High-Altitude Joint Pains (Bends): Their Roentgenographic Aspects1

In deep-sea diving the respiratory gases are forced into solution in the body fluids and tissues as a result of increased pressure. When return to the surface is fairly rapid, these gases are present in a supersaturated state, and bubbles frequently form. Extremely small at first, these go through a period of expansion, followed by gradual absorption. Nitrogen gas, being physiologically inert, is most important in causing these bubbles; its inertness results in their slow absorption. Ascent to altitudes of 25,000 feet or higher in aircraft results in a similar supersaturation of dissolved gases, with a tendency to bubble formation. The intense pain of “caisson disease,” commonly spoken of as diver's “bends,” has its counterpart in aviator's “bends,” resulting from exposure to extremely high altitude. The symptoms can readily be elicited by simulated flight in an altitude chamber. Ordinarily the pain disappears at about 25,000 feet during the return to ground-level pressure. It is thought that the “bends” ...