A variation of the phrenic nerve: case report and review.

During routine dissection in the department of anatomy, the following anatomical variations of the phrenic nerve were observed on the right side of the neck of a 30-year-old male cadaver. The phrenic nerve, in its early course close to its origin, gave a communicating branch to the C5 root of the brachial plexus. At the level of the root of neck just before entering the thorax, the phrenic nerve was located anterior to the subclavian vein. This unique case of phrenic nerve variation gains tremendous importance in the context of subclavian vein cannulation, implanted venous access portals, and supraclavicular nerve block for regional anaesthesia.