The innervation of the trapezius muscle in connection with radical neck-dissection. An anatomical study.

The accessory nerve, the cervical plexus, the sternocleidomastoid and trapezius muscles and neighbouring structures were examined in 47 corpses. Considerable inter- as well as intra-individual differences could be found both in the course and shape of the accessory nerve and in the participation of the cervical plexus in the innervation of the trapezius muscle. The great variation in the manifestation of the shoulder-arm-syndrome in patients after radical neck-dissection can thus be explained. Finally a new method of restoring the innervation of the trapezius muscle is proposed.