Localization Of The Adult Human Brain Language Areas On Transverse Sectional Anatomy And Magnetic Resonance Imaging

【Objective】To approach the localization of the adult human brain language areas on transverse sections anatomy and magnetic resonance imaging precisely, so as to provide sectional anatomical basis for studies of the functional imaging on human brain and facilitate treatment and rehabilitation of aphasia.【Methods】Serial transverse sections of 4 mm thick and MR images of 30 audult cadavers brain specimens and 20 living brain of the healthy volunteers were prepared with the similar scan condition. The brain slices in correspondence with MR scan took the line parallel to the intercommissural line as base one. Localization of the human brain language areas on the transverse sections were studied by comparison of MR images with serial transverse sections of the brains.【Results】1. On the section through the intercommissural line, the appearing rate of the anterior ramus of the lateral sulcus was 13.6% on the left side and 16.7% on the right one, the appearing rate of the triangular part was 20% on the left side and 40% on the right one, the appearing rate of the opercular part was 26.7% on the left side and 30% on the right one. 2. On the section of the splenium of corpus callosum appearing for the first time, the appearing rate of the anterior ramus was 60% on the left side and 53.3% on the right one, the appearing rate of the ascending ramus was 90% on the left side and 83.3% on the right one, the appearing rate of the triangular part was 93.3% on the left side and 86.7% on the right one, the appearing rate of the opercular part was 86.7% on the left side and the right one. 3. On the section through the superior part of the dorsal thalamus, the anterior ramus will disppear, the appearing rate of the ascending ramus was 100% on the left side and 96.7% on the right one, the appearing rate of the triangular part and opercular part was 100% on the left side and the right one respectively, the appearing rate of the transverse temporal gyrus was 40% on the left and 60% on the right. On this section, many brains (60% on the left and 40% on the right) had appeard the posterior ramus of the lateral sulcus, supramarginal gyrus and angular gyrus. 4. On the section through the superior part of the caudate nucleus, the appearing rate of the triangular part was 93.3% on the left side and 73.3% on the right one, the appearing rate of the opercular part was 93.3% on the left side and 90% on the right one. The shape of the the lateral sulcus has changed into "一". The insula and transverse temporal gyrus had disappeared, the appearing rate of the the supramarginal and angular gyrus was 100% respectively. 5. On the section when the corpus callosum will disappear, the appearing rate of the triangular part was 10% on the left side and the right one. the appearing rate of the opercular part was 30.7% on the left side and 26.7% on the right one. the ascending ramus has disappeared, the appearing rate of the interparietal sulcus was 43.3% on the left side and 30% on the right one. the appearing rate of the supramarginal and angular gyri was 100% respectively. 6. On the section through the middle part of the paracentral lobe, the appearing rate of "hand-knod" signal on the precentral gyrus was 93.3% on the left side and 96.7% on the right one separately. The interparietal sulcus has disappeared.【Conclusion】The speech area of Broca appeared on the 1-2 sections between the intercommissural plane and the plane of the splenium of corpus callosum appearing for the first time. The appearing of the anterior ramus of the lateral sulcus was the important signal. The plane through the superior part of the dorsal thalamus was the most ideal section for the speech area of Broca. It would disappear on the 1-2 sections after the the corpus callosum disappeares. The important signal of the appearing of the writing area was the occurrence of "hand-knod" on the precentral gyrus. The supramarginal and angular gyri appears firstly on the section through the superior part of the dorsal thalamus or upper this one. The important signal of the appearing of the supramarginal and angular gyri was the shape of the lateral sulcus changed from "Y" into "一" and the transverse temporal gyrius had disappeared. The most ideal section when the supramarginal and angular gyri appeared was the one through the superior part of the caudate nucleus. The disappearing of the interparietal sulcus indicated that the posterior language areas would disappear.