Research In Microanatomy On The Area Of The Third Ventricle And Its Clinical Utilization

Part 1Microanatomy of the third ventricleobjectives: To investigate the composition and microanatomy of the third ventricle. In further ,we want to offer theoretical guide and anatomical support for clinical utilization.Methods: 15 formalin fixed and 5 fresh normal adult cadaveric brains were evaluated under operation microscope. 50-100ml of red rubber liquid were injected through internal carotid artery and vertebral artery,100-150 ml of blue rubber liquid were injected through internal carotid vein. After opening the calvaria and exposing anatomical structures of the third ventricle ,operative microscope was used to dissect,observe and measure data. Results:1.The anterior wall of third ventricle is composed of lamina terminalis, superior surface of optic chiasm, anterior commissure and fornix coloum. Lamina terminalis starts superiorly from anterior commissure and ends inferiorly to anterior border of optic chiasm, similar to quadrilateral structure. The line of two sides of migration of optic nerve and optic chiasm is the widest place of lamina terminalis. It is thinner in the inferior-anterior margin and thicker in the superior-posterior margin of lamina terminalis; it is gradraually becoming thinner. It is easier to dissect at the middle point of the posterior margin of lamina terminalis ,and it isn't easy to damage related neural structures.2.The roof of the third ventricle is composed of fornix and velum interpositum 3.The posterior wall of the third ventricleb is composed of the pineal body and posterior commissure.4.The floor of the third ventricle is composed of the inferior surface of the optic chiasm ,optic recess, infundibulum and its recess, tuber cinereum , mammilary body , posterior perforating substance and tegmentum of midbrain.5.The lateral wall is composed of thalamus and hypothalamus.There is a hypothalamus sulcus between thalamus and hypothalamus.Conclusions:1.It is proper to cut open the lamina terminalis at the middle point of posterior margin of optic chiasm in the trans-lamina terminalis approach. Because it is the thinnest and the widest position and it is not easy to damage optic chiasm and optic tract.2.The shape of Monro's foramen is related to the size of the lateral ventricle. It is wise to avoid damaging the genu of the internal capsule when dragging the Monro's foramin in the operationKey words: third ventricle, diencephalons, hypothalamus, Monro's foramin, lamina terminalis...