Table 4.

Classification of malrotation of the intestine and clinical significance

Embryonal stage	Type of malrotation	Clinical effect
I Midgut length on superior mesenteric vessels; no rotation	IA Non-rotation	Midgut volvulus
II Withdrawal of duodenum followed by its rotation and fixation	IIA Non-rotation of duodenum: colon rotates normally	Duodenal obstruction by bands
	IIB Reverse rotation of duodenum: and colon	Transverse colon obstruction by superior mesenteric vessels
	IIC Reverse rotation of duodenum: colon rotated normally	Paraduodenal hernia
III Withdrawal of right colon followed by its rotation and fixation	IIIA Normal rotation of duodenum: colon not rotated	Midgut volvulus
	IIIB Incomplete fixation of hepatic flexure	Intermittent duodenal obstruction by “Ladd’s bands”
	IIIC Incomplete attachment of caecum and its mesentery	Volvulus of caecum
	IIID Internal hernias near the ligament of Treitz	Internal hernias