- Scientists have found that young adults are more likely to have peak growth on the lower part of their skull, which is extremely rare.
- They believe that "outer occipital protuberance" has become more common because we spend a lot of time on our phones.
- When we look at a screen, we put pressure on where the neck muscles meet the skull.
- The body can then develop additional layers of bone to cope with the extra weight.
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Young adults are more likely to have growth similar to a peak on their skull, and a scientific study has linked the phenomenon to the rise in use of smartphones and tablets at an early age.
Growth, called external occipital protuberance, occurs at the lower end of the skull and is becoming more common in young adults.
The film was so rare that in 1885, a French scientist named Paul Broca complained of having received a name, according to the BBC.
But a study published in the Journal of Anatomy found that growth was becoming more common, especially among 18-30 year olds. About one-quarter of the 18-30 year olds participating in the study had an occipital outer protuberance.
David Shahar, the Australian health scientists who conducted the research, thinks that the development was triggered by the modern obsession with smartphones.
As people lean over their screens, they put pressure on the muscles of the neck and the skull, he told the BBC. The body then develops more layers of bone in this area to support the extra weight.
Read more: Leaning forward while using the phone can cause a "text neck"
According to the BBC, the protuberance in the skull could be particularly pronounced nowadays because of the considerable time people spend on their phones.
People also had posture problems before the explosion of smart devices, for example when they were reading.
However, the average American read only two hours a day in 1973. Last year, people spent three and a half hours a day on the telephone in the United States.
Another surprise that Shahar encountered in his study was the size of these growths on the skull.
The biggest growth he found was 30 mm long, he told the BBC. For comparison, an Indian bone laboratory wrote a full report on an 8 mm long outer occipital protuberance found in 2012.
Shahar thinks the tips will get bigger as people bend over their handheld devices. But growth in itself should not be dangerous, he said.
"Imagine if you have stalactites and stalagmites, if nobody bother them, they will just keep growing," Shahar told the BBC.