Radiological features and clinical implications of persistent congenital mesocolon: Pictorial essay.

In human foetus, the mesenteries that carry vascular and neural supply to the alimentary tube play an important role in its development and anatomical location within the abdominal cavity. The mesenteric attachments of the small bowel, transverse colon and sigmoid allow them to be intraperitoneally mobile structures. In contrast, the ascending and descending colon lose their mesenteries by fusion with the parietal peritoneum and become fixed in retroperitoneal position along the posterolateral walls of the abdomen. In about 2%-4% of individuals, this process is disrupted, causing a complete or partial retention of their congenital mesocolon. The ascending or descending colon will then remain intraperitoneally mobile, affecting the normal visceral anatomy and causing potential complications. This article reviews the spectrum of radiological manifestations and clinical consequences of these anomalies.

Congenital positional anomalies of the colon: radiographic diagnosis and clinical implications. II. Abnormalities of fixation.

Defective fixation during embryologic development is responsible for a variety of segmental colonic malpositions seen during barium enema examinations. A review of the normal development process of fixation is presented, together with the most common and significant aberrations. On the right side clinical entities such as axial torsion, cecal bascule, retrocolic sigmoid, and pericolic bands are discussed and illustrated. On the left side, the configuration and clinical implications of the malposition of the splenic flexure are analyzed. It is pointed out that reversed configurations of the splenic flexure associated with failure of fixation of the entire descending colon may occur as an isolated congenital abnormality and may not necessarily be associated with renal anomalies. The characteristic radiographic appearance of the persistent descending mesocolon and its potential for complications is in addition emphasized. Familiarization with the radiographic appearance and clinical implications of these common abnormalities is essential in the daily interpretation of barium enema examinations.