The diameter, length of the accessory nerve and its branches, the distance between the accessory nerve and the main trunk of the phrenic nerve were measured adopting the slide gauge with precision of 0.001 millimeter.

• 用精确度为0.；001m m游标卡尺测量各段的直径、长度、副神经及其分支与膈神经主干起始端的距离。