Feeling peckish? Here's why you couldn't bite your own fingers off, actually!

In 2012, a group of researchers, backed by the Ilmenau University of Technology, studied the force and deflection of human fingers trapped in a car window. This project may appear odd if it weren't for the fact that it aimed to develop safer bionic test devices for electric side-door windows. By closely reproducing real-life finger-jamming situations, it can help reduce the risk of serious injuries, especially among children.

Fingers vs the human bite

The researchers conducted tests on the index and little fingers of the left hands of 109 participants and 20 cadaver specimens to determine the subjective maximum tolerable pain threshold. The result? An average force of 42 Newtons for the index finger and 35 Newtons for the little finger. In cadavers (which they used to test the amount of force required to fracture a finger), the applied forces were 1,886 Newtons for the index finger and 1,833 Newtons for the little finger. Fractures in cadaver studies occurred at an average force of 1,485 Newtons.

This is about twice the maximum biting force that human beings can exert with their molars. For comparison, it's also just above the biting power of a jaguar, whose jaws and canine teeth are strong enough to crush the skull of its prey.

The brain's response

Now, let's get back to our carrots. It takes roughly 200 Newtons of force to bite through a raw carrot. The maximum biting force recorded in a human being is around 600 Newtons, far less power than is required to break through bone.

"Plus, a finger obviously has ligaments, tendons, all sorts of other structures which make it difficult to bite through. It's almost impossible to bite through a bone unless you go through the joint in between the bones," plastic surgeon Michael Gartner, known to debunk strange medical stories, said, reacting to a simulation by Zack D. Films.

Besides, even if you could bite off one of your fingers, your brain would stop you before the bone ever even cracks. The prefrontal cortex, anterior cingulate cortex and amygdala, which help to process and regulate emotions within the brain, manage harmful impulses and support rational judgment, act as a protective, inhibitory mechanism to prevent self-injury.

"There is an extreme neurological condition called Lesch-Nyhan syndrome, which basically causes a person to do self-mutilation to the cells, but these are extraordinarily rare neurological diseases," Gartner commented.

So, no harm done, or to be done!