OBJECTIVETo investigate the relations between accessory nerve and its surrounding structures.

METHODSOne hundred and thirty six patients were divided into two groups: has or has no neck surgical history. Neck dissection were performed and the four distance were measured simultaneously. The distance of accessory nerve and the great auricular nerve going out the posterior edge of sternocleidomastoid muscle; the distance of the point accessory nerve going out the posterior edge of sternocleidomastoid muscle to clavicular midpoint; the distance of the point accessory nerve going out the posterior edge of sternocleidomastoid muscle to sternoclavicular articulation; the distance of the point accessory nerve enter trapezius muscle to clavicular midpoint.

RESULTSIn no neck dissection group, the point accessory nerve going out sternomastoid muscle were supra the point of great auricular nerve going out the sternomastoid muscle, the average length of two points is (0. 61 +/- 0. 35) cm , the significance has not observed between genders (P > 0.05), however, there has significant difference between two groups of has or has no neck surgical history (P < 0.05). 88.2% (112/127) accessory nerve going out supra the great auricular within 1.0 cm, 11.8% (15/127) within 1.0 approximately 2.0 cm. 67.7% (86/127) accessory nerve adopt branch from cervical plexus before entering trapezius. The distances of the point accessory nerve going out the posterior edge of sternocleidomastoid muscle to clavicular midpoint and to sternoclavicular articulation were significant relative not with before neck surgical history but gender. The distance of the point accessory nerve enter trapezius muscle to clavicular midpoint is (4.96 +/- 0.78) cm, it has no difference both before neck surgical history and gender (P > 0.05).

CONCLUSIONIn no neck surgical history group,both of the distance that accessory nerve and the great auricular nerve going out the posterior edge of sternocleidomastoid muscle and the point accessory nerve enter trapezius muscle to clavicular midpoint were helpful for search accessory nerve in surgery. But in patients who have neck surgical history or great auricular have been injured, accessory nerve could be looked for associating with the distances of the point accessory nerve going out the posterior edge of sternocleidomastoid muscle to clavicular midpoint and to sternoclavicular articulation; the distance of the point accessory nerve enter trapezius muscle to clavicular midpoint.