An eerie animation based on scans of a developing embryo has captured the formation of the face in the womb.
The video, produced for the BBC series " Inside the Human Body," reveals how sections of the face grow and fit together like a puzzle just three months after conception.
"The three main sections of the puzzle meet in the middle of your top lip, creating the groove that is your philtrum," says BBC's Michael Mosley, whose philtrum is "quite a prominent one."
The 30-second clip strings together 3-D models of the developing face based on scans taken in the first trimester.
"It was a nightmare for structures like the nose and palate, which didn't exist for most of the animation," graphics researcher David Barker told New Scientist."Their formation is a complicated ballet of growth and fusion of moving plates of tissue."
Plates of tissue that fuse at the philtrum, which can be long or short and deep or shallow, depending on a person's genetic makeup. The failure of those plates to fuse can cause a cleft lip or palate. And a smooth philtrum can signal disorders like fetal alcohol syndrome.
"This whole amazing process - the bits coming together to produce a recognizable human face - happens in the womb between two and three months," says Mosley. "If it doesn't happen then, it never will."