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Updated: Jul 13, 2026
3D Ultrasound Imaging: Fast and Cost-effective Morphometry of Musculoskeletal Tissue
Published on: November 27, 2017
The reliability of puborectalis muscle measurements with 3-dimensional ultrasound imaging
Milena M Weinstein1, Sung-Ae Jung, Dolores H Pretorius
1Pelvic Floor Function and Disorder Group, University of California, San Diego, School of Medicine, San Diego, CA, USA.
Objective:
Our aims were to: (1) recognize the anatomic landmarks for measurement of puborectalis muscle on 3-dimensional ultrasound images, (2) assess intra- and interobserver reliability of puborectalis muscle measurements, (3) determine whether there is measurable puborectalis muscle shortening with pelvic floor squeeze, and (4) assess pelvic hiatus symmetry.
Study Design:
Twenty-seven nulliparous asymptomatic women were imaged with 3-dimensional ultrasound at rest and squeeze. Three-dimensional ultrasound volumes were rotated by using a standardized technique and analyzed by 2 observers.
Results:
Anatomic landmarks (lower end of pubic bone and apex of anorectal angle) were recognized consistently. There is significant shortening of puborectalis muscle and pelvic floor hiatus dimensions with squeeze. Inter- and intraobserver correlations demonstrate reproducibility of measurements. Both halves of pelvic floor hiatus are mirror images of each other.
Conclusion:
Three-dimensional ultrasound imaging allows localization of anatomic landmark and yields reliable measurements of the puborectalis muscle and pelvic floor hiatus.
