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Question 675
Anatomy → Region
Classification
Question
SSBAQuestion Header
Anatomy
Question Stem
Which statement best describes the functional significance of anatomical variation in the circle of Willis?
Options
A
It guarantees complete collateral flow after any major arterial occlusion
B
Its variable anatomy may limit compensation following occlusion of a major vessel
C
It prevents occlusion of the internal carotid arteries
D
It supplies only the posterior cerebral circulation
E
It is anatomically identical in all individuals
Explanation
The circle of Willis provides potential collateral circulation, but its anatomy is highly variable and some individuals have inadequate arteries that may not compensate after major-vessel occlusion.
Option Validity
A) Collateral compensation is not guaranteed.
C) The circle does not prevent carotid occlusion.
D) It links anterior and posterior cerebral circulations.
E) Considerable anatomical variation occurs.
Further Reading
Saxena - MRCOG-1 Basic Sciences, Chapter 2: Anatomy, Printed p.10.