n :  either of two loops of blood vessels in the palm of the hand:  a  :  a deeply situated transverse artery that is composed of the terminal part of the radial artery joined to a branch of the ulnar artery and that supplies principally the deep muscles of the hand, thumb, and index finger - called also deep palmar arch   b  :  a superficial arch that is the continuation of the ulnar artery which anastomoses with a branch derived from the radial artery and that sends branches mostly to the fingers - called also superficial palmar arch  .
 
 
 
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