The ear is the organ that detects sound. It not only receives sound, but also aids in balance and body position. The ear is part of the auditory system. Often the entire organ is considered the ear, though it may also be considered just the visible portion. In most mammals, the visible ear is a flap of tissue that is also called the pinna (or auricle in humans) and is the first of many steps in hearing. Vertebrates have a pair of ears placed somewhat symmetrically on opposite sides of the head. This arrangement aids in the ability to localize sound sources. Structure The shape of t...

An earworm, sometimes known as a brainworm, Phrases used to describe an earworm include musical imagery repetition, involuntary musical imagery, and stuck song syndrome. The word ' is a calque from the German ' and was, according to Oliver Sacks, first used in the 1980s. Researchers who have studied and written about the phenomenon include Theodor Reik, Sean Bennett, Oliver Sacks, James Kellaris, Philip Beaman, Vicky Williamson, and, in a more theoretical perspective, Peter Szendy. The phenomenon is common and should not be confused with palinacousis, a rare medical condition caused by da...