Navels, belly buttons, innies or outies … whatever term you use, your umbilicus may have plenty to tell you about the state of your health.

For some, they are the thing of nightmares – omphalophobia (the fear of belly buttons) is a real condition. For others, they are a fashion accessory to be shown off in a crop top, or decorated with a body piercing.

Whatever your feelings about belly buttons, one thing’s for sure - it once joined you to your mother. The umbilical cord is severed at birth to leave just a small clamped stump that progressively withers and falls away a week or two later.

What you’re left with, in most cases, is a small wrinkled depression. That’s if you have an “innie”, as most of us – 90% apparently – do. From this point, the belly button seems to become redundant – other than to gather dust and fluff.

But that’s not the whole story – your navel has more depth to it than just a few millimetres.

The umbilicus is an access point for the vessels carrying blood to and from the foetus. These have come from the placenta and run through the umbilical cord, coated in Wharton’s jelly – a gelatinous connective tissue contained in the cord that insulates and protects them.

There are normally three vessels within the cord. The one carrying oxygen and nutrients to the foetus........

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