How to interpret a functional or motility test - defecography.

Defecography evaluates in real time the morphology of rectum and anal canal in a physiologic setting by injection of a thick barium paste into the rectum and its subsequent evacuation. Because of its ability of structural and functional evaluation, defecography is primarily performed for work up of patients with longstanding constipation, unexplained anal or rectal pain, residual sensation after defecation or suspected prolapse. Technique and interpretation of this examination are outlined in this review.