a non - invasive apparatus and method for measuring fat thickness or content and muscle depth or area parameters grading meat and animals are disclosed . the device includes an ultrasonic transducer and analyzer device which provides a scan information in digitized form . a separate controller moves the ultrasonic transducer along a predetermined path adjacent an animal or carcass while a scans are obtained at predetermined locations along the path . the a scans are digitized and analyzed to determine the tissue interface boundaries . equations are implemented to determine the area of the longissimus muscle and fat tissue thicknesses and a lean content rating for the animal may be determined therefrom . modeling techniques are also used to estimate certain portions of the area of the longissimus muscle of the animal or carcass based upon data gathered during the ultrasound scanning of the carcass . scanning of the ham area and round using the ultrasonic scanner is also suggested to add increased reliability to the data obtained from scanning the rib or loin eye area when used in conjunction therewith in a leanness prediction equation .