A method and apparatus for non-invasive and quantitative assessment of the status of a lumbar vertebral body in a living being for at least one of several quantities (e.g., bone-mineral density, bone mass, etc.) is provided. The method includes the steps of acoustically coupling first and second transducers to nearby skin on opposite sides of a torso of the living being and generating an ultrasound signal and directing the ultrasound signal from the first transducer to the second transducer through the torso. At least a portion of the ultrasound signal passes through the lumbar vertebral body and the second transducer generates an output signal responsive to receipt of the ultrasound signal. The method further includes the step of processing the output signal to obtain an estimate of the at least one quantity.
