When one cracks a knuckle, the stretching of the capsule lowers the pressure inside the joint and creates a vacuum which is filled by the gas previously dissolved in the synovial fluid. This creates a âbubbleâ which then bursts producing the characteristic âpoppingâ or âcrackingâ sound.
DOCTORS: Click here for the Professional Version. Burns are injuries to tissue that result from heat, electricity, radiation, or chemicals. Burns cause varying degrees of pain, blisters, swelling, and skin loss. Deep, extensive burns can cause serious complications, such as shock and severe infections. Small, shallow burns may need only to be kept clean and to have an antibiotic cream applied.
Causes of localized swelling include: 1  Injury to a specific body area. 2  Infection, which can occur in a joint or under the skin. 3  Burns, which can cause swelling at the site of the burn or in a larger area around the burn.  Inflammation that occurs when tissue is irritated by overuse or repeated 1  motion. Insect bites or stings.