Human evolution is at its fastest in 250 years, Australian researchers say, and the proof is in our forearms.

Well, some people’s forearms, anyway.

There’s an increasing rate of adults walking around with three arteries in their forearms when, historically, there has only been two.

In the mid-1880s, about 10 per cent of adults still had their median artery.

Formed in the womb, the artery’s primary purpose is to pump blood into the forearm and hand to support development.

As we prepare to leave the womb and enter the world, that artery is usually replaced by the radial and ulnar arteries.

By the 20th century, research from Flinders University and the University of Adelaide found 10 per cent had tripled.

“That’s a significant increase in a fairly short period of time, when it comes to evolution,” said Dr Teghan Lucas from Flinders University.

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“This increase could have resulted from mutations of genes involved in median artery development or health problems in mothers during pregnancy, or both actually.

“If this trend continues, a majority of people will have median artery of the forearm by 2100.”

Super blood pumpers

So what’s the benefit to be at the forefront (or forearm) of the next stage of human evolution?

The median artery, when it coexists alongside the radial and ulnar arteries, increases the overall blood supply in the body.

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It’s also got the nifty bonus of being able to be used as a replacement artery for other parts of the body, during surgery.

A rough sketch of the median artery vessel, which supplies blood to the forearm and hand. Photo: Professor Maciej Henneberg

“This is micro evolution in modern humans and the median artery is a perfect example of how we’re still evolving because people born more recently have a higher prevalence of this artery when compared to humans from previous generations,” research senior author Maciej Henneberg said.

Professor Henneberg added that while about one-third of Australians have the median artery, everyone will have it by the end of the century, if it continues at the same rate.

The research was published in the Journal of Anatomy earlier this month.

The team reached its findings through collating published data from anatomical literature, and continued research on donated cadavers.