[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/) › Pulmonary anterior cusp [Cardiovascular system](https://durgical.com/en/anatomy/system/cardiovascular-system/) · [Chest](https://durgical.com/en/anatomy/region/chest/) # Pulmonary anterior cusp The anterior cusp is one of the three flaps of the pulmonary valve, the heart's highest and most forward valve, which opens toward the lungs. Official name: Anterior semilunar leaflet of pulmonary valve [See in 3D →](https://durgical.app/?from=durgipedia&lang=en#region=thorax&select=pulmonary_anterior_cusp&side=r) Opens in the Durgical app, no sign-up needed. ## What it is The front cusp of the pulmonary valve. ## What it does One of the three cusps that seal the pulmonary valve. ## Key points - The pulmonary valve is the most anterior and highest heart valve; its closure gives P2, the second and softer part of the second heart sound - Normal splitting of S2 widens on inspiration because P2 comes later; a fixed split suggests an atrial septal defect - Pulmonary stenosis: ejection systolic murmur at the left 2nd intercostal space, often with an ejection click that softens on inspiration ## Key facts **Where** Anterior cusp of pulmonary valve, at top of infundibulum; valve behind sternal end of left 3rd [costal cartilage](https://durgical.com/en/anatomy/costal-cartilage/) **Attaches** Crescent-shaped attachment to pulmonary trunk root; nodule and lunules at free edge **Function** Closes in diastole, preventing backflow into right ventricle; valve heard best at left 2nd intercostal space ## Relations **In front** Front of the [chest](https://durgical.com/en/anatomy/region/chest/) at the left upper sternal border, partly covered by the edge of the left lung and [pleura](https://durgical.com/en/anatomy/pleura/) **Below** Smooth infundibulum (conus arteriosus) of the [right ventricle](https://durgical.com/en/anatomy/right-ventricle/) **Above** [Pulmonary trunk](https://durgical.com/en/anatomy/pulmonary-trunk/) **Behind** [Pulmonary left cusp](https://durgical.com/en/anatomy/left-semilunar-leaflet-of-pulmonary-valve/) and [pulmonary right cusp](https://durgical.com/en/anatomy/right-semilunar-leaflet-of-pulmonary-valve/), meeting it at the commissures ## How to find it Pulmonic area: left 2nd intercostal space at the sternal border. P2 is heard best here; a loud P2 suggests pulmonary hypertension. ## On imaging Echocardiography: parasternal short [axis](https://durgical.com/en/anatomy/axis/) at the base shows the valve and trunk, with the anterior cusp nearest the chest wall; Doppler measures the stenotic gradient. Cardiac MRI measures regurgitation after repair. ## Common problems - Pulmonary stenosis, usually from birth; often treated with a balloon. - Leak after childhood repair of congenital heart disease. ## How it is diagnosed Echocardiogram; cardiac MRI. ## Treatment - Balloon valvuloplasty or valve replacement (surgical or by catheter). ## Clinical notes - Pulmonary stenosis is part of tetralogy of Fallot and is common in Noonan syndrome (thick, dysplastic valve) - Ross procedure: the person's own pulmonary valve replaces the diseased aortic valve and a donor valve takes its place - Transcatheter pulmonary valve implantation is used for failing valves or conduits after congenital repair ## Development It forms from the anterior cushion of the outflow tract, which stays whole; the other two pulmonary cusps come from halves of the lateral cushions shared with the aorta. ## Related conditions - [Pulmonary valve stenosis](https://durgical.com/en/conditions/pulmonary-valve-stenosis/) - [Noonan syndrome](https://durgical.com/en/conditions/noonan-syndrome/) - [Tetralogy of Fallot](https://durgical.com/en/conditions/tetralogy-of-fallot/) ## Test yourself Think of the answer, then tap the question to see it. ## Where is the pulmonary valve heard, and which component of the second heart sound does it give? At the left 2nd intercostal space by the sternum; its closure gives P2, the second and softer part of S2. A loud P2 suggests pulmonary hypertension. ## How does normal splitting of S2 change with inspiration, and what does a fixed split suggest? It widens on inspiration because P2 comes later; a fixed split suggests an atrial septal defect. ## What is the Ross procedure? The person's own pulmonary valve replaces the diseased aortic valve, and a donor valve takes the pulmonary position. [Add to my cards (3)](https://durgical.app/estudiar/?add=/en/anatomy/anterior-semilunar-leaflet-of-pulmonary-valve/) Educational information, not medical advice. For any symptom, see a health professional. ## Its names **Official Latin (TA2)** valvula semilunaris anterior valvae trunci pulmonalis TA2 4012 **Official Spanish (DeCS)** Valva semilunar anterior de la válvula pulmonar DeCS D011664 **English (TA2)** Anterior semilunar leaflet of pulmonary valve **Also called** non-adjacent leaflet of pulmonary valve · anterior semilunar cusp of pulmonary valve · velum semilunare sinistrum ## Related - [Pulmonary trunk](https://durgical.com/en/anatomy/pulmonary-trunk/) Sources: Terminologia Anatomica (TA2); [DeCS](https://decs.bvsalud.org/es/ths/resource/?id=12101); [Anatomy, Thorax, Heart Pulmonic Valve](https://www.ncbi.nlm.nih.gov/books/NBK547706/); 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/anterior-semilunar-leaflet-of-pulmonary-valve/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anatomy/anterior-semilunar-leaflet-of-pulmonary-valve/