High division of the spinal accessory nerve and communication with a C2 branch of the cervical plexus: a previously unreported anatomical variant.

Anatomical variations of the spinal accessory nerve are well known. We describe a previously unreported variant in which the nerve divided high in level II after crossing the internal jugular vein and before entering the sternomastoid muscle. Both branches were joined by a communication from the C2 cervical root. We discuss the clinical implications of this finding.