RESONANT-FREQUENCY OF A PIN-ACCELEROMETER SYSTEM MOUNTED IN BONE

Invasive measurements of spinal motion using intraosseous metal pins h ave become common. For this reason, the resonant frequency of intraoss eous pins attached with accelerometers was determined using two differ ent methods. It was concluded that plucking the pin is a reliable meth od for determining the resonant frequency and, in order to accurately measure bone movement at frequencies up to 32 Hz, the pin diameter sho uld be 2.0 mm or more. With a mass of the accelerometer assembly equal to 27 g, the total pin length should not exceed 80 mm with a bone-acc elerometer distance of 25 mm and a pin diameter of 24 mm.