Mitral anterior leaflet !
The anterior leaflet is the larger flap of the mitral valve, between the left atrium and ventricle; it covers about two-thirds of the opening.
Official name: Anterior leaflet of left atrioventricular valve
Opens in the Durgical app, no sign-up needed.
What it is
The larger, front leaflet of the mitral valve, attached next to the aortic valve.
What it does
Covers about two-thirds of the valve opening; it closes against the posterior leaflet.
Key facts
- Where
- Anteromedial (aortic) leaflet; in fibrous continuity with aortic valve; valve behind left sternum at 4th costal cartilage
- Attaches
- Mitral annulus; chordae tendineae from both anterolateral and posteromedial papillary muscles
- Function
- Closes against posterior leaflet in systole; separates LV inflow from outflow tract; mitral area heard at apex
Relations
- In front
- Left ventricular outflow tract, leading up to the aortic valve
- Behind
- Mitral posterior leaflet, meeting it along the closure line between the anterolateral and posteromedial commissures
- Above
- Left atrium, into which a prolapsing or flail segment bulges in systole
- Below
- Chordae tendineae, including the thick strut chords on its ventricular surface, to both Left ventricle papillary muscles
How to find it
Mitral area: the apex (left 5th intercostal space, midclavicular line), with the person turned onto the left side. Diastolic rumbles are heard with the bell; regurgitant murmurs are holosystolic and spread to the left axilla.
On imaging
Transthoracic echo: the parasternal long axis shows its length and movement; the short axis at the leaflet tips allows tracing of a stenotic orifice. Transesophageal echo names its segments A1 to A3 (lateral to medial) to plan repair.
Common problems
- Mitral regurgitation (leak): from a prolapsing leaflet, a torn chord or a stretched ventricle; causes breathlessness and atrial fibrillation.
- Mitral stenosis (narrowing), mostly after rheumatic fever: still common in parts of Latin America.
- Mitral valve prolapse: a floppy leaflet that bulges back; usually mild.
How it is diagnosed
A heart murmur on exam; echocardiogram (transesophageal for detail).
Treatment
- Medicines for symptoms; regular echo follow-up for mild disease.
- Surgical repair (preferred when possible) or replacement; catheter-based clip repair for some high-risk patients.
Clinical notes
- Balloon commissurotomy suits rheumatic stenosis with pliable, little-calcified leaflets and no more than mild regurgitation; otherwise surgery is considered
- Anterior leaflet prolapse or flail directs the regurgitant jet backward and is harder to repair than posterior prolapse
- Transcatheter edge-to-edge repair clips the middle segments of the two leaflets (A2 to P2) together
Anatomical variants
- An accessory scallop of the anterior leaflet is uncommon (about 2.5% in the cited review)
Development
Both mitral leaflets form from the endocardial cushions of the atrioventricular canal; when the cushions fail to fuse (atrioventricular septal defect), this leaflet is cleft.
Related conditions
- Hunter syndrome (mucopolysaccharidosis type II)
- Mitral stenosis
- Hypertrophic cardiomyopathy
- Mitral valve prolapse
- Hypoplastic left heart syndrome
- Marfan syndrome
- Rheumatic heart disease
- Infective endocarditis
- Mitral regurgitation
Test yourself
Think of the answer, then tap the question to see it.
What is the aortomitral curtain, and why does it matter in endocarditis?
The fibrous continuity of the mitral anterior leaflet with the left and non-coronary aortic cusps; infection and calcium can spread between the two valves.
What are the auscultatory signs of mitral stenosis?
A loud S1, an opening snap after S2 and a low-pitched diastolic rumble at the apex, heard with the bell, the person turned onto the left side.
What causes the «hockey-stick» shape of the mitral anterior leaflet on echo?
Rheumatic mitral stenosis: fused commissures make the leaflet dome in diastole.
How does the mitral anterior leaflet obstruct the outflow tract in hypertrophic cardiomyopathy?
By systolic anterior motion: the leaflet moves toward the septum in systole and narrows the left ventricular outflow tract.
Educational information, not medical advice. For any symptom, see a health professional.
Its names
- Official Latin (TA2)
- cuspis anterior valvae atrioventricularis sinistrae TA2 3989
- Official Spanish (DeCS)
- Cúspide anterior de la válvula mitral DeCS D008943
- English (TA2)
- Anterior leaflet of left atrioventricular valve
- Also called
- aortic leaflet of left atrioventricular valve · anterior cusp of left atrioventricular valve · cuspis ventralis valvulae bicuspidalis · septal leaflet of lefta atrioventricular valve
Related
Sources: Terminologia Anatomica (TA2); DeCS; Anatomy, Thorax, Mitral Valve.
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.
