Morphometric variability of pyramidalis muscle and its clinical significance

Purpose The goal of the study is to analyze the morphometric diversity of the pyramidalis muscle (PM) and to evaluate how it is affected by gender and side of occurrence. Materials and methods Ninety-six (50 male and 46 female) formalin-embalmed Greek cadavers were dissected. Results The PM was present in 93.8 %, usually bilaterally (79.2 %) than unilaterally (14.6 %) ( p = 0.003) and more frequently in females (91.3 %) than in males (68 %) ( p = 0.0001). Side symmetry was detected. The mean length of PM in males and females was 8.37 ± 2.80 and 6.18 ± 1.64 cm on the right and 7.50 ± 2.66 and 6.56 ± 1.68 cm on the left side. Male predominance existed on the right and left-sided PM lengths ( p = 0.0001 and p = 0.054). The mean width of the right-sided PMs in males and females was 1.61 ± 0.55 and 1.50 ± 0.44 cm and the left-sided 1.56 ± 0.53 and 1.55 ± 0.38 cm without gender dimorphism. The positive correlation between the PM length and width indicates a symmetrical muscle augmentation on the two dimensions. Conclusions The study demonstrates that the PM is almost constant in Greeks. Among populations the muscle morphometric variability, its clinical significance and its variable uses will help surgeons when intervening in the lower abdominal wall.