ciliospinal center

n.
  1. The group of preganglionic motor neurons in the first thoracic segment of the spinal cord that become the sympathetic innervation of the dilator muscle of the eye's pupil.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.