[Physiopathology of leg pain]

The real definition of pain, the mechanism of its genesis and the relation with its nociception are now very developed, even to the point of being extremely finely nuanced. The author explains the structure and physiopathology of the nociceptive system, the nociceptors, the role of the neurons in the posterior horn and the spinothalamic duct, and the function of the cerebral cortex. After analysing the international definition of the pain symptom, the author underlines the significance of the subjective component, suffering. There follows an analysis of the specific characteristics of superficial and deep pain (somatic and visceral), of psychical and central pain. The discriminative, affective, emotive, motor vegetative sensorial components and the psychomotor are explained. Finally the mechanism of the genesis of leg pain is examined, with emphasis on the important difference between nociceptive, neurological and projected pain.