<prompt> Tendon of Todaro connects:Coronary sinus to tricuspid valve annulusRidge of muscle connecting IVC and SVCValve in opening of IVCRaised interatrial ridge  <response>: Ans: a Coronary sinus to tricuspid valve annulusRef: Grays Anatomy, The Anatomical Basis of Clinical Practice, Susan Standring, 41st edition, 2016, Page 1000 1001The valve of coronary sinus Thebesian valve is connected to the central fibrous body where the tricuspid valve annulus is attached by tendon of Todaro.Tendon of Todaro is a palpable, round, collagenous bundle present beneath the endocardium subendocardial.Triangle of Koch: Boundaries:Inferiorly - septal cusp of the tricuspid valve,Basally - anteromedial margin of ostium of the coronary sinus,Superiorly - tendon of Todaro.Triangle of Koch is the landmark of atrioventricular node and its atrial connections. 