Morphological Variants of Colon: A Cadaveric Study

Abstract

Background:Outcome of colorectal surgery is greatly influenced by regional variation of colonic morphology and its abnormal peritoneal attachments to the adjacent structures. The present study has been conducted to describe the morphology of colon, anatomical variations and to discuss their embryogenesis and surgical implications^, Methods:Out of 32 cadavers dissected, two were excluded for extensive pathological adhesions of intestine. The detailed anatomy i.e, length, position and attachment of mesentery along with abnormal peritoneal attachments were observed in each segment of colon. Results:Out of 30 cadavers, 4 cadavers showed abnormal morphology. The ascending colon, transverse colon, descending colon and sigmoid colon were abnormally long in 3.3%, 6.6%, 3.3% and 6.6% respectively. In another two cases (6.6%)very short and fixed sigmoid colon were found. Elongated ascending and descending colon were mobile colons with persistence of their mesentery and shortened sigmoid colons got fixed to the pelvic wall by mesenteric absorption. Abnormally long colonic segments had shifted to abnormal positions and were retained there by abnormal peritoneal attachments to their adjacent structures. Conclusion:Sigmoid colon is more variable in length in comparison to other segments of colon. Redundancy can affect any segment of colon. Transverse colon and sigmoid colons are more often elongated than ascending and descending colon. Anomalous internal fixation of the fetal mesentery disturbs the colon’s normal disposition and its relations to adjacent viscera. A fundamental awareness of these variations and preoperative diagnosis through imaging study is particularly important to avert surgical risk.