Fig. 1.

Normal defecography phases: at rest (a), during forced contraction (b) and during defecation (c). Measurement of the ARA with the patient at rest (a), during maximal contraction (b), and during evacuation (c) (blue lines). The ARA decreases during maximal contraction of the anal sphincter and increases during evacuation, followed by descent of the ARJ (black point at the intersection of the two lines defining the ARA). The descent of the ARJ between resting position and evacuation is less than 3.5 cm in normal conditions.