Influence of Body Position on the Defecation Model During Anorectal Manometry.

The test will be performed both in supine and sitting position successively, using 3D HR-ARM. Resting, squeeze pressures, and bear down manoeuvre variables will be obtained. Diagnosis of dyssynergic defecation requires \< 20% relaxation of anal sphincter and/or intrarectal pressure\>40 mmHg during bear down manoeuvre.