n.
乙状结肠

[ noun ]
the s-shaped curve between the descending colon and the rectum
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Sigmoid \Sig"moid\, Sigmoidal \Sig*moid"al\, a. [Gr. ???; ???
sigma + e'i^dos form, likeness: cf. F. sigmo["i]de.]
Curved in two directions, like the letter S, or the Greek
[sigmat].

{Sigmoid flexure} (Anat.), the last curve of the colon before
it terminates in the rectum. See Illust. under
{Digestive}.

{Sigmoid valves}. (Anat.) See {Semilunar valves}, under
{Semilunar}.