The clotting cascade: the three pathways that make up the classical blood coagulation pathway are the intrinsic, extrinsic, and common pathways (Adapted from GrahmColm under Creative Commons Attribution-Share Alike 3.0 Unported license as published on https://​en.​wikipedia.​org/​wiki/​File:​Classical_​blood_​coagulation_​pathway.​png. Downloaded 28 Dec 2013)