THE BIOMECHANICAL BEHAVIOR OF SPHINCTERS: HOW THE THEORY AND THE PRACTICE MISMATCH

Monitoring sphincter activity presents remarkable methodological and conceptual problems. The particular shape, structure and function of the sphincters require an accurate analysis of the objectives of diagnostic procedures and the physical concepts applied. Researchers have developed practical solutions to the description of the sphincter activity not always rigorous on a theoretical basis, and the measurement results are diffi- cult to evaluate and compare, in the event that the contour conditions of the assumed descriptive model are not well defined. A practical solution is to “create” a constant curvature radius chamber by introducing a cylinder within the sphincter and measuring the pressure, linearly proportional to the tangential force strength of the wall. This paper analyzes the coherence between the theoretical basis and the practical solutions of the different methods of sphincter monitoring, to clarify some controversial aspects, highlight the limitations and to suggest possible alternative solutions.