Objective Sacro-coccygeal pilonidal sinus disease is a frequent surgical problem. Some authors assign the low recurrence rates of the Limberg flap to the flattening or elevation of the natal cleft. Summery of the background data: Numerous authors describe a flattening or elevation of the natal cleft as a result of a Limberg flap that originated from the gluteal region. However, thus far these were not quantified. Methods The aim of our study was to quantify the flattening or elevation, respectively, of the natal cleft. In the context of our study on the Limberg flap plasty with a homogenous group of 12 male patients, we measured the depth of the rima ani after the excision and we also measured the thickness of the Limberg flap. Results The median thickness of the rima ani at excision was 3.35 cm [IQR: 2.70; 4.18]. The median thickness of the Limberg flap was 4.85 cm [IQR: 3.90; 5.18]. The thickness of the rima ani after excision was statistically significantly less as compared to the thickness of the Limberg flap (p = 0.002). Conclusion In our study, we have shown the elevation of the crena ani with statistical significance by performing the Limberg flap for the treatment of sacro-coccygeal pilonidal sinus disease, leading to a flattening of the sacro-coccygeal region. As a deep crena ani is a factor in the pathogenesis of pilonidal sinus, the flattening of the sacro-coccygeal region with a Limberg flap plasty, as reported in countless publications, may explain the low recurrence rates.