Abstract. Stress-deformed condition of a membrane has been modelled. The critical radius for a spherical membrane is shown to be half as much again the radius of a non-deformed one. It has been found that upon reaching a critical pressure the membrane may further grow under reduced pressure. Reinforcement of the areas of weakness in the abdominal wall with a tendon of the latissimus dorsi muscle during the surgical procedure allows to reduce the sag significantly and enlarge the critical intracavitary pressure up to acceptable values.

Key words: modelling, stress-deformed condition, membrane.