Shkrobanets A. The development of the organs and structures of the orbit and forming of their topographic relationships during the prenatal period of human ontogenesis

The dissertation is dedicated with a study of the sequence of the anlage, development, the dynamics of the formation of the structures of the organ of vision and the walls of the orbit throughout the entire prenatal period of human ontogenesis. It has been found out that the development of the organ of vision begins in the 4-th week with the appearance of the optic vesicles which give rise to the formation of the primordial of the eyeballs throughout the 5-th week which remain connected with the brain by means of the optic peduncles. The germs of the external muscles of the eyeballs appear during the 7-th week due to a segmentation of the common primordium of densely located mesenchymal cells. Starting with the middle of the 6-th week an ingrowth into the ocular region of the sensory and motor nerves is identified. The interlocation and interrelation of the structures mentioned approximate to definitive ones in the fetuses of the end of the 7-th month. A process of isolating of the ocular region throughout the prefetal period has been traced due to a successive formation of the orbital walls which acquires an osseous structure at the end of the prefetal period.