Strong, thread-like tendons, called chordae tendinae, arise from papillary muscles and insert upon the flaps of tricuspid and bicuspid valves. The valves in the heart allow the flow of blood only in one direction, $i e$, from the atria to the ventricles and from the ventricles to the pulmonary artery or aorta. If chordae tendinae of the tricuspid valve became partially non-functional due to injury then the flow of blood into the pulmonary artery will be reduced.