A biplane cineradiographic technique was used to measure deformation of the myocardium as indicated by small lead spheres implanted into the anterior left ventricular wall of anesthetized dogs. Deformation was resolved into nine separate components for each of the epicardial, middle, and endocardial layers. The data illustrate the mechanical effect of myocardial fiber orientation and the ability of muscle layers to deform differentially. In order to present an overview of all the results, the implications of the deformation components are discussed first separately and then in a coordinated fashion.