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.
Ankle edema is a swelling over either one or both ankles. Swelling of the ankles is quite common, especially if you have been travelling for a long duration. It occurs due to accumulation of excessive fluid in the tissues of the ankle and feet, a condition referred to as ankle edema. As the amount of fluid accumulates, the swelling may rise up into the leg. Due to mans erect posture, the blood in the veins of the leg has to move against gravity towards the heart. This unidirectional flow of blood is ensured by the presence of valves in the veins and the contractions of the leg muscles.