Sulcus (morphology)

In invertebrate zoology, a sulcus is a fold, groove, or boundary, especially at the edges of sclerites or between segments.

In pollen, a grain that is grooved by a sulcus is termed sulcate.

Examples in anatomy

Liver

• Ligamentum teres hepatis fissure
• Ligamentum venosum fissure
• Portal fissure, found in the under-surface of the liver
• Transverse fissure of liver, found in the lower surface of the liver
• Umbilical fissure, found in front of the liver

Lung

• Azygos fissure, of right lung
• Horizontal fissure of right lung
• Oblique fissure, of the right and left lungs

Skull

• Auricular fissure, found in the temporal bone
• Petrotympanic fissure
• Pterygomaxillary fissure
• Sphenoidal fissure, separates the wings and the body of the sphenoid bone
• Superior orbital fissure

Other types

• anal fissure, a break or tear in the skin of the anal canal
• anterior interventricular sulcus
• calcaneal sulcus
• coronal sulcus
• femoral sulcus or intercondylar fossa of femur
• fissure (dentistry), a break in the tooth enamel
• fissure of the nipple, a condition that results from running, breastfeeding and other friction-causing exposures
• fissured tongue, a condition characterized by deep grooves (fissures) in the tongue
• gingival sulcus
• gluteal sulcus
• Henle's fissure, a fissure in the connective tissue between the muscle fibers of the heart
• interlabial sulci
• intermammary sulcus
• intertubercular sulcus, the groove between the lesser and greater tubercules of the humerus (bone of the upper arm)
• lacrimal sulcus (sulcus lacrimalis)
• malleolar sulcus
• palpebral fissure, separates the upper and lower eyelids
• patellar sulcus or intercondylar fossa of femur
• posterior interventricular sulcus
• preauricular sulcus
• radial sulcus (musculospiral groove)
• sagittal sulcus
• separatoral sulcus (depression behind the brow ridges of some primates)
• sigmoid sulcus
• skin fissure, a linear-like cleavage of skin, sometimes defined as extending into the dermis
• sulcus arteriæ vertebralis
• sulcus subtarsalis in the eyelid
• sulcus tubae auditivae
• tympanic sulcus
• urethral sulcus
• ventral median fissure, of the spinal cord

In neuroanatomy

Brain

• Broca's fissure: found in the third left frontal fold of the brain.
• Burdach's fissure: connects the brain's insula and the inner surface of the operculum.
• Calcarine sulcus or Calcerine fissure: extends from the occipital of the cerebrum to the occipital fissure.
• Callosomarginal fissure: found in the medial surface of the cerebrum.
• Central sulcus or Rolando's fissure: separates the brain's frontal and parietal lobes.
• Clevenger's fissure: found in the inferior temporal lobe of the brain
• Collateral fissure: found in the inferior surface of the cerebrum.
• Fissure of Bichat: found below the corpus callosum in the cerebellum of the brain.
• Lateral sulcus or Fissure of Sylvius: separates the frontal and parietal lobes of the brain from the temporal lobe.
• Hippocampal sulcus: a sulcus that extends from the brain's corpus callosum to the tip of the temporal lobe.
• Horizontal fissure or Transverse fissure: found between the cerebrum and the cerebellum. Note that a "transverse fissure" can also be found in the liver and lungs.
• Longitudinal fissure or Medial longitudinal fissure: which divides the cerebrum into the two hemispheres.
• Occipitoparietal fissure: found between the occipital and parietal lobes of the brain.
• Wernicke's fissure: separates the brain's temporal and parietal lobes from the occipital lobe.
• Zygal fissure: found in the cerebrum.

In the brain, a sulcus is a groove formed in the stage of gyrification by the folding of the cortex. There are many sulci and gyri formed. A larger than usual sulcus may instead be called a fissure such as the longitudinal fissure that separates the two hemispheres.