The development of a prosthetic hand capable of mimicking the grasping features of the natural hand will improve the quality of life for below-elbow amputees. This work investigates the existence of a functional relationship between forearm muscle vibratory signals and different functional grips. Simple classifiers were able to distinguish between basic grips with an accuracy of about 75% in one subject. The classification results indicate that a mapping of the vibratory signals to functional grips does exits. Further work is required to investigate if this mapping can be practically exploited for controlling a multifunction prosthetic hand.