Figure 2.

Digital radiographs of the same mouse taken with an IVIS Lumina XRMS live animal imaging system before (3 weeks age) and after (4 weeks age) its right side was subject to daily intermittent limb heating. X-rays were taken in standardized position with the hindlimbs extended and taped down to ensure a true projection of the tibia. Images were rotated so that the spines were aligned at a 90° angle. There were no left-right differences in limb length before the experiments started (top). After 1 week (bottom), the heat-treated right limb was markedly longer than the non-treated left limb as shown by the position of the toes at the bottom of the image. Note that the difference in length is the result of an additive effect of all hindlimb elements. Tibial length was measured from the middle of the proximal articular surface to the distal-most projection of the medial malleolus, shown by the dashed line. The red segment of the line in the right heat-treated limb (bottom) indicates the increase in tibial length relative to the non-treated side (0.16 mm or 1.1% increase in this individual mouse).