Gastrointestinal Radiology > Procedures > Defecography > Defecography (9)

Defecography (cont.)

Normal Defecogram

  • Evacuation is initiated by straining which raises intraabdominal pressure. It begins with several centimeters of descent of the pelvic floor. This is followed by relaxation of the puborectalis muscle and opening of the anal canal.
  • As the process of evacuation continues, the anorectum changes from a funnel shape to an almost straight tube, with practically complete loss of the anorectal angle.
  • During evacuation, defecography normally demonstrates an increase in the anorectal angle, a descent of the anorectal junction, and a widening of the anal canal.
  • Normal subjects are able to eliminate more than two thirds of the contrast material within 30 sec. Complete emptying of the rectum is seen in only one half of patients.

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