Development of the human hypogastric nerve sheath with special reference to the topohistology between the nerve sheath and other prevertebral fascial structures

Semi-serial sections from the lumbosacral region of nine fetuses (8-25 weeks gestation) were examined to clarify the lumbar prevertebral fascial arrangement. The prevertebral fasciae became evident after 12 weeks of age. After 20 weeks of age, the hypogastric nerve (HGN) was sandwiched by two fascial structures; the ventral fascia which seemed to correspond to the mesorectal fascia, whereas the dorsal fascia corresponded to the presacral fascia. These fasciae or the HGN sheaths extended laterally along the ventral aspects of the great vessels and associated lymph follicles. The ventral fascia is, to some extent, fused with the mesocolon descendens on the left side of the body. Notably, the lateral continuation of these two fasciae also sandwiches the left ureter, but not the right ureter, presumably due to modifications by the left-sided fusion fascia. A hypothetical common sheath for the HGN and ureter (i.e., the ureterohypogastric or vesicohypogastric fascia) might thus be an oversimplification. Before retroperitoneal fixation, the morphology of the peritoneal recess along the mesocolon descendens and mesosigmoid suggested interindividual differences in location, shape, and size. Therefore, in adults the ease of surgical separation of the rectum and left-sided colon from the HGN seems to depend on interindividual differences in the development of the embryonic peritoneal recess. On the caudal side of the second sacral segment, fascial structures were restricted along and around the HGN, pelvic splanchnic nerve, and pelvic plexus. The rectal lateral ligament thus seems to represent a kind of migration fascia formed by mechanical stress.     

直肠阴道隔的解剖学研究及其临床意义

目的:为直肠癌切除术,阴道塌陷及影像学提供解剖学依据.方法:25例福尔马林固定的成年女性盆腔标本,14例行正中失状切,在体式镜下观察,11例制成250～750μm厚的水平和矢状位火棉胶切片.结果:直肠阴道隔由前后两层组成.前层是Denonvilliers' fascia,后层是直肠同有筋膜.二者紧贴在一起,向上在直肠子宫陷凹处的腹膜折返下方分开,向下在会阴体上方分开,两侧在阴道后外侧分开.Denonvilliers' fascia在不同水平其两侧的止点不同:在宫颈平面止于宫旁组织,在阴道上部止于阴道旁组织,在阴道中部止于盆筋膜腱弓,在阴道下部止于肛提肌出口的外侧.结论:直肠阴道隔由前方的Denonvilliers' fascia和后方的直肠同有筋膜组成.     

Paravaginal defect: A new classification of fascial and muscle tears in the paravaginal region

The lateral support of the vaginal wall depends on the integrity of the paravaginal section of the visceral pelvic fascia, levator ani, and their connection. Various defects of the muscle and fascia can result in identical clinical findings—ie, the descent of the lateral vaginal sulcus. In this study, we created a realistic scheme for classifying paravaginal defects, based on the complex relationship of the pelvic fascia with the levator ani. Surgical observations, cadaver examinations, and a complex magnetic resonance imaging (MRI)‐based 3‐dimensional (3D) model were used to analyze the spatial relationships of normal and defective anatomy of the female pelvic floor. Descent of the lateral vaginal sulcus can result from a defect in the paravaginal visceral pelvic fascia, levator ani, or both. The fascial defect can be partial or complete, and the muscle defect can vary in location. A detailed illustrated classification is presented. We present a new model of the pathology that underlies a common clinical finding. Clin. Anat. 29:524–529, 2016. © 2016 Wiley Periodicals, Inc.     

Twisted orientation of the muscle bundles in the levator ani functional parts in women: Implications for pelvic floor support mechanism

This study presents a comprehensive investigation of the anatomical features of the levator ani muscle. 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 crucial for the accurate diagnosis and effective treatment of pelvic floor disorders. Previous studies have been limited by the lack of comprehensive three-dimensional analyses; to overcome this limitation, we analysed the levator ani muscle using a novel 3D digitised muscle-mapping approach based on layer-by-layer dissection. From this examination, we determined that the levator ani consists of overlapping muscle bundles with varying orientations, particularly in the anteroinferior portion. Our findings revealed distinct muscle bundles directly attached to the rectum (LA-re) and twisted muscle slings surrounding the anterior (LA-a) and posterior (LA-p) aspects of the rectum, which are considered functional parts of the levator ani. These results suggest that these specific muscle bundles of the levator ani are primarily responsible for functional performance. The levator ani plays a crucial role in rectal elevation, lifting the centre of the perineum and narrowing the levator hiatus. The comprehensive anatomical information provided by our study will enhance diagnosis accuracy and facilitate the development of targeted treatment strategies for pelvic floor disorders in clinical practice.     

The surgical anatomy of the fasciae and the fascial spaces related to the rectum

The perirectal fasciae and their vascular and neural relationships were studied based on the dissection of 46 fresh cadavers. The rectal fascia is a tubular sleeve, areolar in nature, which houses the superior rectal vessels and lymphatics. The nerves which supply fibres to the pelvic plexus run close to the rectum, contained in the urogenital and presacral fasciae. The rectum is attached to these two fasciae by the rectal stalks, which take a spiral course round the rectum, being posterolateral in the upper rectum, lateral in the mid-rectum and anterolateral in the lower rectum. During rectal resection the pelvic nn. may be preserved if the rectal dissection proceeds close to the rectal fascia. After cutting the rectal insertion of the presacral fascia, the lower rectal stalks (paraproctium) come into direct view and can be divided close to the rectal wall with no risk of damage to the pelvic plexus.     

Tomographical anatomy of the pelvis,pelvic floor,and related structures

The sectional anatomy of the pelvic floor was studied in plastinated sections of adult pelves by computed tomography and by magnetic resonance imaging. In sectional anatomy, the levator ani is composed of three portions that can be clearly distinguished by their planes of cleavage and by the course of their fiber bundles. No muscular connections are found between the levator ani portions and the pelvic organs. The fascia of the levator ani is always interposed between the muscle and the pelvic organs. The sectional anatomy of the sphincter ani externus reveals a subdivision into a subcutaneous and a deep portion. Although the puborectalis portion of the levator ani and the deep portion of the sphincter ani externus are more or less continuous, in sectional anatomy they can be distinguished due to their different origins and attachments. Clin. Anat. 10:223–230, 1997. © 1997 Wiley-Liss Inc.     

直肠骶骨筋膜-泌尿生殖层直肠附着处的 临床解剖观察及其临床意义

目的：观察直肠骶骨筋膜与泌尿生殖层及直肠固有筋膜的解剖学关系,探讨在低位直肠手术中解剖处理该 结构在保证直肠系膜完整性及保护自主神经的重要临床意义。方法：回顾性分析 2021 年 1 月至 12 月期间就诊于 宁波大学医学院附属医院肛肠外科的直肠癌患者的临床资料和手术录像,观察直肠骶骨筋膜形态和移行情况。结 果：观察可见直肠骶骨筋膜自骶前筋膜延续,并附着于直肠固有筋膜,年轻男性尤为明显,并且更加质地坚韧。 侧方直肠骶骨筋膜盆壁侧附着于肛提肌腱弓,直肠侧附着于直肠固有筋膜。泌尿生殖层呈环形围绕于直肠周围, 直肠骶骨筋膜是泌尿生殖层的尾侧末梢部分,此末梢附着于直肠固有筋膜。盆壁侧末梢附着于肛提肌腱弓处,直 肠腹侧的泌尿生殖层脏筋膜继续覆盖精囊向尾侧延续。女性筋膜较为薄弱,尤其是直肠腹侧部分,未能清晰观察 其向尾侧和两侧的延续情况。结论：术中应锐性分离泌尿生殖层附着于直肠固有筋膜处,以保护自主神经功能。     

The deep fascia and retinacula of the equine forelimb – structure and innervation

Recent advances in human fascia research have shed new light on the role of the fascial network in movement perception and coordination, transmission of muscle force, and integrative function in body biomechanics. Evolutionary adaptations of equine musculoskeletal apparatus that assure effective terrestrial locomotion are employed in equestrianism, resulting in the wide variety of movements in performing horses, from sophisticated dressage to jumping and high‐speed racing. The high importance of horse motion efficiency in the present‐day equine industry indicates the significance of scientific knowledge of the structure and physiology of equine fasciae. In this study, we investigated the structure and innervation of the deep fascia of the equine forelimb by means of anatomical dissection, histology and immunohistochemistry. Macroscopically, the deep fascia appears as a dense, glossy and whitish lamina of connective tissue continuous with its fibrous reinforcements represented by extensor and flexor retinacula. According to the results of our histological examination, the general structure of the equine forelimb fascia corresponds to the characteristics of the human deep fasciae of the limbs. Although we did find specific features in all sample types, the general composition of all examined fascial tissues follows roughly the same scheme. It is composed of dense, closely packed collagen fibers organized in layers of thick fibrous bundles with sparse elastic fibers. This compact tissue is covered from both internal and external sides by loosely woven laminae of areolar connective tissue where elastic fibers are mixed with collagen. Numerous blood vessels running within the loose connective tissue contribute to the formation of regular vascular network throughout the compact layer of the deep fascia and retinacula. We found nerve fibers of different calibers in all samples analyzed. The fibers are numerous in the areolar connective tissue and near the blood vessels but scarce in the compact layers of collagen. We did not observe any Ruffini, Pacini or Golgi‐Mazzoni corpuscles. In conclusion, the multilayered composition of compact bundles of collagen, sparse elastic fibers in the deep fascia and continuous transition into retinacula probably facilitate resistance to gravitational forces and volume changes during muscle contraction as well as transmission of muscle force during movement. However, further research focused on innervation is needed to clarify whether the deep fascia of the equine forelimb plays a role in proprioception and movement coordination.     

Anatomic approach to the parametrium: value of computed tomographic in vitro study compared to dissection

Summary The aim of this study is to describe the morphology of the normal parametrium by correlating the slices obtained with computed tomography of 12 female cadavers studied after intravascular injection of latex with the dissection findings in 6 of these patients. The upper limit, represented by the isthmus, was defined by the uterine a. and/or a superficial uterine v. and/or the coronary v. (Charpy). The lower limit corresponded to the insertion of the levator ani mm. at the junction of the middle and inferior thirds of the vagina. The paracervical and paravaginal tissues above the levator ani m. and medial to the pelvic fascia covering these muscles were perfectly visualized. The posterior limit, formed by the lateral ligament of the rectum and/or the sacrouterine ligaments, and the anterior limit determined by the umbilico-vesical fascia were more difficult to demonstrate. In this study the parametrium appeared as a highly vascular and essentially venous connective structure with a variable morphology dependent on the uterine position.

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Approche anatomique du paramètre : contribution de l'imagerie tomodensitométriquein vitro confrontée à la dissection

Résumé Le but de cette étude radioanatomique est de décrire la morphologie du paramètre en tomodensitométrie (TDM) en corrélant des coupes TDM de 12 cadavres féminins après injection intra-vasculaire de latex et l'aspect secondairement observé en dissection chez six d'entre eux. La limite crâniale se situant en regard de l'orifice interne du col est repérée par l'artère utérine sousligamentaire et/ou la veine utérine superficielle et/ou la veine coronaire de Charpy. La limite caudale est formée par l'insertion des muscles levator ani à la jonction tiers moyen/tiers inférieur du vagin. Le tissu para-cervical et para-vaginal au dessus de ce plan musculaire et médialement à l'aponévrose pelvienne recouvrant ceux-ci était parfaitement visualisé. La limite dorsale représentée par le ligament latéral rectal et/ou les ligaments utérosacrés ainsi que la limite ventrale définie par l'aponévrose ombilico-vésicale étaient plus difficiles à mettre en évidence. La vascularisation paramétriale est essentiellement sous-tendue par d'importants plexus veineux et un tissu conjonctif de soutien de morphologie variable dépendante de la position utérine.

     

Pelvic and perineal anatomy of the male Gorilla: Selected observations

The anatomy of parts of the pelvic outlet and perineum is described in an adult male gorilla. Two previously undescribed muscles are presented: (1) The puborectalis muscle, completely separated from the levator ani, arises from the region of the symphysis and forms a sling for the rectum while it also substitutes for the perineal membrane. (2) The puboampullaris muscle, a paired smooth muscle, arises from the pubis and inserts into the rectum to elevate the rectum while additionally providing support for the urogenital viscera. The levator ani muscle is recounted to point out its lack of attachment to the pelvic viscera while allowing a hiatus in which the rectum is exposed within the perineum. The sphincter urethrae muscle is presented emphasizing its true sphincteric characteristics, its absence of lateral attachments and its similarity to man. Other muscles of the pelvis and perineum as well as urogenital viscera are described or modified where necessary. The manner in which these structures enter into the support of the pelvic viscera is considered.     

The role of fasciae in Civinini–Morton's syndrome

This study evaluates the pathogenetic role of the perineural connective tissue and foot fasciae in Civinini–Morton's neuroma. Eleven feet (seven male, four female; mean age: 70.9 years) were dissected to analyse the anatomy of inter‐metatarsal space, particularly the dorsal and plantar fasciae and metatarsal transverse ligament (DMTL). The macrosections were prepared for microscopic analysis. Ten Civinini–Morton neuromas obtained from surgery were also analysed. Magnetic resonance images (MRIs) from 40 patients and 29 controls were compared. Dissections showed that the width of the inter‐metatarsal space is established by two fibrous structures: the dorsal foot fascia and the DMTL, which, together, connect the metatarsal bones and resist their splaying. Interosseous muscles spread out into the dorsal fascia of the foot, defining its basal tension. The common digital plantar nerve (CDPN) is encased in concentric layers of fibrous and loose connective tissue, continuous with the vascular sheath and deep foot fascia. Outside this sheath, fibroelastic septa, from DMTL to plantar fascia, and little fat lobules are present, further protecting the nerve against compressive stress. The MRI study revealed high inter‐individual variability in the forefoot structures, although only the thickness of the dorsal fascia represented a statistically significant difference between cases and controls. It was hypothesized that alterations in foot support and altered biomechanics act on the interosseous muscles, increasing the stiffness of the dorsal fascia, particularly at the points where these muscles are inserted. Chronic rigidity of this fascia increases the stiffness of the inter‐metatarsal space, leading to entrapment of the CDPN.     

The fascial connections of the pectineal ligament

In clinical settings, the pectineal ligament forms a basic landmark for surgical approaches. However, to date, the detailed fascial topography of this ligament is not well understood. The aim of this study was to describe the morphology of the pectineal ligament including its fascial connections to surrounding structures. The spatial–topographical relations of 10 fresh and embalmed specimens were dissected, stained, slice plastinated, and analyzed macroscopically, and in three cases histological approaches were also used. The pectineal ligament is attached ventrally and superiorly to the pectineus muscle, connected to the inguinal ligament by the lacunar ligament and to the tendinous origin of rectus abdominis muscle and the iliopubic tract. It forms a site of origin for the internal obturator muscle, and throughout its curved course, the ligament attaches to both the fasciae of iliopsoas and the internal obturator muscle. However, dorsally, these fasciae pass free from the bone, while the pectineal ligament itself is adhered to it. The organ fasciae are seen apart from the pectineal ligament and its connections. The pectineal ligament seems to form a connective tissue junction between the anterior and medial compartment of the thigh. This ligament, however, is free to other compartments arisen from the embryonal gut and to the urogenital ridge. These features of the pectineal ligament are important to consider during orthopedic and trauma surgical approaches, in gynecology, hernia and incontinence surgery, and in operations for pelvic floor and neovaginal reconstructions. Clin. Anat. 32:961–969, 2019. © 2019 Wiley Periodicals, Inc.     

盆腔筋膜的胚胎学研究进展

目的 探讨盆腔筋膜胚胎发育过程,提高对盆腔筋膜结构层次的认识,为直肠癌的外科治疗和影像学诊断提供理论支持。方法 以“胚胎学”“盆腔筋膜”“直肠系膜”为关键词在万方数据、PubMed 数据库查阅1908年6月—2015年6月发表的与直肠筋膜胚胎学研究相关文献,进行汇总分析。结果 盆腔筋膜的胚胎学发育经过间充质期、结缔组织形成期和脂肪组织形成期3个时期逐渐形成完整的环形筋膜结构,以直肠固有筋膜包绕的直肠与直肠系膜构成内层,以盆腔壁层筋膜及前方的Denonvilliers筋膜构成外层,与成人解剖研究中的环形筋膜结构相符。结论 盆腔筋膜的胚胎学研究进一步证实了盆腔筋膜的环形分布理论,为直肠癌影像学诊断及外科治疗提供了理论支持。     

Does the cardinal ligament of the uterus contain a nerve that should be preserved in radical hysterectomy?

The cardinal ligament (CL) of the uterus is present as a specific part of the parametrium when the pararectal and paravesical spaces are developed surgically. According to usual nerve-sparing radical hysterectomy (the Tokyo method), the CL is divided into two parts, the vascular part for dissection and the nerve part that contains the pelvic splanchnic nerve (PSN) as a major target for nerve sparing. In contrast, we hypothesized that the CL and another structure outside of the usual area for surgical dissection, that is, the lateral rectal ligament, are mutually continuous and that the PSN runs through the lateral ligament rather than the CL. In the present study, a combination of routine dissection, fresh cadaver dissection and in situ sectional anatomy revealed that: (i) the CL did not contain the PSN; (ii) a well-defined fascial structure existed in the bottom or dorsal margin of the CL area; and (iii) the pelvic plexus was separated from vascular components of the CL. The present results provide a new perspective for nerve-sparing radical hysterectomy with extensive lateral parametrial dissection of the CL.     

Anatomy of the arcus tendineus fasciae pelvis in females

Because of its proximity to the urethra, the anterior part of the arcus tendineus fasciae pelvis (ATFP) may be used in urethrosuspension procedures for urinary stress incontinence. In this study, 10 embalmed female cadaver hemipelves were dissected and their gross anatomy described. In females, the ATFP is a condensation of the endopelvic fascia. The anterior attachment of the ATFP is to the caudal inner surface of the body of the pubic bone at a site averaging 4 mm lateral to the pubic symphysis and covering an average area of 53 mm(2). Posteriorly, it attaches to the medial surface of the ischial spine. In nine of the 10 hemipelves the first anterior centimeters of the ATFP have a clear lateral fixation either to the lateral part of the levator ani muscle (n = 1), to the fascia covering the obturator internus muscle (n = 7), or to the obturator membrane (n = 1). Medially from the ATFP derives a 2-3-cm long flat fibrous attachment to the posterolateral aspect of the urethra. In eight unembalmed cadavers, the ATFP gave way at a pulling force of 8.2 kg (range = 3.5-11.5 kg). The ATFP resists caudal movement of the proximal anterior vaginal wall and the urethra in the upright posture and, therefore, may be suitable for urethrosuspension procedures.     

坐骨神经鞘膜的形态学观察

目的 明确成人盆部坐骨神经筋膜鞘存在与否及其完整性,为临床坐骨神经阻滞提供形态学依据。方法 选用14具盆腔至腘窝段完整的成人坐骨神经标本,采用局部乳胶注射解剖（10例）,矢状位、水平位断层解剖（2例）,组织学切片（2例）和磁共振（MRI）（20例）等方法来观察坐骨神经盆腔段的形态学特点。
结果 盆部乳胶未沿神经根走行扩散;断层和组织学资料显示,骶丛神经根无完整鞘膜包裹,骶丛神经和闭孔神经之间无筋膜分割;MRI结果与断层结果相符。结论 坐骨神经根在成人盆腔段无完整筋膜鞘包裹,骶旁阻滞可以阻滞到闭孔神经。     

Pes anserinus: layered supportive structure on the medial side of the knee

The pes anserinus is composed of a combination of tendinous insertions of the sartorius, gracilis and semitendinosus muscles. Precise knowledge of the structures on the medial side of the knee and the relationships between fascia and tendons is critical for diagnosis, surgery, and the development of improved operative procedures of the knee. To obtain precise data on the layered structures associated with the fascia cruris on the medial side of the knee and the fibrous bundles attached to them, we dissected nine legs of five adult cadavers. We observed a superficial longitudinal fibrous bundle on the superficial surface of the sartorius and a deep longitudinal fibrous bundle on the aponeurotic membrane covering the tendon of the gracilis muscle. The distal parts of the tendons of the gracilis and semitendinosus were found to have aponeurotic membranes, and these membranes were fused with the fascia cruris. These two longitudinal fibrous bundles and the aponeurotic membranes from the gracilis and semitendinosus tendons fused with the fascia cruris, and a small tendinous expansion from the semimembranosus muscle fused with the aponeurotic membrane from the semitendinosus tendon and tibial collateral ligament as well as the fascia covering the medial head of the gastrocnemius and fascia cruris. Based on the considerable tension from the sartorius, gracilis, semitendinosus, semimembranosus and gastrocnemius muscles, these bundles, membranes, and muscles may act as a complex tensor fasciae cruris muscle and play a significant role as stabilizers of the medial side of the knee joint in the upright posture.     

The surgical anatomy of the fasciae and the fascial spaces related to the rectum

Summary The perirectal fasciae and their vascular and neural relationships were studied based on the dissection of 46 fresh cadavers. The rectal fascia is a tubular sleeve, areolar in nature, which houses the superior rectal vessels and lymphatics. The nerves which supply fibres to the pelvic plexus run close to the rectum, contained in the urogenital and presacral fasciae. The rectum is attached to these two fasciae by the rectal stalks, which take a spiral course round the rectum, being posterolateral in the upper rectum, lateral in the mid-rectum and anterolateral in the lower rectum. During rectal resection the pelvic nn. may be preserved if the rectal dissection proceeds close to the rectal fascia. After cutting the rectal insertion of the presacral fascia, the lower rectal stalks (paraproctium) come into direct view and can be divided close to the rectal wall with no risk of damage to the pelvic plexus.

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Anatomie chirurgicale des fascias et espaces en rapport avec le rectum

Résumé Les fascias péri-rectaux et leurs rapports vasculo-nerveux ont été étudiés par dissection de 46 cadavres frais. Le fascia rectal est un manchon tubulaire, de nature aréolaire, qui enveloppe les vaisseaux rectaux supérieurs et les lymphatiques. Les nerfs qui alimentent le plexus pelvien courent près du rectum, contenus par les fascias uro-génital et pré-sacré. Le rectum est relié à ces deux fascias par les ailerons du rectum, dont le trajet en spirale est postéro-latéral à la partie haute du rectum, latéral à sa partie moyenne, antéro-latéral à sa partie inférieure. Au cours des résections rectales, il est possible de respecter les nerfs pelviens si la dissection du rectum est menée au ras du fascia rectal. Après avoir coupé l'insertion rectale du fascia présacré, les ailerons rectaux inférieurs (paraproctium) sont directement visibles et peuvent être sectionnés au ras de la paroi rectale sans risque de lésion du plexus pelvien.