Chorea is an abnormal involuntary movement disorder, one of a group of neurological disorders called dyskinesias. The term chorea is derived from the Ancient Greek: ÏÎ¿ÏÎµÎ¯Î±, as the quick movements of the feet or hands are comparable to dancing. The term hemichorea refers to chorea of one side of the body, such as chorea of one arm but not both.
Metamorphic rocks are most likely found at a site that is  deep under ground. Metamorphic rocks are formed by other materials  under great amounts of pressure. This pressureâ¦ is caused by plate  collisions in the lithosphere.
Metamorphism must occur below the surface since it occurs as the result of a rock âadjustingâ to heat and pressure. For this reason there is no âintrusive/extrusiveâ distinction required. Some examples of metamorphic rocks are meta-quartzite, gneiss, and schist.