[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Anatomy](https://durgical.com/en/anatomy/) › [Chest](https://durgical.com/en/anatomy/region/chest/) › Tricuspid septal leaflet [Cardiovascular system](https://durgical.com/en/anatomy/system/cardiovascular-system/) · [Chest](https://durgical.com/en/anatomy/region/chest/) # Tricuspid septal leaflet The septal leaflet is the tricuspid valve flap attached along the wall between the ventricles; it closes the inner part of the valve opening. Official name: Septal leaflet of right atrioventricular valve [See in 3D →](https://durgical.app/?from=durgipedia&lang=en#region=thorax&select=tricuspid_septal_leaflet&side=r) Opens in the Durgical app, no sign-up needed. ## What it is The tricuspid leaflet attached to the septum, close to the conduction system. ## What it does Closes the inner part of the valve opening. ## Key points - Its hinge sits slightly closer to the apex than that of the [mitral anterior leaflet](https://durgical.com/en/anatomy/anterior-leaflet-of-left-atrioventricular-valve/); this offset identifies the [right ventricle](https://durgical.com/en/anatomy/right-ventricle/) on echo and is exaggerated in Ebstein anomaly - Stitches near its hinge, as when closing a perimembranous ventricular septal defect, can injure the [bundle of His](https://durgical.com/en/anatomy/atrioventricular-bundle/) and cause complete heart block - Many of its chordae arise straight from the septum; its tissue can partly plug a perimembranous defect, forming a pouch on echo ## Key facts **Where** Along interventricular septum; its annulus borders triangle of Koch, near membranous septum and AV bundle **Attaches** Tricuspid annulus; [chordae tendineae](https://durgical.com/en/anatomy/chordae-tendineae-of-right-atrioventricular-valve/) from septal and posterior papillary muscles and directly from septum **Function** Closes in ventricular systole, preventing backflow into right atrium ## Relations **Medial** [Interventricular septum](https://durgical.com/en/anatomy/interventricular-septum/) and its membranous part, with the left ventricular outflow tract beyond **Above** Aortic root beyond the membranous septum, under the commissure of the [aortic right coronary cusp](https://durgical.com/en/anatomy/right-coronary-leaflet/) and [aortic non-coronary cusp](https://durgical.com/en/anatomy/non-coronary-leaflet-of-aortic-valve/) **In front** [Tricuspid anterior leaflet](https://durgical.com/en/anatomy/superior-leaflet-of-right-atrioventricular-valve/), at the anteroseptal commissure **Behind** [Tricuspid posterior leaflet](https://durgical.com/en/anatomy/inferior-leaflet-of-right-atrioventricular-valve/), at the posteroseptal commissure; the [coronary sinus](https://durgical.com/en/anatomy/coronary-sinus/) opens just above its hinge in the [right atrium](https://durgical.com/en/anatomy/right-atrium/) ## How to find it In the opened right atrium it hangs from the septal wall just in front of the coronary sinus opening. Its hinge forms one side of the triangle of Koch and crosses the membranous septum, splitting it into an atrioventricular part above and an interventricular part below. ## On imaging Apical four-chamber echo shows its hinge a little nearer the apex than the anterior mitral hinge; a much larger displacement points to Ebstein anomaly. Colour Doppler shows jets from perimembranous defects just beneath it. ## Common problems - Tricuspid regurgitation, usually because the right ventricle is enlarged (lung or left-heart disease). - Endocarditis in people who inject drugs. ## How it is diagnosed Echocardiogram. ## Treatment - Treat the cause; surgical repair (ring) during other heart surgery; catheter devices are emerging. ## Clinical notes - Pacing leads usually cross near this leaflet and may impinge on it - In Ebstein anomaly it is usually the most displaced leaflet, often small and stuck to the septum - Tricuspid repair rings are usually open at the septal side, to keep stitches away from the AV node and the bundle of His ## Development It grows down from the fused endocardial cushions in the middle of the atrioventricular canal, beside the septum, which is why many of its chordae come straight off the septal wall. ## Related conditions - [Atrial flutter](https://durgical.com/en/conditions/atrial-flutter/) - [Tricuspid regurgitation and tricuspid valve disease](https://durgical.com/en/conditions/tricuspid-regurgitation-and-tricuspid-valve-disease/) - [Truncus arteriosus, TAPVR and tricuspid atresia](https://durgical.com/en/conditions/truncus-arteriosus-tapvr-and-tricuspid-atresia/) - [Ebstein anomaly](https://durgical.com/en/conditions/ebstein-anomaly/) - [Infective endocarditis](https://durgical.com/en/conditions/infective-endocarditis/) - [Ventricular septal defect](https://durgical.com/en/conditions/ventricular-septal-defect/) ## Test yourself Think of the answer, then tap the question to see it. ## How does the hinge of the tricuspid septal leaflet compare with the mitral anterior leaflet hinge on echo? It sits slightly closer to the apex; this offset identifies the right ventricle, and a much larger displacement points to Ebstein anomaly. ## Why can stitches near the hinge of the tricuspid septal leaflet cause complete heart block? Its annulus borders the triangle of Koch, near the membranous septum, the AV node and the bundle of His. ## Why are tricuspid repair rings usually open at the septal side? To keep stitches away from the AV node and the bundle of His, which lie near the septal leaflet's hinge. [Add to my cards (3)](https://durgical.app/estudiar/?add=/en/anatomy/septal-leaflet-of-right-atrioventricular-valve/) Educational information, not medical advice. For any symptom, see a health professional. ## Its names **Official Latin (TA2)** cuspis septalis valvae atrioventricularis dextrae TA2 3986 **Official Spanish (DeCS)** Cúspide septal de la válvula tricúspide DeCS D014261 **English (TA2)** Septal leaflet of right atrioventricular valve **Also called** septal cusp of right atrioventricular valve · cuspis medialis valvulae tricuspidalis ## Related - [Right atrium](https://durgical.com/en/anatomy/right-atrium/) Sources: Terminologia Anatomica (TA2); [DeCS](https://decs.bvsalud.org/es/ths/resource/?id=14659); [Anatomy, Thorax, Heart](https://www.ncbi.nlm.nih.gov/books/NBK470256/); Anatomy of the Human Body (20th ed.): Development of the Vascular System (Lea & Febiger (Gray's Anatomy, 1918), 1918) · adapted, Public domain. ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/anatomy/septal-leaflet-of-right-atrioventricular-valve/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anatomy/septal-leaflet-of-right-atrioventricular-valve/