Block 5 Neuro Atlas Ch 9 W Expl
Questions and Answers
- 1.
Which of the following arteries is generally found in the areaof the cingulate sulcus and has branches that serve the lowerextremity areas of the somatomotor and somatosensory cor-tex?
- A.
Callosomarginal
- B.
Frontopolar
- C.
Internal parietal
- D.
Parietooccipital
- E.
Pericallosal
Correct Answer
A. CallosomarginalExplanation
The callosomarginal artery lies generally in theregion of the cingulate sulcus and gives rise to branches (para-central branches) that distribute to the anterior and posteriorparacentral gyri.The pericallosal artery is located immediatelysuperior to the corpus callosum and the frontopolar artery serves the medial aspect of the frontal lobe.The internal parietalarteries are the terminal branches of the pericallosal artery; these vessels distribute to the medial portion of the parietal lobe, the precuneus. The parietooccipital artery is one of the terminalbranches (part of P4 ) of the posterior cerebral artery. (p.29,266)Rate this question:
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- 2.
A 44-year-old woman presents to her family physician withintermittent headache and the complaint that she can’t see inher left eye.The examination reveals that the woman is blindin her left eye.When a light is shined into her left eye there isno direct or consensual pupillary light reflex.Magnetic reso-nance angiography (MRA) shows a large aneurysm at the ori-gin of the ophthalmic artery.Which of the following representsthe usual point of origin of this vessel?
- A.
Cavernous part of the internal carotid artery
- B.
Cerebral part of the internal carotid artery
- C.
First segment (A1) of the anterior cerebral artery
- D.
First segment (M1) of the middle cerebral artery
- E.
Petrous part of the internal carotid artery
Correct Answer
B. Cerebral part of the internal carotid arteryExplanation
In most instances (approximately 80%–85%),theophthalmic artery originates from the cerebral portion of theinternal carotid artery just as this parent vessel leaves the cav-ernous sinus and passes through the dura. In a small percentage of cases the ophthalmic artery may originate from other locations on the internal carotid artery,including its cavernous portion.This vessel does not originate from the petrous portion of the internal carotid or from anterior or middle cerebralarteries. (p.25,266)Rate this question:
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- 3.
The venous phase of an angiogram of a 52-year-old man sug-gests a small tumor at what the neuroradiologist refers to as thevenous angle.Which of the following points most specificallydescribes the position of the venous angle?
- A.
Where the internal cerebral vein meets the great cerebralvein
- B.
Where the superficial middle cerebral vein meets the cav-ernous sinus
- C.
Where the thalamostriate vein turns to form the internalcerebral vein
- D.
Where the transverse sinus turns to form the sigmoidsinus
- E.
Where the vein of Labbé meets the vein of Trolard
Correct Answer
C. Where the thalamostriate vein turns to form the internalcerebral veinExplanation
The point at which the thalamostriate vein (also called the superior thalamostriate vein at this position) abruptly turns 180 degrees to form the internal cerebral vein is called the venous angle. This angle is located immediately caudal to the position of the interventricular foramen and is, therefore, an important landmark. The thalamostriate vein is located inthe groove between the thalamus and the caudate nucleus. At the superior aspect of the thalamus, this vein is the superior thalamostriate vein,and, on the inferior surface, it is called the inferior thalamostriate vein. None of the other choices isinvolved in the formation of the venous angle.(p.267)Rate this question:
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- 4.
The superficial middle cerebral vein forms a direct anastomoticjunction with which of the following venous structures on thelateral aspect of the cerebral hemisphere?
- A.
Cavernous sinus
- B.
Confluence of sinuses
- C.
Superior sagittal sinus
- D.
Transverse sinus
- E.
Veins of Labbé and Trolard
Correct Answer
E. Veins of Labbé and TrolardExplanation
The superficial middle cerebral vein is a comparatively obvious venous structure on the lateral surface of the hemisphere that communicates directly with the veins of Trolard (to the superior sagittal sinus) and Labbé (to the trans-verse sinus). The superficial middle cerebral vein also commu-nicates with the cavernous sinus, but this sinus in not on the lateral aspect of the hemisphere as specified in the question. The other choices do not receive venous blood directly from the superficial middle cerebral vein.(p.19,267)Rate this question:
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- 5.
The coronal MRI of a 69-year-old man reveals an infarcted areain the region of the cerebral hemisphere lateral to the internalcapsule but internal to the insular cortex.A comparison ofcoronal and sagittal MRI suggests that the vessels involved arebranches of the middle cerebral artery.Which of the followingbranches or segments of the middle cerebral artery are mostlikely involved in this man?
- A.
Anterior and polar temporal branches
- B.
Insular branches
- C.
Lenticulostriate branches
- D.
Opercular segment
- E.
Uncal artery
Correct Answer
C. Lenticulostriate branchesExplanation
The position of this lesion is in that portion of thehemisphere occupied by the lenticular nucleus; the lenticulostriate branches of the M1 segment of the middle cerebral artery serve this structure. The uncal, anterior, and polar temporal branches originate from the M1 segment but do not serve structures in the area of the hemisphere described. Insular branches(M2 ) and opercular branches (M3) serve cortical structures.(p.25,268)Rate this question:
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- 6.
The anterior and middle cerebral arteries are the terminalbranches of which of the following vascular trunks?
- A.
Basilar artery
- B.
Cavernous part of the internal carotid
- C.
Cerebral part of the internal carotid
- D.
External carotid artery
- E.
Petrous part of the internal carotid
Correct Answer
C. Cerebral part of the internal carotidExplanation
As the internal carotid artery exits the cavernous sinus, it becomes the cerebral part of the internal carotid and, after giving rise to three important small branches (ophthalmic, anterior choroidal, posterior communicating), bifurcates into the anterior and middle cerebral arteries.These two cerebral vessels are the terminal branches of the cerebral partof the internal carotid artery. In approximately 70% to 75% of specimens, the anterior cerebral artery is the smaller of these two terminal branches. None of the other choices gives rise to the anterior and middle cerebral arteries. (p.268)Rate this question:
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- 7.
The superior sagittal sinus,straight sinus,and transverse sinus-es converge at which of the following landmarks?
- A.
Clivus
- B.
Confluens sinuum
- C.
Great cerebral vein
- D.
Jugular foramen
- E.
Venous angle
Correct Answer
B. Confluens sinuumExplanation
The superior sagittal sinus,straight sinus, the two transverse, and the occipital sinus (when present) converge at the confluence of sinuses (confluens sinuum), which is located internal to the external occipital protuberance. The venous angle is the junction of the thalamostriate and the internalcerebral veins, and the great cerebral vein (of Galen) receives the internal cerebral veins and several smaller veins including the basal vein (of Rosenthal) and empties into the straight sinus. The jugular foramen contains the transition from the sigmoid sinus to the internal jugular vein and the terminus of the inferior petrosal sinus.The clivus is composed mainly of the basal part of the occipital bone; this is the location of the basilar plexus. (p.19,23,269–271)Rate this question:
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- 8.
A 47-year-old woman is brought to the emergency departmentby her husband.She has a severe headache,nausea,and is som-nolent.The examination reveals that the woman is hyperten-sive and has papilledema.MRI shows evidence of cerebraledema,bilateral infarcted areas in the thalamus,and a largesinus thrombosis that is blocking the egress of blood throughthe vascular system.This thrombus is most likely located inwhich of the following venous structures?
- A.
Inferior sagittal sinus
- B.
Left sigmoid sinus
- C.
Right transverse sinus
- D.
Straight sinus
- E.
Superior sagittal sinus
Correct Answer
D. Straight sinusExplanation
A key observation in this woman is the bilateral infarcted areas in the thalamus.The straight sinus receives venous flow from both internal cerebral veins; a blockage of flow through the straight sinus would adversely affect both thal-ami.Such a lesion would also cause potential damage to the medial temporal lobe due to the disruption of flow through the basal vein (of Rosenthal).None of the other choices receives venous drainage directly from the thalamus.(p.29,274,276)Rate this question:
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- 9.
A 39-year-old man presents to his family physician with a com-plaint of difficulty swallowing.The history reveals that the manhas had severe recurring headaches over the last 5 days and suf-fered several bouts of vomiting.The examination confirms thedifficulty swallowing,and reveals that the man’s voice is hoarseand gravely,and that he is unable to elevate his left shoulderagainst resistance.MRI shows a dural sinus thrombosis.Basedon this man’s deficits,which of the following represents themost likely location of this thrombus?
- A.
Left cavernous sinus
- B.
Left jugular bulb
- C.
Left transverse sinus
- D.
Right jugular bulb
- E.
Straight sinus
Correct Answer
B. Left jugular bulbExplanation
The deficits experienced by this man (difficulty swallowing, hoarseness, inability to elevate the left shoulder against resistance) point to damage to the glossopharyngeal (IXth),vagus (Xth), and spinal accessory (XIth) nerves or to their roots. All three of these cranial nerves exit the jugular foramen along with the continuity of the sigmoid sinus with the internal jugular vein (jugular bulb or bulb of the jugular vein). In this case,the venous thrombosis is at the left jugular bulb and impinging on these three cranial nerve roots. Dural sinus thrombosis of the other choices may cause certain deficits,but not those experienced by this man.(p.270,276)Rate this question:
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- 10.
Which of the following vessels forms a characteristic loop in thecisterna magna that is prominent on lateral angiograms and,inthe process,supplies blood to the choroid plexus of the fourthventricle?
- A.
Anterior inferior cerebellar artery
- B.
Posterior inferior cerebellar artery
- C.
Posterior spinal artery
- D.
Superior cerebellar artery
- E.
Vertebral artery
Correct Answer
B. Posterior inferior cerebellar arteryExplanation
The posterior inferior cerebellar artery (commonly called PICA) originates from the vertebral artery,courses around the lateral aspect of the medulla, loops sharply into the space of the cisterna magna (giving off small branches to thechoroid plexus in the fourth ventricle),then joins the inferior and medial surface of the cerebellum. None of the other choices forms prominent vascular structures in the cisterna magnaor serves the choroid plexus of the fourth ventricle. (p.272)Rate this question:
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- 11.
The MRI of a 42-year-old man shows a small tumor in thechoroid plexus of the third ventricle.Angiogram and MRA sug-gest that this tumor contains numerous vascular loops. Whichof the following represents the blood supply to this portion ofthe choroid plexus?
- A.
Anterior choroidal artery
- B.
Choroidal branches of AICA
- C.
Choroidal branches of PICA
- D.
Lateral posterior choroidal artery
- E.
Medial posterior choroidal artery
Correct Answer
E. Medial posterior choroidal arteryExplanation
The medial posterior choroidal artery originatesfrom the P2 segment of the posterior cerebral artery, arches around the midbrain, and enters the caudal end of the third ventricle. The anterior choroidal artery serves the choroidplexus in the temporal horn, and the lateral posterior choroidal artery serves the glomus choroideum and extends into the plexi of the temporal horn and the body of the ventricle.These patterns may be somewhat variable. Choroidal branches of anterior inferior cerebellar artery (AICA) serve the choroid plexus extending through the foramen of Luschka, and these branches from the posterior inferior cerebellar artery (PICA) serve the plexus within the fourth ventricle. (p.277)Rate this question:
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- 12.
The angiogram of a 56-year-old woman shows an aneurysmoriginating from the lateral aspect of the basilar bifurcationand extending into the space between the posterior cerebraland superior cerebellar arteries.Based on the structure(s) locat-ed at this point,which of the following deficits would most like-ly be seen in this woman?
- A.
Constriction of the ipsilateral pupil
- B.
Inability to look down and out with the ipsilateral eye
- C.
Inability to look laterally with the ipsilateral eye
- D.
Inability to look up,down,or medially with the ipsilater-al eye
- E.
Loss of pain and thermal sensation from the ipsilateralside of the face
Correct Answer
D. Inability to look up,down,or medially with the ipsilater-al eyeExplanation
The oculomotor nerve (III) is located between theposterior cerebral and superior cerebellar arteries and may be damaged by aneurysms at this location. Most eye movement would be lost (the trochlear (IV) and abducens (VI) nerves areintact) and the ipsilateral pupil would be dilated, not constricted. Sensation from the face is carried on the trigeminal nerve. Movement deficits related to injury to the fourth nerve (looking down and out) or the sixth nerve (looking laterally) are not affected. (p.43,44,273,278)Rate this question:
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- 13.
The position of the posterior communicating artery,as fre-quently seen in MRA,is an important landmark that specifiesthe intersection of which of the following?
- A.
A1 and A2 segments
- B.
M1 and M2 segments
- C.
M2 and M3 segments
- D.
P1 and P2 segments
- E.
P2 and P3 segments
Correct Answer
D. P1 and P2 segmentsExplanation
The posterior communicating artery originates from the cerebral part of the internal carotid artery and courses caudally to join the posterior cerebral artery (PCA). The partof the PCA medial to this intersection is the P1 segment and thepart of the PCA immediately lateral to this junction is the P2 segment. Important branches arise from both of these parts ofthe PCA. None of the other choices have any direct relationshipto the points of origin of the posterior communicating artery. (p.25,273,275)Rate this question:
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- 14.
A 16-year-old boy with developmental delay has been followedsince birth by a pediatric neurologist.A recent MRA is done inwhich major arteries and venous sinuses are visualized.It isconcluded that the pattern of the boy’s venous sinuses is essen-tially normal.Which of the following describes the usual pat-tern of the superior sagittal sinus at the confluence of sinuses?
- A.
Always drains equally into the right and left transversesinuses
- B.
Always drains into the left transverse sinus
- C.
Always drains into the right transverse sinus
- D.
Usually drains into the left transverse sinus
- E.
Usually drains into the right transverse sinus
Correct Answer
E. Usually drains into the right transverse sinusExplanation
The drainage pattern of the superior sagittal sinus at the confluence of sinuses is ariable, including about equal toboth transverse sinuses or mainly to the right or to the left. However, the usual pattern is for the superior sagittal sinus to drain predominately into the right transverse sinus. (p.271)Rate this question:
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