Defecography: principles of technique and interpretation.

After description of the performance, physiology and normal findings of defecography, the main pathology is discussed as intra-anal rectal intussusception, extra-anal rectal intussusception, mucosal prolapse, rectocele, descending perineum syndrome, spastic pelvic floor syndrome and the solitary rectal ulcer syndrome. Finally, the radiation dose and pitfalls are reported.