Figure 1

Simple contrast fistulography. A. Antero-posterior aspect, the contrast agent was given through the external opening at the right-side of the anal channel, note the course of horseshoe fistula tracts; there was a complete arm at the right side (white arrow), while the left-side arms were blind (yellow arrows), B. Oblique aspect, the blind arm of the horseshoe fistula extended into the left gluteal area (arrow), C. Lateral aspect, the connection between the fistula tract and the deep postanal space (arrow) was easily shown.