This study reviews Deformable curves (Active contours). The main strength of Deformable curves stems from their capability to provide to humans or higher processes, several interpretations of image data by supporting interactive mechanisms. Deformable curves offer a unique and powerful approach to segmentation. They are capable of accommodating variability of biological structures. The objective of this study is to study the frameworks of different active contour models, classify the methods according to several properties and compare their properties. This study is expected to yield a very good insight into Deformable curves.