Papillary muscles and tendinous cords of the right ventricle of the human heart: morphological characteristics.

A series of 79 normal human hearts was studied focusing on the morphological characteristics of the papillary muscles of the right ventricle and their tendinous cords (chordae tendineae). The number, incidence, length and shape of the anterior, septal and posterior papillary muscles were observed. The tendinous cords attached to each papillary muscle were counted at their origin. The papillary muscles and the tendinous cords were measured in situ and after the removal of the right atrioventricular valve (tricuspid valve). The anterior and posterior papillary muscles (apm, ppm) were present in 100% of the cases. The septal papillary muscle (spm) was absent in 21.5% of the hearts. The apm presented 1 head in 81% and 2 heads in 19%; it was 19.16 mm in length. The spm was one-headed in 41.7% and presented two heads in 16.5%; the presence of a 3 and 4 heads appeared in 12.7% and 7.6% respectively; the spm was 5.59 mm in length. The ppm had 1 head in 25.4%, 2 heads in 46.8%, 3 heads in 21.5% and 4 heads in 6.3% of the cases; it was 11.53 mm in length. Tendinous cords (TC) varied as follows: from 1 to 11 TC originated in the apm (mean 4.74); from 1 to 8 TC originated in the ppm (mean 2.67) and from 1 to 5 TC originated in the spm (mean 1.77).