Abstract: A method for estimating the bone quality or skeletal status of a vertebrate on the basis of two-dimensional image data comprising information relating to the cortical bone of at least a part of a bone of the vertebrate, the image data being data obtained by exposing at least the part of the bone to electromagnetic radiation, the method comprising estimating the bone quality or skeletal status on the basis of a a grey value difference between oblong density variations in the image data and other parts of the image data. These oblong density variations may be caused by osteoporosis, osteopenia or hyperparathyroidism or other bone disorders is called “intra cortical resorption”, “periosteal resorption”, “endosteal resorption”, “striation”, “scalloping”, or “spongiosation”.