The Disc Donuts
The squishy spacers of your spine
Between every two bones of your spine sits a squishy donut â an intervertebral disc. You have 23 of them, and they're the reason you're a little bit shorter at night than in the morning!
A spinal disc, cut in half
Real anatomy picture coming soon
Real anatomy photo spot: a disc with its tough outer ring and jelly centre, between two vertebrae
Jelly in a donut
Each disc has a tough outer ring â the annulus fibrosus â like a tractor tyre, and a jelly centre â the nucleus pulposus. The jelly lets the disc squash and spring back, absorbing every step, jump, and bounce your spine takes all day long.
The shrinking spine
Through the day, gravity squeezes water out of your discs â little by little, you get shorter! At night, lying down, the discs drink the water back and you wake up taller again. Together your discs make up about a quarter of your spine's height. Measure yourself in the morning and before bed â you might see the difference!
Mr. Bones says: I'm a fictional skeleton, not a doctor! This is for learning and fun. If anything hurts, stop and tell a grown-up you trust.
