Rectosigmoid index

Fig. 1.31a,b. Hirschsprung disease. a Contrast enema shows a distended colon and a small rectum and portion of the colon. The rectosigmoid index is abnormal. b Intraoperative photograph demonstrates the transition zone (arrows) with the shape of an inverted cone... 

Fig. 1.32a-d. Total colonic agan-glionosis. a Plain radiograph of the abdomen demonstrates low obstruction. b,c Anteroposterior and lateral views during contrast enema show the shortened colon compared with the normal redundancy of the neonatal colon, with the flexures pulled down and a normal rectosigmoid index, d Intraoperative photograph shows dilated bowel loops with the transition zone at the distal ileum... 

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