The article proposes a simple mathematical model of the inter-subsonic disk, which also describes the processes of intra- and male-differential fluid diffusion, which was not presented earlier in the works of other authors. The model is represented by two rigid plates, with a tsindidric lining, consisting of a pulposus nucleus and several fibrous rings with deformable walls around. The shape of the wall deflection is described using the Rayleigh method. Immediately after introducing a disturbance into the system, the pressure is assumed to be proportional to the height of the deflection of the walls of the rings. Then the process of diffusion begins and occurs until equal pressure is established throughout the volume.