Identification of the phrenic nerve in surgical exploration of the brachial plexus in obstetrical palsy.

This report describes a simple technique for identifying the phrenic nerve at the beginning of exploration of the brachial plexus in obstetrical palsy. Both the phrenic and supraclavicular nerves originate from the C4 root; therefore, retrograde dissection of the supraclavicular nerve will end at the C4 root and identify the phrenic nerve. This technique is very useful to less experienced surgeons but may also be helpful when the experienced surgeon encounters excessive scarring of the anterior scalene muscle. Finally, the dissected supraclavicular nerve may be used as a cable graft in brachial plexus reconstruction.