What is pain?

Pain is described as burning, sticking or pricking, sharp, dull, throbbing or knifing. Different parts of the body feel pain in different ways. The skin reacts easily. Muscles may not feel puncture by a needle, but ache when they are in spasm or suffer cramp.

Compact bone may be cut without pain but porous bone may be painful when injured. The brain tissue may not be sensitive, but the blood vessels have nerve connections and anything that pulls or stretches the blood vessels in the brain will give a pain in the head. Pain from the intestines may be due to injury of the intestinal wall, stretching of the muscles in the wall or pulling on the tissues that hold the intestines in place.