3. (Aeronautics) any structure corresponding to or resembling the keel of a ship, such as the central member along the bottom of an aircraft fuselage. 4. (Biology) biology a ridgelike part; carina. 5. a poetic word for ship.
Transverse colon and sigmoid colon. The transverse colon and the sigmoid colon have a mesentery (ie, transverse mesocolon and sigmoid mesocolon, respectively), but the ascending colon and descending colon are retroperitoneal, while the cecum is intraperitoneal but uses the mesentery of the ileum.
Mapping the body: the sigmoid colon. The sigmoid colon is towards the bottom right of the large intestine. It is usually patients not doctors who balk at the sight of a medical instrument being unwrapped. But the flatus tube, used to treat a condition of the sigmoid colon, is one no surgeon relishes. The sigmoid is an S-shaped stretch of large bowel, about 40cm long, which leads up to the rectum.