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TRICUSPID VALVE ANNULUS The leaflets are inserted into the annulus. This latter is less fibrous than that of the mitral valve, except in the area of the membranous septum, which forms part of the fibrous skeleton of the heart. The part that corresponds to the free wall is essentially muscular and is related to the right coronary artery.

1

2 3

4

[ 1 Parietal area ]

[ 3 Outflow tract of the left ventricle ]

[ 4 Interventricular septum ]

[ 2 Parietal area, corresponding to the membranous septum ]

Figure 2. Annulus.

TRICUSPID VALVE 45chapter 3

[ 1 Parietal area, insertion of the parietal leaflet ]

[ 2 Right coronary artery ]

[ 1 Septal leaflet ]

[ 2 Septum. Membranous septum ]

[ 3 Free wall of the right ventricle ]

[ 4 Right coronary artery ]

[ 5 Aorta. Cross-section at leaflet level ]

Figure 3. Annulus.

Figure 4. Triscupid valve annulus sectioned at the level of the membranous septum.

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2

1 23

4

4

5

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Figure 5. Pulmonary valve. Intermediate cusp seen from the pulmonary trunk.

Figure 6. Valve cusps.

The pulmonary valve has a similar structure to that of the aortic valve; however, as the arterial pressure in the pulmonary trunk is considerably lower than in the aorta, the cusps and other related structures are not as developed.

[ 1 Left cusp ]

[ 2 Right cusp ]

[ 3 Intermediate cusp ]

[ 4 Fibrous nodule ]

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2

4

3

PULMONARY VALVE 77chapter 5

Figure 7. Intermediate cusp.

Figure 8. Cusp. Attachment to

the valve annulus.

116 AtlAs of CArdiology

It seems that malformations in the distal part of the bulbus cordis are directly related to pulmonary valve stenosis, while subvalvular and infundibular stenoses may be the conse-quence of an abnormal division of the bulbus cordis during the formation of the ventricular septum and supravalvular stenosis may be due to alterations in more distal parts, in the truncus arteriosus.

Figure 9. Close view of the infundibular stenosis of the previous image.

Figure 8. Infundibular subvalvular stenosis in which it is possible to observe, in addition, hypertrophy of the right ventricle.

[ 1 Infundibulum ]

[ 2 Right atrium ]

[ 3 Free wall of the right ventricle ]

[ 4 Interventricular septum ]

[ 5 Septal leaflet of the tricuspid valve ]

4

4

3

5

3

2

1

PULMONARY VALVE STENOSIS 117CHAPTER 8

Figure 10. Subvalvular stenosis.

Figure 11. Hypoplastic pulmonary valve apparatus of the same case as in the previous image.

[ 1 Infundibulum ]

[ 2 Fibrous ring at infundibular level ]

[ 3 Marked valvular hypoplasia ]

1

2 3

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Figure 9. Type III lesion.

Figure 10. Type III lesion. Thickenings are usually found at the site of insertion of the chordae tendineae into the rough area.

Figure 11. Type III lesion. Thickenings in the rough area.

MYXOMATOUS VALVE DEGENERATION 157Chapter 11

Figure 12. Thickenings at the site of attachment of the chordae tendineae.

Figure 13. Important thickening of the site of insertion of the chorda tendinea with the leaflet. A thickened area may also be observed in the

medial area of the chorda tendinea.

Figure 14. Type IV lesion. The leaflets are thickened and wrinkled and there may be a prolapse of thickened tissue towards the atrial surface.