Traditionally Jam doughnuts have been used to metaphorically describe our vertebral discs and in particular a disc bulge! Whilst this may seem logical, it could not be further from the truth comparing these two things.
Here are three reasons why our vertebral discs are NOTHING like a jam doughnut:
1: Our vertebral discs are consistently adapting structures that transduce high levels or force on a daily basis. Jam doughnuts however are simply a delicious treat to eat, that can handle very minimal levels of force.
2: Our discs have the ability to absorb high levels of forces in many different directions, where as Jam doughnuts have a very limited range of forces that they can absorb, but not lacking in deliciousness
3: Our discs have the ability to increase hydration levels through loading them with exercise such as running, which highlights how beneficial running can be for our backs. Jam doughnuts cannot rehydrate themselves, they're just a delicious inanimate object...