There is enough contained in the newly-released Senate report on CIA torture practices to shock anyone’s conscience. News that CIA interrogators threatened violence against the children or parents of detainees, made them stand in stress positions on broken feet, and deprived them of sleep for up to a week at a time is appalling on its face. One needs no medical expertise to parse the horrors described.

But what of “rectal feeding”? At first blush, this practice may have the appearance of legitimacy in cases where detainees refused to eat or drink. One man was put in a head-down position and Ensure was instilled into his rectum. In another case, a whole plate of uneaten food (including nuts, hummus and raisins) was pureed and inserted rectally. While these incidents may sound unpleasant, one might plausibly conclude that this was an acceptable means of hydrating and nourishing recalcitrant prisoners.

This conclusion would be false. There is no legitimate medical use of “rectal feeding.” And the medical professionals involved in these cases surely knew it.

The gastrointestinal (GI) tract performs different digestive functions are various different locations. Even the brief time spent chewing exposes foods to enzymes that begin to break it down. The acidic environment of the stomach, as well as enzymes produced there and by other organs, break down the proteins, fats and sugars further. As digesting food passes through the small intestine, it mixes with chemicals from the liver, and nutrients are absorbed.

None of this happens in the large intestine, of which the rectum is the final segment. While water, electrolytes and sugars can be absorbed before fully-digested food is expelled, the actual digestion occurs meters away. Even following legitimate medical procedures such as gastric bypass, if improperly digested food enters a part of the GI tract not equipped to handle it, it can cause diarrhea and pain (a condition bluntly termed “dumping syndrome”).

Any undigested food inserted into the rectum would simply sit there, only to be expelled back out again. No trained medical provider could possibly expect to nourish a patient this way. In the two decades since I first entered medical school, I have never seen anyone even suggest such a thing. (I checked with a pediatric gastroenterologist of my acquaintance to be sure there were no obscure medical application for this kind of “feeding.” He confirmed that there is not.) Medical personnel involved in these procedures participated in them knowing they were more consistent with a particularly crass episode of South Park rather than any legitimate medical application.

Even if one accepts the highly dubious notion that anyone believed “rectal feedings” were a legitimate means of nourishing someone, there was no reason to consider such extreme measures in the first place. The rule of thumb in medicine is “if the guts works, use it,” meaning that it’s best to use the stomach to hydrate a patient if it’s functioning properly. There is no indication that these detainees couldn’t have had tubes inserted into their stomachs through their noses for the purposes of feeding them, assuming that respecting their right to refuse food had already been thrown out the window. For hydration, an IV would have been effective, as CIA medical officers conceded.

What those same medical officers acknowledge is that using the rectum to hydrate prisoners (which would, in contrast to feeding, at least work) was an effective means of behavior modification. These procedures weren’t undertaken because they were necessary. They were done to give a thin patina of ersatz legitimacy to what is otherwise flagrant sexual assault. The details differ but the intent is the same as in a high-profile case of police brutality.

The treatment of these detainees is a national disgrace. The participation of medical personnel is an egregious violation of medical ethics. Those who did so used their medical training not to care for patients, but to abet their abuse. “Rectal feeding” belongs alongside waterboarding and sleep deprivation on the list of torture methods, and everyone who participated in it knew it at the time.