principal artery of thumb

[prĭnsə-pəl]
n.
  1. An artery with origin in the radial artery, with distribution to the palmar surface and sides of the thumb, and with anastomoses to the arteries on the dorsum of the thumb.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.