Aging-related morphological changes in the obturator internus and levator ani
In brief
Pelvic MRI links aging to coordinated reshaping of two pelvic floor muscles
In 27 women aged 25 to 83 without pelvic floor disorders, MRI shape analysis linked older age to a narrower upper obturator internus, a lower medial groove, and changes in the levator ani, including a wider opening. The cross-sectional study shows age-related muscle remodeling, but cannot establish how these changes affect pelvic floor function or disease.
- Journal
- Journal of anatomy (Q2)
- Published
- 19 October 2026
- Study design
- Cross-sectional study
- Evidence level
- Level 3, Low (CEBM 3b)
- Authors
- Satoru Muro, Junichi Tsuchiya, Takuya Ibara, Akimoto Nimura, Keiichi Akita
- PMID
- 42897888
- DOI
- 10.1111/joa.70256
Why clinicians should know about it
- Picked for Anatomy (top studies of the week, 25 October 2026): MRI morphometry characterizes pelvic muscle shape changes with age
Abstract
Pelvic floor dysfunction is a common condition in adult women. In addition to the levator ani, the obturator internus, a lateral pelvic wall muscle, has been suggested to be anatomically and mechanically associated with pelvic floor morphology. Here, we quantitatively characterized age-related morphological changes in the obturator internus and levator ani using geometric morphometric analysis. We hypothesized a significant association between principal components accounting for major shape variation and age. This cross-sectional study included 27 adult women aged 25-83 years with gynecological conditions but without pelvic floor disorders based on clinical assessment and imaging findings. Standardized pelvic magnetic resonance imaging scans were obtained between April 2024 and July 2024 at a single tertiary care center. Elliptic Fourier analysis was applied to the segmented obturator internus contours; a landmark-based method was used to evaluate the combined shape of the obturator internus and levator ani. Principal component analysis and linear regression were performed to assess associations with age. Procrustes analysis of variance was used to evaluate the overall shape-age relationships. Elliptic Fourier analysis revealed that increasing age was significantly associated with relative narrowing of the superior portion, an inferior morphological shift of the medial surface groove, and increased prominence of the medial eminence of the obturator internus. A landmark-based analysis revealed similar age-related shape changes, including inferiorly directed shape changes of the groove, verticalization of the levator ani, and widening of the levator hiatus. Procrustes analysis revealed a significant relationship between age and overall shape variation. Aging was associated with coordinated age-related morphological remodeling of the obturator internus and levator ani.
Abstract as published, via PubMed.
For healthcare professionals. The summary is generated by AI from the published abstract, and the evidence level is assigned automatically from the study design on the Oxford CEBM hierarchy. Neither is medical advice. Read the full paper before changing practice.