CHAPTER 17 Flashcards
- Interruption of the medial longitudinal fas-
ciculus (MLF) at pontine levels
(A) results in miosis and ptosis
(B)results in paralysis of upward gaze on com-
mand
(C) results in paralysis of lateral gaze on com-
mand
(D) abolishes convergence
(E) abolishes accommodation
l-C. Interruption of the pontine medial longitudinal fasciculus (MLF) results in a medial rectus palsy on attempted conjugate lateral gaze. Convergence remains intact. This syndrome, called internuclear ophthalmoplegia (INO) or medial longitudinal fasciculus (MLF) syndrome, is com- monly seen in multiple sclerosis.
- A 75-year-old coal miner complains of pro-
gressive loss of vision. Visual field examination
shows visual loss in the upper right quadrant
in both visual fields. The lesion would most
likely be in the
(A) right angular gyrus
(B) left cuneus
(C) left temporal lobe
(D) right occipital pole
(E) right lingual gyrus
2-C. Ablation of the anterior temporal lobe destroys the visual radiations that project to the
lower bank of the calcarine sulcus. The field deficit is an upper right homonymous quadranta-
nopia, which is also called Meyer loop quadrantanopia.
- All of the following statements concerning
the optic chiasm are correct EXCEPT
(A) its primary blood supply is from the ante-
rior cerebral and internal carotid arteries
(B) it lies dorsal to the diaphragma sellae
(C) the midsagittal section results in binasal
hemianopia
(D) it contains uncrossed fibers from the tem-
poral hemiretinae
(E) it contains pupillary fibers en route to the
pretectum
3-C. The midsagittal section of the optic chiasm transects fibers from the nasal hemiretinae, re-
sulting in a bitemporal hemianopia.
- All of the following statements concerning
the lateral geniculate body (LGB) are correct
EXCEPT
(A) it is a thalamic nucleus
(B) it receives input from the contralateral vi-
sual field
(C) it is irrigated by the posterior cerebral
artery and the anterior choroidal artery
(D) destruction results in bitemporal hemi-
anopia
(E) it projects to the lingual gyrus and the
cuneus
4-D. Destruction of the optic tract, the lateral geniculate body (LGB), or the geniculocalcarine
tract all result in the same visual field defect, a contralateral homonymous hemianopia.
- All of the following statements concerning
the visual cortex are correct EXCEPT
(A) it corresponds to area 17
(B) it is located on the banks of the calcarine
sulcus
(C) destruction of the upper bank of the cal-
carine sulcus results in a lower ipsilateral
homonymous quadrantanopia
(D) cortical lesions are characterized by mac-
ular sparing
(E) it is irrigated by a branch of the posterior
cerebral artery
5-C. Destruction of the upper bank of the calcarine sulcus interrupts lateral geniculate body
(LGB) fibers, which represent the upper ipsilateral retinal quadrants. The field defect is called a
lower contralateral homonymous quadrantanopia.
- All of the following statements concerning
the pupillary light pathway are correct EXCEPT
(A) transection of the optic tract eliminates
the direct pupillary light response
(B) transection of the optic nerve would not
eliminate the consensual pupillary light
reflex
(C) destruction of the lateral geniculate body
(LGB) would not interrupt the pupillary
light pathway
(D) the efferent limb of the pupillary light re-
flex is the oculomotor nerve (CN III)
(E) axons of the retinal ganglion cells mediat-
ing the pupillary light reflex terminate in
the pretectal nucleus
6-A. Transection of the optic tract would not eliminate the direct pupillary response. Pupillary
fibers in the optic tract project to the pretectal nuclei, which discharge to the ipsilateral and con-
tralateral Edinger-Westphal nuclei.
- All of the following statements concerning
the superior colliculus are correct EXCEPT
(A) it 7.is the tectum of the midbrain
(B) it receives input from the retina and vi-
sual cortex
(C) it plays a role in head and eye movements
(D) it is irrigated by the posterior communi-
cating artery
(E) a unilateral lesion results in contralateral
neglect of visual stimuli
7-D. The superior colliculus is irrigated by the long circumflex branches of the posterior cere- bral arteries (quadrigeminal arteries).
- All of the following statements concerning
the retina are correct EXCEPT
(A) it is derived from the optic vesicle of the
diencephalon
(B) it is sensitive to wavelengths from 400 nm
to 700 nm
(C) retinal ganglion cells project directly to
the visual cortex
(D) retinal ganglion cells project directly to
the hypothalamus
(E) retinal ganglion cells project directly to
the midbrain
8-C. Retinal ganglion cells project to the lateral geniculate body (LGB), which projects to the
primary visual cortex. Retinal ganglion cells project directly to the suprachiasmatic nucleus of
the hypothalamus and to the pretectal nuclei and superior colliculus of the midbrain. The retina
is derived from the optic vesicle of the diencephalon.
- All of the following statements concerning
the optic disk are correct EXCEPT
(A) it is found nasal to the fovea centralis
(B) it is the blind spot
(C) it contains the retinal vessels
(D) it contains myelinated axons from the gan-
glion cell layer
(E) it contains neither rods nor cones
9-D. The optic disk, the optic papilla, is found nasal (medial) to the fovea centralis. It contains
no rods or cones and thus represents a blind spot in the retina. The retinal vessels emerge from
the optic disk. Myelinated axons usually are not found in the retina; when they are present, they
may produce a central scotoma. Myelination of the optic nerve extends from the external part of
the lamina cribrosa to the lateral geniculate body (LGB).
- All of the following statements concerning
the fovea centralis are correct EXCEPT
(A) it plays a role in photopic vision
(B) it lies within the macula lutea
(C) it contains only cones
(D) it is the optic papilla
(E) it is the site of highest visual acuity
10-D. The fovea centralis lies within the macula lutea and represents the locus of highest visual
acuity. The fovea contains only cones, thus subserving color or day (photopic) vision. The fovea
centralis lies temporal (lateral) to the optic disk. The optic disk is the optic papilla.
- All of the following statements concerning
the ganglion cells of the retina are correct EX-
CEPT
(A) they give rise to the optic nerve
(B) they receive direct input from the rods
and cones
(C) they are derived from the diencephalon
(D) they project to the lateral geniculate body
(LGB)
(E) they project directly to the hypothalamus
11-B. The ganglion cells of the retina give rise to the optic nerve and project to the lateral genic-
ulate body (LGB), the hypothalamus, the pretectal nucleus, and the superior colliculus. Input
from the rods and cones is conducted to the ganglion cells via the bipolar cells. The retina is de-
rived from the optic vesicle of the diencephalon. The hypothalamic projection is to the suprachi-
asmatic nucleus, a circadian pacemaker.
- All of the following statements concerning
the optic nerve are correct EXCEPT
(A) it is a myelinated tract of the central ner-
vous system (CNS)
(B) it is a true peripheral nerve
(C) it is invested by leptomeninges
(D) it is incapable of regeneration
(E) its cells of origin are found in the ganglion
cell layer of the retina
12-B. The optic nerve is a myelinated tract of the central nervous system (CNS) that is invested
by the leptomeninges and the dura mater. Its cells of origin are found in the ganglion cell layer
of the retina. It is incapable of regeneration.
- All of the following statements concerning
the subcortical center for lateral gaze are cor-
rect EXCEPT
(A) it receives input from the contralateral
frontal lobe
(B) it projects to the contralateral medial lon-
gitudinal fasciculus (MLF)
(C) it is found in the pons
(D) it is found in the midbrain
(E) it is found within a cranial nerve nucleus
13-D. The subcortical center for lateral gaze is found in the abducent nucleus of the pons, receives
input from the contralateral frontal eye field (area 8), and projects to the contralateral medial lon-
gitudinal fasciculus (MLF). Destruction of the abducent nucleus results in an ipsilateral lateral rec-
tus paralysis and a contralateral medial rectus palsy on attempted lateral gaze. The subcortical cen-
ter for vertical conjugate gaze is located in the midbrain at the level of the posterior commissure.
The response options for items 14-21 are the
same. You will be required to select one answer
for each item in the set.
(A) Bitemporal hemianopia
(B) Binasal hemianopia
(C) Left upper homonymous quadrantanopia
(D) Right lower homonymous quadrantanopia
(E) Left homonymous hemianopia
Match each defect below with the condition it
causes.
14. Transection of the right optic tract
14-E. Transection of the right optic tract results in a left homonymous hemianopia.
The response options for items 14-21 are the
same. You will be required to select one answer
for each item in the set.
(A) Bitemporal hemianopia
(B) Binasal hemianopia
(C) Left upper homonymous quadrantanopia
(D) Right lower homonymous quadrantanopia
(E) Left homonymous hemianopia
Match each defect below with the condition it
causes.
15. Transection of the right Meyer loop
15-C. Transection of the Meyer loop on the right side results in a left upper quadrantanopia (“pie
in the sky”). The Meyer loop is the inferior geniculocalcarine pathway that conveys information
from the inferior retinal quadrants to the inferior bank of the calcarine sulcus, the lingual gyrus.
The response options for items 14-21 are the
same. You will be required to select one answer
for each item in the set.
(A) Bitemporal hemianopia
(B) Binasal hemianopia
(C) Left upper homonymous quadrantanopia
(D) Right lower homonymous quadrantanopia
(E) Left homonymous hemianopia
Match each defect below with the condition it
causes.
16. Midsagittal section of the optic chiasm
16-A. Amidsagittal section of the optic chiasm interrupts the decussating fibers from the nasal
hemiretinae and results in a bitemporal hemianopia.
The response options for items 14-21 are the
same. You will be required to select one answer
for each item in the set.
(A) Bitemporal hemianopia
(B) Binasal hemianopia
(C) Left upper homonymous quadrantanopia
(D) Right lower homonymous quadrantanopia
(E) Left homonymous hemianopia
Match each defect below with the condition it
causes.
17. Tumor of the right lateral geniculate body
(LGB)
17-E. A lesion of the right lateral geniculate body (LGB) produces a left homonymous hemi-
anopia. A lesion of the optic tract, the LGB, or the visual pathway all produce the same field
deficit, a contralateral homonymous hemianopia.
Match the description of the lesion sites in
items 29-34 with the appropriate visual field
defect shown in the FIGURE
- Occlusion of the left posterior cerebral
artery
29-F. Occlusion of the left posterior cerebral artery results in a right homonymous hemianopia
with macular sparing; macular sparing is due to a dual blood supply to the visual cortex.
Match the description of the lesion sites in
items 29-34 with the appropriate visual field
defect shown in the figure.
30. Transection of the left optic nerve at the
chiasm
30-A. Transection of the left optic nerve at the chiasm results in total blindness on the left side
and a scotoma in the right upper temporal quadrant. Fibers from the lower nasal quadrant loop
into the contralateral optic nerve before decussating in the optic chiasma. The field defect is
called a junction scotoma.
Match the description of the lesion sites in
items 29-34 with the appropriate visual field
defect shown in the figure.
31. Craniopharyngioma
31-B. Craniopharyngiomas and pituitary tumors put pressure on the decussating fibers of the
optic chiasma, causing a bitemporal hemianopia.
Match the description of the lesion sites in
items 29-34 with the appropriate visual field
defect shown in the figure.
32. Left temporal lobotomy
32-D. A left temporal lobotomy transects Meyer loop, which projects to the inferior bank of the
calcarine fissure, resulting in a right upper quadrantanopia.
Match the description of the lesion sites in
items 29-34 with the appropriate visual field
defect shown in the figure.
33. Bilateral trauma to the cuneate gyri
33-E. Bilateral trauma to the cuneate gyri results in a lower altitudinal hemianopia.
Match the description of the lesion sites in
items 29-34 with the appropriate visual field
defect shown in the figure.
34. Transection of the left optic tract
34-C. Transection of the left optic tract results in a right hemianopia with macular sparing
Match the description of the lesion sites in
items 35-43 with the appropriate deficit or
pathologic finding shown in the photograph of
the base of the brain.
35. Transection results in polyuria and poly-
dipsia
35-1. Transection of the infundibulum interrupts the supraopticohypophyseal tract. This results
in diabetes insipidus with polydipsia and polyuria (e.g., craniopharyngioma).
Match the description of the lesion sites in
items 35-43 with the appropriate deficit or
pathologic finding shown in the photograph of
the base of the brain.
36. Transection results in ipsilateral ptosis
36-H. Destruction of the oculomotor nerve results in paralysis of the levator palpebrae muscle
with a severe ipsilateral ptosis.
Match the description of the lesion sites in
items 35-43 with the appropriate deficit or
pathologic finding shown in the photograph of
the base of the brain.
37. Transection results in homolateral extor-
tion of the globe
37-G. The trochlear nerve intorts, elevates, and abducts the globe. In fourth nerve palsy, the ip-
silateral eye is extorted. The patent’s chin points to the side of the lesion. Remember, head tilt is
associated with fourth nerve palsy.
Match the description of the lesion sites in
items 35-43 with the appropriate deficit or
pathologic finding shown in the photograph of
the base of the brain.
38. Destruction results in an absent corneal
reflex on the side of testing
38-F. The ophthalmic division of the trigeminal nerve mediates the afferent limb of the corneal
reflex.
Match the description of the lesion sites in
items 35-43 with the appropriate deficit or
pathologic finding shown in the photograph of
the base of the brain.
39. Pathology is seen in Wernicke encephalo-
pathy
39-E. In Wernicke encephalopathy, petechial hemorrhages in the mamillary bodies are com-
monly found, along with capillary hyperplasia, and astrocytic gliosis. Wernicke encephalopathy
is due to a thiamine (vitamin Bx) deficiency.
.Match the description of the lesion sites in
items 35-43 with the appropriate deficit or
pathologic finding shown in the photograph of
the base of the brain.
40. Transection results in a contralateral
hemianopia
40-D. Severance of the optic tract results in contralateral hemianopia.
Match the description of the lesion sites in
items 35-43 with the appropriate deficit or
pathologic finding shown in the photograph of
the base of the brain.
41. Midsagittal section results in a bitemporal
hemianopia
41-C. A midsagittal section through the optic chiasm results in bitemporal hemianopia.
Match the description of the lesion sites in
items 35-43 with the appropriate deficit or
pathologic finding shown in the photograph of
the base of the brain.
42. Transection results in total blindness in
the left eye
42-B. Transection of the optic nerve (fasciculus) results in total blindness of the ipsilateral eye.
Match the description of the lesion sites in
items 35-43 with the appropriate deficit or
pathologic finding shown in the photograph of
the base of the brain.
43. Compression is seen in Foster Kennedy
syndrome
43-A. Foster Kennedy syndrome involves the olfactory tract and the optic nerve. This disorder
may be due to a tumor (olfactory groove meningioma). The signs are ipsilateral anosmia, ipsi-
lateral optic atrophy, and contralateral papilledema.
