Anatomic location of accessory nerve and its clinical significance

Objective:To provide reliable anatomical basis for locating accessory nerve exactly during related neck operations. Methods:The heads, necks and shoulders of 12 cadavers were dissected. The course, surface symbols, branches, and surrounding structures of accessory nerve were observed and measured. Results:After entering into the sternocleidomastoid muscle, 75% of accessory nerves gave off 2 branches and 25% only 1. The distance from accessory nerve to the great auricular nerve was about 1.24±0.51 cm, to clavicular midpoint 10.72±1.67 cm, and 12.46±1.19 cm to sternoclavicular joint after leaving the posterior edge of sternocleidomastoid muscle. The accessory nerve followed an oblique course and was superficial in the neck posterior triangle. The distance from the point of nerve entering trapezius muscle to clavicular midpoint was about 4.95±1.62 cm. Along its course, accessory nerve gave several branches to trapezius muscle.Conclusions:The course of accessory nerve is constant, which is helpful to protect and find out it during the related procedures.