Block 5 Neuro, Spinal Cord And DPS, MCQ's

Damage to the lower motor neurons would result in flaccid paralysis. Flaccid paralysis is characterized by the loss of muscle tone, decreased reflexes, and weakness in the affected muscles. It is caused by the disruption of the communication between the lower motor neurons and the muscles they innervate. This can lead to muscle atrophy and a loss of voluntary movement in the affected area.

Damage to the ventral horn of the spinal cord would result in flaccid paralysis. The ventral horn is responsible for transmitting motor signals from the brain to the muscles, so damage to this area would disrupt the communication and lead to a loss of muscle tone and voluntary movement. Flaccid paralysis is characterized by weak and floppy muscles, as opposed to spastic paralysis which is characterized by stiff and rigid muscles. Hyperreflexia, increased muscle tone, and a positive Babinski sign are all associated with upper motor neuron lesions, not damage to the ventral horn.

The given answer, "Hemisection of the left spinal cord," is the correct explanation for the findings described in the question. The patient's symptoms indicate a lesion on the left side of the spinal cord, affecting both motor and sensory pathways. The left hemiparesis suggests damage to the corticospinal tract on the left side, while the loss of vibratory and joint position sense below C6 on the left side indicates damage to the dorsal column on the left side. The loss of pain and temperature sensation on the left at C6 and on the right below C6 suggests damage to the spinothalamic tract, which crosses over at the level of entry into the spinal cord. These findings are consistent with a hemisection of the left spinal cord.

The lateral funiculus of the spinal cord primarily contains the Lateral Corticospinal tract. This tract is responsible for carrying motor signals from the cerebral cortex to the spinal cord, controlling voluntary movements of the limbs. The other options mentioned, such as alpha motor neurons, anterior corticospinal tract, fasciculus cuneatus, and medial lemniscus, are not primarily found in the lateral funiculus.

The bone fragment lodged into the medial aspect of the dorsal columns in the cervical spinal cord on the left side will most likely affect the touch, pressure, and vibration sensations of the left leg. The dorsal columns are responsible for transmitting sensory information related to touch, pressure, and vibration from the body to the brain. Since the injury is specifically on the left side, it will affect the sensory input from the left leg.

The Romberg's test is used to assess proprioception and the functioning of the posterior columns of the spinal cord. In a positive Romberg's test, the patient loses balance when their eyes are closed but can maintain balance when their eyes are open. This indicates that the patient is relying on visual cues for balance and is unable to compensate for the loss of proprioception caused by damage to the posterior columns. Therefore, the specific task in the test that indicates posterior column damage is the loss of balance with eyes closed.

The dorsal horn of the spinal cord is responsible for receiving sensory information from the body. The substantia gelatinosa is a specific region within the dorsal horn that plays a role in processing and modulating pain signals. It contains interneurons that receive input from sensory neurons and transmit signals to other parts of the spinal cord. Therefore, the substantia gelatinosa is the correct answer as it is a structure found in the dorsal horn of the spinal cord.

In cases of a spinal cord injury, especially in the cervical region, there is often a loss or decrease in reflexes below the level of the injury. This is due to the disruption of the neural pathways that transmit sensory information and reflex responses. In some cases, reflexes may return over time with rehabilitation, but immediately after the injury, decreased reflexes are commonly observed. The other options (increased reflexes, clonus, rigidity, and fasciculations) are not typically associated with spinal cord injuries and may be indicative of other neurological conditions or issues.

The behavior shown by the patient, expressing his desire for a motorized chair and wanting to get back to his studies, suggests that he has accepted his condition and is ready to adapt to his new circumstances. This indicates that he has moved past denial, anger, bargaining, and depression, and has reached the acceptance phase of the grief process.

A lumbar puncture can be an iatrogenic cause for a spinal cord injury. During a lumbar puncture, a needle is inserted into the spinal canal to collect cerebrospinal fluid for diagnostic purposes. If the needle is inserted incorrectly or if there is a complication during the procedure, it can lead to damage or injury to the spinal cord. This injury can result in neurological deficits and spinal cord dysfunction.

The bone fragment lodged into the medial aspect of the dorsal columns in the cervical spinal cord suggests damage to the sensory pathways in the spinal cord. The dorsal columns are responsible for transmitting touch, pressure, and vibratory sense information from the body to the brain. Since the bone fragment is located in the cervical spinal cord, it is likely to affect the sensory input from the ipsilateral (same side) leg. Therefore, the most likely function to be affected in this patient's presentation is touch, pressure, and vibratory sense from the ipsilateral leg.

The dorsal columns are found in the posterior funiculus. Funiculus refers to a bundle of nerve fibers within the spinal cord that carries specific types of information. The dorsal columns, also known as the posterior columns, are responsible for carrying sensory information related to touch, vibration, and proprioception (awareness of body position) from the body to the brain. Therefore, the correct answer is the posterior funiculus.

Syringomyelia is a condition characterized by the presence of a fluid-filled cyst or syrinx within the spinal cord. This cyst typically affects the central canal of the spinal cord and can expand over time, causing damage to nearby structures. The spinothalamic tract, which is responsible for transmitting pain and temperature sensations from the body to the brain, is commonly affected in syringomyelia. This can result in a loss of pain and temperature sensation in the affected areas of the body.

The researcher should make the lesion in the most lateral aspect of the left spinothalamic tract. By doing so, the researcher will specifically target the pathway responsible for transmitting pain and temperature sensation from the right leg. This will result in the subjects feeling no pain and temperature sensation from the right leg, while leaving the pathway for pain and temperature sensation rostral to the arm intact.

The loss of touch and pressure sense in the left lower limb suggests a sensory deficit. Sensory information from the body is carried by axons located in the dorsal funiculus of the spinal cord. The dorsal funiculus is responsible for transmitting sensory information from the body to the brain. Therefore, the loss of touch and pressure sense indicates an issue in the dorsal funiculus of the spinal cord.

Based on the symptoms described, the most likely problem is subacute combined degeneration. This condition is commonly caused by a vitamin B12 deficiency, which can lead to damage to the spinal cord and peripheral nerves. The symptoms of spastic paralysis and loss of touch and pressure perception in both lower limbs align with the characteristic features of subacute combined degeneration.

The spinocerebellar pathway is responsible for transmitting unconscious proprioception. This pathway carries information from the muscles, tendons, and joints to the cerebellum, which helps coordinate and regulate movement. In this scenario, when the female accidentally drops the heavy suitcase, the spinocerebellar pathway would be activated to provide feedback to the cerebellum about the position and movement of her limbs. This information allows the cerebellum to make adjustments and maintain balance and coordination.

A subject with Brown-Sequard syndrome on the left side would exhibit a loss of touch and pressure sense on the left side below the level of the lesion. Brown-Sequard syndrome is a neurological condition characterized by damage to one side of the spinal cord. In this case, the left side of the spinal cord is affected, leading to sensory deficits on the same side of the body below the level of the lesion. This means that the subject would experience a loss of touch and pressure sensation on the left side of their body below the level of the spinal cord damage.

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The correct answer is the Spinal nucleus of V. The Spinal nucleus of V is a second order neuron that is involved in relaying pain and temperature information from the face to the VPM (ventroposteromedial nucleus) of the thalamus. It receives input from the trigeminal nerve and sends the information to the thalamus for further processing and perception of pain and temperature sensations. The other options listed are not specifically involved in relaying pain and temperature information from the face.

The alpha motor neurons located very medially at the lumbar spinal cord level provide voluntary motor innervation to the thigh.

The patient's intact joint position sense suggests that the dorsal column pathway, which is responsible for relaying proprioceptive information, is not damaged. The diminished reflexes in the lower limbs indicate damage to the dorsal spinocerebellar pathway. This pathway carries information from muscle spindles and Golgi tendon organs to the cerebellum, allowing for coordination and fine-tuning of motor movements.

In a patient with established neuro syphilis and damage to the spinal cord, the gait is characterized by high stepping. This refers to a gait pattern where the patient lifts their legs higher than normal while walking. This abnormal gait is caused by the damage to the spinal cord, which can result in weakness or paralysis of the lower limbs. The high stepping gait is a compensatory mechanism used by the patient to clear their feet off the ground and prevent tripping or dragging.

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The correct answer is "About 12,000 new cases per year." This answer is supported by the information provided in the question, which states that there are approximately 12,000 new cases of spinal cord injuries per year in the USA. The other statements in the question provide additional information about the incidence and causes of spinal cord injuries, but the specific number of new cases per year is what is being asked for in the answer.

The patient's ability to walk without difficulty and perform gross motor tasks suggests that the motor pathways involved in these functions are intact. However, the clumsiness observed in the patient's hand while attempting fine motor tasks, such as writing, indicates a problem with the corticospinal tract. The corticospinal tract is responsible for controlling voluntary movements, particularly those involving fine motor skills. Lesions in this pathway can result in distal weakness and impaired fine motor control, which is consistent with the patient's symptoms.