Block 5 Neuro Motor Systems MCQ's
Questions and Answers
- 1.
A 28-year old women experiences drooping in her left lower facial muscles (below the eye). Her forehead remains unaffected. Given her symptoms name (i) the type of lesion (ii) the site of the lesion and (iii) the side of lesion.
- A.
Upper motor neuron lesion, genu of internal capsule, right.
- B.
Lower motor neuron lesion, facial nerve, left.
- C.
Upper motor neuron lesion, trigeminal nerve, right.
- D.
Lower motor neuron lesion, posterior limb of internal capsule, right.
- E.
Upper motor neuron lesion, posterior limb of internal capsule, left.
Correct Answer
A. Upper motor neuron lesion, genu of internal capsule, right.Explanation
The correct answer is upper motor neuron lesion, genu of internal capsule, right. This is because the patient is experiencing drooping in her left lower facial muscles, which indicates a lower motor neuron lesion. The forehead remains unaffected, indicating an upper motor neuron lesion. The site of the lesion is the genu of the internal capsule, which is responsible for controlling the facial muscles. The side of the lesion is right, as the symptoms are occurring on the left side of the face.Rate this question:
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- 2.
Following a motor bike accident, a 22-year old man presents with paraplegia. Name (i) the tract affected (ii) the site of injury and (iii) the type of lesion.
- A.
Corticobulbar tract, genu of internal capsule, bilateral.
- B.
Spinothalamic, thoracic, unilateral.
- C.
Corticospinal tract, rostral to the decussation of pyramids, bilateral.
- D.
Corticospinal tract, thoracic, bilateral.
- E.
Corticospinal tract, posterior limb, unilateral.
Correct Answer
D. Corticospinal tract, thoracic, bilateral.Explanation
The correct answer is Corticospinal tract, thoracic, bilateral. This means that the tract affected is the corticospinal tract, the site of injury is in the thoracic region, and the type of lesion is bilateral. This suggests that the motor bike accident caused damage to the corticospinal tract in the thoracic region on both sides of the body, resulting in paraplegia.Rate this question:
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- 3.
Your elderly neighbor has difficulties in picking up his newspaper properly from his porch and you have also noticed that he exhibits issues with correctly grasping his brandy glass when he invites you over for a drink. He told you that he has problems controlling the distance of his movements. You know this to be which of the following?
- A.
Akinesia
- B.
Dysdiadochokinesia
- C.
Bradykinesia
- D.
Dysphagia
- E.
Dysmetria
Correct Answer
E. DysmetriaExplanation
Based on the given information, the elderly neighbor is experiencing difficulties in controlling the distance of his movements, which is a characteristic symptom of dysmetria. Dysmetria is a neurological condition that affects the coordination of movements, causing inaccurate judgment of distance and over or undershooting of targets. This explains why the neighbor struggles to pick up the newspaper and grasp the brandy glass correctly.Rate this question:
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- 4.
A 57-year-old woman presents with the main complaint of difficulty speaking. The examination reveals that the woman's tongue deviates to the right on attempted protrusion. When she says \\Ah" her soft palate elevates slightly on the left and the uvula deviates to the same side . This combination of deficits most likely indicates a small lesion in which of the following?
- A.
Crus cerebri on the right
- B.
Genu of the internal capsule on the left
- C.
Genu of the internal capsule on the right
- D.
Lateral medulla on the right
- E.
Medial medulla on the right
Correct Answer
B. Genu of the internal capsule on the leftExplanation
The combination of a deviated tongue to the right on attempted protrusion and an elevated soft palate and uvula to the left when saying "Ah" suggests a lesion in the left side of the brain. The genu of the internal capsule contains fibers that control the muscles of the face, tongue, and throat. Therefore, a small lesion in the genu of the internal capsule on the left side could result in these specific deficits.Rate this question:
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- 5.
A 70-year old woman is brought to the emergency department by members of the volunteer fire department of a small town. She primarily complains of weakness. The examination reveals a hemiplegia involving the left upper and lower extremities, sensory losses (pain, thermal sensations, and proprioception) on the left side of the body and face, and a visual deficit in both eyes. MRI shows an area of infarction consistent with the territory served by the anterior choroidal artery. The weakness of the extremities in this woman is most likely due to damage to which of the following?
- A.
Corticospinal fibers on the left
- B.
Corticospinal fibers on the right
- C.
Somatomotor cortex on the right
- D.
Thalamocortical fibers to motor cortex on the right
- E.
Thalamocortical fibers to sensory cortex on the right
Correct Answer
B. Corticospinal fibers on the rightExplanation
The patient's symptoms, including weakness on the left side of the body, sensory losses on the left side, and a visual deficit in both eyes, suggest damage to the right side of the brain. The anterior choroidal artery supplies blood to the internal capsule, which contains the corticospinal fibers. Damage to the corticospinal fibers on the right side would result in weakness on the left side of the body, explaining the patient's symptoms. Therefore, the weakness of the extremities in this woman is most likely due to damage to the corticospinal fibers on the right.Rate this question:
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- 6.
A 47-year-old man is transported to the emergency department from the site of an automobile collision. The examination reveals a paralysis of both lower extremities. Which of the following most specifically identifies this clinical picture?
- A.
Alternating hemiplegia
- B.
Hemiplegia
- C.
Monoplegia
- D.
Quadriplegia
- E.
Paraplegia
Correct Answer
E. ParaplegiaExplanation
Paraplegia is the most specific term that identifies the clinical picture described in the question. Paraplegia refers to the paralysis of both lower extremities, which is consistent with the examination findings of the 47-year-old man. Alternating hemiplegia refers to paralysis that alternates between the right and left sides of the body, hemiplegia refers to paralysis of one side of the body, monoplegia refers to paralysis of a single limb, and quadriplegia refers to paralysis of all four limbs. Therefore, paraplegia is the most appropriate term in this case.Rate this question:
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- 7.
A 37-year-old man is brought to the emergency department with a severe head injury. Within a few hours he is decerebrate (upper and lower extremities extended) and comatose. The extension of his extremities indicates a dominant input to extensor motor neurons through reticulospinal fibers/tracts. Which of the following most specifically describes the position of these activated fibers within the spinal cord?
- A.
Anterolateral area (area of anterolateral system)
- B.
Posterolateral area (area of lateral corticospinal tract)
- C.
Posteriorcolumns
- D.
Posterolateral (dorsolateraI)tract
- E.
Intermediatezone
Correct Answer
A. Anterolateral area (area of anterolateral system)Explanation
The extension of the man's extremities indicates that there is a dominant input to extensor motor neurons through reticulospinal fibers/tracts. The anterolateral area, also known as the area of the anterolateral system, specifically describes the position of these activated fibers within the spinal cord. This area is responsible for transmitting pain and temperature sensations. Therefore, the activation of these fibers in the anterolateral area suggests that the man may be experiencing pain or discomfort as a result of his head injury.Rate this question:
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- 8.
A 23 year old man is brought to the emeregency room from the site of an automobile collision. The neurological examination reveals weakness of the right lower extremity and a loss of pain and thermal sensations on the left side beginning at the level of the umbilicus. CT shows a fracture of the vertebral column with displacement of bone fragments into the vertebral canal. Which of the following represents the most likely level of damage to the spinal cord resulting from the fracture to the vertebral column in this man?
- A.
T6 on the left
- B.
T8 on the left
- C.
T8 on the right
- D.
T10 on the left
- E.
T10 on the right
Correct Answer
C. T8 on the rightExplanation
The most likely level of damage to the spinal cord resulting from the fracture to the vertebral column in this man is T8 on the right. This is indicated by the loss of pain and thermal sensations on the left side beginning at the level of the umbilicus, which is consistent with a lesion at the T8 dermatome. The weakness of the right lower extremity suggests involvement of the descending corticospinal tract, which is also consistent with a T8 level of damage.Rate this question:
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- 9.
Based on their relative locations in the spinal cord, which of the following tracts or fiber bundles would most likely be involved In a lesion located in the immediate vicinity of the lateral corticospinal tract?
- A.
Anterolateral system
- B.
Anterior spinocerebellar tract
- C.
Gracile fasciculus
- D.
Medial longitudinal fasciculus
- E.
Rubrospinal tract
Correct Answer
E. Rubrospinal tractExplanation
A lesion located in the immediate vicinity of the lateral corticospinal tract would most likely involve the rubrospinal tract. The rubrospinal tract is located adjacent to the lateral corticospinal tract in the spinal cord. Lesions in this area can affect the rubrospinal tract, which is responsible for motor control and coordination. The other options, such as the anterolateral system, anterior spinocerebellar tract, gracile fasciculus, and medial longitudinal fasciculus, are not in close proximity to the lateral corticospinal tract and would not be directly affected by a lesion in that area.Rate this question:
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- 10.
A 23 year old man is brought to the emeregency room from the site of an automobile collision. The neurological examination reveals weakness of the right lower extremity and a loss of pain and thermal sensations on the left side beginning at the level of the umbilicus. CT shows a fracture of the vertebral column with displacement of bone fragments into the vertebral canal. Damage to which of the following tracts would correlate with weakness of the lower extremity in this man?
- A.
Left lateral corticospinal tract
- B.
Reticulospinal fibers on the right
- C.
Right lateral corticospinal tract
- D.
Right rubrospinal tract
- E.
Vestibulospinal fibers on the right
Correct Answer
C. Right lateral corticospinal tractExplanation
The neurological examination findings indicate that the patient has weakness of the right lower extremity. This suggests damage to a motor pathway that controls voluntary movement. The corticospinal tract is responsible for voluntary movement and runs on the opposite side of the body. Therefore, damage to the right lateral corticospinal tract would correlate with weakness of the right lower extremity. The other tracts mentioned do not control voluntary movement or are on the opposite side of the body, so they would not be responsible for the observed weakness.Rate this question:
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- 11.
A 44-year old man presents with a "cape-like" loss of sensation (pain and temperature) to his back and arms. An MRI reveals a cyst at the cervical level of his spinal cord. Name (i) the disorder and (ii) the tract that is affected.
- A.
Brown Sequard syndrome, Spinothalamic tract
- B.
Brown Sequard syndrome, Corticospinal tract
- C.
Syringomyelia, Spinothalamrc tract
- D.
Syringomyelia, Corticospinal tract
- E.
Syringomyelia, Tectospinal tract
Correct Answer
C. Syringomyelia, Spinothalamrc tractExplanation
The correct answer is Syringomyelia, Spinothalamic tract. Syringomyelia is a disorder characterized by the formation of a cyst, called a syrinx, within the spinal cord. This cyst can compress and damage the surrounding structures, including the Spinothalamic tract. The Spinothalamic tract is responsible for transmitting pain and temperature sensations from the body to the brain. In this case, the presence of the cyst at the cervical level of the spinal cord is causing a "cape-like" loss of sensation to the back and arms, which is consistent with the involvement of the Spinothalamic tract.Rate this question:
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- 12.
A 54-year-old morbidly obese and hypertensive man is brought to the emergency department after experiencing sudden onset of weakness of his left upper and lower extremities. CT shows an infarcted area in the medulla. Damage to which of the following tracts or fiber bundles of the medulla would most likely explain this deficit?
- A.
Anterolateral system
- B.
Corticospinal fibers
- C.
Medial Lemniscus
- D.
Rubrospinal tract
- E.
Vestibulospinal fibers
Correct Answer
B. Corticospinal fibersExplanation
Damage to the corticospinal fibers would most likely explain the deficit of weakness of the left upper and lower extremities. The corticospinal fibers are responsible for the voluntary movement of the limbs, and damage to these fibers can lead to weakness or paralysis on the opposite side of the body. In this case, the infarcted area in the medulla is affecting the corticospinal fibers, resulting in weakness on the left side.Rate this question:
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- 13.
Damage to the efferent portion of the muscle spindle would involve which of the following fiber types?
- A.
B fibers
- B.
Aa fibers
- C.
C fibers
- D.
Ay fibers
- E.
AB fibers
Correct Answer
D. Ay fibersExplanation
Damage to the efferent portion of the muscle spindle would involve Ay fibers. The muscle spindle is a sensory organ located within skeletal muscles that detects changes in muscle length and tension. It consists of specialized muscle fibers called intrafusal fibers, which are innervated by both sensory (afferent) and motor (efferent) fibers. The Ay fibers are the efferent fibers that innervate the muscle spindle and are responsible for adjusting its sensitivity and maintaining muscle tone. Therefore, damage to the efferent portion of the muscle spindle would affect the Ay fibers.Rate this question:
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- 14.
Which of the following represents the fibers that fan out from the internal capsule into the white matter of the hemisphere?
- A.
Cingulum
- B.
Corona radiata
- C.
Genu of the corpus callosum
- D.
Superior longitudinal fasciculus
- E.
Uncinate fasciculus
Correct Answer
B. Corona radiataExplanation
The correct answer is Corona radiata. The fibers that fan out from the internal capsule into the white matter of the hemisphere are known as the corona radiata. The corona radiata is a collection of nerve fibers that connect the cerebral cortex to other parts of the brain and spinal cord. It is involved in transmitting sensory and motor information between different regions of the brain. The other options listed, such as the cingulum, genu of the corpus callosum, superior longitudinal fasciculus, and uncinate fasciculus, are not specifically associated with fibers that fan out from the internal capsule.Rate this question:
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- 15.
A 64-year old woman presents with headache, lethargy and occasional vomiting, all suggestive of increased intracranial pressure. She also has marked weakness on the left side of her body. An MRI is performed which reveals a glioma invading the white matter between the lenticular nucleus and the thalamus on the right side of her brain. Which of the following is being compressed by this tumor?
- A.
Corticopontine tract
- B.
Anterior commissure
- C.
Anterior limb of internal capsule
- D.
Posterior limb of internal capsule
- E.
Posterior commissure
Correct Answer
D. Posterior limb of internal capsuleExplanation
The glioma in the white matter between the lenticular nucleus and the thalamus on the right side of the brain is compressing the posterior limb of the internal capsule. This can explain the marked weakness on the left side of the woman's body, as the posterior limb of the internal capsule contains descending motor fibers that control movement on the opposite side of the body.Rate this question:
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- 16.
A 22-year-old woman n is suffering from bilateral weakness of her lower limbs. Which of the following represents the most likely location of this lesion?
- A.
A lesion rostral to the pyramidal decussation
- B.
The left genu of the internal capsule
- C.
The right posterior limb of the internal capsule
- D.
A lesion caudal to the pyramidal decussation
- E.
The right genu of the internal capsule
Correct Answer
D. A lesion caudal to the pyramidal decussationExplanation
A lesion caudal to the pyramidal decussation is the most likely location of the lesion causing bilateral weakness of the lower limbs. The pyramidal decussation is the point where the fibers of the corticospinal tract cross over from one side of the brain to the opposite side of the spinal cord. Lesions rostral to the decussation would affect the contralateral side of the body, while lesions caudal to the decussation would affect the ipsilateral side of the body. Therefore, a lesion caudal to the pyramidal decussation would result in bilateral weakness of the lower limbs.Rate this question:
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- 17.
A 34-year old man is rushed to the emergency room from the site of a car accident. An MRI reveals a lesion at the level of the midbrain. His upper and lower limbs are extended. Name (i) the type of rigidity and (ii) the tract/tracts involved in the extension of the limbs.
- A.
Decorticate; Rubrospinal tract
- B.
Decorticate; Medial reticulospinal and lateral vestibulospinal tract
- C.
Decerebrate; Rubrospinal and lateral vestibulospinal tract
- D.
Decerebrate; Rubrospinal tract
- E.
Decerebrate; Medial reticulospinal and lateral vestibulospinal tract
Correct Answer
E. Decerebrate; Medial reticulospinal and lateral vestibulospinal tractExplanation
The correct answer is "Decerebrate; Medial reticulospinal and lateral vestibulospinal tract." Decerebrate rigidity is characterized by extension of both upper and lower limbs. This type of rigidity is caused by damage to the brainstem, specifically the midbrain. The involvement of the medial reticulospinal and lateral vestibulospinal tracts in the extension of the limbs suggests dysfunction in these tracts due to the lesion in the midbrain.Rate this question:
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- 18.
A 24-year-old woman is rushed to the hospital following severe head injuries. She is displaying a specific rigidity that is a result of lesions rostral to the red nucleus. What symptoms is she displaying?
- A.
Lower extremity weakness
- B.
Weakness of the masticatory muscles
- C.
Upper and lower limb extension
- D.
Upper limb flexion and lower limb extension
- E.
Deviation of the tongue on protrusion
Correct Answer
D. Upper limb flexion and lower limb extensionExplanation
The woman is displaying upper limb flexion and lower limb extension. Lesions rostral to the red nucleus can cause a condition known as decerebrate rigidity, which is characterized by extension of the upper limbs and extension of the lower limbs. This is due to disruption of the normal inhibitory pathways that control muscle tone and posture. The other symptoms listed, such as lower extremity weakness, weakness of the masticatory muscles, and deviation of the tongue on protrusion, are not typically associated with lesions rostral to the red nucleus.Rate this question:
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- 19.
A 52-year-old woman who is unable to move her left leg visits your office. Sensory modalities in all of her limbs are retained and there appears to be no sign of weakness in any of her other limbs. In which of the following structures are the cell bodies of lower motor neurons innervating the lower limb located?
- A.
Lamina I-VI
- B.
Lamina VIII, IX
- C.
Lamina X
- D.
Lamina I, II
- E.
Lamina III, IV
Correct Answer
B. Lamina VIII, IXExplanation
The cell bodies of lower motor neurons innervating the lower limb are located in Lamina VIII, IX. This is supported by the fact that the patient is unable to move her left leg, indicating a lower motor neuron lesion. The sensory modalities in all of her limbs are retained, suggesting that the lesion is specific to the motor neurons. The absence of weakness in her other limbs further supports the localization of the lesion to the lower limb. Lamina VIII and IX are known to contain cell bodies of lower motor neurons that control muscle movement.Rate this question:
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- 20.
A 74-year-old woman was residing in a rehabilitation facility while recovering from an infection. She was doing well until one morning she suddenly developed slurred speech and right sided weakness. An emergency neurologist was consulted. Medical history was notable for hypertension, coronary artery disease and a recent onset of atrial fibrillation. Examination revealed weak movements of the right face with only mild forehead involvement. Decreased palate movement on the right, and rightward tongue deviation. The neurologist suspected lacunar infarction, which was confirmed by MRI. Where is the most possible localization?
- A.
Left prefrontal gyrus medial part of the hemisphere
- B.
Right Broca area with involvement of lower part of Broadmann area 4.
- C.
Left posterior limb of internal capsule
- D.
Left genu of internal capsule
- E.
Right posterior limb and genu of internal capsule
Correct Answer
D. Left genu of internal capsuleExplanation
The patient's symptoms of slurred speech and right-sided weakness suggest a stroke. Lacunar infarctions are small, deep infarcts that commonly occur in the internal capsule. The internal capsule contains ascending and descending fibers that connect the cerebral cortex with the brainstem and spinal cord. The left genu of the internal capsule is responsible for motor control, and damage to this area can result in weakness on the opposite side of the body. Therefore, the most likely localization of the lacunar infarction in this patient is the left genu of the internal capsule.Rate this question:
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- 21.
A57-year-old man presents with hoarseness. The neurological examination reveals a deviation of the uvula to the left on phonation, deviation of the tongue to the right on protrusion, and weakness of the facial muscles around the mouth on the right. Which of the following would most likely also be seen in this man?
- A.
Inability to turn his head to the left against resistance
- B.
Inability to turn his head to the right against resistance
- C.
Inability to shrug the right shoulder against resistance
- D.
Weakness of the masticatory muscles on the left
- E.
Weakness of the masticatory muscles on the right
Correct Answer
A. Inability to turn his head to the left against resistanceExplanation
The patient's symptoms of deviation of the uvula to the left on phonation, deviation of the tongue to the right on protrusion, and weakness of the facial muscles around the mouth on the right suggest a lesion in the right cranial nerve XII (hypoglossal nerve) and cranial nerve VII (facial nerve). These nerves innervate the muscles responsible for movement of the tongue, uvula, and facial muscles. The most likely additional symptom that would be seen in this man is an inability to turn his head to the left against resistance, indicating weakness or paralysis of the right sternocleidomastoid muscle, which is innervated by the right cranial nerve XI (accessory nerve).Rate this question:
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- 22.
A 57-year-old obese man is brought to the emergency department by his wife. The examination reveals that cranial nerve function is normal but the man has bilateral weakness of his lower extremities. He has no sensory deficits. MRI shows a small infarcted area in the general region of the cervical spinal cord-medulla junction. Which of the following represents the most likely location of this lesion?
- A.
Caudal part of the pyramidal decussation
- B.
Lateral corticospinal tract on the left
- C.
Pyramids bilaterally
- D.
Pyramid on the right
- E.
Rostral part of the pyramidal decussation
Correct Answer
A. Caudal part of the pyramidal decussationExplanation
The most likely location of the lesion in this case is the caudal part of the pyramidal decussation. This is because the patient has bilateral weakness of his lower extremities, which suggests a lesion affecting the descending motor pathways. The pyramidal decussation is the site where the fibers of the corticospinal tracts cross over from one side of the brain to the opposite side of the spinal cord. Lesions in this region can result in bilateral motor deficits, which is consistent with the patient's presentation.Rate this question:
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- 23.
As a medical student, you are tapping the patellar tendon to activate the knee jerk reflex. The resulting reflex is within a normal range. Which sensory organ is activated in response to this stimulus?
- A.
Golgi tendon organ
- B.
Merkel cell
- C.
Pacinian corpuscle
- D.
Muscle spindle
- E.
Ruffini ending
Correct Answer
D. Muscle spindleExplanation
When tapping the patellar tendon, the resulting knee jerk reflex is activated by the muscle spindle. Muscle spindles are sensory receptors located within the muscle fibers and are responsible for detecting changes in muscle length and the rate of change. They play a crucial role in the stretch reflex, which helps to maintain posture and prevent overstretching of muscles. When the patellar tendon is tapped, the muscle spindle is activated, sending sensory information to the spinal cord, which then triggers the reflexive contraction of the quadriceps muscle, resulting in the knee jerk reflex.Rate this question:
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- 24.
A 79~year old man is experiencing peripheral nerve damage of his lower right limb. Which of the following is characteristic of lower motor neuron damage?
- A.
Hyperreflexia
- B.
Increased tone
- C.
Hyporeflexia
- D.
Spastic paralysis
- E.
Increased muscle mass
Correct Answer
C. HyporeflexiaExplanation
Hyporeflexia is characteristic of lower motor neuron damage. Lower motor neurons are responsible for transmitting signals from the central nervous system to the muscles, and damage to these neurons can result in a decrease in reflexes. This can manifest as reduced or absent reflex responses when the affected limb is stimulated. The other options, such as hyperreflexia, increased tone, spastic paralysis, and increased muscle mass, are more indicative of upper motor neuron damage.Rate this question:
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Aug 24, 2023Quiz Edited by
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Jan 24, 2012Quiz Created by
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