Objective To describe a framework for visualizing the perineal body's complex anatomy using thin-slice MR imaging. Study Design Two mm-thick MR images were acquired in 11 women with normal pelvic support and no incontinence/prolapse symptoms. Anatomic structures were analyzed in axial, sagittal and coronal slices. 3-D models were generated from these images. Results Three distinct perineal body regions are visible on MRI: (1) a superficial region at the level of the vestibular bulb, (2) a mid region at the proximal end of the superficial transverse perineal muscle, and (3) a deep region at the level of the midurethra and puborectalis muscle. Structures are best visualized on axial scans while cranio-caudal relationships are appreciated on sagittal scans. The 3-D model further clarifies inter-relationships. Conclusion Advances in MR technology allow visualization of perineal body anatomy in living women and development of 3D models which enhance our understanding of its three different regions: superficial, mid and deep.

Objective To evaluate whether major levator ani muscle defects were associated with differences in postoperative vaginal support after primary surgery for pelvic organ prolapse (POP). Methods A retrospective chart review of a subgroup of patients in the Organ Prolapse and Levator (OPAL) study. Of the 247 women recruited into OPAL, 107 underwent surgery for prolapse and were the cohort for the present analysis. Major levator ani defects were diagnosed when more than 50% of the pubovisceral muscle was missing on MRI. Postoperative vaginal support was assessed via POP-quantification system. Postoperative anatomic outcome was analyzed according to levator ani defect status, as determined by MRI. Results Support of the anterior vaginal wall 2 cm above the hymen occurred among 62% of women with normal levator ani muscles/minor defects and 35% of those with major defects. Support of the anterior wall 1 cm above the hymen occurred among 32% women with normal muscles /minor defects and 59% of those with major defects. Levator ani defects were not associated with differences in postoperative apical/posterior vaginal support. Conclusion Six weeks after primary surgery for prolapse, women with normal levator ani muscles/minor defects had better anterior vaginal support than those with major levator defects.

Objective-Recent cadaver research demonstrates the perineal membrane's ventral and dorsal portions and close relationship to the levator ani muscle. This study seeks to show these relationships in women by magnetic resonance (MR) images.Methods-The subjects were 20 asymptomatic nulliparous women with normal pelvic examinations. MR images were acquired in multiple planes. Anatomical relationships from cadaver studies were examined in these planes.Results-In the coronal plane the ventral perineal membrane forms an interconnected complex with the compressor urethrae, vestibular bulb and levator ani. The dorsal part connects the levator ani and vaginal side wall via a distinct band to the ischiopubic ramus. In the sagittal plane the parallel position of perineal membrane and levator ani are seen. Conclusion-The perineal membrane's anatomical features can be seen in women with MR. The close relationship between the perineal membrane and levator ani is evident.

Objective This study assesses relative contributions of "midline defects" (widening of the vagina) and "paravaginal defects" (separation of the lateral vagina from the pelvic sidewall). Methods Ten women with anterior predominant prolapse and 10 with normal support underwent pelvic MR imaging. 3-D models of the anterior vaginal wall (AVW) were generated to determine locations of the lateral AVW margin, vaginal width, and apical position. Results The lateral AVW margin was farther from its normal position in cases than controls throughout most of the vaginal length, most pronounced midvagina (effect sizes 2.2–2.8). Vaginal widths differed in the midvagina with an effect size of 1.0. Strong correlations between apical and paravaginal support were evident in mid and upper vagina (r=0.77–0.93). Conclusions Changes in lateral AVW location were considerably greater than changes in vaginal width in cases vs controls, both in number of sites affected and effect sizes. These "paravaginal defects" are highly correlated with apical descent.

Introduction and hypothesis-Two-dimensional magnetic resonance imaging (MRI) demonstrates apical support and vaginal length contribute to anterior wall prolapse (AWP). This paper describes a novel three-dimensional technique to examine the vagina and its relationship to pelvic sidewalls at rest and Valsalva.