The topic of wrist or carpal instability has been a source of confusion and miscommunication for decades. The terminology can often be difficult to understand and one surgeon's concept of instability may be completely different from another's. This is by no means a comprehensive review of carpal instability, which has often been the focus of numerous multi-volume textbooks. The purpose of this paper is to detail the basics of carpal instability, the anatomy, pathomechanics, terminology and basic principles of treatment.