Regions of interest (ROIs) created in ImageJ: A sequence of instructions requiring some user input and performing some logical steps was created as a text file in the ImageJ programming language. For ImageJ, such a list is called a “macro.” Line “a” is drawn by the user as a tangent to the caudoproximal endosteal surface of the ulna, and three points are identified by mouse clicks on the edge of the medial humeral condyle (MHC). This user input allows for the automatic creation of the circular outline of the humeral condyle, together with three lines originating in the center of the MHC at angles of 45° “b,” 110° “c,” and 130° “d” to line “a,” a line “e” parallel to line “a” dividing the area bounded by lines “a,” “b,” and “d” and the humeral condylar, into two regions with areas in the ratio 1 (upper/cranial) to 2 (lower/caudal); line “f” is created again automatically by the macro, perpendicular to line “d” through the point of intersection between lines “d” and “a.” Finally, the user marks three points: P1 at the intersection of line “f” with the ulnar cranial endosteal cortex, and P2 and P3 at the points where lines “d” and “f” cross the periosteal caudal ulnar cortex, respectively. This allows the automatic creation of line “g,” which is parallel to line “d” and passes through P1, and line “h,” which joins P2 and P3. The macro then creates ROIs as follows: ROI-1, distal ulnar trochlear notch (UTN); ROI-2, middle UTN; ROI-3, caudal UTN (single area); ROI-4, cortical bone; ROI-5, bone marrow. The macro takes measurements from these five ROIs. The recorded measurements for each were mean, median, standard deviation, and area. The completed macro sequence thus creates lines and regions according to strict reproducible criteria.