In caissons disease pain in joint is because of -

Ans. is 'a' i.e., Nitrogen bubble Caisson's diseaseo Caisson's disease, (also called decompression sicknessQ, Bendst Diver's Paralysis, Dysbarism) is a particular form of gas embolism, which occurs when individuals are exposed to sudden lowering of atmospheric pressure like - rapid ascend of scuba and deep sea divers0, individuals in unpressurized aircraft in rapid ascent (e.g., in pilotsQ), underwater construction workers and extra-vehicular activity from spacecraft.o When air is breathed at high pressure (e.g., during a deep sea dive), increased amounts of gas (particularly nitrogen) become dissolved in the blood and tissues. If the diver then ascends (depressurizes) too rapidly, the nitrogen expands in the tissues and bubbles out of solution in the blood to form gas emboli.o Since bubbles can form in or migrate to any part of the body, it can produce many symptoms, and its effects may vary from joint pain, ischemia in tissues to paralysis and death,o The rapid formation of gas bubbles within skeletal muscles and supporting tissues in and about joints is responsible for the painful condition called the bends. In the lungs, edema hemorrhages, and focal atelectasis or emphysema may appear, leading to respiratory distress, the so-called chokes,o Treatment of gas embolism requires placing the individual in a compression chamber where the barometric pressure may be raised, thus forcing the gas bubbles back into solution. Subsequent slow decompression theoretically permits gradual resorption and exhalation of the gases so that obstructive bubbles do not re-form.