lumbrical muscle of hand

n.
  1. Any of four muscles whose origins are from the finger and hand tendons, with insertion into the extensor tendon on the dorsum of each of the four fingers; with nerve supply from the median and ulnar nerves; and whose actions flex the proximal phalanges and extend the middle and distal phalanges.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.