- Scientists found young adults are more likely to have a spike-like growth on the lower end of their skull that used to be extremely rare.
- They believe the growth of a "external occipital protuberance" has become more frequent because we spend so much time on our phones.
- When we hunch over a screen, we put pressure on the spot where the neck muscles meet the skull.
- The body can then develop extra layers of bone to cope with the extra weight.
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Young adults are more likely to have a spike-like growth on their skull, and a scientific study has linked the phenomenon to the rise in use of smartphones and tablets from a young age.
The growth, known as an external occipital protuberance, appears at the lower end of the skull, and is increasingly common in young adults
The feature used to be so rare that in 1885 a French scientist called Paul Broca complained that it had been given a name, according to the BBC.
But a study published in the Journal of Anatomy found that the growth was becoming more frequent — especially among 18 to 30-year-olds. About a quarter of 18-30-year-olds in the study had an external occipital protuberance.
David Shahar, the Australian health scientists who conducted the research, believes the development was triggered by the modern obsession with smartphones.
As people hunch over their screens, they put pressure on where the neck muscles meet the skull, he told the BBC. The body then develops more bone layers in that area to be able to hold the extra weight.
Read more: Leaning forward during phone use may cause 'text neck'
The protuberance in the skull could be especially pronounced nowadays because of the vast amount of time people spend on their phones, according to the BBC.
People also had posture issues before the explosion of smart devices, for example when they were reading.
But the average American only read for two hours a day in 1973. Last year, people spent a daily three and a half hours on their phones in the US.
Another surprise Shahar encountered in his study was just how big these growths on the skulls were.
The most substantial growth he found was 30mm long, he told the BBC. To compare, an Indian laboratory that specializes in bones wrote an entire report on an 8mm long external occipital protuberance it found in 2012.
Shahar believes that the spikes will keep getting bigger as people keep hunching over their handheld devices. But the growth on its own should not be dangerous, he said.
"Imagine if you have stalactites and stalagmites, if no one is bothering them, they will just keep growing," Shahar told the BBC.