Figure 4a. UGD. (a) CT scan shows the apices of the UGD fat planes (arrowheads). Note that the UGD (arrows) is contiguous to the prostatic apex (a). The right UGD fat plane at the level of the lower obturator internus muscle is outlined with white. (b) Contiguous section obtained below a shows the continuation of the UGD (arrow). Arrowhead = apex of the UGD fat plane.