Structural characteristics of musculus sphincter ani externus dissected from people of different ages

The aim of our study was to investigate the structure, microtopography and quantitative characteristics of musculus sphincter ani externus dissected from people of different ages. It was shown that different parts of musculus sphincter ani externus (subcutaneous, superficial and profound) are characterized by significant morphological differences, particularly associated with the number and size of muscular fascicles separated by thin interlayers of connective tissue. The greatest number of muscular fascicles was found in the subcutaneous part of the sphincter and the lowest number of muscular fascicles was observed in the superficial part of the muscle. We also found that in elderly population this muscle is characterized by the thin muscular fascicles separated by the wide interlayers of connective tissue. According to our data the greatest cross sectional area of muscular fascicles (478 ± 63 μm2) was observed in adolescents and the lowest cross sectional area of muscular fascicles (216 ± 40 μm2) was found in elderly people