The radial and ulnar arteries usually replace the median artery during developmental stages in the womb, so most adults obviously don’t have a median artery, but increasing numbers of cases retain it, so a person can have all three arteries.
The median artery is now present in about 35% of people and researchers predict that people born 80 years from now will all carry a median artery if the trend continues.
“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,” said senior author Professor Maciej Henneberg, a researcher in the Biological Anthropology and Comparative Anatomy Research Unit at the University of Adelaide and the Institute of Evolutionary Medicine at the University of Zurich.
“This is microevolution 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.”
In the study, Professor Henneberg and colleagues aimed to investigate the prevalence of persistent median arteries in postnatal humans over the last 250 years and to test the hypothesis that a secular trend of increase in its prevalence has occurred.
They found a total of 26 median arteries in 78 upper limbs (a prevalence rate of 33.3%) obtained from Australians aged 51 to 101 years.
“Our study into 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,” said lead author Dr. Teghan Lucas, a researcher in the Department of Archaeology at Flinders University and the School of Medical Sciences at the University of New South Wales.
“Since the 18th century, anatomists have been studying the prevalence of this artery in adults and our study shows it’s clearly 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 actually,” he added.
“If this trend continues, a majority of people will have median artery of the forearm by 2100.”
“When the median artery prevalence reaches 50% or more, it should not be considered as a variant, but as a normal human structure,” the authors said.
Lucas.et al. find that the prevalence of the persistent median artery in postnatal life approximately tripled over the last 125 years.