This issue’s Featured Visible Human Movie shows the digital anatomy of the anal canal (Videoclips 1A and 1B). A corresponding 12 mhz radial array EUS image is also provided in Video Clip 2.

The anal canal can be somewhat mysterious to physicians not trained in surgical specialties. It is an area that is often affected by maladies (fissures, hemorrhoids, fistulae, tears) and conditions (incontinence, constipation), but this region seems to not receive much attention in most medical training programs. Tumors that destroy the anal canal can have a devastating psychosocial impact on patients. For those of us actively involved in the local staging of rectal cancers, it is not unusual to hear patients ask “Am I going to have to have a bag?”

Hemorrhoids and hemorrhoidal bleeding, on the other hand, are so common that they can almost be considered a normal finding. Interested readers may also wish to see an example of enlarged hemorrhoidal veins treated by banding from the Digital Atlas of Video Education (DAVE) project by clicking here. To view this video at this link, one must have installed Realplayer on their computer. Instructions for installation are provided at the DAVE site.

Axial and sagital cross sectional images of the anal canal are shown (Figures 1 and 2). A link to the Visible Human dataset is provided below Figure 1 for those who are interesting in studying this area in more detail. We encourage readers to review these files and explore the data set to become more familiar with this regional anatomy.

Figure 1: Click here to launch Interactive Atlas	Figure 2