Tension, Stress and Modulus of Elasticity of the Urinary Bladder Wall

Transmural bladder pressure, i.e. the difference between the intravesical and perivesical pressures, was continuously registered during slow filling of the bladder in nine healthy men. On the basis of the pressure thus obtained, the surface tension of the bladder was calculated. From the latter and from the assumed thickness of the bladder wall, the normal stress in the wall and a differential modulus of elasticity were calculated. The surface tension, the normal stress and the differential modulus of elasticity increased markedly as the radius of the bladder increased. The logarithm of the maximal differential modulus of elasticity registered was linearly correlated to the bladder radius. This relationship makes it possible to predict in normal subjects the differential modulus of elasticity from the bladder radius and thereby obtain information regarding possible abnormalities in the mechanical properties of the bladder wall.