Comparison between results of the present study and those conducted previously (mean ± standard deviation).

<p>Comparison between results of the present study and those conducted previously (mean ± standard deviation).</p

Data distribution by sex–no statistically significant differences were observed except for the heart weight.

<p>Data distribution by sex–no statistically significant differences were observed except for the heart weight.</p

Three different types of muscular arrangement in the middle sector of the cavotricuspid isthmus.

<p>The anatomical position of samples has not been maintained during the taking photos to get a better picture of cavotricuspid isthmus sectors. (A) trabeculae (N = 87; 62.1%); (B) intertrabecular recesses (N = 35; 25.0%); (C) trabecular bridges (N = 18; 12.9%); *–electrocardiological catheter.</p

Schemes of the final ramifications of the distal terminal crest muscle fibers (orange) into the lower part of the right atrium (types A–I; see Table 3).

<p>Smaller bands branching from the major crest were not presented with the exception of types B and C in which the main muscle band is absent. CSO–coronary sinus ostium; CTI–cavotricuspid isthmus; EuchV–Eustachian valve; FO–fossa ovalis; IVC–inferior vena cava; SL–septal leaflet; SVC–superior vena cava.</p

Patterns of the final ramifications of the terminal crest muscle fibers into the lower part of the right atrium.

<p>Patterns of the final ramifications of the terminal crest muscle fibers into the lower part of the right atrium.</p

Photograph of a cadaveric heart specimen showing the cavotricuspid isthmus area and a schematic view of the investigated heart region (mean ± standard deviations).

<p>AV–atrioventricular; CS–coronary sinus ostium; FO–fossa ovalis; IVC–inferior vena cava.</p

Double sub-Eustachian recess (R₁ and R₂).

<p>CS–coronary sinus ostium; ER–Eustachian ridge.</p