Retroperitoneal fasciae as barriers for nerve and arterial passages connecting the retroperitoneal region to the peritoneal organs.

The fascia of the pancreatic head is referred to as the retropancreatic fascia of Treitz, and that of the body and tail of the pancreas is named the retropancreatic fascia of Toldt. However, the spatial relationship between the nerves, fascia, and the distribution of the fascia on the dorsal side of the pancreas remains unclear. Therefore, this study aimed to explore the distribution of these fasciae and elucidate the spatial relationship between the nerves and arteries connecting the retroperitoneal space and the peritoneal organs by studying eight cadavers using macroscopic anatomical examination, wide-range serial sectioning, and three-dimensional reconstruction. The fasciae of Treitz and Toldt converge caudally to the root of the superior mesenteric artery (SMA), forming a narrower gap around the roots of the celiac trunk and SMA than in the celiac plexus. The fasciae eventually get closer to each other, and the boundary between them becomes obscured, providing coverage to the anterior surface of the aorta between the SMA and the inferior mesenteric artery. The celiac plexus does not penetrate the fascia but converges before spreading into the pancreas. Similarly, the arteries pass through this gap in the fasciae. Our findings suggest that the retroperitoneal space and peritoneal organs are connected through a narrow no-fascia area, with the distribution of the fascia relating to nervous and vascular pathways. Our findings reveal that the distribution of the avascular plane may provide a crucial anatomical foundation for abdominal digestive organ surgery by reducing bleeding volume and determining the dissection region.

Anatomy of muscle connections in the male urethra and anorectal canal.

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.

Denonvilliers' fascia as a potential nerve-course marker for the female urinary bladder.

OBJECTIVES: This study investigated the relationship between Denonvilliers' fascia (DF) and the pelvic plexus branches in women and explored the possibility of using the DF as a positional marker in nerve-sparing radical hysterectomy (RH). METHODS: This study included eight female cadavers. The DF, its lateral border, and the pelvic autonomic nerves running lateral to the DF were dissected and examined. The pelvis was cut into two along the mid-sagittal line. The uterine artery, deep uterine veins, vesical veins, and nerve branches to the pelvic organs were carefully dissected. RESULTS: The nerves ran sagitally, while the DF ran perpendicularly to them. The rectovaginal ligament was continuous with the DF, forming a single structure. The DF attached perpendicularly and seamlessly to the pelvic plexus. The pelvic plexus branches were classified into a ventral part branching to the bladder, uterus, and upper vagina and a dorsal part branching to the lower vagina and rectum as well as into four courses. Nerves were attached to the rectovaginal ligament and ran on its surface to the bladder ventral to the DF. The uterine branches split from the common trunk of these nerves. The most dorsal branch to the bladder primarily had a common trunk with the uterine branch, which is the most important and should be preserved in nerve-sparing Okabayashi RH. CONCLUSION: The DF can be used as a marker for nerve course, particularly in one of the bladder branches running directly superior to the DF, which can be preserved in nerve-sparing Okabayashi RH.

Morphometric Analysis of the Tibial Attachment Shape of the Anterior Cruciate Ligament and Its Relationship With the Location of the Anterior Horn of the Lateral Meniscus.

BACKGROUND: The success of anterior cruciate ligament (ACL) reconstruction relies on the accurate replication of the native ACL anatomy, including attachment shapes. The tibial attachment of the ACL exhibits significant shape variations with elliptical, C, and triangular shapes, highlighting the need for objective classification methods and additional information to identify individual anatomic variations. HYPOTHESIS: The location of the attachment of the anterior horn of the lateral meniscus (AHLM) may determine the shape of the ACL attachment. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: The study used 25 knees from 17 Japanese cadavers for macroscopic anatomic examination and quantitative analysis. The shape of the ACL attachment was quantified using principal component analysis with elliptical Fourier descriptors, whereas the AHLM location was quantified by measuring its mediolateral and anteroposterior positions on the superior surface of the tibia. Reliability was assessed statistically. RESULTS: The shape of the tibial attachment of the ACL varied among individuals and was classified as elliptical, C-shaped, or triangular. Scatterplots of the principal components of the ACL attachment shape showed overlapping regions of elliptical, C-shaped, and triangular ACL attachments, indicating that a C-shaped attachment is intermediate between elliptical and triangular attachments. The location of the AHLM attachment also varied, with areas in the anterolateral, anteromedial, or posteromedial region. The ACL shape and AHLM location were related, with elliptical, C-shaped, and triangular ACL attachments corresponding to anterolateral, anteromedial, and posteromedial AHLM attachments, respectively. CONCLUSION: The AHLM attachment location influences the shape of the ACL attachment. Information on the location of the AHLM attachment can aid in predicting the shape of the ACL attachment during ACL reconstruction, potentially improving footprint coverage.

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.

Significant relationship between musculoaponeurotic attachment of the abdominal and thigh adductor muscles to the pubis: implications for the diagnosis of groin pain.

Groin pain is prevalent in orthopedic and sports medicine, causing reduced mobility and limiting sports activity. To effectively manage groin pain, understanding the detailed anatomy of supporting muscles is crucial. This study aimed to investigate the musculoaponeurotic attachments on the pubis and the relationship among intramuscular aponeuroses of abdominal and thigh adductor musculatures. Macroscopic analyses were performed in 10 pelvic halves. The bone morphology of the pubis was assessed in two pelvic halves using microcomputed tomography. Histological investigations were conducted in two pelvic halves. The external oblique aponeurosis extended to the adductor longus aponeurosis, forming conjoined aponeurosis, which attached to a small impression distal to the pubic crest. The gracilis aponeurosis merges with the adductor brevis aponeurosis and is attached to the proximal part of the inferior pubic ramus. The rectus abdominis and pyramidalis aponeuroses were attached to the pubic crest and intermingled with the gracilis-adductor brevis aponeurosis, forming bilateral conjoined aponeurosis, which attached to a broad area covering the anteroinferior surface of the pubis. Histologically, these two areas of conjoined aponeuroses were attached to the pubis via the fibrocartilage enthesis. Microcomputed tomography revealed two distinctive bone morphologies, a small impression and an elongated osseous prominence on pubis, corresponded to the two areas of conjoined aponeuroses. This study demonstrated close relationships between the aponeurotic attachment of the external oblique and adductor longus, and between the rectus abdominis, pyramidalis, gracilis, and adductor brevis. The findings of aponeurotic complexes would aid in diagnostic and surgical approaches for athletic groin pain.

Surgical anatomy of the dorsal pancreatic artery: Considering embryonic development.

OBJECTIVES: The dorsal pancreatic artery (DPA) is a pancreatic branch with various anatomical variations. Previous studies mostly focused on the origin of the DPA, and its pathways and branching patterns have rarely been examined. The purpose of this study was to investigate the branching patterns and pathways of the DPA. METHODS: This study included 110 patients who underwent computed tomography scans. We examined the pathways and branching patterns of the DPA. RESULTS: The DPA was identified in 101 patients (92%), and originated from the splenic artery in 30 patients (31%), the common hepatic artery in 17 patients (17%), the celiac trunk in 10 patients (10%), the superior mesenteric artery in 27 patients (27%), the replaced right hepatic artery in 7 patients (7%), the inferior pancreaticoduodenal artery in 5 patients (5%), and other arteries in 3 patients (3%). Four distinct types of branches were identified as follows: the superior branch (32%), the inferior branch (86%), the right branch (80%), and the accessory middle colic artery (12%). Additionally, the arcs of Buhler and Riolan were observed in two patients each and their anastomotic vessels followed almost the same pathway as the DPA. CONCLUSION: A number of variations of the DPA were observed with regard to its origin and branching pattern; however, the DPA and its branches always ran along the same pathway, as summarized in Fig. 4. The anatomical information gained from this study may contribute to performing safe pancreatic resections.

Histological study of the structural layers around the esophagus in the lower mediastinum.

BACKGROUND: In Japan, the transhiatal approach, including lower mediastinal lymph node dissection, is widely performed for Siewert type II esophagogastric junction adenocarcinoma. This procedure is generally performed in a magnified view using laparoscopy or a robotic system, therefore, the microanatomy of the lower mediastinum is important. However, mediastinal microanatomy is still unclear and classification of lower mediastinal lymph nodes is not currently based on fascia or other microanatomical structures. AIM: To clarify the fascia and layer structures of the lower mediastinum and classify the lower mediastinal tissue. METHODS: We dissected the esophagus and surrounding organs en-bloc from seven cadavers fixed in 10% formalin. Organs and tissues were then cut at the level of the lower thoracic esophagus, embedded in paraffin, and serially sectioned. Tissue sections were stained with Hematoxylin-Eosin (all cadavers) and immunostained for the lymphatic endothelial marker D2-40 (three cadavers). We observed the periesophageal fasciae and layers, and defined lymph node boundaries based on the fasciae. Lymphatic vessels around the esophagus were observed on immunostained tissue sections. RESULTS: We identified two fasciae, A and B. We then classified lower mediastinal tissue into three areas, paraesophageal, paraaortic, and intermediate, using these fasciae as boundaries. Lymph nodes were found to be present and were counted in each area. The dorsal part of the intermediate area was thicker on the caudal side than on the cranial side in all cadavers. On the dorsal side, no blood vessels penetrated the fasciae in six of the seven cadavers, whereas the proper esophageal artery penetrated fascia B in one cadaver. D2-40 immunostaining showed lymphatic vessel connections between the paraesophageal and intermediate areas on the lateral and ventral sides of the esophagus, but no lymphatic connection between areas on the dorsal side of the esophagus. CONCLUSION: Histological studies identified two fasciae surrounding the esophagus in the lower mediastinum and the layers separated by these fasciae were used to classify the lower mediastinal tissues.

Distribution of splenic artery lymph nodes and splenic hilar lymph nodes.

BACKGROUND: Total gastrectomy with splenectomy is the standard treatment for advanced proximal gastric cancer with greater-curvature invasion. As an alternative to splenectomy, laparoscopic spleen-preserving splenic hilar lymph node (LN) dissection (SPSHLD) has been developed. With SPSHLD, the posterior splenic hilar LNs are left behind. AIM: To clarify the distribution of splenic hilar (No. 10) and splenic artery (No. 11p and 11d) LNs and to verify the possibility of omitting posterior LN dissection in laparoscopic SPSHLD from an anatomical standpoint. METHODS: Hematoxylin & eosin-stained specimens were prepared from six cadavers, and the distribution of LN No. 10, 11p, and 11d was evaluated. In addition, heatmaps were constructed and three-dimensional reconstructions were created to visualize the LN distribution for qualitative evaluation. RESULTS: There was little difference in the number of No. 10 LNs between the anterior and posterior sides. For LN No. 11p and 11d, the anterior LNs were more numerous than the posterior LNs in all cases. The number of posterior LNs increased toward the hilar side. Heatmaps and three-dimensional reconstructions showed that LN No. 11p was more abundant in the superficial area, while LN No. 11d and 10 were more abundant in the deep intervascular area. CONCLUSION: The number of posterior LNs increased toward the hilum and was not neglectable. Thus, surgeons should consider that some posterior No. 10 and No. 11d LNs may remain after SPSHLD.

The Use of the Deep Brachial Artery as the Recipient Artery for Free Perforator Flap Transfer: An Anatomic Study and Clinical Applications.

Background and Objectives: Soft tissue reconstruction after sarcoma ablation in the posterior aspect of the upper arm has been commonly addressed using the pedicled latissimus dorsi musculo-cutaneous flap. The use of a free flap for coverage of this region has not been reported in detail. The goal of this study was to characterize the anatomical configuration of the deep brachial artery in the posterior upper arm and assess its clinical utility as a recipient artery for free-flap transfers. Materials and Methods: In total, 18 upper arms from 9 cadavers were used for anatomical study to identify the deep brachial artery's origin and point of crossing the x-axis, which was set from the acromion to the medial epicondyle of the humerus. Measurements of the diameter were taken at each point. The anatomic findings of the deep brachial artery were employed clinically in the reconstruction of the posterior upper arm after sarcoma resection using free flaps in 6 patients. Results: The deep brachial artery was found in all specimens between the long head and the lateral head of the triceps brachii muscle, and it crossed the x-axis at an average distance of 13.2 ± 2.9 cm from the acromion, with an average diameter of 1.9 ± 0.49 mm. In all 6 clinical cases, the superficial circumflex iliac perforator flap was transferred to cover the defect. The average size of the recipient artery, the deep brachial artery, was 1.8 mm (range, from 1.2 to 2.0 mm). The average diameter of the pedicle artery, the superficial circumflex iliac artery, was 1.5 mm (range, from 1.2 to 1.8 mm). All flaps survived completely with no postoperative complications. Conclusions: The deep brachial artery can be a reliable recipient artery in free-flap transfers for posterior upper arm reconstruction, given its anatomical consistency and sufficient diameter.

Origin, course, and distribution of the posterior femoral cutaneous nerve and the spatial relationship among its branches.

This study aimed to elucidate the origin, course, and distribution of the branches of the posterior femoral cutaneous nerve, considering the segmental and dorsoventral compositions of the sacral plexus, including the pudendal nerve. The buttocks and thighs of five cadavers were analyzed bilaterally. The branches emerged from the sacral plexus, which was divided dorsally to ventrally into the superior gluteal, inferior gluteal, common peroneal, tibial, and pudendal nerves. It descended lateral to the ischial tuberosity and comprised the thigh, gluteal, and perineal branches. As for the thigh and gluteal branches, the dorsoventral order of those originating from the sacral plexus corresponded to the lateromedial order of their distribution. However, the dorsoventral boundary was displaced at the inferior margin of the gluteus maximus between the thigh and gluteal branches. The perineal branch originated from the ventral branch of the nerve roots. In addition, the pudendal nerve branches, which ran medially to the ischial tuberosity, were distributed in the medial part of the inferior gluteal region. These branches should be distinguished from the gluteal branches; the former should be classified as the medial inferior cluneal nerves and the latter as the lateral ones. Finally, the medial part of the inferior gluteal region was distributed by branches of the dorsal sacral rami, which may correspond to the medial cluneal nerves. Thus, the composition of the posterior femoral cutaneous nerve is considered necessary when considering the dorsoventral relationships of the sacral plexus and boundaries of the dorsal and ventral rami.

Histological study of the thin membranous dense connective tissues around the curving portion of the bilateral recurrent laryngeal nerves.

OBJECTIVE/AIM: We aimed to demonstrate the anatomical relationship between the recurrent laryngeal nerves (RLNs), thin membranous dense connective tissue (TMDCT [e.g., the visceral or vascular sheaths around the esophagus]), and the lymph nodes around the esophagus at the curving portion of the RLNs for rational and efficient lymph node dissection. METHODS: Transverse sections of the mediastinum at 5 mm or 1 mm intervals were obtained from four cadavers. Hematoxylin and eosin staining and Elastica van Gieson staining were performed. RESULTS: The visceral sheaths could not be clearly observed the curving portions of the bilateral RLNs, which were observed on the cranial and medial side of the great vessels (aortic arch and right subclavian artery [SCA]). The vascular sheaths could be clearly observed. The bilateral RLNs diverged from the bilateral vagus nerves, which ran along with the vascular sheaths, went up around the caudal side of the great vessels and the vascular sheath, and ran cranially on the medial side of the visceral sheath. Visceral sheaths were not observed around the region containing the left tracheobronchial lymph nodes (No. 106tbL) or the right recurrent nerve lymph nodes (No. 106recR). The regions containing the left recurrent nerve lymph nodes (No. 106recL) and the right cervical paraesophageal lymph nodes (No. 101R) were observed on the medial side of the visceral sheath, with the RLN. CONCLUSION: The recurrent nerve, which branched off from the vagus nerve descending along the vascular sheath, ascended the medial side of the visceral sheath after inversion. However, no clear visceral sheath could be identified in the inverted area. Therefore, during radical esophagectomy, the visceral sheath along No. 101R or 106recL may be recognized and available.

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.

The present report presents details of the method for combining wide-range serial sectioning and 3D reconstruction using an adult cadaver. For several decades, anatomists have utilized a variety of non-destructive three-dimensional (3D) visualization methods to complement gross anatomical analysis methods. These include vascular casting for the visualization of vascular morphology and micro-CT for the visualization of bone morphology. However, these conventional methods are restricted by the properties and sizes of the target structures. Here, we introduce a method to conduct 3D reconstruction based on wide-range serial histological sections from adult cadavers, which overcomes previous restrictions. An attempt at 3D visualization of the female pelvic floor muscles provides a detailed description of the procedure. Supplemental video and 3D PDF files allow multifaceted observation of 3D images. Wide-range serial sectioning visualizes morphology beyond the scope of conventional methods, while 3D reconstruction enables non-destructive 3D visualization of any structure that can be observed on a histological section, including skeletal muscle, smooth muscle, ligaments, cartilage, connective tissue, blood vessels, nerves, lymph nodes, and glands. The novel combination of both methods is instrumental in meso-anatomy, a discipline intermediate between macro-anatomy and micro-anatomy.

Pelvic floor and perineal muscles: a dynamic coordination between skeletal and smooth muscles on pelvic floor stabilization.

The purpose of this review is to present our researches on the pelvic outlet muscles, including the pelvic floor and perineal muscles, which are responsible for urinary function, defecation, sexual function, and core stability, and to discuss the insights into the mechanism of pelvic floor stabilization based on the findings. Our studies are conducted using a combination of macroscopic examination, immunohistological analysis, 3D reconstruction, and imaging. Unlike most previous reports, this article describes not only on skeletal muscle but also on smooth muscle structures in the pelvic floor and perineum to encourage new understanding. The skeletal muscles of the pelvic outlet are continuous, which means that they share muscle bundles. They form three muscle slings that pass anterior and posterior to the anal canal, thus serving as the foundation of pelvic floor support. The smooth muscle of the pelvic outlet, in addition to forming the walls of the viscera, also extends in three dimensions. This continuous smooth muscle occupies the central region of the pelvic floor and perineum, thus revising the conventional understanding of the perineal body. At the interface between the levator ani and pelvic viscera, smooth muscle forms characteristic structures that transfer the lifting power of the levator ani to the pelvic viscera. The findings suggest new concepts of pelvic floor stabilization mechanisms, such as dynamic coordination between skeletal and smooth muscles. These two types of muscles possibly coordinate the direction and force of muscle contraction with each other.

Anatomical basis for contribution of hip joint motion by the obturator internus to defaecation/urinary functions by the levator ani via the obturator fascia.

The functional association between hip joint motion and defaecation/urinary function has attracted considerable research and clinical attention owing to the potential novel approaches for pelvic floor rehabilitation; however, the anatomical basis remains unclear. This study, therefore, aimed to analyse the anatomical basis of force transmission between the obturator internus, a muscle of the hip joint, and the levator ani, a muscle of the pelvic floor. Twenty-three cadavers were used for macroscopic and histological analyses. The three-dimensional structures of the muscles and fascia were recorded using a high-definition camera and a 3D scanner. The arrangement and attachment of the muscle fibres, tendons and fascia were visualised using histological sections stained with Masson's trichrome. The obturator internus and levator ani were in broad contact through the obturator fascia. The height of their contact area was 24.6 ± 9.1 mm. Histologically, the obturator internus and levator ani shared a large area of the obturator fascia, and the obturator fascia provided the attachment of several muscle layers of the levator ani. The contribution of hip joint motion to defaecation/urinary function can be explained by the broad 'planar' contact between the obturator internus and levator ani. This anatomical feature suggests that movement of the obturator internus creates the foundation for the function of the levator ani and contributes to pelvic floor support through the obturator fascia. This study provides an anatomical basis for the effectiveness of the hip muscles in improving defaecation/urinary function by enabling balanced and proper movements.

Significance of the broad non-bony attachments of the anterior cruciate ligament on the tibial side.

Knowledge of the anatomy of the anterior cruciate ligament (ACL) is important to understand the function and pathology of the knee joint. However, on the tibial side of ACL, its structural relationships with the articular cartilage and lateral meniscus remain unclear. Furthermore, conventional research methods are limited to analyzing the bone attachments. We provide a comprehensive, three-dimensional anatomical description of the tibial side of the ACL that questions the principle that "a ligament is necessarily a structure connecting a bone to another bone." In our study, 11 knees from 6 cadavers were used for macroscopic anatomical examinations, serial-section histological analyses, and three-dimensional reconstructions. The attachments of the tibial side of ACL consisted of attachments to the bone (102.6 ± 27.5 mm2), articular cartilage (40.9 ± 13.6 mm2), and lateral meniscus (6.5 ± 4.6 mm2), suggesting that the ACL has close structural relationships with the articular cartilage and lateral meniscus. Our study demonstrates that the tibial side of the ACL is not attached to the bone surface only and provides new perspectives on ligamentous attachments. Considering its attachment to the articular cartilage would enable more accurate functional evaluations of the mechanical tensioning of the ACL.

An Anatomical Study of Posterior Trunk Recipient Vessels, and Comparisons of Outcome following Pedicled- and Free-Flap Transfers for Treatment of Sarcoma in the Posterior Trunk.

BACKGROUND: Reconstruction after wide resection of a large sarcoma arising in the posterior trunk may require free-flap transfer to reduce the postoperative complications. Here, we describe the recipient vessels on the whole posterior trunk. Moreover, to show the reliability of these vessels, we describe an institutional series of free-flap reconstruction. METHODS: In the cadaveric study, 20 posterior trunk regions from 10 fixed cadavers were dissected. The location and the diameter of the perforating artery and vein on the posterior were documented. In the clinical study, 54 patients undergoing immediate reconstruction surgery with only a pedicled flap (n = 45) and with a free flap (n = 9) after sarcoma resection on the posterior trunk between July 2005 and September 2021 were identified. One-to-one propensity score matching was performed to compare the postoperative complications. RESULTS: In the cadaveric study, a total of 178 perforators were identified. The average diameter of the superficial cervical artery (SCA) and vein, dorsal scapular artery (DSA) and vein, medial branch of dorsal intercostal artery perforator (m-DICAP) and vein, lateral branch of dorsal intercostal artery perforator (l-DICAP) and vein, and dorsolateral intercostal artery perforator (DLICAP) and vein were 1.03, 1.67, 1.38, 1.84, 1.28, 1.84, 1.01, 1.60, 1.11, and 1.70 mm. In the clinical study, the propensity score-matched analysis involving eight pairs showed a significantly higher occurrence of total complications in the pedicled-flap group than the free-flap group (62.5 vs. 0%, p = 0.03). CONCLUSION: The cadaveric study showed that the perforators from the SCA, DSA, and posterior intercostal artery are constantly present. The clinical study demonstrated the feasibility and reliability of a free-flap transfer.

Positional relationship between the lateral border of Denonvilliers' fascia and pelvic plexus.

Denonvilliers' fascia is an important landmark of the dissection layer during prostate or rectal surgeries. However, there are few reports on its lateral extension. This anatomical study aimed to define the lateral border of Denonvilliers' fascia and use it as an anatomical landmark to identify the origin and distribution of the nerve branches of the pelvic plexus. We investigated the lateral extent and position of the lateral border of Denonvilliers' fascia through macroscopic examination of 12 pelvic halves from eight cadavers and histological examination of two cadavers. The Denonvilliers' fascia extended laterally to be attached to the pelvic plexus on the lateral border. The origins of nerve branches from the pelvic plexus to the pelvic organs, except the rectum, were located anterior or anterosuperior to the lateral border of Denonvilliers' fascia. The origins of nerve branches to the prostate were mainly anterior to the lateral border of Denonvilliers' fascia; however, in 3/12 pelvic halves, the nerve branches originated in the region posteroinferior to the lateral border of Denonvilliers' fascia. The attachment point of Denonvilliers' fascia to the prostate was more superior in these three pelvic halves (distance from the top point of the posterior surface of the prostate to the attachment point, 5.6 ± 1.9 mm) than that in the other nine pelvic halves (10.1 ± 3.6 mm). The lateral border of Denonvilliers' fascia is closely related to the pelvic plexus, suggesting its usefulness as an anatomical landmark to identify the origin of nerve branches from the pelvic plexus.

Anatomy of Cowper's gland in humans suggesting a secretion and emission mechanism facilitated by cooperation of striated and smooth muscles.

This study presents the detailed anatomy of the Cowper's gland in humans. Elucidating the mechanism of secretion and emission of the Cowper's gland requires analysis of the muscles around the Cowper's gland. We hypothesized that the Cowper's gland involves not only smooth muscle but also the striated muscles of the pelvic floor. Here, we provide comprehensive and three-dimensional anatomy of the Cowper's gland and its surrounding structures, which overcomes the current local and planar understanding. In this study, seven male corpses of body donors were used to conduct macroscopic anatomy, histology, and three-dimensional reconstruction. The Cowper's gland was surrounded laterally and posterosuperiorly by striated and smooth muscles, respectively. The striated muscle bundle was connected from the superficial transverse perineal muscle, levator ani, and external anal sphincter to the external urethral sphincter (rhabdosphincter). The smooth muscle was part of the deep transverse perineal muscle and entered between the bilateral Cowper's glands and lobules. Our findings indicate that the secretion and emission of the Cowper's gland in humans are carried out through the cooperation of striated and smooth muscles.