Objective To verify the possibility and exactly of ultrasound diagnosing peripheral nerve injection injury,by high-frequency ultrund observing the rabbits' injection injured sciatic nerve and contrasting with pathology.Methods Twenty-two rabbits were enrolled in this study,anesthetized by injected phenobarbital sodium through the ear edge vein.The rabbits' left sciatic nerve were punctured and cidomycin was injected by ultrasound guided.Ultrasound examination on the left sciatic nerve was performed at different time.After each examination 2 rabbits were killed and dissected the affected limb.The sciatic nerve was observed by eyes and under microscope.Results After injection,the sciatic nerves' outer diameter,inner diameter,thickness of the epineurium,the proportion of epineurium was increased (P ＜ 0.05),internal echo of the nerves was reduced (P ＜ 0.05),epineurium became rough (P ＜ 0.05),demarcation with surrounding tissue became gradually fuzzy (P ＜ 0.05),the nerves became rigid (P ＜ 0.05).Observed by microcrope,after injection,hyperemia and hemorrhage of endoneurium and epineurium,inflammatory cell infiltration,damaged nerve fiber structures,desmoplasia inside and outside nerve can be seen.Conclusions The sonogram of injection injured nerve vary in different periods,and related with pathological changes.High-frequency ultrasound is a reliable imaging method of diagnosing sciatic nerve injection injury.