The term 'edema' refers to the swelling caused by abnormal accumulation of fluid beneath the skin, or in the body cavities. When the retention of fluid occurs in lower limbs or extremities, it is referred to as peripheral edema. Fluid retention in the ankles and feet could be attributed to congestive heart failure, rolled ankle/sprain, pregnancy, hypertension, injury to the ligament/tendons in the ankles, sitting in a position for an extended period, the use of certain drugs, venous insufficiency, blood clots in the veins of the legs that prevent the return flow of blood from the legs to the heart, etc. In severe cases, edema could also be accompanied by skin changes, ulcers, etc.