Block 5 Problem Quiz #2

The foramen of Megendie is the correct answer because it is the opening through which cerebrospinal fluid (CSF) flows from the fourth ventricle to the cistern magna. In this case, the child has hydrocephalus due to a tumor in the fourth ventricle, so the CSF flow through this foramen would be disrupted, leading to the accumulation of fluid and the development of hydrocephalus.

The correct answer is Planum temporale. The Planum temporale is an area of the brain that is involved in language functions. It has been found that there is a measurable volume difference between the right and left hemisphere of the brain in relation to the degree of lateralization of language functions. This suggests that the Planum temporale plays a role in the lateralization of language functions.

The correct answer is that CSF flows from the 4th ventricle to the cistern magna via the median aperture. This is characteristic of CSF flow under normal conditions. The presence of a tumor in the 4th ventricle and enlargement of all ventricles may disrupt the normal flow of CSF, leading to chronic headaches.

Left hemineglect is a condition where an individual is unable to attend or be aware of stimuli on one side of their body or environment, usually the left side. This condition is typically caused by damage to the right hemisphere of the brain. The right hemisphere is responsible for processing sensory information from the left side of the body and the left side of the environment. Therefore, when there is a lesion in the right hemisphere, it can result in left hemineglect.

In neuro syphilis with 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 is due to the damage to the spinal cord affecting the nerves that control muscle movement and coordination. The high stepping gait is a compensatory mechanism to overcome weakness or loss of muscle control in the lower extremities.

A lesion at the level of the cerebral peduncle would affect the descending fibers of the corticospinal tract. The corticospinal tract is responsible for voluntary movement, and disruption of these axons can lead to abnormal reflexes. A positive Babinski sign is an abnormal reflex where the big toe extends upward and the other toes fan out when the sole of the foot is stimulated. This reflex is normally present in infants but should disappear as the corticospinal tract matures. The presence of a positive Babinski sign in an adult indicates an upper motor neuron lesion, such as a lesion at the level of the cerebral peduncle.

SVA axons are contained in cranial nerves CN VII (Facial nerve), CN IX (Glossopharyngeal nerve), and CN X (Vagus nerve).

If the mesencephalon fails to develop, it would result in the loss of the oculomotor nuclei. The oculomotor nuclei are located in the midbrain and are responsible for controlling the movement of the eye muscles. Without the development of the mesencephalon, which is part of the midbrain, the oculomotor nuclei would not form properly or may not form at all, leading to a loss of control over eye movements.

The left middle cerebral artery is likely to be compromised in this scenario because it supplies blood to the motor and sensory areas of the brain responsible for controlling movement and sensation in the right upper limb. A stroke in this artery can result in paralysis and loss of sensation on the opposite side of the body, known as contralateral hemiparesis and hemisensory loss.

Based on the information given, the stroke occurred in the small branches of the middle cerebral artery that supplies Brodmann's areas 41/42. These areas are part of the auditory cortex responsible for processing sound and speech. Therefore, it is expected that the individual will have difficulty hearing as a result of the stroke affecting these areas.

The left pons is involved in this case because the patient is experiencing a right-sided hemiplegia and right-sided cerebellar ataxia. The pons is responsible for coordinating movement and balance, and damage to the left side of the pons can result in weakness and lack of coordination on the opposite side of the body. The inability to abduct the left eye suggests involvement of the cranial nerves, which are also located in the pons. Therefore, the correct answer is the left pons.

If the Foramen of Megendie is obstructed, it would result in non-communicating hydrocephalus. The Foramen of Megendie is a small opening in the roof of the fourth ventricle of the brain, and when it becomes blocked, the cerebrospinal fluid (CSF) is unable to flow freely from the ventricles to the subarachnoid space. This leads to an accumulation of CSF within the ventricles, causing increased pressure on the brain and resulting in hydrocephalus. Non-communicating hydrocephalus refers to a type of hydrocephalus where the obstruction prevents the free flow of CSF between the ventricles and the subarachnoid space.

The correct answer is CN V; Left Trigemino-Thalamic tract. The patient's loss of pain sensation on the right side of his face suggests that the trigeminal nerve (CN V) is affected. The trigeminal nerve carries sensory information, including pain, from the face to the brain. The left Trigemino-Thalamic tract is responsible for transmitting this sensory information from the trigeminal nerve to the thalamus, which then relays it to the sensory cortex for processing. Therefore, a lesion to the left Trigemino-Thalamic tract would result in the deficit exhibited in this case.

The left dorsolateral prefrontal cortex is not involved in language for a person who is left-dominant. This area of the brain is responsible for executive functions such as working memory, attention, and decision-making, but it is not directly involved in language processing. The other areas listed (left opercular gyrus, left angular gyrus, right plenum temporale, and right primary auditory cortex) are all involved in language processing and comprehension.

The symptoms described in the question, including paralysis of upward gaze and loss of the consensual pupillary light reflex, suggest dysfunction of the pineal gland. The pineal gland is responsible for producing melatonin, which regulates sleep-wake cycles, and is also involved in the regulation of circadian rhythms. Dysfunction of the pineal gland can lead to disruptions in these processes, resulting in symptoms such as those described in the patient. The other options listed do not have a direct association with the symptoms described.

The asymmetry of planum temporale surface is the anatomical marker of lateralization of language. This refers to the unevenness or difference in the surface area of the planum temporale, which is a region in the temporal lobe of the brain. Studies have shown that the planum temporale is typically larger in the left hemisphere of the brain, which is associated with language processing. This anatomical difference is believed to be related to the specialization of the left hemisphere for language functions.

The non-dominant equivalent to Wernicke area is responsible for prosodic aspects of language. Prosody refers to the patterns of stress, intonation, and rhythm in speech that convey meaning and emotion. This area helps in understanding and producing the melodic and rhythmic aspects of language, such as tone of voice, emphasis, and pitch variations. It plays a crucial role in conveying the intended message and emotions through speech.