Objective To investigate the value of high resolution ultrasonography in demonstrating the anatomical variations of the median vessels and median nerve in the carpal tunnel and its clinical significance.Methods A total of 1000 wrists of 500 healthy volunteers were included in the study.The location and shape of the bifid median nerve

persistent median artery and persistent median vein were recorded.The diameter of the persistent median artery and persistent median vein in the carpal tunnel were measured.The cross-sectional area of the bifid median nerve two trunks was measured at the level of the pisiform.Results ①bifid median nerve was observed in 34 cases（41 wrists）

the positive rate was 4.1 %

all bifid median nerves were divided into two trunks.The cross-sectional area of the radial trunk was greater than the cross-sectional area of the ulnaris trunk in all bifid median nerves at the level of the pisiform [（0.075±0.015）cm2 vs.（0.023±0.005）cm2]

and the difference was statistically significant（P

<

0.05）.In 27 cases with unilateral bifid median nerve

there was no significant difference between the sum of the cross-sectional area of two trunks and the cross-sectional area of the same position on the contralateral side.②Persistent median artery was observed in 15 cases（20 wrists）

the positive rate was 2.0%

the diameter of persistent median artery was 0.04-0.19 cm

the average diameter was（0.11±0.04）cm

9 cases（13 wrists） were accompanied by persistent median vein

the positive rate was 1.3%.③Among 34 cases of bifid median nerve and 15 cases of persistent median artery

13 cases（16 wrists） of bifid median nerve coexisted with persistent median artery

accounting for 39% and 80%

respectively

the difference was statistically significant（χ

2

=9.050

P=0.003）.Conclusion The anatomical variations of the median vessels and median nerve in the carpal tunnel in normal adults could be well depicted by high resolution ultrasonography

it is helpful for clinicians to accurately diagnose carpal tunnel syndrome and has good application value.