Leg pain from degenerative disc disease can also result if the nerve root is compressed. This happens because as the disc degenerates it shrinks and moves, and as a result, there is not as much room for the nerve roots. This is also known as foraminal stenosis. Leg pain from a compressed and inflamed nerve root is typically shooting and electric.
Altruistic behaviour is therefore the opposite of egoistic behaviour. It involves intention to help others when used of human behaviour, but the fact that some animal behaviour is judged to be altruistic indicates that there are two possible bases to a definition: intentionality, and behavioural effects.
an apparently unselfish concern for others or behavior that provides benefit to others at some cost to the individual. In contrast to selfishness, altruism represents a need to help or assist others, without regard to rewards or returned favors. In animal behavior it is difficult to understand how altruism could evolve since natural selection operates on individuals.