The umbilical canal revisited: historical anatomy and radiologic implications of a commonly misnamed CT finding

BACKGROUND: The increasing use of cross-sectional imaging-particularly abdominal computed tomography (CT)-together with the global rise in obesity has brought renewed attention to a fat-containing structure posterior to the umbilical scar that is frequently labeled as an "umbilical hernia" in radiology reports. Historical anatomical literature, however, describes this configuration as the umbilical canal, a variable, habitus-dependent space between the posterior surface of the linea alba and a reinforcing lamella of the transversalis fascia, often filled with preperitoneal fat and containing embryologic remnants of the umbilical vessels. PURPOSE: To revisit the anatomical foundations of the umbilical canal, correlate classical descriptions with modern CT appearances, and examine how contemporary surgical risk metrics may be inappropriately extrapolated to this structure. DISCUSSION: Classical anatomical and surgical literature-from Scarpa, Richet, Gauderon, and Cullen to early twentieth-century surgical pathology-consistently distinguishes true umbilical hernia, defined by a peritoneal-lined sac, a fascial neck, and visceral content, from preperitoneal fat protrusions within the linea alba. Modern CT imaging frequently demonstrates a funnel-shaped, fat-filled tract posterior to the umbilical scar that corresponds to the historically described umbilical canal rather than a true hernia. Because this configuration lacks a peritoneal sac and a discrete fascial neck, applying hernia-based morphologic risk metrics may lead to diagnostic ambiguity. CONCLUSION: Recognizing the umbilical canal as a distinct anatomical configuration rather than a true umbilical hernia may improve terminological precision in radiology reporting, enhance interdisciplinary communication, and help avoid potential overdiagnosis and unnecessary surgical referral.