The splenic flexure is the junction between the transverse colon and the descending colon and is usually the most cranial portion of the colon.  It is the embryological junction point between the midgut and hindgut, and is the watershed of two circulations so that it is the border where the circulations of the SMA and IMA meet.  Its drainage is via the corresponding mesenteric veins into the SMV and then portal circulation.  It is attached to the diaphragm by the phrenicocolic ligament.  Like the hepatic flexure it can also vary in length and at its longest can be quite redundant with similar radiological difficulties to uncoil it during a barium enema.

Applied Anatomy

The colon cutoff sign (Pickhardt) is a characteristic finding in patients with pancreatitis where the inflammatory process extends along the tail of the pancreas to the left side where it comes into contact with a triangular ligament that connects the left colon to the diaphragm- just to the left of the lateral aspect of the transverse mesocolon.  This ligament is called the phrenicocolic ligament because it is connected to the diaphragm (phrenic) on the one end and the colon on the other.  As the inflammatory process spreads along this ligament it comes into contact and spreads the inflammatory process to the splenic flexure and proximal descending colon resulting in a reversible stricture caused by a combination of swelling and spasm.