. Cunningham's Text-book of anatomy. Anatomy. THE CEEEBEAL COMMISSURES AND SEPTUM PELLUCIDUM. 629 upper end of the hippocampal formation so that it becomes removed far from the lamina terminalis. The fibres of the fimbria which are prolonged forwards under the corpus callosum and septum pellucidum to bridge this great gap form the crus fornicis on each side. As a rule in the human adult brain the crura fornicis of the two hemispheres become crowded together at the median plane so as to obscure the connecting lamella which serves as a matrix for the commissura hippocampi (Fig. 557, C); but the
. Cunningham's Text-book of anatomy. Anatomy. THE CEEEBEAL COMMISSURES AND SEPTUM PELLUCIDUM. 629 upper end of the hippocampal formation so that it becomes removed far from the lamina terminalis. The fibres of the fimbria which are prolonged forwards under the corpus callosum and septum pellucidum to bridge this great gap form the crus fornicis on each side. As a rule in the human adult brain the crura fornicis of the two hemispheres become crowded together at the median plane so as to obscure the connecting lamella which serves as a matrix for the commissura hippocampi (Fig. 557, C); but the true arrangement can be seen in the brains of fcetuses of the sixth, seventh, and eighth months, and is at once revealed in the adult if the corpus callosum is raised up by an accumulation of fluid in the lateral ventricles (hydrocephalus), so as to put a strain upon the septum pellucidum. The mass formed by the crura fornicis and their commissure is called the corpus fornicis. The fascia dentata appears as a curious notched band behind and below the fimbria; its upper end passes on to the under surface of the splenium of the corpus callosum, where it tapers and ends (fasciola cinerea); but as it dwindles the upper end of the hippocampus emerges upon the surface below and behind it and passes into a thin film of gray matter—indusium griseum—which is prolonged on to the upper surface of the corpus callosum. It proceeds forward, becoming as a rule still Vestiaes of the supracallosal uippocampus Septum pellucidum. • Olfactory bulb Vestiaes of the precallosal hippocampus Paraterminal body ippoca-mp. h|ppC Fig. 557.—Three Stages en the Development of the Corpus Callosum. more attenuated, and after surrounding the anterior end (genu) of the corpus callosum it passes downwards towards the trigonum olfactorium along the line that separates the corpus paraterminale from the neopallium. The indusium represents the atrophied remains of the anterior part of the hippocampal arc of t
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectanatomy, bookyear1914
