A sensing assemblage for capturing a transit time, phase, or frequency of energy waves propagating through a medium is disclosed to measure a parameter of the muscular-skeletal system. The sensing assemblage comprises a transducer and a waveguide. The transducer is coupled to the waveguide at a first location. A reflective surface can be coupled to the waveguide at a second location. The reflective surface is configured to reflect energy waves away from the reflective surface. An interface material that is transmissive to acoustic energy waves can be placed between the transducer and a waveguide to improve transfer.
