Is the Evaluation of Anal Distensibility by Endoflip® Technique Useful for the Diagnosis of Anismus?

Inclusion Criteria: * patient older than 18 years * patient with distal constipation defined according to the Rome IV criteria, for at least 3 months and verified by a transit time study showing a predominant slowing of markers at the recto-sigmoid level. * patient who read and signed the informed consent form Exclusion Criteria: * Patients with a predominant right of left colonic constipation; * Pregnant woman or woman with no effective contraception and of childbearing age * Patient with inflammatory bowel disease, ischemic colitis, history of colon or rectal cancer, infectious colitis or proctologic disease. * Patient with anorectal malformation * Patient with an history of pelvic floor radiotherapy * Patient with a digestive stoma * Insertion of the probe impossible or painful * Patient who has participated to a clinical trial within 30 days prior to the inclusion visit * Patient not understanding or reading French * Patients under guardianship, curatorship, safeguard of justice * Patient without liberty by administrative or judicial decision