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The Missing Link

The Missing Link #13-Thirteen

by Lin Abigail Tan

~A weekly column exploring the delightful, most arbitrary intricacies of our world through the lens of medicine~

My favorite word was “triskaidekaphobia” for the longest time, simply because it seemed so idiosyncratic, granting bookish delight with its awkward, jutting syllables and “haha I know how to spell it” prestige. As you can probably tell from its Greek (“treiskaideka”) and English (“-phobia”) roots, it means “extreme fear of the number thirteen.” 

Lucky number thirteen. Why is it so superstitious, anyway? There are a number of reasons, actually, ranging from biblical references to ancient calendars to Norse mythology. In ancient Sumer (located in Mesopotamia, it was the world’s first complex civilization), the number twelve was seen as the “perfect” number; the Sumerians devised a numerical system that is still used to calculate time today. The number immediately preceding it, by popular conjecture, was seen as strange and unnatural. In the Bible, Judas Iscariot, the man who would eventually betray Jesus, was the thirteenth guest at the Last Supper. Similarly, in ancient Norse lore, it was said that the God of Mischief, Loki, introduced evil to the world when he arrived as the thirteenth guest at a dinner party in Valhalla. Even though the superstition has long-ago origins, there is a modern-day impact: Friday the thirteenth sees financial losses running into the millions ($) as people avoid traveling, shopping, or even working. 

However, thirteen is not always seen as unlucky. In China, the word for “thirteen” sounds like the word for “birth”, thus giving connotations of life and growth. And in the field of science and mathematics, thirteen is just like any other number (prime, of course, but so what?) 

Listed here are some topics in science and healthcare that relate to this quirky, popular, oft-misunderstood number. 

  • Aluminum: Element 13 on the periodic table is heavily utilized in the pharmaceutical industry. Aluminum hydroxide acts as an antacid and is used to treat a plethora of digestive maladies, such as heartburn and acid indigestion. It can also help reduce phosphate levels in patients with certain kidney conditions by binding to it in the gut, thus reducing levels in the rest of the body. 
  • Chromosomes: Trisomy 13, also known Patau syndrome, is a chromosomal condition in which the body contains an extra copy of Chromosome 13 in some or all of its cells. It’s characterized by severe intellectual disability and physical abnormalities, including brain/spinal cord defects, microphthalmia (small or poorly developed eyes), and cleft palate. Sadly, most infants born with this condition do not live past their first year. 
  • Nuclear medicine: Ammonia N-13 is a chemical compound used in conjunction with PET scans to visualize the myocardium (muscular tissue of the heart) in patients with suspected or existing coronary artery disease. It is administered intravenously.


“If a black cat crosses your path, it signifies that the animal is going somewhere.” 

~Groucho Marx 

Works Cited 

Aluminum Hydroxide Uses, Side Effects & Warnings.”

Ammonia N-13.” DrugBank.

Maranzani, Barbara. “What’s So Unlucky About the Number 13? .”, 22 Aug. 2018.“

Trisomy 13 – Genetics Home Reference – NIH.” U.S. National Library of Medicine, National Institutes of Health.

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