This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Neuroanatomy, Head and Neck, Subject name: Anatomy
Injury to which of the following nerve in the diagram, may affect respiratory movements: 
Select and explain. 
A. A, B. B, C. C, D. D
A: A
Answer: A: A 
Explanation: Injury to phrenic nerve (marker 'A') compromises diaphragm (and respiratory movements). Phrenic nerve ('A') is identified running anterior to scalenus anterior muscle option B - Sympathetic chain option C - Vagus nerve option D - Recurrent laryngeal nerve