BAROTRAUMA

any of several disorders arising from changes in pressure upon the body. Man is adapted to live at an atmospheric pressure of 760 millimetres (the pressure at sea level). When he ventures under water or into the upper atmospheres of space, the surrounding pressure varies from that of his usual environment. Most body tissue is either solid or liquid and remains virtually unaffected by pressure changes; in certain cavities of the body, however, such as the ears, sinuses, lungs, and intestines, there are air pockets that either expand or contract in response to changes in pressure. Several complications arising from changes in pressure are commonly known as squeezes: ear squeeze; thoracic squeeze; intestinal squeeze (qq.v.). See also decompression sickness; nitrogen narcosis.