Mitral Valve Anatomy

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.