sigmoideo

Sigmoideo is a term used in Spanish and Portuguese to describe an S-shaped form or to refer to structures that have a sigmoid shape. In anatomy, it most often denotes the sigmoid colon, the S-shaped portion of the large intestine that connects the descending colon to the rectum.

The sigmoid colon sits in the lower left abdomen, is intraperitoneal, and is supported by the mesosigmoid. Its curved path accommodates temporary storage of feces and gradual transit to the rectum; peristaltic contractions move content forward. The arterial supply comes from the sigmoid arteries, branches of the inferior mesenteric artery, and venous drainage mirrors this via the inferior mesenteric vein. Innervation includes parasympathetic fibers from the pelvic nerves and sympathetic fibers from the mesenteric plexuses.

Clinical relevance: The sigmoid colon is a common site for diverticular disease and can develop sigmoid volvulus, a twisting of the colon around its mesentery that may cause obstruction. Diagnosis often involves imaging studies or colonoscopy, and management depends on the underlying condition.

Other uses: In mathematics and related fields, sigmoidea or sigmoide describes an S-shaped curve, most notably the sigmoid function. This curve maps real-valued inputs to a bounded range and is widely used in statistics, machine learning, growth models, and dose–response analyses.

Etymology: From Greek sigmoeidēs meaning “S-shaped,” via Latin sigmoidus. In Romance languages, sigmoide or sigmoideo forms are used to describe both the shape and related anatomical structures.