bipennate

[bī-pĕnāt′]
adj.
  1. Of or relating to a muscle with a central tendon toward which the fibers converge on either side like the barbs of a feather.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.