Objective

2

To explore the significance of confluence site and trunk morphology of the median nerve.

Methods

2

Eighty cadaver specimens （42 males， 38 females） were selected for arm dissection. The lengths of the medial cord and lateral cord of the median nerve and the main trunk length of the median nerve after convergence were measured， and the distance from the acromion to the skin corresponding to the junction of the median nerve was measured. Classification was performed based on the different confluence sites. The anteroposterior and transverse diameters of the main trunk of the median nerve after convergence were measured to calculate the flattening ratio.

Pearson

method was used to analyze the correlation between the average lengths of the medial and lateral cords and the flattening ratio.

Results

2

Based on the different junction of the medial and lateral cords of the median nerve in the arm， they were divided into three types： high-confluence type （76.25%）， median-confluence type （18.75%） and low-confluence type （5.00%）. The distance from the acromion to the skin corresponding to the junction of the median nerve was （12.8±0.9） cm for the high-confluence type， （19.5±1.1） cm for the median-confluence type， and （35.0±1.5） cm for the low-confluence type. The flattening ratio was （3.25±2.16） for the high-confluence type， （1.19±0.15） for the median-confluence type， and （1.01±0.01） for the low-confl

uence type. There was a significant positive correlation between the mean length of the medial and lateral cords of the median nerve and the flattening ratio of the median nerve （

r

=0.898，

P

<

0.01）.

Conclusion

2

The high-confluence type accounts for the largest proportion of the junction of the median nerve， the median-confluence type has a smaller proportion， and the low-confluence type has the smallest proportion. Furthermore， the lower the confluence of the medial and lateral cords of the median nerve， the smaller the flattening ratio.