Humans Are Evolving: Science discover Extra Artery Growing In Our Arm

According to a study published in the Journal of Anatomy last year by researchers from the University of Adelaide as well as Flinders University in Australia, an artery that temporarily goes to the centre of the forearms while a child is still in the womb isn’t disappearing as often as it did earlier, giving most adults an extra channel of vascular tissue.

The scientists claim that since the 18th century, anatomists have been looking at the presence of this artery in adults and their recent study has highlighted that it has been increasing considerably.

According to Teghan Lucas from Flinders University, the prevalence was around 10 percent in individuals born in the mid-1880s which turned to 30 percent for people born in the 20th century. From an evolutionary standpoint that’s a considerable spike in such a short span of time. 

The artery in question — the median artery — is known to form early in the human development cycle and helps move blood down the centre of our arms to enrich the growing hand. However, at around 8 weeks, this regresses leaving the job to other vessels – the radial and the ulnar arteries. 

According to anatomists, it is not guaranteed that the median artery will phase away. Instead in many cases, it stays there for a month or even more.

To understand how prevalent this blood channel has been, researchers examined 80 limbs from cadavers donated by Australians of European descent. The donors aged from 51 to 101, indicating most were born in the first half of the 20th century.

Looking at the frequency of finding the median artery that was also capable of a good blood supply, the research team compared the figures with previous records and found that the artery was three times more common in adults today than it was over a century ago. These findings hint that natural selection is favouring those who have retained this extra bit of blood supply.

Lucas explained in a conversation with ScienceAlert, “This increase could have resulted from mutations of genes involved in median artery development or health problems in mothers during pregnancy, or both actually.”

While the existence of this additional artery means we could give fingers or forearms more blood flow to make them stronger and more impactful, they also put us at a greater risk of carpal tunnel syndrome, forcing us to use our hands less.

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

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