fissura

[fĭ-surə, -shurə]
n. pl. fis•su•rae (-surē, -shurē)
  1. A deep fissure, cleft, or slit.
  2. A particularly deep sulcus of the surface of the brain or spinal cord.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.