We carried out finite element analysis to evaluate the deformation, cross sectional area and flow resistance of the capillaries in the skin and fat at a bone prominence when the bone is compressed to the mattress and floor by 200 mN per 1 mm model-thickness. The finite element model consists of skin, fat, bone and mattress or floor. The compressive force is determined so as to obtain the maximum surface pressure of 13 kPa on a contact surface of the mattress. Comparisons of cross sectional area and flow resistance of the capillaries for various degrees of extensibility in the skin, we found that the elasticity of skin had a large influence on the deformation of a capillary in the fat. We also found that the floor caused a significant decrease in cross sectional area and a significant increase in flow resistance under compressions to the floor.