Morphological spectrum of the septal papillary muscle complex and chordal support in the human tricuspid valve: a quantitative anatomical study

Figures

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  Fig. 1. Representative view of the right ventricle of a human heart illustrating the tricuspid valve and the subvalvular apparatus: a macroscopic specimen of the opened right ventricle showing the tricuspid valve leaflets, papillary muscles, and chordae tendineae; and b corresponding schematic illustration highlighting the spatial relationships of the septal/medial papillary muscle complex within the right ventricle. MCA and MCA-derived chordae tendineae are indicated in red, whereas MPS and MPS-derived chordae tendineae are indicated in blue. Colored arrows identify the corresponding papillary muscles. MCA and MPS are shown as components of the septal/medial papillary muscle complex, while representing anatomically distinct muscular heads with separate origins. MCA, papillary muscle of the conus arteriosus; MPS, septal papillary muscles; APM, anterior papillary muscle; PPM, posterior papillary muscle; CA, anterior leaflet; Com a, anteroseptal commissure; CS, septal leaflet; Com p, posteroseptal commissure; CP, posterior leaflet; FO, fossa ovalis

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  Fig. 2. Schematic representation of the tricuspid valve illustrating the predefined regions used for the analysis of chordae tendineae insertions. The septal leaflet is subdivided into three zones: anterior (CSa), middle (CSm), and posterior (CSp). MCA and MCA-derived chordae tendineae are indicated in red, whereas MPS and MPS-derived chordae tendineae are indicated in blue. Colored arrows identify the corresponding papillary muscles. Although shown as components of the septal/medial papillary muscle complex, MCA and MPS represent anatomically distinct muscular heads with potentially separate origins. MCA, papillary muscle of the conus arteriosus; MPS, septal papillary muscles; APM, anterior papillary muscle; PPM, posterior papillary muscle; CA, anterior leaflet; Com a, anteroseptal commissure; CS, septal leaflet; CSa, anterior zone of the septal leaflet; CSm, middle zone of the septal leaflet; CSp, posterior zone of the septal leaflet; Com p, posteroseptal commissure; CP, posterior leaflet

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  Fig. 3. Representative close-up macroscopic views of the papillary muscle of the conus arteriosus region showing four patterns of chordal insertion: a chordae inserting exclusively into the anterior leaflet; b chordae inserting into the anterior leaflet and anteroseptal commissure; c chordae inserting into the anterior leaflet and anterior zone of the septal leaflet; and d chordae inserting into all three regions. MCA, papillary muscle of the conus arteriosus; MPS, septal papillary muscles; CA, anterior leaflet; Com a, anteroseptal commissure; CSa, anterior zone of the septal leaflet

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  Fig. 4. Comparative distribution of chordae tendineae from MCA and MPS across regions of the tricuspid valve. Bars show mean ± SD per heart (N = 111). Asterisks denote significant differences between MCA and MPS within each region (***p < 0.001, Wilcoxon signed-rank tests with Holm–Bonferroni correction). MCA, papillary muscle of the conus arteriosus; MPS, septal papillary muscles; CA, anterior leaflet; Com a, anteroseptal commissure; CS, septal leaflet