Thoretics

Question 1

circulation of intracranial fluid

Answer 1

choroid plexus in the ventricules -> lateral ventricules -> -> foramina of Munro -> 3rd ventricule -> Sylvian aqueduct -> 4th ventricule -> foramina of Luschka and Magendie -> subarachnoid space -> arachnoid villi -> cerebral venous system

Question 2

Normal CSF pressure

Answer 2

10-18 cm H20

Question 3

Increased ICP in Ultrasound

Answer 3

distended external diameter of the optic nerve sheath 5.0-5.7 mm or greater at 3.0 mm behind the globe. crescent sign - echolucent area in anterior intraorbital nerve . Lateral gaze (thirty degree test lead to 10% reduction in diameter on A-scan in the presence of excess fluid

Question 4

Lower nasal optic nerve fibers traverse the chiasm

Answer 4

inferiorly and anteriorly

Question 5

Upper nasal optic nerve fibers traverse the chiasm

Answer 5

high and posteriorly - craniopharyngioma

Question 6

incongruous Hemianopia

Answer 6

anterior retrochiasmal visual pathways

Question 7

asymmetrical hemianopic defects

Answer 7

Lesions of the lateral geniculate body

Question 8

Optic tract lesions - appearance of the disc

Answer 8

The ipsi disc manifests atrophy of the superior and inferior aspects of the neuroretinal rim (fibres from the temporal retina), while the contralateral disc manifests a ‘bow tie’ pattern (nasal and nasal macular fibres).

Question 9

‘pie in the sky’

Answer 9

contralateral superior homonymous quadrantanopia - Temporal radiations , because the inferior fibres of the optic radiations, which subserve the upper visual fields, first sweep anteroinferiorly (Meyer loop). May contralateral hemisensory disturbance and hemiparesis.

Question 10

Temporal radiations

Answer 10

contralateral superior homonymous quadrantanopia (‘pie in the sky’), because the inferior fibres of the optic radiations, which subserve the upper visual fields, first sweep anteroinferiorly (Meyer loop). May contralateral hemisensory disturbance and hemiparesis.

Question 11

‘pie on the floor’

Answer 11

Anterior parietal radiations - contralateral inferior homonymous quadrantanopia because the superior fibres of the radiations/ Associated features of dominant parietal lobe disease include acalculia, agraphia, left–right disorientation and finger agnosia. Non-dominant lobe lesions may cause dressing and constitutional apraxia and spatial neglect

Question 12

Anterior parietal radiations

Answer 12

contralateral inferior homonymous quadrantanopia (‘pie on the floor’) because the superior fibres of the radiations, which subserve the inferior visual fields . Associated features of dominant parietal lobe disease include acalculia, agraphia, left–right disorientation and finger agnosia. Non-dominant lobe lesions may cause dressing and constitutional apraxia and spatial neglect

Question 13

homonymous hemianopia with no other neurological deficit - what is the cause

Answer 13

Stroke in the territory of the posterior cerebral artery is responsible for over 90%

Question 14

Where in cortex are represented peripheral visual fields

Answer 14

anteriorly (posterior cerebral artery)

Question 15

Main radiations

Answer 15

complete homonymous hemianopia. Optokinetic nystagmus - smooth pursuit pathways towards the side of the lesion. ○ If the lesion is in the occipital lobe, the smooth pursuit pathways are intact and OKN will be symmetrical

Question 16

complete homonymous hemianopia

Answer 16

Main radiations. homonymous hemianopia is complete when the visual field defect respects the vertical meridian, has macular splitting, and involves the entire hemifield on the affected side