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Background and Aims Normally, the nerves arising from the brachial plexus are placed around a single axillary artery (AA) in different positions.[1,2] At axilla, two arteries can occur in 2.6% to 9.2% of population. Double AA in ultrasonographic image has already been described, but in the published images, the two arteries were neither equal in caliber nor equidistant from the axillary vein (AV). They were described as either larger superficial and smaller deep axillary arteries combination or defined as an accessory artery.[1,2] The double AA of equal caliber is described only in a cadaver.
Conclusions The ultrasound image showed two axillary arteries of equal caliber, equal depth, and equidistance from a single AV at the center. The vein indented due to the mild pressure exerted by the probe which helped to differentiate it from arteries. The brachial plexus was identified by the ultrasonographic appearance as bunch of small round hypoechoic structures. The brachial plexus was seen between the axillary arteries and it was closer to the medial AA [figure 1]. The nerves arising from the brachial plexus were not seen separately as median, ulnar, radial, and musculocutaneous nerves, but as a single mass within a single sheath. There is a compelling similarity of this ultrasound image with the face of an owl. We emphasize the appearance of brachial plexus as a single mass within a single sheath in case of a double AA of equal caliber. This knowledge is important to give a successful brachial plexus blockade at the axilla in this anatomic variant.