Anatomical variation in the course of the phrenic nerve

Anatomical variations of the phrenic nerve are classified as variation in the origin, course, or as the presence of the accessory phrenic nerve. Origins or combinations of branches may differ from patient to patient. Some variations of phrenic nerve are very common and can cause complications in performing very simple and standard procedures. We have detected an anatomical variation of phrenic nerve in the right lateral cervical region during routine dissection. The localization of the right phrenic nerve was detected ventrally from the right subclavian vein. Variation was not found on the left side of the same cadaver. The relationship of the subclavian vein and the phrenic nerve and their variations should be familiar to anesthesiologists during subclavian vein cannulation and practice of suprascapular nerve block.