Objectives:​ The mechanical strengths of the swine heart, liver, and spleen were determined by measuring the force that initiated the rupture of the organs.

Methods:​ The force was loaded by the compression of a detection bar onto the organ, and the breaking stress was calculated by dividing the force by the bar's contact area. The forces were measured with five measurements in five of each type of organ with and without the serous membrane (SM).

Results:​ The breaking stresses of the heart were 14.1 +/- 0.7 kg/cm2 (mean +/- SEM) with intact epicardium and 8.1 +/- 0.6 without it;​ those of the spleen were 9.0 +/- 0.9 with its capsule and 1.8 +/- 0.1 without the capsule, and those of the liver were 4.6 +/- 0.3 with and 3.6 +/- 0.3 without the SM. A three-way layout analysis of variance showed that the organs, their SM and individual swine were independent determinants of the breaking stresses.

Conclusion:​ With the intact SM, the heart was strongest and the liver was weakest. When the SM was not present, the spleen lost 80% of its strength, the liver 22% of its strength, and the heart lost 43% of its strength.