# Can people (or other animals) ever be backwards? **URL:** \ **Category:** Factual Questions\ **Created:** [May 15, 2012, 8:17pm UTC](https://boards.straightdope.com/t/can-people-or-other-animals-ever-be-backwards/622016 "2012-05-15T20:17:46Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![tdn](https://avatars.discourse-cdn.com/v4/letter/t/94ad74/32.png) [@tdn](https://boards.straightdope.com/u/tdn)\ **Post date:** [May 15, 2012, 8:17pm UTC](https://boards.straightdope.com/t/can-people-or-other-animals-ever-be-backwards/622016/1 "2012-05-15T20:17:46Z")
Has there ever been a case where a person was backwards, i.e. heart on the right, liver on the left? Does it ever happen to animals? I wondered about this when I was sitting on a beach with probably millions of univalve shells, all of which had the same right-hand twist. Not a single one had a left-hand twist. Is this even possible? ---
**Author:** ![Disgscen](https://avatars.discourse-cdn.com/v4/letter/d/f05b48/32.png) [@Disgscen](https://boards.straightdope.com/u/Disgscen)\ **Post date:** [May 15, 2012, 8:21pm UTC](https://boards.straightdope.com/t/can-people-or-other-animals-ever-be-backwards/622016/2 "2012-05-15T20:21:16Z")
Situs inversus ---
**Author:** ![DCnDC](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dcndc/32/2842_2.png) [@DCnDC](https://boards.straightdope.com/u/DCnDC)\ **Post date:** [May 15, 2012, 8:22pm UTC](https://boards.straightdope.com/t/can-people-or-other-animals-ever-be-backwards/622016/3 "2012-05-15T20:22:27Z")
Yes. It’s called _[situs inversus](http://en.wikipedia.org/wiki/Situs_inversus)_. It can occur in other animals, but it’s quite rare. ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [May 15, 2012, 8:29pm UTC](https://boards.straightdope.com/t/can-people-or-other-animals-ever-be-backwards/622016/4 "2012-05-15T20:29:38Z")
That’s not backwards, it’s mirror image. FYI. ---
**Author:** ![Lasciel](https://avatars.discourse-cdn.com/v4/letter/l/e79b87/32.png) [@Lasciel](https://boards.straightdope.com/u/Lasciel)\ **Post date:** [May 15, 2012, 8:43pm UTC](https://boards.straightdope.com/t/can-people-or-other-animals-ever-be-backwards/622016/5 "2012-05-15T20:43:31Z")
You can find lefty shells also - I lived very near the beach, and spent entire summers wandering around collecting. I have found perhaps a handful over about 10 years worth of summers. ---
**Author:** ![DCnDC](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dcndc/32/2842_2.png) [@DCnDC](https://boards.straightdope.com/u/DCnDC)\ **Post date:** [May 15, 2012, 8:44pm UTC](https://boards.straightdope.com/t/can-people-or-other-animals-ever-be-backwards/622016/6 "2012-05-15T20:44:23Z")
> [@John\_Mace](#): > > That’s not backwards, it’s mirror image. FYI. I don’t think that’s what the OP was referring to but in that case it would be _[situs ambiguus](http://en.wikipedia.org/wiki/Heterotaxy)_ or heterotaxia, more specifically [Ivemark syndrome](http://en.wikipedia.org/wiki/Ivemark_syndrome). It’s extremely rare and patients rarely survive long but there are cases of patients [living a mostly normal life](http://www.dailymail.co.uk/health/article-1185690/TheJigsaw-Kid-spleens-liver-left-lungs.html). ---
**Author:** ![Hilarity\_N.Suze](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hilarity_n.suze/32/6223_2.png) [@Hilarity\_N.Suze](https://boards.straightdope.com/u/Hilarity_N.Suze)\ **Post date:** [May 15, 2012, 8:51pm UTC](https://boards.straightdope.com/t/can-people-or-other-animals-ever-be-backwards/622016/7 "2012-05-15T20:51:42Z")
I’m sure it happens in other animals. My uncle: it was not discovered until he was 17 and taking his physical to join the Navy. Apparently there were many yucks about the enemy not being able to shoot him in the heart, etc., but it’s not THAT far off. The doctors weren’t sure how to put this on his dog tags, but felt it ought to be there. A coworker’s sister: Not discovered until she was 44 and having a C-section with her FOURTH CHILD. Honestly? You’d think someone would have noticed somewhere down the line. In my uncle’s case it’s quite possible that the Navy physical was his first one ever (it was also the last one he had for about 50 years). ---
**Author:** ![Smeghead](https://avatars.discourse-cdn.com/v4/letter/s/f1d935/32.png) [@Smeghead](https://boards.straightdope.com/u/Smeghead)\ **Post date:** [May 15, 2012, 9:45pm UTC](https://boards.straightdope.com/t/can-people-or-other-animals-ever-be-backwards/622016/8 "2012-05-15T21:45:40Z")
As a side note, it’s a somewhat surprising fact that situs inversus is caused by a defect in cilia - you know, those little hair-like wavy projections that cells have. In the very early stages of development, cilia are supposed to set up a current that causes certain growth factors to be deposited on one side and not the other. This gradient is what determines the left-right differentiation. If the cilia don’t work properly, the gradient isn’t set up, and the two sides are identified more or less at random, so about half of the people with this defect end up with them swapped. ---
**Author:** ![md2000](https://avatars.discourse-cdn.com/v4/letter/m/73ab20/32.png) [@md2000](https://boards.straightdope.com/u/md2000)\ **Post date:** [May 16, 2012, 12:27am UTC](https://boards.straightdope.com/t/can-people-or-other-animals-ever-be-backwards/622016/9 "2012-05-16T00:27:44Z")
Goldfinger. ---
**Author:** ![AClockworkMelon](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aclockworkmelon/32/10803_2.png) [@AClockworkMelon](https://boards.straightdope.com/u/AClockworkMelon)\ **Post date:** [May 16, 2012, 1:01am UTC](https://boards.straightdope.com/t/can-people-or-other-animals-ever-be-backwards/622016/10 "2012-05-16T01:01:19Z")
> [@tdn](#): > > Has there ever been a case where a person was backwards, i.e. heart on the right, liver on the left? Apparently that’s the case with [Catherine O’Hara](http://upload.wikimedia.org/wikipedia/commons/1/16/CATHERINE_OHARA.jpg). ---
**Author:** ![matt\_mcl](https://avatars.discourse-cdn.com/v4/letter/m/7ab992/32.png) [@matt\_mcl](https://boards.straightdope.com/u/matt_mcl)\ **Post date:** [May 16, 2012, 1:27am UTC](https://boards.straightdope.com/t/can-people-or-other-animals-ever-be-backwards/622016/11 "2012-05-16T01:27:07Z")
Situs inversus is the general term; the state of having your heart, specifically, on the right-hand side is _dextrocardia._ If dextrocardia is present as part of _situs inversus totalis_ – the reversal of all the internal organs – people can often live perfectly normal lives and the condition can indeed go undetected for many years, as **Hilarity** notes. Still, there is a 5-10% chance of congenital heart defects such as transposition of the great vessels. Situs inversus totalis affects about 1 in 10,000 people. However, if dextrocardia is present alone, or if the organs except for the heart are mirrored – _situs inversus with levocardia_ – the prevalence of heart malformation is far higher. Other issues include needing the positions of stethoscopes, EKG leads, and other devices adjusted accordingly (which is no doubt why **Hilarity** ’s uncle needed to have it on his dog tag), as well as difficulty with physical compatibility if a transplant is needed. BTW, the normal placement of organs is referred to as _situs solitus_. ---
**Author:** ![SeaDragonTattoo](https://avatars.discourse-cdn.com/v4/letter/s/df705f/32.png) [@SeaDragonTattoo](https://boards.straightdope.com/u/SeaDragonTattoo)\ **Post date:** [May 16, 2012, 1:41am UTC](https://boards.straightdope.com/t/can-people-or-other-animals-ever-be-backwards/622016/12 "2012-05-16T01:41:39Z")
I’ve seen it once, in a cat, in the twelve years and thousands of cats I’ve worked with. We thought the x-ray was somehow messed up (digital format, so no film to get backwards) and re-took them three times before the doctor determined they were correct and the cat was the one that was wrong. It was there for GI issues, but was 4 years old already, so apparently everything that was “mirrored” was done so correctly enough for a normal life. ---
**Author:** ![Enola\_Gay](https://avatars.discourse-cdn.com/v4/letter/e/3ab097/32.png) [@Enola\_Gay](https://boards.straightdope.com/u/Enola_Gay)\ **Post date:** [May 16, 2012, 2:04am UTC](https://boards.straightdope.com/t/can-people-or-other-animals-ever-be-backwards/622016/13 "2012-05-16T02:04:19Z")
I think that all sorts of systems in human anatomy can be transposed. My friend had a baby with [Transposition of the Great Vessels](http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0002535/) (surgically corrected at birth) where the aorta and pulmonary artery were flip-flopped. Most of the human body is symmetrical, but for those systems that aren’t…I should think that anything could go awry during embryonic development. ---
**Author:** ![JWT\_Kottekoe](https://avatars.discourse-cdn.com/v4/letter/j/3ec8ea/32.png) [@JWT\_Kottekoe](https://boards.straightdope.com/u/JWT_Kottekoe)\ **Post date:** [May 16, 2012, 2:13am UTC](https://boards.straightdope.com/t/can-people-or-other-animals-ever-be-backwards/622016/14 "2012-05-16T02:13:15Z")
> [@Smeghead](#): > > As a side note, it’s a somewhat surprising fact that situs inversus is caused by a defect in cilia - you know, those little hair-like wavy projections that cells have. And how do the cilia know which way to turn? Because each one is a helix with a handed (non-mirror symmetric) twist. And how do the cilia know which way to twist? Because they are made of twisted protein fibers. And how do the fibers know which way? Because the proteins are twisted. And how do the proteins know which way to twist? Because the amino acids are handed. So the assymetry of people is directly traceable to the handedness of the tiny little amino acid molecules. It had to be that way, but it is remarkable to me that we now understand it. ---
**Author:** ![KarlGrenze](https://avatars.discourse-cdn.com/v4/letter/k/dbc845/32.png) [@KarlGrenze](https://boards.straightdope.com/u/KarlGrenze)\ **Post date:** [May 16, 2012, 2:35am UTC](https://boards.straightdope.com/t/can-people-or-other-animals-ever-be-backwards/622016/15 "2012-05-16T02:35:15Z")
Ciliary dyskenesia, which is the condition of messed-up cilia, and situs inversus, associated with it, are also present in dogs and some lab animals (rodents). Dogs may present with respiratory problems and/or infertility because of the defective cilia. I don’t think situs inversus itself causes lots of problems, and is generally found in necropsy. ---
**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\ **Post date:** [May 16, 2012, 3:15am UTC](https://boards.straightdope.com/t/can-people-or-other-animals-ever-be-backwards/622016/16 "2012-05-16T03:15:13Z")
I knew someone who was completely flipped, for his complete chest & abdominal contents – heart was on the right side, liver & kidneys reversed, even stomach & intestines flipped from the normal orientation. I guess that’s called _situs inversus totalis_ (so my ignorance fought, at least). He was 17 at the time, about 10 years ago, and is surviving just fine. ---
**Author:** ![Smeghead](https://avatars.discourse-cdn.com/v4/letter/s/f1d935/32.png) [@Smeghead](https://boards.straightdope.com/u/Smeghead)\ **Post date:** [May 16, 2012, 10:49am UTC](https://boards.straightdope.com/t/can-people-or-other-animals-ever-be-backwards/622016/17 "2012-05-16T10:49:09Z")
> [@t-bonham@scc.net](#): > > I knew someone who was completely flipped, for his complete chest & abdominal contents – heart was on the right side, liver & kidneys reversed, even stomach & intestines flipped from the normal orientation. I guess that’s called _situs inversus totalis_ (so my ignorance fought, at least). He was 17 at the time, about 10 years ago, and is surviving just fine. It should be pointed out, however, that in cases of identical twins, where one is reversed, the reversed twin has an over 83% chance of becoming evil. Early signs are premature baldness and/or development of a goatee. ---
**Author:** ![tdn](https://avatars.discourse-cdn.com/v4/letter/t/94ad74/32.png) [@tdn](https://boards.straightdope.com/u/tdn)\ **Post date:** [May 16, 2012, 1:53pm UTC](https://boards.straightdope.com/t/can-people-or-other-animals-ever-be-backwards/622016/18 "2012-05-16T13:53:51Z")
> [@Smeghead](#): > > It should be pointed out, however, that in cases of identical twins, where one is reversed, the reversed twin has an over 83% chance of becoming evil. Early signs are premature baldness and/or development of a goatee. True enough. I did away with my “good” twin decades ago. Mwa ha ha, and shit. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [May 16, 2012, 1:55pm UTC](https://boards.straightdope.com/t/can-people-or-other-animals-ever-be-backwards/622016/19 "2012-05-16T13:55:04Z")
My Dad is situs inversus. When he was a kid, they used to parade the interns through his hospital room to examine him, because it’s quite rare. ---
**Author:** ![panache45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/panache45/32/64_2.png) [@panache45](https://boards.straightdope.com/u/panache45)\ **Post date:** [May 16, 2012, 4:14pm UTC](https://boards.straightdope.com/t/can-people-or-other-animals-ever-be-backwards/622016/20 "2012-05-16T16:14:43Z")
Many years ago, one of my uncles-to-be was shot by another uncle (10 years old, long story), causing a great deal of damage to his innards. It was discovered, in surgery, that he had _situs inversus._ The “family legend” was that the impact caused his heart to jump to the other side. Not bloody likely. [Next page](https://boards.straightdope.com/t/can-people-or-other-animals-ever-be-backwards/622016.md?page=2)