During surgery at the root of the neck, an attending surgeon cautions her resident to locate important structures which need to be protected. One of these is the phrenic nerve, responsible for the innervation of the diaphragm and thus, respiration. The phrenic nerve can be positively identified by which of the following anatomical relationships?
- It is found immediately between the common carotid artery and the internal jugular vein.
- It lies immediately between the esophagus and the trachea.
- It lies on the scalenus medius muscle.
- It wraps around the right subclavian artery.
- The suprascapular and transverse cervical arteries cross over it anteriorly.
Answer(s): D
Explanation:
At the root of the neck, the phrenic nerve (C3, C4, C5) lies on the scalenus anterior muscle, not the scalenus medius (choice C). The transverse cervical and suprascapular arteries course over it. The vagus (tenth cranial) nerve, not the phrenic nerve is located between the common carotid artery and the internal jugular vein (choice A). The recurrent laryngeal branch from the vagus nerve wraps around the right subclavian artery (choice D), and courses cranially between the esophagus and the trachea (choice B).