Assuming that scene objects' displacements are quasi-homogeneous on a segment based analysis, a first approach to study the two dimensional motion of the main coronary arteries is proposed. A knowledge-based system extracts and interprets the dynamic information. Motion interpretations are obtained in two temporal image sequences acquired in standard conditions. A preliminary example of the system interpretation using declarative knowledge and data representation is shown. The application of the homogeneous segment concept has permitted to obtain a suitable arteries' motion analysis.