The Mystery of the Innie vs. Outie: Scientists Discover anatomical Structure Behind Navel Shape
PARIS – For centuries, the simple question of whether one has an “innie” or an “outie” navel has been a matter of casual observation. Now,groundbreaking research reveals the anatomical reason behind this common variation,perhaps impacting surgical techniques and our understanding of abdominal health. A team led by Satoru Muro has identified a previously uncharacterized fibrous structure – dubbed the ”umbilical sheath” - beneath the skin around the navel, which appears to play a key role in determining its shape.
The finding, published following microscopic analysis of tissue samples from five human bodies, offers a potential explanation for why some individuals are born with a concave navel while others have a protruding one. More importantly, understanding this “umbilical sheath” – composed of collagen fibers arranged in a circular sleeve – could lead to improved surgical practices, specifically in reducing the risk of incisional hernias, a complication affecting 3 to 20% of patients undergoing abdominal surgery. These hernias often occur at the site of incision, frequently the navel.
Researchers found the sheath anchors the umbilical depression to deeper fascial tissues, and its advancement or robustness may explain the prominence of navels. “This structure is made up of collagen fibers, arranged in a circular way as a sleeve, which we have baptized “umbilical sheath,” explains Muro. ”This sheath anchors umbilical depression towards deep fascias, now the curved shape in the interior of the navel.”
Currently, the study is limited to individuals with concave navels. Further research, including analysis of a broader sample encompassing people with protruding navels, is planned to confirm these initial findings.
“This article illuminates part of our anatomy still largely ignored, with implications surgicals concrete, especially for laparoscopic interventions,” notes Kat Sanders, professor of anatomy at the University of Sydney. Laparoscopic surgery utilizes small incisions and internal cameras to perform operations, and a deeper understanding of the umbilical sheath could refine these procedures.
