Podcast
Questions and Answers
A patient exhibits increased muscle tone, exaggerated reflexes, and a positive Babinski sign. These findings are MOST indicative of a lesion affecting which of the following?
A patient exhibits increased muscle tone, exaggerated reflexes, and a positive Babinski sign. These findings are MOST indicative of a lesion affecting which of the following?
- Lower motor neurons
- Muscle spindles
- Peripheral nerves
- Upper motor neurons (correct)
During a neurological examination, a doctor observes that a patient is experiencing loss of fine touch and proprioception on the right side of their body. Where is the MOST likely location of the lesion?
During a neurological examination, a doctor observes that a patient is experiencing loss of fine touch and proprioception on the right side of their body. Where is the MOST likely location of the lesion?
- Right corticospinal tract
- Left dorsal column/medial lemniscus pathway (correct)
- Left vestibulospinal tract
- Right spinothalamic tract
According to Henneman's size principle, which type of motor unit is typically recruited FIRST for a low-intensity muscle contraction?
According to Henneman's size principle, which type of motor unit is typically recruited FIRST for a low-intensity muscle contraction?
- Large, slow-twitch motor units
- Small, slow-twitch motor units (correct)
- Small, fast-twitch motor units
- Large, fast-twitch motor units
A patient who sustained a spinal cord injury at T4 is exhibiting a sudden onset of severe hypertension, a pounding headache, and profuse sweating above the level of the lesion. Which condition is MOST likely causing these symptoms?
A patient who sustained a spinal cord injury at T4 is exhibiting a sudden onset of severe hypertension, a pounding headache, and profuse sweating above the level of the lesion. Which condition is MOST likely causing these symptoms?
Damage to the anterior spinal cord will MOST likely result in which of the following clinical presentations?
Damage to the anterior spinal cord will MOST likely result in which of the following clinical presentations?
A patient presents with weakness in both upper extremities but normal strength in the lower extremities following a hyperextension injury to the neck. Which spinal cord syndrome is MOST consistent with this presentation?
A patient presents with weakness in both upper extremities but normal strength in the lower extremities following a hyperextension injury to the neck. Which spinal cord syndrome is MOST consistent with this presentation?
Which of the following BEST describes the function of gamma motor neurons?
Which of the following BEST describes the function of gamma motor neurons?
A patient is diagnosed with diabetic polyneuropathy. Which sensory modalities are MOST likely to be affected?
A patient is diagnosed with diabetic polyneuropathy. Which sensory modalities are MOST likely to be affected?
Following a stroke, a patient exhibits impaired postural control and balance. Which descending tract is MOST likely affected?
Following a stroke, a patient exhibits impaired postural control and balance. Which descending tract is MOST likely affected?
A patient with a spinal cord injury at the level of S3 is MOST likely to experience which type of bladder dysfunction?
A patient with a spinal cord injury at the level of S3 is MOST likely to experience which type of bladder dysfunction?
Flashcards
Lower Motor Neurons (LMNs)
Lower Motor Neurons (LMNs)
Neurons controlling skeletal muscles, organized in functional pools.
Motor Units
Motor Units
Alpha neurons control force, gamma neurons manage sensory and tension feedback.
Henneman’s Size Principle
Henneman’s Size Principle
Smaller, slow-twitch motor units activate before larger, fast-twitch units.
Reflexes
Reflexes
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Common LMN Disorders
Common LMN Disorders
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Sensory Receptors
Sensory Receptors
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Dorsal Column/Medial Lemniscus (DCML)
Dorsal Column/Medial Lemniscus (DCML)
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Spinothalamic Tract
Spinothalamic Tract
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Pyramidal Tracts
Pyramidal Tracts
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Extrapyramidal Tracts
Extrapyramidal Tracts
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Study Notes
Lower Motor Neurons (LMNs)
- Control skeletal muscles
- Organized in pools according to function
Motor Units
- Alpha motor neurons control force and movement
- Gamma motor neurons provide sensory feedback and regulate tension
Henneman’s Size Principle
- Small, slow-twitch motor units activate first
- Progressively larger, fast-twitch units are recruited as needed
Reflexes
- Spinal reflexes assist in maintaining movement and posture
- Brainstem reflexes are essential for balance
- Cortical reflexes also contribute to motor control and posture
Common LMN Disorders
- Guillain-Barré syndrome affects the peripheral nerves
- Diabetic Polyneuropathy is nerve damage caused by diabetes
- Amyotrophic Lateral Sclerosis (ALS) affects both LMNs and Upper Motor Neurons (UMNs)
Receptors
- Mechanoreceptors respond to touch
- Thermoreceptors respond to temperature
- Chemoreceptors respond to chemical stimuli
Sensory Pathway: Dorsal Column/Medial Lemniscus (DCML)
- Fine touch
- Proprioception
Sensory Pathway: Spinothalamic Tract
- Pain
- Temperature
- Crude touch
Sensory Pathway: Divergent Pathways
- Influence emotions
- Influence cognition
- Pain modulation
Peripheral Neuropathies
- Mononeuropathy involves a single nerve
- Polyneuropathy involves multiple nerves
- Diabetic neuropathy is an example of polyneuropathy
Descending Tracts: Pyramidal
- Corticospinal and Corticobulbar tracts
- Control voluntary movement
Descending Tracts: Extrapyramidal
- Vestibulospinal tract controls posture
- Reticulospinal tract controls balance
- Rubrospinal tract contributes to motor control
- Tectospinal tract mediates reflexive movements to visual and auditory stimuli
UMN Lesions
- Cause spasticity
- Cause hyperreflexia
- Result in a positive Babinski sign
Spinal Cord Syndromes: Central Cord
- Upper extremity (UE) weakness
Spinal Cord Syndromes: Anterior Cord
- Loss of motor function
Spinal Cord Syndromes: Brown-Séquard
- Ipsilateral motor loss
- Contralateral pain and temperature loss
Autonomic Dysreflexia
- Life-threatening condition
- Occurs in spinal cord injuries (SCI) above T6
- Symptoms include high blood pressure and headache
Bladder Dysfunction: Hypertonic (spastic)
- Occurs with Upper Motor Neuron (UMN) injury
- Spinal cord injury (SCI) above S2
Bladder Dysfunction: Hypotonic (flaccid)
- Occurs with Lower Motor Neuron (LMN) injury
- Spinal cord injury (SCI) at or below S2
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