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Question 683
Anatomy → Region
Classification
Question
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Anatomy
Question Stem
During dissection at the root of the left lung, which relationship correctly distinguishes the phrenic nerve from the vagus nerve?
Options
A
Both nerves pass anterior to the lung root
B
Both nerves pass posterior to the lung root
C
Phrenic passes anterior and vagus passes posterior to the lung root
D
Vagus passes anterior and phrenic passes posterior to the lung root
E
Phrenic enters the lung root while vagus crosses the diaphragm
Explanation
Below the aortic arch the left phrenic nerve crosses in front of the root of the left lung, whereas the left vagus reaches the posterior aspect of the lung root.
Option Validity
A) The vagus is posterior to the lung root.
B) The phrenic is anterior to the lung root.
D) This reverses the anatomical relationship.
E) Neither relationship is described this way.
Further Reading
Saxena - MRCOG-1 Basic Sciences, Chapter 2: Anatomy, Printed p.13.