ArticleClinical anatomy (New York, N.Y.)2020
Coexistence of Dense and Sparse Areas in the Longitudinal Smooth Muscle of the Anal Canal: Anatomical and Histological Analyses Inspired by Magnetic Resonance Images.
Article in Clinical anatomy (New York, N.Y.), 2020. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 12 papers.
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Who cites it
12 citing papers in PubMed, 20 citations in OpenAlex.
- Histological architecture of the intersphincteric region of the anal canal: implications for the anatomical basis of anal fistula pathways.International journal of colorectal disease · 2026Article
- New anatomical insight into the muscular structure of the anal canal: revealing Treitz muscle as a directional shift of the internal anal sphincter.Annals of coloproctology · 2025Article
- Novel Anatomical Findings in Robot-Assisted Prostatectomy and Optimal Dissection Layer Selection for Preserving Urethral Support Structures.The Prostate · 2025Article
- Presence of smooth muscle continuous with the rectal and vaginal walls in the deep perineal space prompts reconsideration of the deep transverse perineal muscle.Scientific reports · 2025Article
- Three-dimensional heterogeneity of smooth muscle fiber density anterior to the rectum in males: quantitative analysis with implications for transanal total mesorectal excision.International journal of colorectal disease · 2025Article
- Three-dimensional Analysis of the Distribution of Smooth and Skeletal Muscle Tissue Around the Female Urethra.International urogynecology journal · 2025Article
- Twisted orientation of the muscle bundles in the levator ani functional parts in women: Implications for pelvic floor support mechanism.Journal of anatomy · 2024Article
- Novel combination method of wide-range serial sectioning and 3D reconstruction visualizing both macro-level dynamics and micro-level interactions in an attempt to analyze the female pelvic floor.Anatomical science international · 2023Review
- Pelvic floor and perineal muscles: a dynamic coordination between skeletal and smooth muscles on pelvic floor stabilization.Anatomical science international · 2023Review
- Review
- Anatomy of Cowper's gland in humans suggesting a secretion and emission mechanism facilitated by cooperation of striated and smooth muscles.Scientific reports · 2021Article
- The series of smooth muscle structures in the pelvic floors of men: Dynamic coordination of smooth and skeletal muscles.Clinical anatomy (New York, N.Y.) · 2021Article
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Authors and funding
6 authors at 2 institutions in 1 country.
Funding
Abstract
Magnetic resonance images of the anal canal show small, circular, low-intensity areas arranged in a row and a high-intensity area surrounding them internally and externally in the longitudinal muscle layer that cannot be explained by current anatomical findings. The purpose of this study was to elucidate the detailed structure of the longitudinal smooth muscle of the anal canal and to interpret the magnetic resonance image of the longitudinal muscle. Specimens for macroscopic anatomy and histology were obtained from six and seven cadavers, respectively. The histological nature of the longitudinal muscle was examined by staining serial transverse and coronal sections of the lateral wall of the anal canal with Masson's trichrome stain and using immunohistochemistry for smooth and skeletal muscle fibers. Dense and sparse areas of smooth muscle fibers coexisted in the longitudinal muscle layer. The dense areas formed columnar muscle bundles approximately 1.0-1.5 mm in diameter, and they continued from the longitudinal muscle bundles of the rectum. The columnar muscle bundles of the longitudinal anal muscle were internally and externally surrounded by sparsely arranged smooth muscle fibers that ran longitudinally. The coexistence of dense and sparse areas of smooth muscle fibers suggests that the structure of the smooth muscle is optimized for its function. This histological nature is probably reflected in the magnetic resonance image of the longitudinal muscle as the coexistence of low- and high-intensity areas. Clin. Anat. 33:619-626, 2020. © 2019 Wiley Periodicals, Inc.
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