Anatomy General 7ea949f5 Phrenic nerve is A Motor nerve to diaphragm B Arises chiefly from 3rd cervical nerve, also receives contribution from 4th and 5th cervical nerves C The nerve runs vertically on the anterior surface of scalenus anterior D It lies anterior to prevertebral fascia High-Yield Explanation Phrenic nerve is a mixed nerve, mainly arises from 4th cervical nerve. It lies behind prevertebral fascia and in front of scalenus anterior.