Igneous rock (derived from the Latin word ignis meaning fire) is one of the three main rock types, the others being sedimentary and metamorphic rock. Igneous rock is formed through the cooling and solidification of magma or lava. Igneous rock may form with or without crystallization, either below the surface as intrusive (plutonic) rocks or on the surface as extrusive (volcanic) rocks. This magma can be derived from partial melts of pre-existing rocks in either a planet's mantle or crust. Typically, the me..
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.
