The median artery has been considered an embryonic structure. It has been described as a foetal vessel that supplies the hand and regresses with the development of the radial and ulnar arteries. However, various prevalences have been reported in adults since the 18th century.
A new study by Flinders University has shown a significant increase in the prevalence of the median artery in humans since the late 19th century. The prevalence of the artery over generations shows that modern humans are evolving at a faster rate than at any point in the past 250 years.
When a child initially develops in the mother’s womb, the median artery is the main blood vessel that feeds blood to the forearm and hand. However, as two arteries that are present in adults grow, the median artery disappears.
Most adults naturally lack a median artery since the radial and ulnar arteries typically replace it during foetal development. However, an increasing percentage of adults have a median artery, allowing a person to have all three arteries.
This evolutionary trend will continue in those born 80 years from today, with the median artery becoming common in the human forearm.
Dr. Teghan Lucas from Flinders University says, “Since the 18th century, anatomists have been studying the prevalence of this artery in adults, and our study shows it’s increasing. The prevalence was around 10% in people born in the mid-1880s compared to 30% in those born in the late 20th century, so that’s a significant increase in a fairly short period of time when it comes to evolution.”
“This increase could have resulted from mutations of genes involved in median artery development or health problems in mothers during pregnancy, or both. If this trend continues, most people will have a median forearm artery by 2100.”
Senior author Professor Maciej Henneberg who is also a member of the Institute of Evolutionary Medicine at the University of Zurich, Switzerland, says the median artery offers benefits because it increases overall blood supply and can be used as a replacement in surgical procedures in other parts of the human body.
“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.”
“We’ve collected all the data published in anatomical literature and continued to dissect cadavers donated for studies in Adelaide, and we found about one-third of Australians have the median artery in their forearm, and everyone will have it by the end of the century if this process continues.”
- Teghan Lucas, Jaliya Kunaratilake, Maciej Henneberg. Recently increased prevalence of the human median artery of the forearm: A microevolutionary change. Journal Of Anatomy. DOI: 10.1111/joa.13224