Objective      To investigate the efficacy of ultrasound guided Shamrock and short-axis in-plane methods in visualization of lumbar plexus block by comparing their accessibility

range and effect on ultrasonic imaging.       Methods      Thirty patients that underwent lumbar plexus block anesthesia for unilateral knee meniscus injury in our hospital from June to December 2015 were selected as study subjects. They were randomly and equally divided into 2 groups. The indexes

i.e. image positioning time

lumbar plexus depth

ultrasound visibility score (UVS) and ultrasonic imaging range

were recorded.       Results      All patients accomplished this study．There were no statistical differences between the 2 groups in the sex

age and weight. The difference of lumbar plexus depth between the 2 groups was not significant either. The positioning time of Shamrock group was shorter than that of short-axis in-plane group (35.9±20.1 vs 53.7±21.2 s

P0.01). For both the UVS and imaging range

Shamrock group was significantly higher than short-axis in-plane group (P0.01)

with respective values of UVS (2.8±0.4 vs 2.1±0.8 points) and range (5.9±0.5 vs 3.5±0.6).       Conclusion      Shamrock method is superior to short-axis in-plane method in ultrasonic visualization of lumbar plexus block.