Mechanical and functional characterization of the diaphragmatic lymphatic network.

The development of transplantation procedures and increased clinical problems involving edema and cancer have created a growing need for detailed studies of the lymphatic system due to its role as a component in the circulatory system and as a component in the immunological system. In the initial phase of the present study, we measured the compliance of the lymphatic vessel wall in vivo and performed ex vivo mechanical tests on diaphragmatic tissue strips. A finite element model (FEM) was thus developed, using the vessel’s actual dimensions, its compliance Measurement and the diaphragmatic tissue’s elastic module. Visualization of the model’s stress distribution then showed the functional differences between superficial, intermediate and deep lymphatic vessels. The next step was to delve into the study of the lymphatic network with vertical connections draining from superficial capillaries to deeper collecting vessels though, given their anatomical position, these are rather challenging to assess experimentally. The experimental data thus obtained was then processed in the lumped parameter model, clarifying significantly the way in which the lymph is drained by the diaphragmatic lymphatic network considering both superficial and deep lymphatic vessels. In part III of the present thesis, we developed a mathematical model that include ribs diaphragm and lungs to quantify and visualize the stress distribution that are generated on the diaphragm, and therefore on the lymphatic vessels, during a whole breathing cycle. The result is a simulation of a normal breathing.