Anatomy Phrenic nerve innervates the diaphragm. What is the root value of phrenic nerve? A C2, C3, C4 B C3, C4, C5 C C4, C5, T1 D C5, Tl, T2 💡 Explanation Phrenic nerve innervates the diaphragm. What is the root value of phrenic nerve? ✓ Correct Answer: B. C3, C4, C5