Hold the mouse or rat in a position that allows examination of the paws. 2. Place constant tension-calipers on the ankle medial lateral and determine thickness a minimum of two times to ensure accuracy. Constant-tension calipers offer the advantage of speed but can yield falsely low values for inflamed joints if the tension is too great. 3. Repeat procedure to measure the tarsal thickness dorsal ventral of the same paw. 4. Repeat steps 2 and 3 for each paw.