When she stubbed her toe on the rock, Katherine exclaimed that she was experiencing severe algesthesis.
Pain exists beyond a simple touch
Pain warns our brains of danger and tells us to act to correct the situation, or to avoid whatever caused the pain.
Is there anyone who does not have vivid memories of burning one's hand on a hot stove and quickly withdrawing it? Pain is a powerful reminder and so we learn to be very careful and to avoid whatever caused it.
Pain does not always warn us of danger. It comes too late for us to avoid a bad sunburn, and a tumor in the brain can grow unnoticed because the tissue within our skulls has no pain receptors.
There are more pain receptors in the skin than other types of skin sensors, but they are not evenly distributed; for example, the neck and eyelids are densely covered, but there are few receptors on the soles of the feet and on the balls of the thumb, which is why a needle prick for a blood sample is often done on one of the thumbs.