1.
A 61-year-old man is brought to the emergency department after a fall from his garage roof. The examination reveals a hemiplegia on the left, a loss of vibratory sense on the left, and a loss of pain and thermal sensation on the right side involving the upper and lower extremities. These deficits are characteristically seen in which of the following syndromes?
Correct Answer
B. Brown-Sequard
Explanation
The patient in this scenario presents with a combination of symptoms that are characteristic of Brown-Sequard syndrome. Brown-Sequard syndrome is a neurological condition caused by damage to one side of the spinal cord. It is typically associated with a loss of motor function and vibratory sense on one side of the body (hemiplegia and loss of vibratory sense on the left side in this case) and a loss of pain and thermal sensation on the opposite side (right side involving the upper and lower extremities in this case). This pattern of symptoms is consistent with the presentation described in the question.
2.
A 92-year-old woman is brought to the emergency department by her caregiver. The woman had suddenly become drowsy and confused. The examination revealed no cranial nerve deficits and age-normal motor function, but a loss of pain, thermal, vibratory, and discriminative touch sensations on one side of the body excluding the head. CT shows a small infarcted area.
(i) Which of the following structures is the most likely location of this lesion?
Correct Answer
D. Ventral posterolateral nucleus
Explanation
The most likely location of the lesion in this case is the ventral posterolateral nucleus. This is supported by the symptoms described, which include a loss of pain, thermal, vibratory, and discriminative touch sensations on one side of the body excluding the head. The ventral posterolateral nucleus is responsible for relaying sensory information from the body to the cerebral cortex, and a lesion in this area would result in a loss of these sensations on one side of the body.
3.
A 92-year-old woman is brought to the emergency department by her caregiver. The woman had suddenly become drowsy and confused. The examination revealed no cranial nerve deficits and age-normal motor function, but a loss of pain, thermal, vibratory, and discriminative touch sensations on one side of the body excluding the head. CT shows a small infarcted area.
(ii) The loss of pain and thermal sensations experienced by this woman would most likely correlate with a lesion involving which of the following structures?
Correct Answer
B. Anterolateral system
Explanation
The loss of pain and thermal sensations on one side of the body excluding the head suggests a lesion involving the anterolateral system. The anterolateral system is responsible for transmitting pain and temperature sensations from the body to the brain. Lesions in this system can result in a loss of these sensations on the contralateral side of the body. The other structures listed are not specifically involved in transmitting pain and thermal sensations.
4.
Damage to which of the following fiber bundles or tracts would most likely explain the loss of vibratory sensation of the left lower limb?
Correct Answer
D. Gracile fasciculus on the left
Explanation
Damage to the gracile fasciculus on the left would most likely explain the loss of vibratory sensation in the left lower limb. The gracile fasciculus is responsible for transmitting sensory information related to proprioception, vibration, and fine touch from the lower limbs and lower trunk. Damage to this tract on the left side would result in a loss of vibratory sensation specifically in the left lower limb.
5.
An 88-year-old man is brought to the emergency department by his daughter. She indicates that he complained of weakness of his "arm" and "leg" (upper and lower extremities) on the right side and of "seeing two of everything" (double vision-diplopia). CT shows an infarcted area in the medial area of the pons at the pons-medulla junction. The infarcted area is consistent with the vascular territory served by paramedian branches of the basilar artery.
(i) Weakness of the extremities on the right can be explained by damage to which of the following structures?
Correct Answer
A. Corticospinal fibers on the left
Explanation
The weakness of the extremities on the right side can be explained by damage to the corticospinal fibers on the left side. The corticospinal fibers are responsible for transmitting motor commands from the brain to the spinal cord, which then control the movement of the limbs. In this case, the infarcted area in the medial area of the pons at the pons-medulla junction, which is in the vascular territory served by paramedian branches of the basilar artery, has likely caused damage to the corticospinal fibers on the left side, resulting in weakness on the right side of the body.
6.
An 88-year-old man is brought to the emergency department by his daughter. She indicates that he complained of weakness of his "arm" and "leg" (upper and lower extremities) on the right side and of "seeing two of everything" (double vision-diplopia). CT shows an infarcted area in the medial area of the pons at the pons-medulla junction. The infarcted area is consistent with the vascular territory served by paramedian branches of the basilar artery.
(ii) Injury to which of the following structures in this man is most specifically related to the loss of pain and thermal sensations on the body below the neck?
Correct Answer
A. Anterolateral system
Explanation
The loss of pain and thermal sensations on the body below the neck is most specifically related to the injury to the Anterolateral system. The Anterolateral system, also known as the spinothalamic tract, is responsible for transmitting pain and temperature sensations from the body to the brain. In this case, the infarcted area in the medial area of the pons at the pons-medulla junction, which is consistent with the vascular territory served by paramedian branches of the basilar artery, is likely causing damage to the Anterolateral system, leading to the loss of pain and thermal sensations.
7.
An 88-year-old man is brought to the emergency department by his daughter. She indicates that he complained of weakness of his "arm" and "leg" (upper and lower extremities) on the right side and of "seeing two of everything" (double vision-diplopia). CT shows an infarcted area in the medial area of the pons at the pons-medulla junction. The infarcted area is consistent with the vascular territory served by paramedian branches of the basilar artery.
(iii) Damage to which of the following structures would most specifically explain the loss of pain and thermal sensations on the man's face?
Correct Answer
E. Spinal trigeminal tract
Explanation
The spinal trigeminal tract is responsible for transmitting pain and thermal sensations from the face to the brain. Damage to this structure would specifically explain the loss of pain and thermal sensations on the man's face.
8.
A 79-year-old woman is brought to the emergency department after a fall in her home from which she was unable to get up. The examination reveals a deviation of the tongue to the left on protrusion, a pronounced weakness of the right upper and lower extremities, and a loss of position and vibratory sense and discriminative touch on the right side of the body below the neck. CT shows an infarcted area in the medulla .
(i) Which of the following represents the best localizing sign in this patient?
Correct Answer
A. Deviation of the tongue
Explanation
The best localizing sign in this patient is the deviation of the tongue to the left on protrusion. This is indicative of a lesion in the medulla, which can affect the hypoglossal nerve (cranial nerve XII) that innervates the tongue muscles. The other findings mentioned, such as weakness in the right upper and lower extremities and sensory loss on the right side of the body, are also consistent with a medullary infarct, but the deviation of the tongue is the most specific and localized sign.
9.
A 79-year-old woman is brought to the emergency department after a fall in her home from which she was unable to get up. The examination reveals a deviation of the tongue to the left on protrusion, a pronounced weakness of the right upper and lower extremities, and a loss of position and vibratory sense and discriminative touch on the right side of the body below the neck. CT shows an infarcted area in the medulla .
(ii) Damage to which of the following tracts or fiber bundles would most likely give rise to the sensory deficits experienced by this patient?
Correct Answer
B. Medial lemniscus
Explanation
The patient's presentation of loss of position and vibratory sense and discriminative touch on the right side of the body below the neck suggests a sensory deficit. The medial lemniscus is responsible for transmitting tactile and proprioceptive information from the body to the brain. Damage to the medial lemniscus, such as the infarcted area in the medulla seen on CT, would disrupt the transmission of these sensory signals, leading to the sensory deficits experienced by the patient.
10.
A 15-year-old boy is brought to the emergency department after an accident on his father's farm. The examination reveals weakness of the left lower extremity, but no frank paralysis. There is a loss of pinprick sensation on the right side beginning at the T8 dermatome (about half way between the nipple and umbilicus), and dorsiflexion of the great toe in response to plantar stimulation. Based on this examination, which of the following represents the most likely approximate location of this lesion?
Correct Answer
A. T6 on the left side
Explanation
Based on the examination findings, the weakness of the left lower extremity and loss of pinprick sensation on the right side starting at the T8 dermatome, it suggests a lesion in the spinal cord. The fact that the weakness and sensory loss are on opposite sides of the body indicates a lesion in the spinal cord that crosses over. The most likely location of this lesion is at the level where the sensory and motor pathways cross, which is at the T6 dermatome on the left side.
11.
An 80-year-old woman is brought to the emergency department from an assisted care facility. The woman, who is in a wheelchair, complains of not feeling well, numbness on her face, and being hoarse, although she claims not to have a cold. The examination reveals a loss of pain and thermal sensations on the right side of her face and the left side of her body. CT shows an infarcted area in the lateral portion of the medulla. A lesion of which of the following structures in this woman would explain the loss of pain and thermal sensations on her body excluding the head?
Correct Answer
B. Anterolateral system on the right
Explanation
The anterolateral system is responsible for transmitting pain and temperature sensations from the body to the brain. In this case, the patient has a loss of pain and thermal sensations on the right side of her face and the left side of her body. This suggests a lesion in the anterolateral system on the right side, as it would affect the contralateral side of the body. The other options, such as the anterolateral system on the left, medial lemniscus on the left, spinal trigeminal nucleus on the left, and spinal trigeminal tract on the left, would not explain the loss of pain and thermal sensations on the right side of the body.
12.
In the course of a neurological examination of a 23-year-old man, the physician places her index finger on the midline of the mandible and taps it with a percussion hammer stimulating the afferent limb of the jaw (jaw-jerk) reflex. Collateral fibers from which of the following brain stem nuclei enterthetrigeminaI motarnueleusto initiate the motor response?
Correct Answer
B. MesencepHalic
Explanation
The correct answer is Mesencephalic. The jaw-jerk reflex involves the stimulation of the afferent limb of the reflex, which is the sensory information from the jaw. This sensory information is carried by the mesencephalic nucleus of the trigeminal nerve, located in the midbrain. The mesencephalic nucleus then sends motor signals to the muscles of mastication, initiating the motor response.
13.
The facial sensory deficits experienced by this woman are explained by a lesion to the axons of cell bodies located in which of the following structures?
Correct Answer
B. Left trigeminal ganglion
Explanation
The facial sensory deficits experienced by this woman can be explained by a lesion to the axons of cell bodies located in the left trigeminal ganglion. The trigeminal ganglion is responsible for relaying sensory information from the face to the brain. Lesions or damage to this ganglion can result in deficits in facial sensation on the affected side.
14.
The loss of pain and thermal sensations experienced by this woman on the right side of her body (excluding the face) is most likely the result of damage to which of the following structures?
Correct Answer
A. Anterolateral system fibers on the left
Explanation
The loss of pain and thermal sensations on the right side of the body (excluding the face) suggests damage to the anterolateral system fibers on the left side. The anterolateral system is responsible for transmitting pain and temperature sensations from the body to the brain. Damage to the fibers on the left side would result in a loss of these sensations on the opposite side of the body.
15.
An ll-year-old girl is brought to the family physician by her mother. The mother explains that the girl has been complaining that her hands and arms "feel runny." In fact, the mother states that the girl cut her little finger, but did not resize it until she saw blood. The examination reveals a bilateral loss of pain and thermal sensation on the upper extremities and shoulder. Which of the following is the most likely cause of this deficit in this girl?
Correct Answer
E. Syringomyelia
Explanation
The girl's symptoms of bilateral loss of pain and thermal sensation on the upper extremities and shoulder are consistent with a syringomyelia. Syringomyelia is a condition characterized by the formation of a fluid-filled cavity within the spinal cord. This can lead to compression and damage to the nerve fibers responsible for transmitting pain and temperature sensations. The other options, such as Brawn-Sequard syndrome, Posterior inferior cerebellar artery syndrome, Tabes dorsalis, and Syringobulbia, do not typically present with the same pattern of sensory loss described in the case.
16.
You touch the edge of a coin with your right index finger. This tactile information is sent to cortex by a tract that crosses the neuroaxis at which point in the nervous system?
Correct Answer
E. Caudal medulla
Explanation
When you touch the edge of a coin with your right index finger, the tactile information is sent to the cortex by a tract that crosses the neuroaxis at the caudal medulla. The caudal medulla is a region in the lower part of the brainstem where sensory information from the body is processed and relayed to the cortex. This crossing of the neuroaxis at the caudal medulla is known as decussation, where sensory information from one side of the body is transmitted to the opposite side of the brain.
17.
During a neurological examination a 49-year old woman's Romberg's test is positive. Which of the following is the major structure that has been affected?
Correct Answer
D. Dorsal columns
Explanation
The Romberg's test is used to assess proprioception and balance. A positive Romberg's test indicates a loss of proprioception, which is the ability to sense the position and movement of body parts. The major structure responsible for proprioception is the dorsal columns of the spinal cord. Therefore, if the Romberg's test is positive, it suggests that the dorsal columns have been affected.
18.
A 26-year old woman is in an automobile accident. A neurological exam reveals loss of touch, vibration and proprioception in her lower right limb. What is the adaptation rate and receptive field size of Meissner's corpuscles in response to touch under normal conditions?
Correct Answer
A. Adapt rapidly to stimuli and have a small receptive field
Explanation
Meissner's corpuscles are sensory receptors located in the skin that are responsible for detecting light touch and vibration. They adapt rapidly to stimuli, meaning that they quickly respond to changes in touch sensation. They also have a small receptive field, which means that they are highly sensitive to touch in a specific area. In this case, the loss of touch, vibration, and proprioception in the woman's lower right limb suggests damage to the Meissner's corpuscles in that area, leading to the loss of these sensations.
19.
A patient presents with weakness in the limbs on the left side of the body as well as loss of pain and temperature sensitivity on the left side of the body. Damage to which fibers types could elicit such pain/temperature symptoms?
Correct Answer
B. Type C fibers
Explanation
Damage to type C fibers could elicit such pain/temperature symptoms. Type C fibers are unmyelinated and transmit slow, dull, and chronic pain sensations as well as temperature sensations. Damage to these fibers would result in a loss of pain and temperature sensitivity on the left side of the body.
20.
Following a series of strokes a 76~year old woman complains of Hypogeusia . In the pathway that is affected where are the cell bodies of the third order sensory neurons located?
Correct Answer
C. VPM (Ventral posteromedial nucleus; of the thalamus)
Explanation
The cell bodies of the third order sensory neurons that are affected in the pathway of hypogeusia are located in the VPM (Ventral posteromedial nucleus) of the thalamus.
21.
A 26-year footballer collides with a member of the opposition during a soccer match. A couple of days later he meets with his physician and complains of hyposmia. Which of the following statements is correct in relation to normal olfaction?
Correct Answer
B. The main output cell of the olfactory bulb is the mitral cell
Explanation
The main output cell of the olfactory bulb is the mitral cell. This means that the mitral cells receive input from the primary olfactory neurons and transmit that information to other areas of the brain for further processing. The primary olfactory neurons, on the other hand, are responsible for detecting odors and sending signals to the olfactory bulb. The other statements in the options are not related to the main output cell of the olfactory bulb.