| precentral gyrus | Bounded posteriorly by the central sulcus and anteriorly by the precentral sulcus. Synonym: gyrus precentralis, anterior central convolution, anterior central gyrus, ascending frontal convolution, ascending frontal gyrus. (05 Mar 2000) |
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| prepiriform gyrus | A gyrus covering deeply placed amygdaloid nucleus; concerned with olfactory function. Synonym: anterior piriform gyrus. (05 Mar 2000) |
| hippocampal gyrus | A long convolution on the medial surface of the temporal lobe, forming the lower part of the fornicate gyrus, extending from behind the splenium corporis callosi forward along the dentate gyrus of the hippocampus from which it is demarcated by the hippocampal fissure. The anterior extreme of the gyrus curves back upon itself, forming the uncus, the major location of the olfactory cortex. See: entorhinal area. Synonym: gyrus parahippocampalis, hippocampal convolution, hippocampal gyrus. (05 Mar 2000) |
| splenial gyrus | The band of cortex on the medial surface of the cerebral hemisphere which passes around the splenium of the corpus callosum, narrowing anteriorly and finally blending with the indusium griseum. (05 Mar 2000) |
| straight gyrus | A gyrus running along the medial part of the orbital surface of the frontal lobe of the cerebral hemisphere. It is bounded laterally by the olfactory sulcus. Synonym: gyrus rectus. (05 Mar 2000) |
| subcallosal gyrus | A slender vertical whitish band immediately anterior to the lamina terminalis and anterior commissure; contrary to its name, it is not a cortical convolution but is the ventral continuation of the transparent septum. Synonym: area subcallosa, gyrus paraterminalis, gyrus subcallosus, pedunculus corporis callosi, corpus paraterminale, paraterminal body, paraterminal gyrus, peduncle of corpus callosum, precommissural septal area, subcallosal area, Zuckerkandl's convolution. (05 Mar 2000) |
| superior frontal gyrus | A broad convolution running in an anteroposterior direction on the medial edge of the convex surface and of each frontal lobe. Synonym: gyrus frontalis superior, marginal gyrus, superior frontal convolution. (05 Mar 2000) |
| superior occipital gyrus | A gyrus lying above the lateral occipital sulcus on the lateral surface of the occipital lobe. (05 Mar 2000) |
| superior parietal gyrus | The area of the convex surface of the parietal lobe of the cerebrum lying between the longitudinal fissure and the interparietal sulcus behind the posterior central gyrus; it is continuous with the precuneus on the medial aspect of the hemisphere. Synonym: lobulus parietalis superior, superior parietal gyrus. (05 Mar 2000) |
| superior temporal gyrus | A longitudinal gyrus on the lateral surface of the temporal lobe between the lateral (sylvian) fissure and the superior temporal sulcus. Synonym: gyrus temporalis superior, first temporal convolution, superior temporal convolution. (05 Mar 2000) |
| supracallosal gyrus | A thin layer of gray matter on the dorsal surface of the corpus callosum in which the medial and lateral longitudinal stria lie embedded. The indusium griseum is a rudimentary component of the hippocampus, continuous caudally around the splenium of the corpus callosum with the fasciolar gyrus, a slender convolution in turn continuous with the dentate gyrus of the hippocampus; rostrally the indusium griseum curves around the genu and rostrum of corpus callosum and extends ventralward to the olfactory trigone as the tenia tecta or rudimentum hippocampi, hidden in the depth of the posterior parolfactory sulcus that marks the anterior border of the subcallosal gyrus or precommissural septum. Synonym: supracallosal gyrus. (05 Mar 2000) |
| deep transitional gyrus | The transverse gyrus of the embryo which in development becomes buried in the depth of the central sulcus of the cerebral hemisphere. Dentate gyrus, one of the two interlocking gyri composing the hippocampus, the other one being the Ammon's horn. Synonym: gyrus dentatus, dentate fascia, fascia dentata hippocampi. (05 Mar 2000) |
| supramarginal gyrus | A folded convolution capping the posterior extremity of the lateral (sylvian) sulcus; together with the angular gyrus, it forms the inferior half of the parietal lobe. Synonym: gyrus supramarginalis, supramarginal convolution. (05 Mar 2000) |
| dentate gyrus | Serrated strip of gray matter under the medial border of the hippocampus and in its depths. It is an archicortex which develops along the edge of the hippocampal fissure and which consists of molecular, granular, and polymorphic layers. The molecular layer is continuous with that of the hippocampus in the depths of the hippocampal fissure. (carpenter and sutin, human neuroanatomy, 8th ed, p626) (12 Dec 1998) |
| isthmus of cingulate gyrus | The narrowing of the cingulate gyrus, at its transition with the hippocampal gyrus behind and below the splenium of the corpus callosum, caused by the anterior extension of the conjoined parieto-occipital and calcarine sulci. Synonym: isthmus gyri cinguli, isthmus of gyrus fornicatus, isthmus of limbic lobe. (05 Mar 2000) |