves, where else do fibers from the Corticobulbar Tract terminate?

    <p>Sensory relay nuclei</p> Signup and view all the answers

    What type of neurons does the Pons/Medulla Lateral Vestibulospinal Tract innervate?

    <p>Motor neurons</p> Signup and view all the answers

    Which part of the brainstem or bulbar region receives the terminations of fibers from the Corticobulbar Tract?

    <p>Reticular formation</p> Signup and view all the answers

    What is the primary source of afferents for the Pons/Medulla Lateral Vestibulospinal Tract?

    <p>Vestibular nerve and cerebellum</p> Signup and view all the answers

    Which function is specific to the Medial Vestibulospinal Tract compared to the Lateral Vestibulospinal Tract?

    <p>Excites neck up to back motor neurons only</p> Signup and view all the answers

    A patient with a lesion of the left lateral funiculus of the lumbar segment of the spinal cord will present with weakness in which limb?

    <p>Right arm</p> Signup and view all the answers

    Which tract arising from the midbrain facilitates the activity of flexor muscle groups in response to visual stimuli?

    <p>Rubrospinal Tract</p> Signup and view all the answers

    Which part of the spinal cord do the extrapyramidal tracts arising from the midbrain cross before descending to terminate in the anterior gray horn?

    <p>Lateral funiculus decussation</p> Signup and view all the answers

    Which tract mediates reflex postural movements and is functionally similar to the Corticospinal Tract?

    <p>Medullary Reticulospinal Tract</p> Signup and view all the answers

    Which tracts arising from the pons/medulla are responsible for facilitating indirect pathways in controlling muscle activity?

    <p>Pontine Reticulospinal Tract</p> Signup and view all the answers

    What is the primary function of the Rubrospinal Tract in movement coordination?

    <p>Directly stimulate lower motor neurons</p> Signup and view all the answers

    What motor function would be affected by a lesion below the Pyramidal Decussation in the Medulla Oblongata?

    <p>Lower facial expression control</p> Signup and view all the answers

    Where are the ventral CST fibers located within the spinal cord?

    <p>Anterior funiculus near the anterior median fissure</p> Signup and view all the answers

    Which part of the midbrain is primarily responsible for controlling the lower limbs?

    <p>Laterally located fibers</p> Signup and view all the answers

    In a spinal cord lesion scenario, which side of the body would exhibit paralysis?

    <p>Ipsilateral side</p> Signup and view all the answers

    What is the primary role of transverse pontocerebellar fibers within the Pons?

    <p>Facilitation of corticospinal tracts</p> Signup and view all the answers

    Which condition is most likely to result from a lesion affecting fibers above the Pyramidal Decussation?

    <p>Bilateral upper limb weakness</p> Signup and view all the answers

    In a patient with atrophied and deviated tongue to the RIGHT, what type of lesion is likely present?

    <p>Upper Motor Neuron (UMN) on the LEFT side</p> Signup and view all the answers

    A patient with a stroke presenting with tongue deviation to the RIGHT but not atrophy most likely has a lesion in the:

    <p>Left Lower Motor Neuron (LMN)</p> Signup and view all the answers

    What is the expected presentation of a patient with a stroke affecting the LEFT hypoglossal nucleus?

    <p>No tongue deviation or atrophy</p> Signup and view all the answers

    When observing a patient with tongue deviation to the RIGHT due to a LEFT hemisphere stroke, which motor neuron type is most likely affected?

    <p>Corticobulbar UMN</p> Signup and view all the answers

    A patient with inability to move the lower LEFT half of the face but can still wrinkle both eyebrows likely has a lesion in the:

    <p>Left Upper Motor Neuron (UMN)</p> Signup and view all the answers

    Which type of lesion would result in a presentation of tongue deviation to the ipsilateral side with atrophy?

    <p>Right Lower Motor Neuron (LMN)</p> Signup and view all the answers

    What is the origin of the Rubrospinal Tract?

    <p>Red nucleus</p> Signup and view all the answers

    How do fibers of the Rubrospinal Tract reach the spinal cord?

    <p>Descend down the brainstem</p> Signup and view all the answers

    What is the main function of the Rubrospinal Tract?

    <p>Influence tone control of flexor muscles</p> Signup and view all the answers

    Where do the fibers of the Rubrospinal Tract terminate within the spinal cord?

    <p>Anterior gray column</p> Signup and view all the answers

    What is the functional similarity between the Rubrospinal Tract and the Corticospinal Tract?

    <p>Control of skilled movement coordination</p> Signup and view all the answers

    In what part of the spinal cord do the fibers of the Rubrospinal Tract enter for termination?

    <p>Anterior gray column</p> Signup and view all the answers

    Where would motor deficits be observed in a patient with a lesion below the pyramidal decussation?

    <p>Ipsilateral to the lesion</p> Signup and view all the answers

    Which tract is responsible for contralateral loss of pain and thermal sensation below the level of the lesion?

    <p>Lateral Spinothalamic Tract</p> Signup and view all the answers

    In a patient with ipsilateral motor deficits, which type of lesion can be ruled out?

    <p>Spinal Cord lesion</p> Signup and view all the answers

    What is the significance of fibers crossing in the medulla for pain and thermal sensation?

    <p>It allows for localization of sensations</p> Signup and view all the answers

    What manifestation would be expected in a patient with a lesion above the pyramidal decussation?

    <p>Contralateral motor deficits</p> Signup and view all the answers

    Which area would exhibit symptoms if there were a spinal cord lesion present?

    <p>Opposite side of the body</p> Signup and view all the answers

    A lesion in the RIGHT hypoglossal nucleus would manifest with which of the following neurologic findings?

    <p>Tongue deviated to the RIGHT, no atrophy</p> Signup and view all the answers

    Where do Corticobulbar tract fibers pass through in the internal capsule?

    <p>Genu</p> Signup and view all the answers

    If a lesion involves the LEFT Corticobulbar Tract projecting to the facial motor nucleus, which part of the face would experience weakness?

    <p>LEFT lower half</p> Signup and view all the answers

    Which part of the internal capsule contains the corticospinal tract fibers?

    <p>Anterior limb</p> Signup and view all the answers

    A lesion involving the dorsolateral portion of the LEFT sensorimotor cortex would result in which neurologic manifestation?

    <p>Weakness of the LEFT arm</p> Signup and view all the answers

    Where do corticospinal tract fibers pass through in the internal capsule?

    <p>Anterior limb</p> Signup and view all the answers

    Which grade of Deep Tendon Reflexes indicates a slight but definitely present response, which may or may not be normal?

    <p>1+</p> Signup and view all the answers

    What is the characteristic feature of a 4+ Deep Tendon Reflex?

    <p>A tap elicits a repeating reflex (clonus); always abnormal</p> Signup and view all the answers

    What can be elicited in the flexor muscles of fingers, biceps, calf, and quadriceps muscles?

    <p>Clonus</p> Signup and view all the answers

    What characterizes an Upper Motor Neuron (UMN) lesion in relation to clonus?

    <p>With clonus</p> Signup and view all the answers

    How is the Babinski reflex elicited according to the text?

    <p>By striking the sole of the foot up to the base of the toes</p> Signup and view all the answers

    What is the primary function of the Supplementary Motor Area as described in the text?

    <p>Facilitate movements performed on both sides of the body</p> Signup and view all the answers

    If there is an occlusion in the Middle Cerebral Artery (MCA), what neurological manifestation is likely to be observed according to the text?

    <p>Weakness in face and upper extremities</p> Signup and view all the answers

    Which area of the cerebral hemisphere is represented by a blue circle in Figure 6 as described in the text?

    <p>Paracentral Lobule</p> Signup and view all the answers

    What is a significant consequence of an occlusion in the Anterior Cerebral Artery (ACA) according to the text?

    <p>Impaired lower limb movement</p> Signup and view all the answers

    Which lobule is located at the most medial portion of BA 6, anterior to the Paracentral Lobule, as described in the text?

    <p>Frontal Lobe</p> Signup and view all the answers

    What is a distinctive feature of the movements controlled by the Paracentral Lobule based on the information provided?

    <p>Gross motor movements involving large muscle groups</p> Signup and view all the answers

    Which cortical areas give rise to fibers of the corticobulbar tract?

    <p>Primary motor cortex, premotor cortex, and frontal eye fields</p> Signup and view all the answers

    Where do fibers of the corticobulbar tract terminate in the brainstem?

    <p>Brainstem</p> Signup and view all the answers

    Which cranial nerves receive projections from the corticobulbar tract?

    <p>All cranial nerves except I, II, and VIII</p> Signup and view all the answers

    Which structure receives corticoreticular fibers from the corticobulbar tract?

    <p>Reticular formation in pons &amp; medulla</p> Signup and view all the answers

    What is the primary function of the sensory relay nuclei that receive inputs from the corticobulbar tract?

    <p>Controlling inputs going into the brain</p> Signup and view all the answers

    What is a distinctive characteristic of fasciculations that makes them specific for LMN involvement?

    <p>Slow destruction of anterior horn cells</p> Signup and view all the answers

    In a patient with symptoms of progressive muscular atrophy and paralysis, which type of neuron damage is likely occurring?

    <p>Progressive impairment of anterior horn cells</p> Signup and view all the answers

    Which condition would present with both upper motor neuron (UMN) and lower motor neuron (LMN) characteristics?

    <p>Amyotrophic lateral sclerosis (ALS)</p> Signup and view all the answers

    What distinguishes LMN from UMN involvement in terms of paresis presentation?

    <p>Gradual progression of paresis in LMN damage</p> Signup and view all the answers

    Which symptom would be expected in a patient with amyotrophic lateral sclerosis (ALS) but not in poliomyelitis?

    <p>Spasticity</p> Signup and view all the answers

    If a patient presents with multiple cranial nerve deficits ipsilateral to the lesion, where in the brainstem could the lesion be located?

    <p>Midbrain</p> Signup and view all the answers

    In relation to motor deficits caused by a brainstem lesion, where are these deficits typically observed?

    <p>Contralateral to the lesion</p> Signup and view all the answers

    What type of facial deficit is typically associated with a UMN lesion in the brain?

    <p>Central facial paralysis</p> Signup and view all the answers

    In a patient who is drowsy with abnormal MSE but normal cranial nerves, what area of the cerebral cortex may be affected?

    <p>Motor and sensory cortex</p> Signup and view all the answers

    Where would a lesion need to occur to result in motor and sensory deficits on the same side of the body?

    <p>Parietal lobe</p> Signup and view all the answers

    If a patient were to have a lesion in the internal capsule affecting motor and sensory areas of the face and upper extremity, which symptoms would most likely be observed?

    <p>Both motor and sensory deficits</p> Signup and view all the answers

    What is the primary role of the pyramidal decussations in the corticospinal tract?

    <p>Facilitate contralateral motor control of the body</p> Signup and view all the answers

    What distinguishes the Medullary (Lateral) Reticulospinal Tract from the Pontine Reticulospinal Tract?

    <p>Inhibition of motor activity vs facilitation of motor activity</p> Signup and view all the answers

    In a patient with a lesion involving the Spinal cord ventral CST, what paralysis would be expected?

    <p>Ipsilateral paralysis of upper limb</p> Signup and view all the answers

    What type of motor deficit would be observed in a patient with a lesion affecting the Corticospinal Tract fibers above the pyramidal decussation?

    <p>Contralateral motor deficits</p> Signup and view all the answers

    How do lesions within the cerebral cortex above the pyramidal decussations typically affect motor functions?

    <p>Result in contralateral motor deficits</p> Signup and view all the answers

    Where are the fibers of the lateral CST located within the spinal cord?

    <p>Lateral funiculus</p> Signup and view all the answers

    What type of paralysis is typically seen in a patient with an Upper Motor Neuron lesion?

    <p>Complete paralysis</p> Signup and view all the answers

    Which type of paralysis involves one limb only?

    <p>Monoplegia</p> Signup and view all the answers

    What is the primary difference in muscle tone between Upper Motor Neuron and Lower Motor Neuron lesions?

    <p>Spasticity</p> Signup and view all the answers

    Which term describes the condition where unused muscle shrinks over time due to lack of therapy or exercise?

    <p>Muscle atrophy</p> Signup and view all the answers

    Which lesion type is associated with early muscle atrophy due to damage to anterior horn cells?

    <p>Lower Motor Neuron lesion</p> Signup and view all the answers

    What is a distinguishing characteristic of Lower Motor Neuron lesions compared to Upper Motor Neuron lesions?

    <p>Fasciculations</p> Signup and view all the answers

    What is the term used to describe a lesion at the left sensory motor cortex face area or corticobulbar tract fibers?

    <p>Supranuclear Lesion</p> Signup and view all the answers

    In Central Facial Paralysis, what part of the face is affected by the lesion?

    <p>Lower half on the contralateral side</p> Signup and view all the answers

    What is the characteristic paralysis seen in Peripheral Facial Paralysis?

    <p>Lower half on the ipsilateral side</p> Signup and view all the answers

    Which cranial nerve deficit pattern is typically observed in a patient with Central Facial Paralysis?

    <p>Multiple cranial nerve deficits contralateral to the lesion</p> Signup and view all the answers

    What distinguishes Bell's Palsy from Central Facial Paralysis?

    <p>Bilateral facial muscle involvement in Bell's Palsy</p> Signup and view all the answers

    What is the expected result of a lesion affecting the ventral portion of the Corticobulbar Tract?

    <p>Contralateral lower facial weakness</p> Signup and view all the answers

    What is the primary distinguishing feature between the presentation of progressive muscular atrophy in upper motor neuron (UMN) and lower motor neuron (LMN) involvement?

    <p>Paresis in UMN and paralysis in LMN</p> Signup and view all the answers

    If a patient initially presents with weakness due to destruction of neurons in the anterior gray horn, what will be the eventual outcome once the neurons are completely destroyed?

    <p>Paralysis</p> Signup and view all the answers

    What would be a specific symptom observed in both upper motor neuron (UMN) and lower motor neuron (LMN) involvement in poliomyelitis?

    <p>(+) Babinski sign</p> Signup and view all the answers

    In the context of spinal cord injuries, what manifestation indicates that not all injuries would present with lower motor neuron (LMN) features?

    <p>Spasticity</p> Signup and view all the answers

    Which condition specifically presents with a slow destruction of the anterior horn cells leading to characteristics such as paresis and fasciculations?

    <p>Progressive muscular atrophy</p> Signup and view all the answers

    What is the primary function attributed to the Pontine (Medial) Reticulospinal Tract?

    <p>Facilitating extensor motor neurons</p> Signup and view all the answers

    Where do fibers of the Medial Vestibulospinal Tract terminate within the spinal cord?

    <p>Rexed Laminae VII &amp; VIII</p> Signup and view all the answers

    Which region serves as the origin of the 1st order neuron in the corticospinal tract?

    <p>Lateral vestibular nucleus</p> Signup and view all the answers

    What distinguishes between the functions of the Medullary Reticulospinal Tract and the Pontine Reticulospinal Tract?

    <p>Exciting neck and back motor neurons</p> Signup and view all the answers

    What is distinctive about the manifestation of extrapyramidal tracts compared to pyramidal tracts based on the provided information?

    <p>Facilitating reflex postural movements</p> Signup and view all the answers

    Which function can be influenced by the Medullary Reticulospinal Tract but not by the Pontine Reticulospinal Tract?

    <p>Exciting neck and back motor neurons</p> Signup and view all the answers

    What is the primary role of the 1st order neuron in the descending pathway?

    <p>Acts as an interconnecting neuron</p> Signup and view all the answers

    Which component is essential for a reflex to occur without requiring processing from higher centers?

    <p>Afferent neuron</p> Signup and view all the answers

    What distinguishes the axon of the 3rd order neuron in the descending pathway from that of the 1st order neuron?

    <p>Short axon</p> Signup and view all the answers

    Which is a characteristic feature of the pyramidal tract?

    <p>Responsible for voluntary, skilled movement coordination</p> Signup and view all the answers

    What would be the consequence of damage to the 2nd order neuron in the descending pathway?

    <p>Loss of communication between spinal cord and cerebral cortex</p> Signup and view all the answers

    What is a key function of the Rubrospinal Tract in movement coordination?

    <p>Coordinates fine motor movements</p> Signup and view all the answers

    What is a characteristic symptom specific to Lower Motor Neuron (LMN) involvement in the context of amyotrophic lateral sclerosis?

    <p>Fasciculations</p> Signup and view all the answers

    In the context of spinal cord injuries, what manifestation would suggest damage to the anterior gray column of the spinal cord?

    <p>Paralysis</p> Signup and view all the answers

    Which motor neuron condition is characterized by a slow destruction of the anterior horn cells resulting in paresis and fasciculations?

    <p>Lou Gehrig disease</p> Signup and view all the answers

    If only the tracts were affected due to a spinal cord injury, which manifestation would be evident?

    <p>Spasticity</p> Signup and view all the answers

    What symptom is typically seen when both Upper Motor Neuron (UMN) and Lower Motor Neuron (LMN) conditions coexist?

    <ul> <li>Babinski sign</li> </ul> Signup and view all the answers

    What is the clinical presentation that distinguishes an Upper Motor Neuron lesion from a Lower Motor Neuron lesion?

    <p>Spasticity in muscle tone vs. Flaccidity in muscle tone</p> Signup and view all the answers

    What type of paralysis is typically seen in Monoplegia?

    <p>Paralysis of one limb only</p> Signup and view all the answers

    Which manifestation would be indicative of a lesion involving the Medullary Reticulospinal Tract?

    <p>Excitatory to flexor motor neurons</p> Signup and view all the answers

    In paralysis due to a lesion above the pyramidal decussation, what would be expected regarding limb involvement?

    <p>Contralateral limb paralysis</p> Signup and view all the answers

    What factor contributed to the re-emergence of polio cases in the Philippines despite being declared polio-free by WHO?

    <p>Mutation of the poliovirus</p> Signup and view all the answers

    Which area of the body would experience weakness if the LEFT Corticobulbar Tract projecting to the facial motor nucleus is affected?

    <p>Left half of the face</p> Signup and view all the answers

    What is the normal response to a scratch or stroke on the abdominal muscles to elicit the superficial abdominal reflex?

    <p>Contraction of the corresponding muscles</p> Signup and view all the answers

    Which cranial nerve nucleus is located close to the midline at the dorsal portion of the pons?

    <p>Facial motor nucleus (CN VII)</p> Signup and view all the answers

    What is a characteristic of an UMN lesion with regard to the cremasteric reflex?

    <p>Absence of the reflex</p> Signup and view all the answers

    Where does the hypoglossal nucleus (CN XII) span along in the brainstem?

    <p>Medulla oblongata</p> Signup and view all the answers

    What is a common presentation in LMN lesions regarding muscle fasciculations?

    <p>Twitching of the muscle fibers</p> Signup and view all the answers

    In an UMN lesion, what would be observed regarding the superficial abdominal reflex?

    <p>Extension of the corresponding muscles</p> Signup and view all the answers

    Which artery supplies the area of the face and upper extremities?

    <p>Middle Cerebral Artery (MCA)</p> Signup and view all the answers

    In which part of the internal capsule do fibers of the corticospinal tract to the lower extremities pass through?

    <p>Posterior limb</p> Signup and view all the answers

    What symptoms would a patient exhibit if there is a lesion in the left sensorimotor cortex involving loss of pain, thermal sensation, and decreased vibratory sensation on the right side?

    <p>Weakness in the lower extremities on the right side</p> Signup and view all the answers

    Which area would likely be affected if there is an occlusion of the vessel supplying the middle cerebral artery (MCA)?

    <p>Face and upper extremities on the contralateral side</p> Signup and view all the answers

    What distinguishes a cortical lesion from a lesion in the internal capsule?

    <p>Presence of abnormal MSE</p> Signup and view all the answers

    What characterizes a lesion involving loss of pain, thermal sensation, and decreased vibratory sensation?

    <p>Contralateral sensory deficits</p> Signup and view all the answers

    Study Notes

    Here are the study notes:

    Motor Neuron Lesions

    • Motor neuron lesions can be classified into two types: Upper Motor Neuron (UMN) lesions and Lower Motor Neuron (LMN) lesions.

    Upper Motor Neuron (UMN) Lesions

    • Characteristics:
      • No muscle atrophy initially
      • If patient cannot exercise or have therapy, may develop disuse atrophy
      • Spasticity in muscle tone
      • Hyperreflexia
      • Clonus present
      • Babinski reflex present
      • Loss of certain superficial reflexes (e.g. superficial abdominal reflex, cremasteric reflex)

    Lower Motor Neuron (LMN) Lesions

    • Characteristics:
      • Muscle atrophy early on
      • Flaccidity in muscle tone
      • Areflexia (absence of reflexes)
      • No clonus
      • No Babinski reflex
      • Fasciculations (twitching of muscle)

    Corticospinal Tract

    • A descending tract responsible for the primary control of voluntary movement
    • Divided into two main tracts:
      • Corticospinal tract: pathways for voluntary, discrete, skilled movements
      • Corticobulbar tract: pathways for voluntary movements of the face, tongue, and pharynx

    Pyramidal Tract

    • Originates from the primary motor cortex and premotor cortex
    • Fibers pass through the internal capsule, crus cerebri, pons, and medulla oblongata
    • Forms the pyramids in the medulla oblongata
    • Fibers cross at the pyramidal decussation and form the lateral corticospinal tract
    • Lesions above the pyramidal decussation affect contralateral regions, while lesions below affect ipsilateral regions

    Corticobulbar Tract

    • Originates from the primary motor cortex and premotor cortex
    • Fibers pass through the internal capsule, crus cerebri, and pons
    • Controls voluntary movements of the face, tongue, and pharynx

    Reflex Arc

    • A reflex arc consists of:
      • Receptor organ
      • Afferent neuron
      • Efferent neuron
      • Effector organ
    • Damage to any of these components would abolish the reflex### Motor Homunculus
    • Representations of the body on the primary motor and premotor cortex
    • Each part of the body is represented on a specific portion of the primary and premotor cortex
      • Tongue and larynx: lowest lateral portion close to the Sylvian fissure
      • Lips and face: ventral
      • Fingers and hands: dorsolateral
      • Arms and trunk: superior
      • Perineal muscles, legs, and feet: medial

    Precentral Gyrus (BA 4)

    • Primary motor cortex
    • Functional area: 1/3 of the axons of the pyramidal tract arise
    • Pyramidal cells of Betz:
      • Give rise to 10% of precentral gyrus or 3% of entire corticospinal tract
      • Located at the 5th layer of the cortical surface
      • Send their axons directly to the anterior horn cells in the spinal cord
      • Responsible for highly-skilled movements

    Paracentral Lobule

    • Area surrounding the central sulcus
    • Represents lower limbs in the motor homunculus
    • Comprises of:
      • BA 4
      • BA 3, 1, 2
      • BA 5

    Clinical Correlation

    • Anterior cerebral artery (ACA): supplies the medial portions of the cerebral hemispheres
      • Occlusion: result in weakness in the lower extremities
    • Middle cerebral artery (MCA): supplies the dorsal and lateral portions of the cerebral hemispheres
      • Occlusion: result in weakness in the face and upper extremities

    Supplementary Motor Area

    • Located in the medial frontal gyrus on the medial surface of the hemisphere
    • Plays a special role in integrating movements that are performed simultaneously on both sides of the body
    • Stimulation results in contralateral limb movement
    • Needs a stronger stimulus than primary motor area

    Corticospinal Tract

    • A descending tract responsible for the primary control of voluntary movement
    • Pathways for voluntary, discrete, skilled movements
    • Uncrossed fibers (10-15%): eventually cross before terminating on the anterior horn
    • Crossed fibers (75-90%): form pyramidal decussations terminating on the anterior horn

    Extrapyramidal System

    • Plays a supporting role in the production of well-coordinated movements
    • Includes:
      • Basal ganglia (nuclei)
      • Cerebellum

    Pyramidal Tract

    • Responsible for the primary control of voluntary movement
    • Carried out through two main tracts:
      • Corticospinal tract
      • Corticobulbar tract

    Motor Neuron Lesions

    • Upper motor neuron (UMN) lesion:
      • Weakness or paralysis of the affected limb
      • Reflexes are usually increased
    • Lower motor neuron (LMN) lesion:
      • Weakness or paralysis of the affected limb
      • Reflexes are usually decreased or absent

    Corticobulbar Tract

    • Origin: cerebral cortex
    • Destination: bulbar region or brainstem
    • Arises from face region of primary motor cortex (BA 4), premotor (BA 6), frontal eye fields (BA 8)
    • Fibers project to:
      • Motor nuclei of CNs III, IV, V, VI, VII, IX, X, XI & XII
      • Parts of reticular formation (corticoreticular fibers) in pons & medulla
      • Sensory relay nuclei (gracilis, cuneatus, sensory trigeminal nuclei, & nucleus of solitary fasciculus)

    Rubrospinal Tract

    • Origin: red nucleus
    • Fibers: crossed
    • Termination: internuncial neurons in all spinal cord segments
    • Function: facilitates the activity of flexor muscle groups, functionally similar to the CST

    Reticulospinal Tracts

      1. Pontine (medial) reticulospinal tract:
      • Origin: pons
      • Fibers: almost entirely ipsilateral
      • Termination: Lamina VII & VIII
      • Function: facilitatory to extensor motor neurons
      1. Medullary (lateral) reticulospinal tract:
      • Origin: medulla
      • Fibers: both crossed and uncrossed
      • Termination: Lamina VII & IX
      • Function: inhibitory to extensor motor neurons

    Vestibulospinal Tracts

      1. Lateral vestibulospinal tract:
      • Origin: lateral vestibular nucleus
      • Termination: Rexed Laminae VII & VIII
      • Fibers: uncrossed
      • Afferents: from vestibular nerve and cerebellum
      • Function: maintenance of upright posture and balance
      1. Medial vestibulospinal tract:
      • Origin: medial vestibular nucleus
      • Termination: same laminae as the lateral vestibulospinal tract
      • Fibers: both crossed and uncrossed
      • Afferents: from primary vestibular and cerebellum
      • Function: maintenance of upright postureHere are the study notes for the text:

    Mental Status Exam (MSE)

    • Patient is drowsy but arousable, speaks very slowly and with effort
    • Motor strength of 2/5 over the right upper extremity

    Pyramidal Tracts

    • Ipsilateral loss of motor function → Fibers below the pyramidal decussation
    • If the lesion is above the pyramidal decussation, it would produce loss of motor function contralateral to the side of the lesion
    • Contralateral loss of pain and thermal sensation below the level of the lesion → Fibers in lateral funiculus (of the lateral spinothalamic tract) are axons of N2 which have already crossed

    Spinal Cord Injuries

    • UMN (Upper Motor Neuron) lesions: If only the tracts were affected
    • LMN (Lower Motor Neuron) lesions: If the lesion was on the anterior gray column of the spinal cord, anterior horn cells will be damaged
    • Poliomyelitis: It could be upper or lower manifestation → NOT all spinal cord injuries would present with LMN manifestations
    • Amyotrophic Lateral Sclerosis (Lou Gehrig Disease): A progressive neurological disease that affects the motor neurons

    Brainstem Lesions

    • With CN deficits (nerves exit ipsilateral to their symptoms) → Midbrain: CN III → Pons: CN V, VI, VII → Medulla: CN IX, XI, XII
    • Clue if brainstem lesion is present → Multiple cranial nerve deficits (ipsilateral)
    • Deficits → CN deficits: Ipsilateral to the lesion → Motor deficits: Contralateral to the lesion

    Corticobulbar Tract

    • Origin: Cerebral cortex
    • Destination: Bulbar region or brainstem
    • Arises from face region of primary motor cortex (BA 4), premotor (BA 6), frontal eye fields (BA 8)
    • Fibers would pass through the corona radiata, genu of the internal capsule, and terminate in the brainstem
    • Fibers would project to: → Motor nuclei of CNs III, IV, V, VI, VII, IX, X, XI & XII
    • Exceptions are I, II, and VIII which are purely sensory

    Motor Neuron Lesions

    • Moves muscle group with full resistance
    • Muscle Atrophy:
      • UMN lesion: No muscle atrophy initially; if the patient will not be able to have therapy or exercise, may develop disuse atrophy
      • LMN lesion: With muscle atrophy early on; due to damage to anterior horn cells which have give nutrition to the muscles they innervate (trophic effect)

    Rubrospinal Tract

    • "Rubro" = "red"
    • Origin: Red nucleus (at the level of superior colliculus)
    • Fibers: → Cross immediately in the ventral tegmental decussation → Descend down the brainstem → Enter lateral funiculus of spinal cord
    • Termination: → Internuncial neurons (anterior gray column) in all spinal cord levels (Lamina V, VI, VII)
    • Function: → Influence tone control/facilitates the activity of flexor muscle groups → Functionally similar to the CST; said to assist the CST in its function

    Clinical Correlation

    • Anterior cerebral artery (ACA) → Supplies the medial portions of the cerebral hemispheres → Occlusion: result to weakness in the lower extremities
    • Middle cerebral artery (MCA) → Supplies the dorsal and lateral portions of the cerebral hemispheres → Occlusion: result to weakness in the face and upper extremities

    Pons/Medulla

    • Lateral Vestibulospinal Tract:
      • Origin: Lateral vestibular nucleus
      • Termination: → Descends in anterolateral funiculus and terminates in Rexed Laminae VII & VIII on alpha & gamma motor neurons from cervical and lumbosacral levels
      • Function: → Maintenance of upright posture and balance → Excites extensor motor neurons innervating the neck, back, forelimb, and hindlimb muscles
    • Medial Vestibulospinal Tract:
      • Origin: Medial vestibular nucleus
      • Termination: → Descends in MLF → Anterior funiculus (as far as mid-thoracic level) → Terminates in the same laminae as the Lateral Vestibulospinal Tract (Rexed Laminae VII & VIII)
      • Function: → Maintains upright posture → Excites the neck up to the back motor neurons only

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    Description

    Test your knowledge on pyramidal and extrapyramidal tracts in the motor system with this anatomy quiz. Topics covered include corticospinal, corticobulbar, and extrapyramidal tracts along with associated motor neuron lesions and CNS circuitry.

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