| paracentral fissure | A curved fissure (sulcus) on the medial surface of the cerebral hemisphere, bounding the paracentral gyrus and separating it from the precuneus and the cingulate gyrus. (05 Mar 2000) |
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| parieto-occipital fissure | A very deep, almost vertically oriented fissure on the medial surface of the cerebral cortex, marking the border between the parietal lobe and the cuneus of the occipital lobe; its lower part curves forward and fuses with the anterior extent of the calcarine fissure (sulcus calcarinus); the great depth of this combined fissure causes a bulge in the medial wall of the occipital horn of the lateral ventricle, the calcar avis. Synonym: sulcus parieto-occipitalis, fissura parietooccipitalis, parieto-occipital fissure. (05 Mar 2000) |
| vestibular fissure of cochlea | A fine fissure in the lower part of the first turn of the cochlea, formed by a spiral lamina which projects from the outer wall of the cochlea but does not quite reach the osseous spiral lamina, thus leaving a narrow gap. (05 Mar 2000) |
| caudal transverse fissure | A transverse fissure on the visceral surface of the liver between the caudate and quadrate lobes, lodging the portal vein, hepatic artery, hepatic nerve plexus, hepatic ducts, and lymphatic vessels. Synonym: caudal transverse fissure, portal fissure. (05 Mar 2000) |
| glaserian fissure | A fissure between the tympanic and petrous portions of the temporal bone; it transmits the chorda tympani nerve through a small patent portion, the anterior canaliculus of the chorda tympani. Synonym: fissura petrotympanica, glaserian fissure. (05 Mar 2000) |
| rhinal fissure | The shallow rostral continuation of the collateral sulcus that delimits the rostral part of the parahippocampal gyrus from the fusiform or lateral occipitotemporal gyrus. One of the oldest sulci of the pallium, it marks the border between the neocortex and the allocortical (olfactory). Synonym: sulcus rhinalis, rhinal fissure. (05 Mar 2000) |
| great horizontal fissure | Horizontal fissure that divides the ansiform lobule into its major parts, crus I (superior semilunar lobule) and crus II (inferior semilunar lobule). Synonym: fissura horizontalis cerebelli, great horizontal fissure. (05 Mar 2000) |
| great longitudinal fissure | The deep cleft separating the two hemispheres of the cerebrum. Synonym: fissura longitudinalis cerebri, great longitudinal fissure. (05 Mar 2000) |
| right sagittal fissure | A sagittal groove on the undersurface of the liver formed by the fossa vesicae felleae anteriorly and the sulcus venae cavae posteriorly. (05 Mar 2000) |
| petro-occipital fissure | A fissure between the petrous part of the temporal bone and the basilar part of the occipital bone that extends anteromedially from the jugular foramen; includes the jugular foramem (at its posterior end). Synonym: fissura petro-occipitalis, Ecker's fissure. (05 Mar 2000) |
| petrosquamous fissure | A shallow fissure indicating externally the line of fusion of the petrous and squamous portions of the temporal bone. Synonym: fissura petrosquamosa. (05 Mar 2000) |
| petrotympanic fissure | A fissure between the tympanic and petrous portions of the temporal bone; it transmits the chorda tympani nerve through a small patent portion, the anterior canaliculus of the chorda tympani. Synonym: fissura petrotympanica, glaserian fissure. (05 Mar 2000) |
| choroidal fissure | The narrow cleft along the medial wall of the lateral ventricle along the margins of which the choroid plexus is attached; it lies between the upper surface of the thalamus and lateral edge of the fornix in the central part of the ventricle and between the terminal stria and fimbria hippocampi in the inferior horn. Synonym: fissura choroidea. (05 Mar 2000) |
| choroid fissure | In the embryo, the temporary gap in the ventral margin of the developing optic cup. Synonym: choroid fissure, choroid fissure, choroidal fissure. (05 Mar 2000) |
| Clevenger's fissure | The sulcus on the basal aspect of the temporal lobe that separates the fusiform gyrus from the inferior temporal gyrus on its lateral side. Synonym: sulcus temporalis inferior, Clevenger's fissure. (05 Mar 2000) |