Peak Penetration Force during Stabbing of Chest Wall with a Ceremonial Sword

Background: The force required for a sword to penetrate the human chest was identified as an important issue for the defense in a case of homicide by stabbing. Previous literature on penetration force had tested knives but not swords. Objective: The objective of the current study was to determine the peak force during penetration of a surrogate for human tissue with a ceremonial sword. Methods: The sword was secured to an MK-10 Tensile Tester and forced to penetrate a pork rib cut at speeds of 350 mm/min and 1100 mm/min, including both regions of rib and cartilage for pork ribs without skin or covered with a layer of porcine skin. Results: In the case of the pork ribs without skin, the mean peak penetration force at a speed of 350 mm/min was 11.0 N compared to a mean of 10.5 N at a speed of 1100 mm/min. The distributions of peak penetration forces at the two speeds were not significantly different. In the case of the pork ribs covered with porcine skin, the mean peak penetration force at a speed of 350 mm/min was 50.0 N compared to a mean of 47.6 N at a speed of 1100 mm/min. The distributions of peak penetration forces at the two speeds were again not significantly different. Conclusion: Forces of less than 50 N would be required for a ceremonial sword to penetrate the tissues of the human chest, although there is a risk of penetration for forces as low as 5 N when the effect of the porcine skin is not considered. Furthermore, the force required for penetration did not vary significantly over a three-fold speed of penetration.