Disturbing Disorders: Sirenomelia (Mermaid Syndrome)

The sea king down there had been a widower for years, and his old mother kept house for him…she was an altogether praiseworthy person, particularly so because she was extremely fond of her granddaughters, the little sea princesses. They were six lovely girls, but the youngest was the most beautiful of them all. Her skin was as soft and tender as a rose petal, and her eyes were as blue as the deep sea, but like all the others she had no feet. Her body ended in a fish tail.

Hans Christen Anderson, The Little Mermaid, 1837.

Mermaids have teased our imagination for thousands of years. One of the earliest tales originated in ancient Assyria, where the goddess Atargatis transformed herself into a mermaid out of shame for accidentally killing her human lover. Homer called them sirens in the Odyssey, and described them as beautiful singing creatures who lure sailors to their deaths. Throughout history, these seductive beings have been associated with floods, storms, shipwrecks and drownings. They have been depicted in countless mediums: in Etrurian sculptures, in Greek jewelry, and in bas-relief on ancient Roman tombs. Christopher Columbus even reported seeing these mythical creatures on his voyage to the Caribbean in 1493.

But could our concept of what a mermaid looks like actually have originated from a real medical disorder?

M2Sirenomelia is a lethal condition characterised by rotation and fusion of the legs, resulting in what often looks like a fish tail (left). It occurs when the umbilical cord fails to form two arteries, thus preventing a sufficient blood supply from reaching the fetus. As a result, the single artery steals the blood and nutrition from the lower body and diverts it back up to the placenta. Due to malnutrition, the fetus fails to develop two separate limbs.

Sirenomelia, also known as ‘Mermaid Syndrome’, is extremely rare. It affects 1 in 100,000 babies and is 100 times more likely to occur in identical twins. Usually, those born with this condition die within days.

Over the course of my research, I’ve found very little about  the disorder’s history. There are snippets here and there which claim that fetuses born with sirenomelia were sometimes preserved in jars and put on display in ‘freak shows’ during the 19th century—but these sources are frustratingly vague. There is brief mention of the condition in a four-volume atlas published in 1891 titled Human Monstrosities, but nothing that hints at how medical practitioners understood sirenomelia in earlier periods.

Perhaps because the disorder is so rare, it’s also been hard for me to locate specimens in anatomical collections. My search in the Hunterian Museum at the Royal College of Surgeons in London came up cold. I did, however, find an early 20th-century example at the National Museum of Health & Medicine in Washington D.C. There are also three fetuses in the Anatomical Museum of the Second University of Naples, which have undergone 3D bone reconstructions (two pictured below).



By far the largest number of fetuses comes from the Vrolik Museum in Amsterdam, which consists of more than 5,000 specimens of human and animal anatomy, embryology, pathology and congenital anomalies. The collection was founded by Gerardus Crolik (1755 – 185) and his son, Willem Vrolik (1801 – 1863), who both wrote extensively on anatomical deformities in the 18th and 19th centuries. The Vrolik Museum has both wet preparations and skeletal remains, all of which are on display to the public today.

Unlike the first disorder I examined in this series—Harlequin Ichthyosis—sirenomelia is extremely fatal. There are no accounts of anyone with this condition surviving in the past. Most died within days of being born due to kidney and bladder failure. Even today, the odds are against those with sirenomelia, though there are a handful of examples of children living past infancy.

In 1988, Tiffany Yorks underwent surgery to separate her legs before her first birthday. She continues to suffer from mobility issues due to her fragile leg bones, and compensates by using crutches of a wheelchair to move around. At the age of 26, she is the longest-surviving sirenomelia patient to date.

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By | 2014-09-09T14:29:33+00:00 September 9th, 2014|Casebooks|29 Comments


  1. H Stiles (@HStiles1) September 9, 2014 at 2:43 pm - Reply

    Some of you may recall the infamaous Grady Stiles (no relation!) aka ‘lobster boy’ – who had ectrodactyly which is similar in some ways –

  2. carolynloyel September 9, 2014 at 4:01 pm - Reply

    There was also this girl who passed away a few years ago but I think she lived until she was about 10. I remember seeing her on Oprah. http://www.oprah.com/health/The-Only-Living-Mermaid-Girl

  3. Dr. Mom September 9, 2014 at 4:56 pm - Reply

    Fascinating stuff! Thank you!

  4. slivarth September 9, 2014 at 5:50 pm - Reply

    There is also the case of Milagros Cerron from Peru, born with the disorder and somehow making progress.

    It is not directly related to medicine, but this cheerful creature: http://eol.org/pages/328641/overview is widely regarded as a potential candidate for mermaid myth creation.

    However, as in case of any myth, it perhaps needed some other source of ‘fuel’ to kindle, like those fetal deformations. One can only dread to think how they were interpreted in times of limited education and general superstition.

    Great article!

  5. @snibla64 September 9, 2014 at 6:31 pm - Reply

    Fascinating stuff. You never cease to amaze and delight. Keep it up! 🙂

  6. AF September 9, 2014 at 6:31 pm - Reply

    Small chance, but maybe an inspiration for medieval stories of the race of people with a large single foot, which they could use to shade themselves from the sun? They’re mentioned in John Mandeville, among others.

  7. Jennifer September 10, 2014 at 8:01 am - Reply

    The Berlin Museum of Medical History at the Charité also has at least one specimen. They have an impressive collection open to the public, but ask that no photos are taken.

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  9. […] Disturbing Disorders: Sirenomelia (Mermaid Syndrome). […]

  10. […] FitzHarris continues her “Disturbing Disorders” series with a piece on sirenomelia. (A quick search in our collection brings up eight titles that reference this disorder, including […]

  11. Bjerglund September 14, 2014 at 10:11 am - Reply

    There is also a fetus with Sirenomelia at the Medical Museion (http://www.museion.ku.dk/) in Copenhagen. Unfortunately I can’t find a picture of it at their website, but I’m sure they can provide you with one incl. more details on it if you contact them 🙂

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  14. […] is quite specific and in-depth. Some of these casebooks stand out, such as the case of “Mermaid Syndrome” or Sirenomelia, a brief history of Harlequin Ichthyosis, the history of dentures entitled […]

  15. […] rare malformation happens when the umbilical cord fails to form two arteries, leaving only enough blood supply for […]

  16. bunnieslair October 29, 2014 at 3:13 pm - Reply

    The Mutter Museum has a Sirenomelia specimen, as can be seen in this video: https://www.youtube.com/watch?v=li23RYOSgWQ

    • jenn September 14, 2015 at 7:04 am - Reply

      This “specimen” as you say is a person from a family with people that grieve the loss, not a thing…even if the person was maintained to learn from, it doesn’t take away the fact that what you are referring to is A PERSON WITH SIRENOMELIA – not just a specimen! My tumor is A specimen… But referring to someone a family lost that way is hurtful and mean, how hard is it to recognize that born or not, lived minutes, days, weeks, months, or years – what you are looking at/speaking of is a person!

  17. bunnieslair October 29, 2014 at 3:17 pm - Reply

    The Mutter Museum has a Sirenomelia specimen, as can been seen in this video:

  18. […] One of my favorite blogs, wrote a fantastic piece that connected the presence of this syndrome to the myth of the mermaid in cultural and social history (http://thechirurgeonsapprentice.com/2014/09/09/disturbing-disorders-sirenomelia-mermaid-syndrome/) […]

  19. Alyssa February 25, 2015 at 9:33 pm - Reply

    This thing is so sad

  20. Alyssa February 25, 2015 at 9:35 pm - Reply


  21. Rita April 11, 2015 at 3:21 am - Reply

    Having given birth to a child with sirenomelia I find some of the comments a bit disturbing. He was a beautiful boy from the waist up. He only lived about 10 minutes. Didn’t get to take him home; didn’t get to make memories with him, etc. In 1981 I couldn’t get on the internet to read more about it and blamed myself for years thinking something I did caused it to happen. And the person closest to me at the time even planted in my mind that ‘maybe’ our child was in a big glass container in some medical training facility (why would one’s husband even suggest such a thing?) I can understand curiosity, truly. But for every baby born with this condition there are parents who are grieving their loss…some of us even still. A little sensitivity goes a very long way.

    • herschelian April 12, 2015 at 11:14 am - Reply

      Oh Rita, my heart bleeds for you, and your little son who was born with this fatal condition; Articles like this – and some of the comments – must seem very heartless, but I am sure they are not meant to be so.
      Sirenomelia is obviously extremely rare, and I and others would never have heard of it were it not for this blog post. I am glad that now I DO know about it – all the possible physiological problems that come with being a member of the human race make us what we are, an extraordinary life form that should leave us awed and amazed at the wonder and terror of being born at all.
      It should not rob us of compassion. As you rightly say, a little sensitivity goes a long way.

    • Butterfly1980 March 21, 2016 at 7:39 pm - Reply

      I gave birth to a son in 1998 with sirenomelia. I was only 17 at the time. I chose to be induced and give birth to him at 19 weeks in order to have testing done on him. He had so many defects that he died 2 days before my induction. I got to see him after and hold him though. It’s such a rare, high mortality ocurrence and the fact that even a couple of these children grew up is amazing to me. I will always carry him in my heart and wonder what he would have been like. I know it’s nothing I did or didn’t do that caused this, it just happened. I’m sorry you lost your little boy.

  22. Muhinzi Ronnie May 6, 2015 at 12:57 pm - Reply

    How does the sirenomelia patients mate?

    • jenn September 14, 2015 at 6:38 am - Reply

      That would depend on the genitals there and reproductive organs – I belive (its been a while) that when I watched the learning channel that had Shiloh’s story, she didn’t have repruductive organs, so had she lived passed puberty, she wouldn’t of had biological children, but if a female has overies they could try a surrogate and IVF, if a male had sperm he could also use reproductive assistance, but let’s be real, if most die at/near birth – they don’t have kids and even should someone with this challenge lives through puberty, and has the items needed…they would do it exactly the same as any other person with reproductive challenges. If you’re asking how “more are created,” then since it isn’t a genetic condition – its a blood flow issue not providing enough blood to the area…then when the same happens again, another child has the condition and associated challenges.

  23. veronica May 7, 2015 at 10:17 pm - Reply

    It is a rare disorder and about 1/2% of 100% of people have it

  24. […] in which the legs are fused together, giving them the appearance of a mermaid’s tail. It occurs when the umbilical cord fails to form two arteries, thus preventing a sufficient blood supply from […]

  25. […] of the skeleton has not been confirmed, but if it is Sirenomelia it doesn’t fit into any of the subtypes (Fitzharris […]

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