Objective: The levator ani is a critical component of the pelvic floor; however, its intricate anatomy and functionality are poorly understood. Understanding the precise anatomy of the levator ani is important for the accurate diagnosis and effective treatment of pelvic floor disorders. The purpose of this study was to comprehensively analyze the muscle bundles of the levator ani to clarify the stratified relationship of the muscle bundles.
Methods: Thirty-one female cadavers (mean age at death, 86.6 years; age range, 49–103 years) were used for the macroscopic examination and 3D digitized muscle isolation based on layer-by-layer dissection.
Results: The levator ani, particularly in its anteroinferior portion, exhibited a complex layered structure comprising overlapping muscle bundles with varying orientations. This portion of the levator ani contained muscle bundles that are anatomically associated with the rectum. Some muscle bundles directly attach to the rectum, whereas others surrounded the anterior and posterior aspects of the rectum.
Conclusion: Our findings suggest that these specific muscle bundles of the levator ani are primarily responsible for pelvic floor support mechanism. The comprehensive anatomical information provided by our study will facilitate the development of targeted diagnosis and treatment strategies for pelvic floor disorders in clinical practice.
Keywords: defecation; levator ani; pelvic floor; perineum; urination