| Popis: |
THE PURPOSE of this display is to present in pictorial form the development of the human chiasm and its relations to contiguous structures. For convenience the display has been divided to correspond approximately to the trimesters of gestation. CABINET I The development of the visual pathway begins very early in the life of the human embryo, about the 3.2 mm. stage, when the optic vesicles become established. The anlage of the chiasm occupies the floor of the forebrain between the optic stalks at the junction of the telencephalon and the diencephalon (Figs. 1, 5, and 7). Axones from the ganglion cells in the retinas grow toward the brain, where they enter the floor of the third ventricle and partially decussate to form the optic chiasm (Figs. 2, 3, 7, and 8). During the first month the lumens of the optic stalks are quite wide and open into the cavity of |
