Morphometric parameters of a descending sigmoid sphincter (DSS) were defined in 32 patients of both sexes aged 20-71 years (average age: 48.0 +/- 2.2 years) with various forms of colon lumen at the site of sphincter. Densitometric indices of DSS and surrounding soft tissues were estimated. Vital morphological peculiarities of descending-sigmoid junction of the colon were demonstrated, and the diameter of the colon at the level of a sphincter was defined. The data obtained confirm the anatomical character of the colon sphincters and may be used as a basis for the interpretation of optical and virtual endoscopic images and DSS description for the application in differential diagnostics and precision surgery of various colon diseases.