About the data: We used the family income data from the 2013 American Community Survey. This counts only families, which the government defines as households with two or more people related by birth, marriage or adoption. The graph focuses on families living in the country's 30 most populous cities.
Foot, leg, and ankle swelling. Painless swelling of the feet and ankles is a common problem, especially among older people. Abnormal buildup of fluid in the ankles, feet, and legs can cause swelling. This fluid buildup and swelling is called edema. Painless swelling may affect both legs and may include the calves or even the thighs. The effect of gravity makes the swelling most noticeable in the lower part of the body.
Edema: The Most Common Cause. In the general population, swollen ankles are often caused by edema, which is the most common cause in elderly individuals. Edema simply means that excess water accumulation in the body causes swelling of the soft tissues under the skin. When the swelling is of the extremities, such as the ankles or feet, it is called peripheral edema.