Structure of the optic canal in human ontogenesis.

The aim of this work is to reveal the optic canal (OC) development regularities. It is of importance to identify the anatomical preconditions of tunnel syndrome and other pathologies of the OC. One hundred and five human embryos (195 OC, out of them 98 - left-hand, 97 - right-hand) from 4 up to 70 mm parietococcygeal length (PCL) have been studied. The diameters of the optic nerve (ON) and OC in its orbital, cranial apertures and middle part have been defined. In the same way the distances between the OC walls and the ON and ophthalmic artery have been measured. We have come to the conclusion that the morphogenesis of the OC walls is an asynchronous process. The development of the OC upper wall is retarded. Some asymmetry of the morphometric characteristics of the right and left OC has been revealed. The development of the OC depends on the organization of all its elements. The periods of the OC development have been identified. The OC constitutional features of its aperture form, the size of the OC walls and its apertures, ON size, the correlation between ON and OC diameters of the OC cranial and orbital apertures and "waist", and the arrangement of the OC compartments were revealed. The individual and typical features of the OC structure, revealed as a result of computer tomography (CT) analysis, account for CT effectiveness in the diagnosis of OC changes and the structures located in it.