[The enlarged retrorectal space--indicative of specific pathology or only unspecific symptom of disease in the true pelvis? (author's transl)].

The retrorectal space was measured on the lateral view of the rectum during double contrast barium enema examination in 300 patients in whom no abnormality of the rectum, sacrum or in the true pelvis was demonstrated clinically or radiographically. The measurement obtained is the distance between posterior wall of the rectum and the anterior surface of the sacrum between S2 and S5. The measurements at S5 are considered most accurate, since at this level the rectum will be positively in midline. The normal width at S5 is between 0.2 and 1.5 cm. In connection with other symptoms, a distance between 1.5 and 2 cm should be regarded as suspicious and above 1 cm as definitely abnormal, as was demonstrated in 95 cases with diffuse and localized enlargement of the retrorectal space. An abnormal measurement of greater than 2 cm however is an unspecific symptom and should not by itself be considered indicative of specific pathology, but rather should lend supporting evidence to other abnormal findings in the true pelvis.