Journeys: Nerves. Stop 4

Pins and needles

Sit on a folded leg for a long time, and it goes numb. A nerve is squashed, so signals can't get through. Stretch the leg out!

The nerve is free! Now tickle the foot with a feather to wake it up.

Prickly? Those are pins and needles. The signals are running up the nerve to the brain again.

A squashed nerve lets no signals through, so the leg goes numb. Pins and needles say the signals are back.