Morphological features of papillary muscles in the right ventricle

Our study was performed by dissecting formalinized cord, aiming at:the number of bodies of each papillary muscle in the right ventricle, the shape of the muscular body, also the morphological characteristics of the tendon chordaes. The anterior papillary muscles of the right ventricle, were studied on 54 cords, finding a total of 82 papillary muscles. Unique anterior papillary was found in 59.26% of case, representing 38.10% of total anterior papillary muscles.

In 29.63% of cases, the anterior papillary muscle was double and in 11.11% of cases was threefold. The conical shape we found in 57.32% of the anterior papillary muscles, and the cylindrical shape encountered in 29.27% of cases.

In case of double papilaery muscles, sometimes beeing joined at various levels between them, they realized particular aspects in each 2.44 % of cases, presenting the „N” and „H” letter appearance and in 1.22% of cases one of the two papilary presented an arcuate shape. At the unique papillary in one case (1.22%) we have found pyramidal forms and reversed „V” letter.

The valvular tendinous chordae of the anterior papillaries, we have pursued on a number of 78 papillary muscles and we found that most frequently they broke loose from the superior side, in 41.03% of cases detaching from the tip of conical unique papillaries romthe superior si of those cylindrical. The posterior papillar muscles of the rght ventricle we studied on 42 cords, presenting 69 papillary muscles. Single posterior papillary muscle we found in 52.38% of cases, in 33.33% of cases was double, triple in 11.90% of cases and in one case (2.38%) the posterior papillry was quadruple. Most commonly, the posterior papillary muscle presents a conical shape, aspect found in 65.22% of cases, in 27.54% of cases was cylindric, in 2.90% of cases we found a papillary muscle in reversed „Y” shape (at double papillary), and in one single case (1.54%) we found one arcuated papillary (in one double paillary), one irregular papillary (at unique papillaries) and one papillary in reversed „N” letter (between two muscular bodies of one triple papillary).

Valvular chordaes of the posterior papillary muscles, most frequently broke loose from the tip or superior edge of the papillary, aspect found in 35.48% of cases. Septal papillary muscles that we studied on 43 cords, were represented either by a number of 3-5 beams, or 5-9 simpe chordae tendons, both tipes could present or not at their origin on the septomarginal strip, a muscular cone. Rarely can present 1-3 large muscular cones that sometimes can be considered true papillary muscles.

We found the arterial muscle cone, present in all cases, beeing represented by chordae bundles arising from a muscular cone and rarely not showing muscular cone at his origin or can be represented by two beams of valvular chordae. We encountered one case where septal papillaries were represented by 3 conical muscular bodies, well represented, comparable in size with the anterior and posterior papillary muscles, especially the superior and inferior muscular bodies, the middle beeing shorter. We found in 13.95% of cases the existence of the posterior’s angle papillary muscle of the right ventricle, conical and cylindrical papillary muscle, that sent tendon chordae only to the septal leaflet.