The mitral valve, also known as the bicuspid valve or left atrioventricular valve, lies between the left atrium and left ventricle. It is a dual flap valve made up of the mitral annulus, two leaflets (anterior and posterior), chordae tendineae connecting the leaflets to the papillary muscles of the left ventricle, and the left ventricular wall. The mitral valve apparatus works to ensure unidirectional blood flow from the left atrium to the left ventricle during diastole and prevent backflow during systole.

1. MITRAL VALVE - ANATOMY
Dr. Kunwar Sidharth
Saurabh

2. MITRAL VALVE
• ALSO KNOWN AS BICUSPID VALVE OR LEFT AV
VALVE.
• DUAL FLAP VALVE
• LIES BETWEEN LA AND LV

4. Cardiac Skeleton
• It is a high density single structure
of connective tissue (collagen) that forms and
anchors the valves and influences the forces
exerted through them.
• The cardiac skeleton separates and partitions
the atria from the ventricles

6. • The right and left fibrous rings of heart (anuli
fibrosi cordis) surround
the atrioventricular and arterial orifices.
• The right fibrous ring is known as the anulus
fibrosus dexter cordis, and the left is known as
the anulus fibrosus sinister cordis.
• The right fibrous trigone is continuous with the
central fibrous body.
• This is the strongest part of the fibrous cardiac
skeleton

7. • The valve rings, central body and skeleton of
the heart consisting of collagen are
impermeable to electrical propagation.
• The only channel allowed through this
collagen barrier is represented by a sinus that
opens up to the atrioventricular node and
exits to the bundle of His.
• The cardiac skeleton ensures that the
electrical and autonomic energy generated
above is ushered below and cannot return.
• The muscle origins/insertions of many of
the cardiomyocytes are anchored to opposite
sides of the valve rings.

8. MITRAL APPARATUS
• LEFT ATRIAL WALL
• ANNULUS
• CHORDAE TENDINAE
• PAPILLARY MUSCLES
• LEFT VENTRICULAR WALL

11. LEFT ATRIAL WALL
• Left atrial myocardium extends over the
proximal portion of the posterior leaflet.
• Left atrial enlargement can result in mitral
regurgitation by affecting posterior leaflet
• The anterior leaflet is not affected because of
its attachment to root of aorta

12. MITRAL ANNULUS
• Fibrous rings that connect with the leaflets.
• Not a continuous ring around the mitral
orifice.
• D- shaped
• The aortic valve is located between ventricular
septum and the mitral valve.

13. • The annulus functions as sphincter that
contracts and reduces the surface area of the
valve during the systole to ensure complete
closure of the leaflets.
• Annular dilatation of the mitral valve causes
poor leaflet apposition – resulting in MR.

14. MITRAL VALVE LEAFLETS
• Continuous veil inserted around the
circumference of the mitral orifice.
• The free edges of the leaflets have several
indentations.
• Two of these indentations, the anterolateral and
the posteromedial commissures divide the leaflet
into anterior and posterior.
• These commissures can be accurately identified
by the insertion of the commissural chordae
tendinae into the leaflets.

15. • Normally the leaflets are thin, pliable,
translucent and soft.
• Each leaflet has an atrial and a ventricular
surface.
• The combined area of leaflets is twice as that
of mitral orfice

17. Anterior Leaflet
• It is also anchored to the aortic root, unlike
the posterior leaflet.
• AKA Aortic, Septal, Greater or anteromedial
leaflet.
• The anterior leaflet is large and triangular in
shape, inserted on about 1/3rd of annulus.
• There are 2 zones – Rough and Clear , as per
the insertion of chordae tendinae.

18. • The clear zone is devoid of direct chordal
insertions.
• In continuation with aortic valve through aortic
mitral annulus and forms a boundary of LVOT.
• This region of continuity is 1/4th of the annulus,
corresponds to the region between half of left
coronary cusp, and half the non coronary cusp of
aortic valve.
• Limits of this attachment are demarcated by left
and right fibrous trigones.
• AV node and bundle of HIS are at risk of damage
near right trigone.

20. Posterior Leaflet
• Ventricular , Mural , Smaller or Posterolateral
leaflet. Scallop shaped.
• It has a wider attachment to the annulus than
the anterior leaflet. (2/3rd )
• 3 zones – Rough , Clear and Basal (receives
chordae directly from left ventricular
trabeculae)

21. SEGMENTAL CLASSIFICATION
A1 AND P1 –
ANTEROLATERAL
A2 AND P2 – MIDDLE
A3 AND P3 -
POSTEROMEDIAL

22. CHORDAE TENDINAE
• Small fibrous strings that originate either from the apical portion of
the papillary muscles or directly from the ventricular wall and insert
into the valve leaflets or muscle.
• Misalignment of leaflets, may put undue stress on chordae and may
cause rupture.
• Order of chordae –
– First order – inserted into free margin
– Second order – few mm back from free margin
– Third order – inserted at the base.

23. COMMISSURAL CHORDAE
• Chordae that insert into the interleaflet or
commissural areas located at the junction of
anterior and posterior leaflet.
• Two types –
– Posteromedial
– Anterolateral
• Shorter than the others and originate from
highest tip of papillary muscle.

24. LEAFLET CHORDAE
• Insert into anterior or posterior leaflets.
• 2 types of chordae on anterior leaflet-
– Rough zone chordae – insert into distal portion on
leaflet
– Strut chordae – branch before inserting into
anterior leaflet

25. PAPPILARY MUSCLES AND THE LEFT
VENTRICULAR WALL
• Muscular components of the apparatus.
• Normally arise from the apex and middle third
of left ventricular wall.
• Crescent shaped, conforms to the curvature of
the free wall of left ventricle.
• Anterolateral is larger than posteromedial
• LCx/LAD – SUPPLIES ANTEROMEDIAL
• RCA – SUPPLIES POSTEROMEDIAL

26. • Anterolateral – Attached to left half of anterior
and posterior leaflet by chordae tendinae
• Posterolateral – attached to right half.
• 4-12 chordae originating from each.
• Types of papillary muscle –
– Type 1 to 4.

27. • Design of mitral valve provides largest possible
orifice during diastolic phase.
• The valve opens as the anterior leaflet opens
and swings freely away from posterior leaflet
• Dimensions are enhanced by flexion of
anterior leaflet.
• During systole, anterior leaflet straightens and
extends towards posterior leaflet.
• Posterior leaflet acts as shelf to stop the
movement of anterior leaflet as they appose.