Upper neck spinal accessory nerve identification during neck dissection.

Iatrogenic injury to the spinal accessory nerve (SAN) during neck dissection may result in significant and avoidable morbidity in the form of 'shoulder syndrome'. The authors describe a simple method, based on the anatomy of the sternocleidomastoid muscle (SCM), which allows consistent and rapid identification of the SAN in the upper neck during dissection, thereby facilitating its preservation.