Passmedicine

Question 1

What is the radial nerve responsible for?

Answer 1

A shaft fracture of the humerus is most likely to cause damage to the radial nerve.

The radial nerve is responsible for wrist extension.

Question 2

What is the median nerve responsible for?

Answer 2

Wrist flexion, opposition of the thumb and abduction of the thumb are mediated by the median nerve.

Question 3

What is the ulnar nerve responsible for?

Answer 3

Adduction of the fingers is mediated by the ulnar nerve.

Question 4

What is Wernicke’s aphasia?

Answer 4

Damage to Wernicke’s area can result in Wernicke’s aphasia, also known as a receptive aphasia. It is characterised by fluent speech that doesn’t make sense and an inability to understand written or spoken language. Wernicke’s area is located within the temporal lobe of the dominant hemisphere (e.g. 95% of right handed people have their wernicke’s area in their left hemisphere).

Question 5

How does cerebellar infarcts present?

Answer 5

Cerebellar infarcts can impair speech by causing dysarthria and slurred speech. These lesions do not typically affect a patients understanding of language

Question 6

What does damage to the Broca’s area present as?

Answer 6

Broca’s area is found within the frontal lobe. Damage to this structure results in an expressive aphasia, the opposite of a receptive aphasia. Here patients have an impaired ability to produce language but can still understand it.

Question 7

How does parietal lobe injury present?

Answer 7

Parietal lobe injury can result in reduced sensation and weakness in affected limbs. Additionally, damage to the optic tracts within the parietal lobe can result in visual deficits.

Question 8

Where does autonomic dysreflexia occur?

Answer 8

Autonomic dysreflexia occurs above the level of T6. T5 to T9 are the nerve roots of the greater splanchnic nerve. The greater splanchnic nerve serves a key role in mediating the sympathetic nervous system. If there is an injury above the level of T6 then the control of the greater splanchnic nerve is disrupted. This means that the sympathetic nervous system can no longer be adequately inhibited. Autonomic dysreflexia, therefore, causes an uncontrolled sympathetic response (usually this is a large increase in blood pressure). This mainly occurs in patients who have a spinal cord injury at or above the level of T6.

Question 9

What are the consequences of subthalamic nucleus lesion?

Answer 9

Subthalamic nucleus is the correct option. Lesions to this part of the basal ganglia cause a contralateral hemiballismus. In this case the lesion is most likely cause by the hyperglycaemia, which is the second most common reported cause for hemiballismus; most common being stroke.

Question 10

What are the consequences of caudate lesion?

Answer 10

Caudate is incorrect as this region is implicated in the pathophysiology of Parkinson’s disease and is part of the brain’s reward circuit.
Huntington chorea

Question 11

What are the consequences of Globus pallidus nucleus lesion?

Answer 11

Globus pallidus is incorrect as it is implicated in progressive neurological disorders characterized by symptoms like tremors, such as Parkinson’s.

Question 12

What are the consequences of putamen lesion?

Answer 12

Putamen is incorrect as the region is involved in other movement disorders, such as Parkinson’s and Tourette’s.

Question 13

What are the consequences of substantia nigra lesion?

Answer 13

Substantia nigra is incorrect as this region is implicated in Parkinsonisms, not ballismus.

Question 14

What are the consequences of parietal lobe lesion?

Answer 14

• sensory inattention
• apraxias
• astereognosis (tactile agnosia)
• inferior homonymous quadrantanopia
• Gerstmann’s syndrome (lesion of dominant parietal): alexia, acalculia, finger agnosia and right-left disorientation

Question 15

What are the consequences of occipital lobe lesion?

Answer 15

• homonymous hemianopia (with macula sparing)
• cortical blindness
• visual agnosia

Question 16

What are the consequences of temporal lobe lesion?

Answer 16

• Wernicke’s aphasia: this area ‘forms’ the speech before ‘sending it’ to Brocas area. Lesions result in word substituion, neologisms but speech remains fluent
• superior homonymous quadrantanopia
• auditory agnosia
• prosopagnosia (difficulty recognising faces)

Question 17

What are the consequences of frontal lobe lesion?

Answer 17

-expressive (Broca's) aphasia: located on the posterior aspect of the frontal lobe, in the inferior frontal gyrus. Speech is non-fluent, laboured, and halting
disinhibition
-perseveration
-anosmia
-inability to generate a list

Question 18

What are the consequences of cerebellar lesion?

Answer 18

• midline lesions: gait and truncal ataxia

- hemisphere lesions: intention tremor, past pointing, -dysdiadokinesis, nystagmus