Outpatient measurement of perineal descent.

One hundred and fifty-eight consecutive patients attending a rectal clinic have undergone measurement of perineal descent at rest and during straining by a simple noninvasive method. In nine patients (5.7%) the perineum was assessed as being below the ischial tuberosities at rest, whilst a further nine patients (5.7%) had abnormal descent (greater than 2.5 cm) during straining. Sixteen of the 18 patients with abnormal descent at rest or on straining were female and in ten (56%) a diagnosis of haemorrhoids was made at the initial clinic attendance. Parity of four or more was associated with a greater degree of descent during straining (P less than 0.05) than in women having a single pregnancy only.