Myxedema (British English: Myxoedema) is a term used synonymously with severe hypothyroidism. It is also to describe a dermatological change that can occur in hypothyroidism, and some forms of hyperthyroidism. This article discusses the dermatological changes.
A circle is a simple closed shape in Euclidean geometry. It is the set of all points in a plane that are at a given distance from a given point, the centre; equivalently it is the curve traced out by a point that moves so that its distance from a given point is constant. The distance between any of the points and the centre is called the radius.