tegmental nucleus

n.
  1. Either of two small round cell groups in the caudal part of the midbrain, associated with the mamillary body via the mamillary peduncle and mamillotegmental tract.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.