SBA — Single Best Answer · Review
Question 669
Anatomy → Region
Classification
Question
SSBAQuestion Header
Which sequence most accurately describes formation of the posterior cerebral circulation?
Question Stem
Select the single best answer.
Options
A
Common carotid arteries unite to form the basilar artery, which divides into anterior cerebral arteries
B
Vertebral arteries arise from the subclavian arteries, unite to form the basilar artery, which gives rise to the posterior cerebral arteries
C
Internal carotid arteries unite to form the basilar artery, which gives rise to posterior inferior cerebellar arteries
D
Vertebral arteries arise from the common carotid arteries and continue separately as posterior cerebral arteries
E
Posterior communicating arteries unite to form the basilar artery, which divides into middle cerebral arteries
Explanation
The posterior cerebral circulation is supplied mainly by the vertebral arteries, which arise from the subclavian arteries. The vertebral arteries fuse intracranially to form the basilar artery, which subsequently branches to form the posterior cerebral arteries.
Option Validity
A) The basilar artery is formed by the vertebral arteries, not the common carotid arteries.
C) The internal carotid arteries form the anterior cerebral circulation; they do not unite to form the basilar artery.
D) Vertebral arteries arise from the subclavian arteries and fuse to form the basilar artery.
E) Posterior communicating arteries do not unite to form the basilar artery.
Further Reading
Saxena R. Textbook for MRCOG-1. Chapter 2: Anatomy, p.10.