Ultrasound assessment of the vulnerability of the internal organs to stabbing: determining safety standards for stab-resistant body armour.

Stab-resistant body armour may not always prevent the passage of a blade into the human body. The depth to which a knife may 'safely' enter the human body before it breaches the internal organs was explored by ultrasound scanning of 25 healthy volunteers. Variations in the minimum skin-to-organ distances for the organs as a function of posture are described. To determine the optimum body coverage by stab-resistant armour, the movement during the breathing cycle and the maximum exposure of the organs beneath the lower costal margin at full inspiration were measured. Although the population studied was small, trends in the vulnerability of the internal organs to the passage of a blade into the body were identified.