Sem 2 Neuro, DPS, Week 2 - Spinal Cord

When there is damage to the lower motor neurons, the patient would experience flaccid paralysis. Flaccid paralysis is characterized by weakened or absent muscle tone, resulting in muscle weakness and an inability to move the affected muscles. This is in contrast to spastic paralysis, which is caused by damage to the upper motor neurons and is characterized by increased muscle tone, hyperreflexia, and a positive Babinski sign. Therefore, in this case, the patient would not exhibit spastic paralysis, hyperreflexia, increased muscle tone, or a positive Babinski sign.

Damage to the ventral horn of the spinal cord would result in flaccid paralysis. Flaccid paralysis is characterized by the loss of muscle tone and voluntary movement in the affected muscles. This occurs because the damage to the ventral horn disrupts the motor neurons that innervate the muscles, leading to a loss of muscle function. In contrast, spastic paralysis is caused by damage to the upper motor neurons and is characterized by increased muscle tone and hyperreflexia. Therefore, in this patient, we would expect to see flaccid paralysis rather than spastic paralysis, hyperreflexia, increased muscle tone, or a positive Babinski sign.

The given answer, "Hemisection of the left spinal cord," is correct because the patient's symptoms are consistent with Brown-Séquard syndrome, which is characterized by a lesion or injury to one half of the spinal cord. In this case, the left side of the spinal cord is affected, resulting in loss of vibratory and joint position sense below C6 on the same side as the weakness. Additionally, there is loss of pain and temperature sensation on the left at C6 only and on the right below C6. This pattern of findings is indicative of a hemisection or partial damage to the left side of the spinal cord.

Loss of balance with his eyes closed indicates that the patient has suffered posterior column damage. The Romberg's test is used to evaluate proprioception and the patient's ability to maintain balance. When the patient closes their eyes during the test, they rely solely on proprioception to maintain balance. If there is damage to the posterior columns of the spinal cord, which are responsible for proprioception, the patient will have difficulty maintaining balance and will sway or fall. This is why a positive Romberg's test with loss of balance with eyes closed indicates posterior column damage.

After a traumatic injury like a fall from a high building resulting in a fractured cervical vertebra and spinal cord damage, it is expected to see decreased reflexes. This is because the injury affects the communication between the brain and the spinal cord, leading to a disruption in the reflex arc. The damaged nerves are unable to transmit signals properly, resulting in a decrease in reflex responses.

Based on the symptoms described, it is likely that the great-aunt is experiencing subacute combined degeneration. This condition is typically caused by a deficiency in vitamin B12, which can lead to neurological symptoms such as spastic paralysis and a loss of touch and pressure perception in the lower limbs. The other options, including Brown-Sequard syndrome, syringomyelia, amyotrophic lateral sclerosis (ALS), and tabes dorsalis, do not typically present with the same combination of symptoms seen in this case.

A lumbar puncture can be an iatrogenic cause for a spinal cord injury because it involves inserting a needle into the spinal canal, which can potentially damage the spinal cord if not performed correctly. While neurosyphilis, meningitis, motor vehicle accidents, and osteoporosis can all lead to spinal cord injuries, they are not iatrogenic causes as they are not caused by medical procedures or interventions.

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 and trunk. The other options listed, such as alpha motor neurons, anterior corticospinal tract, fasciculus cuneatus, and medial lemniscus, are found in other regions of the spinal cord and serve different functions.

The dorsal columns, also known as the posterior columns, are located in the posterior funiculus of the spinal cord. These columns contain sensory nerve fibers that carry information related to touch, vibration, and proprioception from the body to the brain.

The spinocerebellar pathway is most likely to be directly responsible for transmitting unconscious proprioception. This pathway carries information from proprioceptors in the muscles, tendons, and joints to the cerebellum, which is involved in coordinating movement and maintaining balance. This pathway does not involve conscious perception of proprioception, which is why it is referred to as "unconscious" proprioception. The other pathways listed, such as the neospinothalamic, spinoreticular, dorsal column-medial lemniscus, and spinomesencephalic pathways, are not primarily involved in transmitting proprioceptive information.

The dorsal horn of the spinal cord contains the substantia gelatinosa. This is a gel-like substance that is involved in processing pain and temperature sensations. It is responsible for modulating the transmission of pain signals to the brain. The substantia gelatinosa contains interneurons that receive sensory input from peripheral nerves and transmit it to other areas of the spinal cord and brain. It plays a crucial role in the processing and modulation of pain signals.

The behavior shown by the patient, expressing a desire for a motorized chair to resume 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 the initial stages of denial, anger, bargaining, and depression, and has come to terms with his paralysis.

Syringomyelia is a condition characterized by the formation of a fluid-filled cyst or syrinx within the spinal cord. This cyst can disrupt the normal functioning of the spinal cord and affect different tracts. In syringomyelia, the spinothalamic tract is commonly affected. The spinothalamic tract is responsible for transmitting pain and temperature sensations from the body to the brain. Damage to this tract can lead to sensory disturbances, such as loss of pain and temperature sensation, in the affected areas of the body.

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 such as touch, pressure, and vibration from the body to the brain. Since the bone fragment is affecting the dorsal columns on the left side, it will disrupt the transmission of sensory signals from the left leg, leading to a loss or impairment of touch, pressure, and vibration sensations in that leg.

An occlusion of the anterior spinal artery at the T10 spinal cord level would result in bilateral loss of voluntary motor function below the level of occlusion. This is because the anterior spinal artery supplies blood to the anterior portion of the spinal cord, which contains the motor pathways. When this artery is occluded, it leads to a lack of blood supply and subsequent damage to the motor pathways, resulting in a loss of voluntary motor function on both sides of the body below the level of the occlusion.

The most lateral aspect of the left spinothalamic tract should be lesioned in order to achieve the desired result. This is because the spinothalamic tract carries pain and temperature sensations from the contralateral side of the body. By lesioning the most lateral aspect of the left spinothalamic tract, the researcher can selectively block pain and temperature sensations from the right leg while leaving the sensations rostral to the arm unaffected.

Alpha motor neurons in the lumbar spinal cord are involved in innervating muscles of the lower limbs, including those of the thigh. These neurons control voluntary movements by sending signals to the muscles. Specifically, at the lumbar level, they are crucial for the motor control of muscles in the thigh, which include the quadriceps and hamstrings.

The bone fragment lodged into the medial aspect of the dorsal columns in the cervical spinal cord is likely to affect the sensory pathways that transmit touch, pressure, and vibratory sense from the ipsilateral leg. This is because the dorsal columns are responsible for transmitting these sensory modalities from the lower body to the brain. The fact that the injury is on the medial aspect of the dorsal columns suggests that it will specifically affect the sensory pathways that are closer to the midline of the body, which includes the ipsilateral leg.

The correct answer is the Spinal nucleus of V. This is because the Spinal nucleus of V is responsible for relaying pain and temperature information from the face to the VPM (ventral posterior medial) nucleus of the thalamus. The other options listed are not specifically involved in relaying pain and temperature information from the face.

A Brown-Sequard syndrome is a neurological condition caused by damage to one side of the spinal cord. The syndrome is characterized by a loss of motor function and proprioception (sense of body position) on the same side as the lesion, and a loss of pain and temperature sensation on the opposite side. In this case, the subject would exhibit a loss of touch and pressure sense on the left side below the level of the lesion, which is consistent with the characteristics of Brown-Sequard syndrome.

The patient's intact joint position sense suggests that the dorsal column pathway, which carries proprioceptive information, is intact. The diminished reflexes in the lower limbs indicate damage to the pathway responsible for transmitting this information to the cerebellum, which is the dorsal spinocerebellar pathway.

Axons carrying touch and pressure sensation information are found in the dorsal funiculus of the spinal cord. The dorsal funiculus is responsible for transmitting sensory information from the body to the brain. In this case, the loss of touch and pressure sense in the left lower limb suggests a problem with the axons in the dorsal funiculus on the same side of the body.

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. The other statements in the question provide additional information about the incidence and prevalence of spinal cord injuries in the USA, but the statement about 12,000 new cases per year specifically addresses the question being asked.

The patient's presentation of distal weakness and clumsiness in the hand during fine motor tasks suggests a lesion in the corticospinal tract. The corticospinal tract is responsible for carrying motor signals from the cerebral cortex to the spinal cord, controlling voluntary movements. Damage to this tract can result in weakness and loss of fine motor control, especially in the distal extremities. The absence of cranial nerve signs and normal sensory testing suggest that the lesion is specific to the corticospinal tract rather than involving other neurological structures.

In patients with established neuro syphilis and damage to the spinal cord, the gait is typically characterized by high stepping. This refers to a gait pattern where the patient lifts their legs higher than normal while walking, often resulting in exaggerated knee and hip flexion. This gait abnormality is caused by the damage to the nerves in the spinal cord, leading to weakness or paralysis of the lower limbs and a loss of coordination. The high stepping gait is a result of the patient's attempt to compensate for the muscle weakness and maintain balance while walking.

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