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Three‐dimensional transperineal sonographic characteristics of the anal sphincter complex in nulliparous women
Author(s) -
Huang W.C.,
Yang S.H.,
Yang J.M.
Publication year - 2007
Publication title -
ultrasound in obstetrics and gynecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.202
H-Index - 141
eISSN - 1469-0705
pISSN - 0960-7692
DOI - 10.1002/uog.4083
Subject(s) - medicine , external anal sphincter , sagittal plane , anal sphincter , sphincter , internal anal sphincter , anal canal , anatomy , pelvic floor , anus , coronal plane , urethral sphincter , pelvic floor dysfunction , surgery , rectum , urethra
Abstract Objective To explore the morphological characteristics and normal biometry of the anal sphincter complex in nulliparous Chinese women using three‐dimensional (3D) transperineal ultrasound. Methods 3D sonographic data from 55 nulliparous Chinese women (aged 19–38 years) who had no pelvic organ prolapse and no symptoms of pelvic floor dysfunction were retrieved from an image dataset and analyzed by offline post‐processing. The morphological characteristics of the external and internal anal sphincters, puborectalis muscle and perineal body were assessed in the sagittal, coronal and axial views. Results The external anal sphincter had three sonographic components: the circular main body, a subcutaneous part and an extension portion. It was significantly thinner at 12 o'clock than at the 3, 6 and 9 o'clock positions. The internal anal sphincter was seen as dark echolucent strips of equal thickness. In the mid‐sagittal view, it started from the anal verge and ended at the anorectal junction. The perineal body was an ovoid structure covering the upper margin of the external sphincter, while the puborectalis muscle was banana‐shaped in the sagittal view and was located behind the anorectal junction, extending downward along the inferior margin of the posterior external sphincter extension. Sonographic characteristics of the anal sphincter complex did not vary with age, weight, height or body mass index. Conclusions 3D transperineal ultrasound clearly demonstrates the spatial relationships of each component of the anal sphincter complex. This should allow standardized measurement of the complex for investigations of its function. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.