Background and Aims Visualisation and separate blockade of the four main constituent nerves (radial, median, ulnar, musculocutaneous) increases success rate of ultrasound guided Brachial plexus block at the axillary level.^1,2,3,4But upper limb is still positioned as if performing landmark-oriented approach described by Winnie with shoulder and elbow in 90 degrees (°). ⁴

Here, we aimed to find the optimum arm position for visualisation of brachial plexus at the axilla with ultrasound.

Methods After institutional Ethics Committee approval this observational study was conducted in 23 consenting individuals above 18 yr of age. The ultrasound probe was placed in short axis at the intersectionof the pectoralis major muscle and the biceps brachii muscle with probe pressure just enough to cause light compression of veins. Each arm was placed in three different positions, shoulder at 90 ° and elbow at 90 °, shoulder at 90 ° and elbow at 0 ° and shoulder at 120 ° and elbow at 90 ° where the nerves were assessed using a six point visibility scale.

The path of each nerve was traced down for confirmation. Distance from skin to axillary artery, skin to individual nerves, artery to nerves was measured.

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Abstract B109 Figure 1

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Abstract B109 Figure 2

Results There was no significant difference in visibility scores of the individual nerves and the distances measured in the three positions except the skin -artery distance which was the least in the 120/90 position(p=0.010). The radial nerve poorly visualised in all positions.

Conclusions No single arm position improved the visibility of the nerves.