fissure (fish'ur) [L. fissura, cleft]
A groove, natural division, cleft, slit, or deep furrow in the brain, liver, spinal cord, and other organs. Synonym: fissura
2. An ulcer or cracklike sore.
3. A break in the enamel of a tooth. fissural, adjective
A painful linear ulcer on the margin of the anus. It is a common problem in infancy and fairly common in constipated adults.
Conservative, nonoperative care heals most anal fissures. Patients should be advised to drink a lot of water to lubricate stools, adopt a high-fiber diet, and take a stool softener to ease the passage of stool. Sitting in a warm bath several times a day may help relax the anal sphincters. Medicated creams or ointments may provide topical anesthesia to the anus.
Patients who do not improve with medical therapies may require local injection of botulinum toxin to relax the sphincters or surgery to repair chronic fissures.
anterior median fissure
In the spinal cord, the groove that runs along the ventral midline.
A fissure of the petrous portion of the temporal bone.
branchial fissure See: cleft
Broca's fissure See: Broca, Pierre-Paul
Burdach's fissure See: Burdach, Karl
The fissure extending from the occipital end of the cerebrum to the occipitoparietal fissure.
A conspicuous fissure in the medial surface of the cerebral hemisphere running above and concentric with the curved upper surface of the corpus callosum.
central fissureRolando fissure.
A fissure that consists of five deep horizontal (transverse) grooves that separate the cerebellum into its lobes and lobules.
Clevenger fissure See: Clevenger fissure
The fissure on the inferior surface of the cerebral hemisphere separating the subcalcarine and subcollateral gyri.
A narrow slit posterior to the mandibular fossa of the temporal bone. The chorda tympani nerve passes through it.
Henle fissure See: Henle, Friedrich J.
The fissure extending from the posterior part of the corpus callosum to the tip of the temporal lobe of the brain.
horizontal fissureTransverse fissure (3).
inferior orbital fissure
The fissure at the apex of the orbit through which the infraorbital blood vessels and maxillary branch of the trigeminal nerve pass.
interparietal fissureIntraparietal sulcus.
lateral fissureFissure of Sylvius.
1. The fissure on the lower surface of the liver.
2. A fissure that separates the cerebral hemispheres. The corpus callosum, which connects the hemispheres, is at the base of the fissure.
oblique fissure of lung
In each lung, the deep groove separating the bottom and side of the upper lobe from the top and side of the lower lobe.
The fissure between the occipital and parietal lobes of the brain.
The opening separating the upper and lower eyelids.
The opening into the undersurface of the liver. It continues into the liver as the portal canal.
The anterior division of the sylvian fissure.
Rolando fissure See: Rolando, Luigi
sphenoidal fissure, sphenoid fissure
The fissure separating the wings and body of the sphenoid bone.
sylvian fissure See: Sylvius, Franciscus
fissure of Sylvius See: Sylvius, Franciscus
1. The fissure between the cerebellum and cerebrum.
2. The fissure on the lower surface of the liver that serves as the hilum transmitting vessels and ducts to the liver.
3. The fissure that divides the upper right lobe of the lung from the middle right lobe. Synonym: horizontal fissure
The anterior portion of the longitudinal fissure of the liver. It contains the round ligament, the obliterated umbilical vein.