an ultrasound densitometer is disclosed in which ultrasonic transducers are located spaced apart in a water bath into which the heel of a person may be inserted . the transit time of an ultrasonic pulse through the water and heel and the attenuation of the pulse may be measured to evaluate the physical properties of the bone in the heel . a central controller coordinates the ultrasonic measurement with the automatic filling and draining of the water bath to ensure hygienic and repeatable operation . the water may be preheated to reduce patient discomfort and to improve the reduced by preheating water in a separate pre - fill chamber during the previous scan . gravity feed of the water reduces the complexity of the water handling and provides extremely quiet operation . a toe peg in the water bath , which fits between the patient &# 39 ; s toes , and a calf support help to reduce patient motion during the measuring .