2732: Bursa of Fabricius

Explain xkcd: It's 'cause you're dumb.
Jump to: navigation, search
Bursa of Fabricius
If an anatomical structure is named for a person, it means they were the only person to have it. Pierre Paul Broca had a special area of his brain that created powerful magnetic fields, enabling him to do 19th century fMRI research.
Title text: If an anatomical structure is named for a person, it means they were the only person to have it. Pierre Paul Broca had a special area of his brain that created powerful magnetic fields, enabling him to do 19th century fMRI research.


The Bursa of Fabricius is an organ found in birds that is necessary for the development of their immune systems.

This comic claims that the 16th century anatomist Hieronymus Fabricius (for whom the organ was named) had that organ and therefore was able to fly like a bird. However, despite being found only in birds, this organ does not in fact contribute directly to flight. Also, given that it only exists in birds, it is doubtful that Fabricius also independently had this same anatomical feature. [citation needed]

Many scientific and mathematical discoveries, including anatomical structures, are named after the people who discovered or described them. For example, the islets of Langerhans were discovered by Paul Langerhans. Likewise, rare diseases are often named for the doctor who first describes the disease to the medical community, or for a researcher who identifies the specifics involved. They may attempt to set their own name to it, for posterity, or they are later honored in this manner by those who recognize their vital contribution to the field, such as with Parkinson's disease.

In other cases, rare diseases are named for the first or most famous (possibly even the only) person known to have had the disease. For instance ALS is commonly known as Lou Gehrig's disease in the US because of baseball player Lou Gehrig having notably developed the condition. Outside of the US, it may be more known just as "amyotrophic lateral sclerosis" (alternatively "motor neurone disease") or, for simplicity, the initials ALS (or MND).

The title text continues with the idea from the comic claiming that anatomical structures are solely possessed by the human for which they are named, in another similar example. Pierre Paul Broca, a French physician, anatomist and anthropologist, was known for his research on what is now known as Broca's area, a region of the brain used for speech and language processing. The premise being that, having this feature, he was uniquely gifted with the special ability to created powerful magnetic fields, enabling him to do fMRI research in the 19th century. Later in the same year Broca was again referenced in 2780: Physical Quantities.

Broca did not[citation needed] do fMRI research, a powerful method of non-intrusively imaging and analyzing the internal structures of the living human body (amongst other things), as it was not invented in his lifetime. Nor is it likely that this ability could be 'naturally' possessed by any individual, such as he. He did, however, physically study brains of known speech-impaired patients who had then subsequently died, determining what damage (in the area of the brain which was then to be named for him) was directly related to their specific group of ailments. Today, we can safely view this area in living people, using fMRI, and directly connect what we see with the current condition of patients. This increases our knowledge of the brain, as with the mythical abilities Randall gave Broca, but also possibly even allows us to help those currently under the effects of any observed damage (not necessarily possible by any 19th century physician, even with this superpowered form of vision to assist them).

In reality, if Broca was the only person to have ever possessed Broca's area then this might have meant that only he had ever had the power of speech (as we understand it), which would indeed give him a very special ability; but one begging a number of other vital questions, if only anybody else could have asked them...

This may also be a nod to the Discworld character "Bursar", a wizard at Unseen University who can fly because he once hallucinated that he could, and so now he can.


[An almost bald man with hair around the neck and a full beard, is shown flying in the top right part of the image, swooping down from the sky with arms outstretched in front of him while yelling. Three dotted lines behind him indicate his path. Two people look up at him from the bottom left corner, a man with a wide-brimmed hat and a black haired woman with a scarf over her hair, which is hanging down behind her. She is holding both her hands up to her mouth. At the top of the panel there is text:]
The bursa of Fabricius is a lymphoid organ found only in birds and in 16th century anatomist Hieronymus Fabricius, to whom it conferred the power of flight.
Hieronymus Fabricius: Wheee

comment.png add a comment! ⋅ comment.png add a topic (use sparingly)! ⋅ Icons-mini-action refresh blue.gif refresh comments!


One of the reasons for the success of humans is that the tools of humans do not depend on the structure and strength of the human body. Using fire as an example, a single person with a fire stick can burn down an entire forest in a matter of hours. Fire is not limited by the person who started it. The same goes for any other tool we make. ~ Megan she/her talk contribs 18:35, 1 February 2023 (UTC)

Here's the wiki for Bursa of Frabricius: https://en.wikipedia.org/wiki/Bursa_of_Fabricius
And the wiki for Hieronymus Fabricius: https://en.wikipedia.org/wiki/Hieronymus_Fabricius Mr. I (talk) 18:51, 1 February 2023 (UTC)

So that's why I can't find the Gräfenberg spot! LunarNapolean (talk) 20:34, 1 February 2023 (UTC)

Perhaps you should have met Frau Gräfenberg? 22:10, 1 February 2023 (UTC)

At first I thought the top character was swinging on a rope like in https://xkcd.com/208/, but now I see he's actually flying. So is he supposed to be Fabricius? Barmar (talk) 22:15, 1 February 2023 (UTC)

Yes - seems kind of obvious given that the comic is about the fact that Fabricius could fly... ;-) --Kynde (talk) 08:02, 2 February 2023 (UTC)

Perhaps the presence of the organ in avian dinosaurs prevented their demise after the asteroid. KingPenguin (talk) 23:33, 1 February 2023 (UTC)

omg return of safari hat guy from 603!! 00:44, 2 February 2023 (UTC)Bumpf

Uhm no. Not drawn the same way at all. --Kynde (talk) 08:02, 2 February 2023 (UTC)

Adam's apple is named for the legend that a piece of forbidden fruit was stuck in the biblical Adam's throat. I guess you could call him the discoverer, but that's a stretch. 06:21, 2 February 2023 (UTC)

'Adam's Apple' isn't named after its 'discoverer', but after the Biblical Adam, because it resembles having a piece of the 'forbidden fruit' stuck in one's throat. The earliest use of the name occurs in a 1662 English translation of Thomas Bartholin's 1651 work 'Anatomia', but the Latin phrase translated, 'pomum Adami', had been in use in medical texts across Europe from at least 1600AD. 06:31, 2 February 2023 (UTC)

Yes the start of the explanation makes no sense at all. Will rewrite --Kynde (talk) 08:02, 2 February 2023 (UTC)

"Sometimes, anatomical sections are named after their first discoverer in a similar fashion: Broca's area, Adam's apple, Achille's tendon, and so on."
Broca's area, yes. Adam's apple, as per above, refers to a Biblical story, Achilles tendon (not "Achille's tendon") refers to the Illiad. Terrible, terrible examples. 06:33, 2 February 2023 (UTC)

No the entire top section is BS. Also it has nothing to do with gaming. Will delete any ref to that and rewrite. --Kynde (talk) 08:02, 2 February 2023 (UTC)

So was Paul Langerhans the only resident of his own private archipelago, the islets of Langerhans? https://en.wikipedia.org/wiki/Pancreatic_islets162.158.79.193 19:10, 2 February 2023 (UTC)

Should we a link to the list of lots of parts. https://en.wikipedia.org/wiki/List_of_human_anatomical_parts_named_after_people

It's worth noting that if Mr. Broca indeed was the sole owner of Broca's area, he'd also be the only one able to name the area (after himself, evidently). PotatoGod (talk) 23:26, 3 February 2023 (UTC)

I don't know if Randal scans the discussions for comic ideas. However, I would suggest one about a mistaken belief that body parts have been named after their inventors, not their discoverers. These Are Not The Comments You Are Looking For (talk) 02:43, 5 February 2023 (UTC)

I'm quite sure Randall tries to stay as far away from any forum that discusses and analyzes his comics ;-) And while he may be aware there is this explain xkcd and at least ones have linked to it from a comic, that was a special case. Also I think he tries to avoid getting ideas directly from other people. The one time he did a comic that someone had already done he made a special header saying so... xkcd 1723 --Kynde (talk) 17:45, 10 February 2023 (UTC)