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Muro S, Shoji S, Suriyut J, Akita K. Anatomy of muscle connections in the male urethra and anorectal canal. BJU Int 2024; 133:752-759. [PMID: 38456568 DOI: 10.1111/bju.16307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2024]
Abstract
OBJECTIVES To elucidate the male urethral muscular structure and its relationship with the anorectal canal muscles, as establishing an anatomical foundation for urethral function will contribute to the prevention, diagnosis, and treatment of urinary incontinence. METHODS Eight male cadavers were used. Using a multifaceted approach, we performed macroscopic anatomical examination, histological analysis of wide-range serial sectioning and immunostaining, and three-dimensional (3D) reconstruction from histological sections. In the macroscopic anatomical examination, pelvic halves were meticulously dissected in layers from the medial aspect. In the histological analysis, the tissue, including the urethra and anorectal canal, was serially sectioned in the horizontal plane. The muscular structures were reconstructed and visualised in 3D. RESULTS The membranous portion of the urethra had three muscle layers: the longitudinal and circular muscles (smooth muscle) and the external urethral sphincter (skeletal muscle). The circular muscle was connected posteriorly to the longitudinal rectal muscle. The external urethral sphincter had a horseshoe shape, with its posterior ends continuing to the external anal sphincter, forming a 3D ring-like sphincter. CONCLUSION This study revealed skeletal and smooth muscle connections between the male urethra and anorectal canal, enabling urethral compression and closure. These anatomical muscle connections suggest a functional linkage between them.
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Affiliation(s)
- Satoru Muro
- Department of Clinical Anatomy, Tokyo Medical and Dental University (TMDU), Bunkyo-ku, Tokyo, Japan
| | - Sunao Shoji
- Department of Urology, Tokai University School of Medicine, Isehara, Kanagawa, Japan
| | - Janyaruk Suriyut
- Department of Anatomy, Faculty of Medicine, Srinakharinwirot University, Bangkok, Thailand
| | - Keiichi Akita
- Department of Clinical Anatomy, Tokyo Medical and Dental University (TMDU), Bunkyo-ku, Tokyo, Japan
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Evaluation of morphological features of palatopharyngeus insertion into the thyroid cartilage. Anat Sci Int 2023:10.1007/s12565-023-00709-7. [PMID: 36877447 DOI: 10.1007/s12565-023-00709-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Accepted: 02/22/2023] [Indexed: 03/07/2023]
Abstract
The attachment of the palatopharyngeus extended from the posterior end of the thyroid cartilage to the posterior margin of the inferior constrictor attachment that might contribute to successive swallowing movements. Laryngeal elevation is essential for proper swallowing and breathing. Recently, clinical research has demonstrated that the palatopharyngeus, a longitudinal muscle of the pharynx, is involved in the elevation of the larynx. However, the morphological relationship between the larynx and palatopharyngeus remains unclear. In the present study, we analyzed the attachment site and characteristics of the palatopharyngeus in the thyroid cartilage. We evaluated 14 halves of seven heads from Japanese cadavers (average age: 76.4 years); 12 halves, anatomically and two halves histologically. A part of the palatopharyngeus, which originated from the inferior aspect of the palatine aponeurosis, was attached to the inner and outer surfaces of the thyroid cartilage through collagen fibers. The attachment area extends from the posterior end of the thyroid cartilage to the posterior margin of the attachment site of the inferior constrictor. The palatopharyngeus may elevate the larynx with the suprahyoid muscles and contribute to successive movements of swallowing with surrounding muscles. Based on our findings and previous studies, palatopharyngeus with various muscle bundle directions may be essential for the coordination of continuous swallowing events.
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Zhao J, Ma H, Wang Y, Song T, Wu D, Yin N. Cadaveric Study and Micro-Computed Tomography of the Anatomy of Palatine Aponeurosis and its Link to the Soft Palate Muscles and Pharyngeal Muscles. Cleft Palate Craniofac J 2023; 60:319-326. [PMID: 34812076 DOI: 10.1177/10556656211063109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
OBJECTIVE There have been few studies on the anatomy of palatine aponeurosis (PA). Herein, we elucidated the relationship between the PA and soft palate muscles and pharyngeal muscles. DESIGN Two cadaveric specimens were dissected to observe the gross anatomy of the PA. Six cadaveric specimens were processed and scanned by micro-computed tomography to determine the elaborate anatomy. Images were exported to Mimics software to reconstruct a three-dimensional model. RESULTS The PA covered the anterior (32.1%-38.8%) of the soft palate, extending from the tensor veli palatini (TVP) and connecting to 3 muscles: palatopharyngeus (PP), uvula muscle, and superior pharyngeal constrictor (SC). The SC and PP are attached to the PA on the medial side of the pterygoid hamulus. SC muscle fibers were attached to the hamulus, forming a distinct gap between the hamulus. Some muscle fibers of the PP and uvula originated from the PA. The PA extended from the TVP to the midline and the posterior edge of the hard palate. The PA was not uniformly distributed, which was complementary to the attached muscles in thickness. CONCLUSIONS PA, as a flexible fibrous membrane, maintains the shape of the soft palate. It extends from the TVP and covers anteriorly about one-third of the soft palate. The PA provides a platform for the soft palate muscles and pharyngeal muscles, connecting to the PP, uvula muscle, and SC. These muscles are important for palatopharyngeal closure and middle-ear function. It is necessary to minimize the damage to the PA during surgical interventions.
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Affiliation(s)
- Jiuli Zhao
- Plastic Surgery Hospital, 74698Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Hengyuan Ma
- Plastic Surgery Hospital, 74698Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yongqian Wang
- Plastic Surgery Hospital, 74698Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Tao Song
- Plastic Surgery Hospital, 74698Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Di Wu
- Plastic Surgery Hospital, 74698Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Ningbei Yin
- Plastic Surgery Hospital, 74698Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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Bordoni B, Escher AR, Toccafondi A, Mapelli L, Banfi P. Obstructive Sleep Apnea and Role of the Diaphragm. Cureus 2022; 14:e29004. [PMID: 36159353 PMCID: PMC9495286 DOI: 10.7759/cureus.29004] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/10/2022] [Indexed: 11/07/2022] Open
Abstract
Obstructive sleep apnea (OSA) causes multiple local and systemic pathophysiological consequences, which lead to an increase in morbidity and mortality in patients suffering from this disorder. OSA presents with various nocturnal events of apnoeas or hypopneas and with sub-clinical airflow limitations during wakefulness. OSA involves a large percentage of the population, particularly men, but the estimate of OSA patients could be much broader than data from the literature. Most of the research carried out in the muscle field is to understand the causes of the presence of chronic nocturnal desaturation and focus on the genioglossus muscle and other muscles related to dilating the upper airways. Sparse research has been published regarding the diaphragm muscle, which is the main muscle structure to insufflate air into the airways. The article reviews the functional anatomy of the muscles used to open the upper respiratory tract and the non-physiological adaptation that follows in the presence of OSA, as well as the functional anatomy and pathological adaptive aspects of the diaphragm muscle. The intent of the text is to highlight the disparity of clinical interest between the dilator muscles and the diaphragm, trying to stimulate a broader approach to patient evaluation.
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Three-Dimensional Anatomy of the Palatopharyngeus and Its Relation to the Levator Veli Palatini Based on Micro-Computed Tomography. Plast Reconstr Surg 2021; 148:389e-397e. [PMID: 34432689 DOI: 10.1097/prs.0000000000008275] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Although multiple studies have been reported on the palatopharyngeus and levator veli palatini, their subtle anatomy and functions remain unclear. The authors elucidated the relationship between these muscles and their functional implications based on three-dimensional digital techniques. METHODS Cadaveric specimens were stained with iodine-potassium iodide and scanned using micro-computed tomography. The muscle fibers were drawn on the exported Imaging and Communications in Medicine images to reconstruct a three-dimensional model and further simplified. RESULTS In the soft palate, the palatopharyngeus was divided into three bundles. The largest inferior head was found to attach to the palatine aponeurosis, soft palate, and the hard palate on the oral side, which occupied approximately the anterior 28.4 to 36.2 percent of the soft palate in the midline. The superior head was thin and attached to the palatine aponeurosis and the surrounding mucosa on the nasal side. The posterior head was located posterior to the levator veli palatini with fibers attaching to the levator veli palatini and the median portion of the uvula. The levator veli palatini was clasped by the three heads of the palatopharyngeus. The fasciculi of the palatopharyngeus converged into a bundle of muscles at the pharynx and inserted into the lateral and posterior pharyngeal wall. CONCLUSIONS The palatopharyngeus is the largest muscle that connects the soft palate and pharyngeal wall; it closely coordinates with the levator veli palatini to control levator veli palatini overlifting, narrow the velopharyngeal port with the help of the superior constrictor, and elevate the pharynx. The palatopharyngeus and levator veli palatini help each other in velopharyngeal closure through coordination from other muscles.
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Fukino K, Tsutsumi M, Nimura A, Miwa K, Ono T, Akita K. Reply to "Palatopharyngeus muscle in pharyngoplasty surgery for OSAS: cut or not to cut?". Eur Arch Otorhinolaryngol 2021; 278:2659-2660. [PMID: 33885972 DOI: 10.1007/s00405-021-06821-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 04/09/2021] [Indexed: 11/28/2022]
Affiliation(s)
- Keiko Fukino
- Department of Orthodontic Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
| | - Masahiro Tsutsumi
- Department of Clinical Anatomy, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Yushima 1-5-45, Bunkyo-ku, Tokyo, 113-8519, Japan.,Inclusive Medical Science Research Institute, Morinomiya University of Medical Sciences, 1-26-16 Nankokita, Suminoe-ku, Osaka city, Osaka, 559-8611, Japan
| | - Akimoto Nimura
- Department of Functional Joint Anatomy, Graduate School of Medical and Dental Science, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8519, Japan
| | - Koh Miwa
- Department of Clinical Anatomy, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Yushima 1-5-45, Bunkyo-ku, Tokyo, 113-8519, Japan
| | - Takashi Ono
- Department of Orthodontic Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
| | - Keiichi Akita
- Department of Clinical Anatomy, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Yushima 1-5-45, Bunkyo-ku, Tokyo, 113-8519, Japan.
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Fukino K, Tsutsumi M, Nimura A, Miwa K, Ono T, Akita K. Anatomy of inferior end of palatopharyngeus: its contribution to upper esophageal sphincter opening. Eur Arch Otorhinolaryngol 2020; 278:749-754. [PMID: 33083866 PMCID: PMC7895782 DOI: 10.1007/s00405-020-06437-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 10/12/2020] [Indexed: 11/03/2022]
Abstract
PURPOSE The palatopharyngeus is one of the longitudinal pharyngeal muscles which contributes to swallowing. It is reported that the palatopharyngeus has muscle bundles in various directions and with attachment sites, and each muscle bundle has a specific function. Although previous reports suggest that the palatopharyngeus is partly interlaced with some parts of the inferior constrictor, the precise relationship remains unclear. The purpose of this study was to examine the precise manner of the connection between the palatopharyngeus and inferior constrictor, and to examine the histological characteristics of this connection. METHODS We examined 15 halves of nine heads from Japanese cadavers (average age: 76.1 years); 12 halves, macroscopically, and three halves, histologically. RESULTS Our observation suggests that the palatopharyngeus spreads radially on the inner aspect of the pharyngeal wall. The most inferior portion of the palatopharyngeus extended to the inner surface of the cricopharyngeal part of the inferior constrictor. Histological analysis showed that the inferior end of the palatopharyngeus continued into the dense connective tissue located at the level of the cricoid cartilage. The dense connective tissue not only covered the inner surface of the inferior constrictor but also entered its muscle bundles and enveloped them. CONCLUSION Therefore, the palatopharyngeus interlaced the cricopharyngeal part of the inferior constrictor through the dense connective tissues. The findings of this study show that the palatopharyngeus may act on the upper esophageal sphincter directly and help in its opening with the aid of the pulling forces in the superolateral direction.
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Affiliation(s)
- Keiko Fukino
- Department of Orthodontic Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
| | - Masahiro Tsutsumi
- Department of Clinical Anatomy, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8519, Japan
| | - Akimoto Nimura
- Department of Functional Joint Anatomy, Graduate School of Medical and Dental Science, Tokyo Medical and Dental University, Tokyo, Japan
| | - Koh Miwa
- Department of Clinical Anatomy, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8519, Japan
| | - Takashi Ono
- Department of Orthodontic Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
| | - Keiichi Akita
- Department of Clinical Anatomy, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8519, Japan.
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Bae Y, Perta K, Obert K, Kalmar E. Contracted Extravelar Segments of the Levator Veli Palatini Muscle: A Magnetic Resonance Imaging Morphometric Study. Cleft Palate Craniofac J 2020; 58:118-125. [PMID: 32551942 DOI: 10.1177/1055665620933472] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVES To provide detailed descriptions of contraction-induced morphometric changes in the extravelar segments of the levator veli palatini (LVP) muscle using 3-dimensional (3-D) magnetic resonance imaging (MRI). DESIGN Three-dimensional MRI data were acquired at rest and during "silent /i/" from 4 singers. During silent /i/, participants voluntarily sustained velar elevation while breathing orally for the entire scan time. Focusing on the extravelar segments, LVP length, angle of the muscle origin, and cross-sectional area (CSA), measurements were obtained and compared between tasks. RESULTS Three of the 4 participants exhibited the expected patterns of change following concentric contraction of the LVP muscle. Consistent changes from the resting to the contracted state included reductions in LVP length by 13.5% and angle of the muscle origin by 9.8%, as well as increases in CSAs by 22.1%, on average. CONCLUSIONS This study presented high-resolution data of the LVP muscle behavior with the first in vivo 3-D measurements of the contracted LVP muscle, which can be useful for the validation of computational models that aim at describing biomechanical properties of the LVP muscle in future research. The active behavior of the extravelar LVP muscle also provides some insight on optimal LVP muscle geometry to consider during cleft palate repair.
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Affiliation(s)
- Youkyung Bae
- Department of Speech and Hearing Science, 215745The Ohio State University, Columbus, OH, USA
| | - Karen Perta
- Department of Speech and Hearing Science, 215745The Ohio State University, Columbus, OH, USA
| | - Kerrie Obert
- Department of Otolaryngology, 215745The Ohio State University, Columbus, OH, USA
| | - Eileen Kalmar
- Department of Biomedical Education and Anatomy, 12305The Ohio State University, Columbus, OH, USA
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An anatomical study of the anterior wall of the hypopharyngeal and the cervical esophageal junction. Auris Nasus Larynx 2020; 47:849-855. [PMID: 32376069 DOI: 10.1016/j.anl.2020.04.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 03/10/2020] [Accepted: 04/14/2020] [Indexed: 11/21/2022]
Abstract
OBJECTIVE The upper esophageal sphincter plays a significant role by forming a physical barrier at the junction of the hypopharynx and the cervical esophagus. As few studies have focused on the ventral aspect of this junction, the contribution of the anterior wall of the cervical esophagus to upper esophageal sphincter function remains unknown. The purpose of this study was to examine the muscle fibers' arrangement at the junction, especially of those forming its anterior wall. METHODS Thirteen specimens from 13 Japanese cadavers were analyzed. Six specimens were dissected macroscopically, while the remaining seven were examined histologically. RESULTS The outer longitudinal layer of the proximal esophagus was well-developed anterolaterally. The uppermost fibers of the inner circular layer of the esophagus ascended longitudinally. The anterolateral part of the outer longitudinal layer and the uppermost region of the inner circular layer were continuous with the median tendinous band, in turn reaching superior to the cricoid cartilage. Histological analysis showed that the tendinous band was also continuous with the superior part of the perichondrium of the cricoid cartilage and with the aponeurosis of the transverse and oblique arytenoids. CONCLUSION The well-developed anterolateral region of the outer longitudinal layer and the uppermost fibers of the inner circular layer were continuous with the median tendinous band, which reached superior to the cricoid cartilage. The contraction of the proximal esophagus may result in protrusion of the anteromedian esophageal wall into the lumen, thereby supporting the closure of the upper esophageal sphincter.
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