Sigmoid valvulus rotations occurs

(Anticlockwise) (1197-LB) (1192-B &L 25th)SIGMOID-VOLVULUS - Most common cause of large bowel obstruction in indigenous black Africans* Rotation nearly always occurs in an anticlockwise direction* Predisposing factors include high-residue diet and chronic constipation* Predisposing causes - 1 Band of adhesions (peridiverticulitis) Overloaded pelvic colon, Long pelvic mesocolon, narrow attachment of pelvic mesocolon* Plain film of abdomen - The distended loop may assume a "coffee bean" shape* In caecal Volvulus the concavity of the "coffee bean" points towards the right lower abdominal quadrants, and in sigmoid Volvulus it points towards the left lower quadrant.* On barium enema a "bird's beak" or ace of spades" deformity with spiral narrowing of the upper end of the lower segment is pathognomic. Between attacks barium enema may reveal sigmoid megacolon - 739/CSDT l1th