Tiny Knee Bone, Once Lost in Humans, Is Making a Comeback

The fabella disappeared from our lineage millions of years ago, but over the last century, its presence in people’s knees has become more common.

Written byJef Akst

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The fabella (small dot on the right of each scan) is a little bone embedded in a tendon of the knee in some people.
MICHAEL BERTHAUME, IMPERIAL COLLEGE LONDON

Textbooks will tell you that the human body contains 206 bones. But sometimes, there are 208. The fabella, a small bone in a tendon behind the knee, was lost over the course of early human evolution, but these days it’s becoming more common, according to a study published this week (April 17) in the Journal of Anatomy.

The bone has been linked to knee problems, and the authors argue that the fabella should be taken into account when treating people with knee pain.

Michael Berthaume of Imperial College London and his colleagues gathered data from more than 21,000 studies of the knee spanning the past 150 years, and found that between 1918 and 2018, the fabella has become more than three times ...

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Meet the Author

Jef Akst
Jef (an unusual nickname for Jennifer) got her master’s degree from Indiana University in April 2009 studying the mating behavior of seahorses. After four years of diving off the Gulf Coast of Tampa and performing behavioral experiments at the Tennessee Aquarium in Chattanooga, she left research to pursue a career in science writing. As The Scientist's managing editor, Jef edited features and oversaw the production of the TS Digest and quarterly print magazine. In 2022, her feature on uterus transplantation earned first place in the trade category of the Awards for Excellence in Health Care Journalism. She is a member of the National Association of Science Writers.
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