Fissure
in ordinary language, a cleft; a narrow opening made by the parting or opening of any substance; a crack. In botany the opening of seedvessels, anthers etc. In heraldry, the fourth part of the bend sinister. In sinister. geology, a crack in the strata, produced by volcanic or earthquake action, sidence, or any other cause. of Glaser: In anatomy, a fissure in the ear, separating the upper margin of the tympanic plate from the glenoid fossa.
Fissure of Rolando: In anatomy, a fissure separating the parietal from the frontal lobe of the cerebrum. Fissure of Sylvius: In anatomy, a fissure or deep cleft commencing on the under sur- FISSURE NEEDLE face of the brain, and passing trans- versely outward to the lateral surface of the hemisphere, where it divides into two limbs. Fissures of Santorini: In anatomy, irregular gaps transversely dividing the cartilaginous tube of the ear. Great fissure of Bichat: In ear. anatomy, a fissure connecting the two limbs of the fissure of Sylvius.