A compound sensor for biomechanical analyses of buttock soft tissue in vivo

A sensor for in vivo biomechanical characterization of buttock soft tissue has been developed and evaluated. The sensor measures interface pressure, a pplied force, tilt, and rotation angle of the sensor head, and the thicknes ses of multiple soft tissue layers. A composite ultrasonic transducer using a 1-3 ceramic-polymer structure was developed for the sensor. The sensor c an identify subcutaneous soft tissue interfaces 5 to 65 mm below the skin s urface with a 0.26-mm axial resolution, pressure over the range of 0 to 68 kPa, and force over the range of 0 to 3.6 kg. Our purpose for developing th e sensor was to study the biomechanical characteristics of buttock soft tis sues. Successful identification of distinguishing characteristics in person s with a susceptibility to pressure ulcers may result in the development of a risk assessment tool based on tissue characterization.