fissura

[ fĭ-surə, -shurə ]

n. pl. fis•su•rae (-surē, -shurē)

A deep fissure, cleft, or slit.
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.