The oppermost skin layer, stratum corneum, represents the most important barrier of the body against hazards like pathogens or chemicals. In this Thesis, the nanostructure of the lipid matrix as most important structure for this function was investigated. The method applied for this purpose, the neutron diffraction allows for a nanometre scale resolution of the multilamellar structure. The focus was on the C24/18 Ceramides [NP] and [AP], as two of the most abundant and thus most likely most important molecules of the lipid matrix. Due to the use of deuterium-labelled ceramides it was furthermore possible, to resolve the spatial organisation of the otherwise undetectable hydrocarbon chains. A structure consisting of repeating 5.45 nm long lamellae with overlapping C24 chains was described. Furthermore, it was possible, to show that the two D- and L-Isomers of the ceramide [AP] resulted in notably different structures. The not naturally occurring L-ceramide [AP] results in a more crystalline structure. Beyond that, it was possible, to show, that the lamellar structure is almost uninfluenced by the addition of a very long C46/18 Ceramide, an analogue of the natural ceramide [EOS].