septum pellucidum

[pə-lōōsĭ-dəm]
n. pl. septa pel•lu•ci•da (-də)
  1. A thin membrane of nervous tissue that forms the medial wall of the lateral ventricles in the brain.septum lucidum
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.