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.

Mixed-methods study of medical students' attitudes toward peer physical examinations in Japan.

BACKGROUND: Most Japanese medical schools likely continue to rely on peer physical examination (PPE) as a tool to for teaching physical examination skills to students. However, the attitudes of medical students in Japan toward PPEs have not be identified. Therefore, we evaluated students' attitudes toward PPE in a Japanese medical school as a preparation for developing a PPE policy tailored to the context of Japanese culture. METHODS: We conducted a mixed-methods study with an explanatory sequential approach, in which qualitative data were used to interpret the quantitative findings. Surveys and interviews were conducted with medical students and junior residents at a Japanese university. A total of 63 medical students and 50 junior residents responded to the questionnaire. We interviewed 16 participants to reach theoretical saturation and investigated the attitudes of medical students toward PPE and the themes emerging from the interview data, providing detailed descriptions of the quantitative findings. RESULTS: Female participants were significantly more likely than male participants to report varying degrees of resistance to being a model patient during PPE (male: 59.7%, female: 87%, p < 0.001). Most of the participants who took on the role of patients that involved undressing were males. The participants expected improvements in issues related to the guarantee of freedom to refuse to be a model patient and measures to protect confidentiality. Approximately 22% of the participants reported that they witnessed incidental findings (including variations within the normal range) in front of other students during PPE. CONCLUSIONS: The findings imply that medical students expect high levels of autonomy and confidentiality when volunteering as model patients during PPE. Thus, developing a PPE policy suitable for Japanese culture may be effective in establishing a student-centered PPE environment.

Guidelines for cadaver dissection in education and research of clinical medicine (The Japan Surgical Society and The Japanese Association of Anatomists).

This article translates the guidelines for cadaver surgical training (CST) published in 2012 by Japan Surgical Society (JSS) and Japanese Association of Anatomists from Japanese to English. These guidelines are based on Japanese laws and enable the usage of donated cadavers for CST and clinical research. The following are the conditions to implement the activities outlined in the guidelines. The aim is to improve medicine and to contribute to social welfare. Activities should only be carried out at medical or dental universities under the centralized control by the department of anatomy under the regulation of Japanese law. Upon the usage of cadavers, registered donors must provide a written informed-consent for their body to be used for CST and other activities of clinical medicine. Commercial use of cadavers and profit-based CST is strongly prohibited. Moreover, all the cadaver-related activities except for the commercial-based ones require the approval of the University's Institutional Review Board (IRB) before implementation. The expert committee organized at each university for the implementation of CST should summarize the implementation of the program and report the details of the training program, operating costs, and conflicts of interest to the CST Promotion Committee of JSS.

Intra-mural distribution of the blood vessels in the stomach demonstrated by contrast medium injection: a cadaver study.

PURPOSE: With advances in diagnostic imaging techniques of gastric cancer screening with X-ray fluoroscopy, it has been suggested that mucosal projections induced by the vessels distributed in the submucosal layer of the stomach may be mistaken for abnormal mucosal folds. In this study, we aimed to describe the distribution of blood vessels in the submucosal layer of the stomach to improve the diagnostic accuracy of screening of gastric cancer. METHODS: Twenty-four stomachs from Japanese cadavers were used in this study. Uncolored or colored contrast agents were injected into arteries and/or veins for macroscopic analyses, X-ray imaging, and methyl salicylate clearing. In addition, histological analysis was performed to examine blood vessels distributed inside the stomach wall. RESULTS: Following contrast agent injection, thick blood vessels were distributed perpendicular to both curvature sides, and branches parallel to both curvature sides flowed from these thick blood vessels, and a vascular network was formed throughout the stomach wall. This vascular network had intra-mural anastomoses connecting both curvature sides. Moreover, in histological analyses, blood vessels depicted by injection were mainly distributed in the submucosal layer. CONCLUSION: This study strongly suggests that the mucosal projections induced by arteries and veins in the submucosal layer could be mistaken for abnormal mucosal folds. Therefore, a better understanding of the vascular distribution in the submucosal layer is important to improve diagnostic accuracy from imaging studies of the stomach. The information provided by this research may facilitate better accuracy in diagnosis and reduce the number of unnecessary invasive procedures.

Medial elbow anatomy: A paradigm shift for UCL injury prevention and management.

To improve the management outcomes and diagnostic accuracy of the ulnar collateral ligament (UCL) injury, the anatomy of the medial side of the elbow joint is necessary to be understood in terms of the periarticular surroundings rather than the specific ligaments. The aim of this study was to anatomically clarify the medial side of the elbow joint in terms of the tendinous structures and joint capsule. We conducted a descriptive anatomical study of 23 embalmed cadaveric elbows. We macroscopically analyzed the relationship between the flexor pronator muscles (FPMs) and the joint capsule in 10 elbows, histologically analyzed in 6 elbows, and observed the bone morphology through micro computed tomography in 7 elbows. The two tendinous septa (TS) were found: between the pronator teres (PT) and flexor digitorum superficial (FDS) muscles, and between the FDS and flexor carpi ulnaris (FCU) muscles. These two TS are connected to the medial part of the brachialis tendon, deep aponeurosis of the FDS, and FCU to form the tendinous complex, which linked the humeroulnar joint and could not be histologically separated from each other. Moreover, the capsule of the humeroulnar joint under the tendinous complex had attachment on the ST of 7 mm width. The two TS, the brachialis tendon, the deep FDS and FCU aponeuroses, and the joint capsule linked the humeroulnar joint. These anatomical findings could lead to a paradigm shift in the prevention, diagnosis, and treatment of UCL injuries in baseball players. Clin. Anat. 32:379-389, 2019. © 2018 The Authors. Clinical Anatomy published by Wiley Periodicals, Inc. on behalf of American Association of Clinical Anatomists.

Anatomical study of the left superior mediastinal lymphatics for tracheal branches of left recurrent laryngeal nerve-preserving mediastinoscope-assisted surgery in esophageal cancer.

PURPOSE: Curative treatment of esophageal cancer requires meticulous superior mediastinal lymphadenectomy, in addition to esophagectomy, because superior mediastinal lymph node metastases are common in esophageal cancer. When preserving the tracheal branches of the left recurrent laryngeal nerve (RLN), good anatomical understanding is required for confirmation of the positional relationships between the courses of lymphatic vessels, lymph node distribution, and the left RLN and its tracheal branches. We performed a detailed anatomical examination of these relationships. METHODS: Macroscopic anatomical observation and histological examination was performed on cadavers. In addition to hematoxylin and eosin staining, immunostaining using antipodoplanin antibody D2-40 (podoplanin) was performed to identify the lymphatic vessels. RESULTS: The tracheal branches of the left RLN were clearly observed, but no lymphatic vessels crossing the ventral or dorsal side of the branches were identified either macro-anatomically or histologically. CONCLUSION: No complex lymphatic network structure straddling the plane composed of tracheal branches of the left RLN was found in the left superior mediastinum. This suggests that dissection of the lymph nodes around the left RLN via the pneumomediastinum method using the left cervical approach may allow preservation of the tracheal branches of the left RLN by maintaining dissection accuracy.

A Cadaver Study to Assess the Feasibility of a Cross-Nerve Transfer of the Infraorbital Nerve for Patients With Peripheral Infraorbital Nerve Injury.

BACKGROUND: Patients with facial fracture or head and neck surgery sometimes suffer from infraorbital nerve injury. This injury results in severe hemilateral numbness in the midfacial area. The infraorbital nerve ends with two major branches; the infra nasal branch (INB) and superior labial branch (SLB). In this study, we assessed the feasibility of cross-nerve transfer of the INB and SLB based on a cadaver study. METHODS: The INB/SLB from a total 20 sides of 10 cadavers (2 men and 8 women; average age, 79.9 years) were dissected. The distribution patterns of the INB and SLB, the distance between the INB/SLB and the piriform aperture, and the shortest distance between the INB/SLB were estimated. RESULTS: Three distribution patterns of the INB and SLB were observed, that is type A (65%); only the INB is thick enough for a nerve transfer, type B (20%); only the SLB is thick enough for a nerve transfer, and a combination of types A and B (15%). The distance between the INB, SLB and the piriform aperture was on average 8.61 and 10.81 mm in each. The shortest distance between the INB and SLB was on average 11.34 ± 3.7 mm. CONCLUSIONS: The INB and SLB existed in all the specimens and could be found approximately 1 cm below the piriform aperture. The average distance between the INB and SLB was approximately 11 mm. These results imply the feasibility of a cross-nerve transfer of the distal part of the infraorbital nerve.

Prospective analyses of female urinary incontinence symptoms following total hip arthroplasty.

INTRODUCTION AND HYPOTHESIS: Some patients with hip osteoarthritis report that urinary incontinence (UI) is improved following total hip arthroplasty (THA). However, the type and severity of UI remain unclear. In this study, we hypothesize that both stress urinary incontinence (SUI) and urge urinary incontinence (UUI) are improved after THA. We assess the characteristics of UI and discuss the anatomical factors related to UI and THA for improved treatment outcome. METHODS: Fifty patients with UI who underwent direct anterior-approach THA were evaluated. Type of UI was assessed using four questionnaires: Core Lower Urinary Tract Symptom Score (CLSS), Urogenital Distress Inventory Short Form (UDI-6), International Prostate Symptom Score (IPSS), and Overactive Bladder Symptom Score (OABSS). Uroflowmetry and postvoid residual urine were measured using ultrasound technology. Hip-joint function was evaluated using Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and range of motion (ROM). RESULTS: Of the 50 patients, 21 had SUI, 16 had mixed urinary incontinence (MUI), and eight had urgency urinary incontinence (UUI). In total, 36 patients were better than improved (72 %). The rate of cured and improved was 76 % for SUI, 100 % MUI, and 50 % UUI. The improvement of ROM was more significant in cured or improved patients than in stable or worse patients. CONCLUSIONS: Improvement in mild UI may be an added benefit for those undergoing THA for hip-joint disorders. These data suggest that for patients with hip-joint disorder, hip-joint treatment could prove to also be a useful treatment for UI.

Morphology of the region anterior to the anal canal in males: visualization of the anterior bundle of the longitudinal muscle by transanal ultrasonography.

PURPOSE: The anterior bundle of the longitudinal muscle in the region anterior to the anal canal in males has been described, although the anatomical details remain unclear. The present study was undertaken to clarify the precise morphology of the anterior bundle of the longitudinal muscle and its relationship to the surrounding structures, and to visualize the anterior bundle of the longitudinal muscle via transanal ultrasonography. METHODS: Histological examination was carried out using seven male cadavers; an additional three male cadavers were used for transanal ultrasonography, and the ultrasonography images were compared with the actual sagittal sections. In addition, transanal ultrasonography images of 50 male patients at Tokatsu-Tsujinaka Hospital were studied. RESULTS: The region anterior to the anal canal consisted of smooth muscles and skeletal muscles. The anterior bundle of the longitudinal muscle was situated between the bulbospongiosus and the external anal sphincter, and consisted of smooth muscle. The bundle was identified in the transanal ultrasonography of cadavers by comparison with the actual sections. Transanal ultrasonography images of living bodies showed the anterior bundle of the longitudinal muscle as a hypoechoic layer of approximately 17.7 mm in length. CONCLUSIONS: The detailed anatomical findings of the anterior bundle of the longitudinal muscle suggested "an alternate arrangement of smooth muscles and skeletal muscles" in the region anterior to the anal canal and facilitated the visualization of the anterior bundle of the longitudinal muscle in transanal ultrasonography.

Topographic Anatomy of the Anal Sphincter Complex and Levator Ani Muscle as It Relates to Intersphincteric Resection for Very Low Rectal Disease.

BACKGROUND: Intersphincteric resection has become a widely used treatment for patients with rectal cancer. However, the detailed anatomy of the anal canal related to this procedure has remained unclear. OBJECTIVE: The purpose of this study was to clarify the detailed anatomy of the anal canal. DESIGN: This is a descriptive study. SETTINGS: Histologic evaluations of paraffin-embedded tissue specimens were conducted at a tertiary referral hospital. PATIENTS: Tissue specimens were obtained from cadavers of 5 adults and from 13 patients who underwent abdominoperineal resection for rectal cancer. MAIN OUTCOME MEASURES: Sagittal sections from 9 circumferential portions of the cadaveric anal canal (histologic staining) and 3 circumferential portions from patients were studied (immunohistochemistry for smooth and skeletal muscle fibers). RESULTS: Longitudinal fibers between the internal and external anal sphincters consisted primarily of smooth muscle fibers that continued from the longitudinal muscle of the rectum. The levator ani muscle attached directly to the lateral surface of the longitudinal smooth muscle of the rectum. The length of the attachment was longer in the anterolateral portion and shorter in the posterior portion of the anal canal. In the lateral and posterior portions, the levator ani muscle partially overlapped the external anal sphincter; however, there was less overlap in the anterolateral portion. In the posterior portion, thick smooth muscle was present on the surface of the levator ani muscle and it continued to the longitudinal muscle of the rectum. LIMITATIONS: We observed only limited portions in some surgical specimens because of obstruction by tumors. CONCLUSIONS: The levator ani muscle attaches directly to the longitudinal muscle of the rectum. The spatial relationship between the smooth and skeletal muscles differed in different portions of the anal canal. For intersphincteric resection, dissection must be performed between the longitudinal muscle of the rectum and the levator ani muscle/external anal sphincter, and the appropriate surgical lines must be selected based on the specific structural characteristics of each portion.

An anatomic study of the attachments on the condylar process of the mandible: muscle bundles from the temporalis.

PURPOSE: The aim of this study was to evaluate anatomically the relationship between bone and muscles by detailed observation of the bone shape and the structure of muscles to facilitate an understanding of the function of the muscles involved in jaw movement. METHODS: 36 specimens of 24 Japanese cadavers were examined. The insertion areas were marked using a radiopaque marker and examined by micro-computed tomography. For morphological observation, we used 101 condylar processes. In addition, we made histological sections in some specimens to observe the detailed attachments of the muscle. RESULTS: Based on the micro-CT images and dissection findings, the lateral pterygoid muscle was found to be most frequently inserted into the anterior impression and attached to the medial impression of the process. According to the histological observations, the lateral pterygoid muscle mainly inserted to the condylar process. The micro-CT images indicated that the obvious bony ridge was lateral to the pterygoid fovea on the condylar process in all specimens. The midmedial muscle bundle of the temporalis was attached to the ridge. Based on the morphological observations, the ridge was situated on the lateral area of the condylar process. CONCLUSIONS: Since dysfunction of the temporomandibular joint is likely closely related to both the lateral pterygoid muscle and also the temporalis, further studies are necessary to evaluate the function of these muscles and consider jaw movement.

Anatomic observation of the running space of the suprascapular nerve at the suprascapular notch in the same direction as the nerve.

PURPOSE: The configuration of suprascapular notch was previously analysed from the anteroposterior viewing. However, the approach direction of the suprascapular nerve (SSN) to the inlet of the suprascapular notch is consistently craniocaudal and mediolateral. We propose a new method to observe the suprascapular notch according to the running course of the SSN. We reviewed the anatomic characteristics of the suprascapular notch in relation to the nerve. METHODS: In 30 formalin-fixed cadaveric shoulders, the morphology of the suprascapular notch and the attachments of the superior transverse scapular ligament (STSL) were examined from both the anteroposterior and the nerve approach direction. The dimensions of the opening of the SSN passage were measured. RESULTS: By observing from the nerve approach direction, the inlet of the suprascapular notch was recognized to be a space-bordered by the medial wall of the coracoid process, the deep fascia of subscapularis, and the STSL. The STSL formed a sheet-like structure, which ran parallel to the nerve and also to the deep fascia of subscapularis. The attachment of the ligament to the coracoid process was located at the posteromedial corner rather than the medial side. CONCLUSION: Based on the present study, the space between the STSL and deep fascia of the subscapularis formed the space for the nerve to run through. As a clinical implication, this new method to assess the suprascapular notch in the nerve approach direction might develop the imaging techniques for evaluation of SSN entrapment.

The anatomic relationship between the morphology of the greater tubercle of the humerus and the insertion of the infraspinatus tendon.

BACKGROUND: The objective of this study was to evaluate the topographic relationship between the morphology of the greater tubercle and the insertion of the tendon of the infraspinatus. MATERIALS AND METHODS: First, we defined an impression of the greater tubercle, which has not been recognized in classic textbooks, as the "lateral impression" and then measured the dimensions of the "lateral impression" of the greater tubercle in 71 samples of dry bone of humeri. Next, we examined 16 cadaveric humeri with rotator cuff tendons by micro-computed tomography to analyze the positional relationship between the lateral impression and the infraspinatus tendon. RESULTS: In all samples of dry bones, the lateral impression could be identified as a triangle shape. The lateral impression was composed of the border with the highest impression (mean, 6.3 mm), the border with the middle impression (mean, 5.0 mm), and the border with the lateral wall of the greater tubercle (mean, 8.5 mm). In all samples of humeri with rotator cuffs, we could confirm the lateral impression, and the border between the highest impression and the lateral impression corresponded to the anterior border of the insertion of the infraspinatus tendon. CONCLUSION: We propose a new anatomic concept of the lateral impression that could enable the precise diagnosis of and facilitate repair techniques for infraspinatus tear, according to specific anatomic characteristics, by applying 3-dimensional computed tomography assessment preoperatively.

Clinical characterization and identification of duplication breakpoints in a Japanese family with Xq28 duplication syndrome including MECP2.

Xq28 duplication syndrome including MECP2 is a neurodevelopmental disorder characterized by axial hypotonia at infancy, severe intellectual disability, developmental delay, mild characteristic facial appearance, epilepsy, regression, and recurrent infections in males. We identified a Japanese family of Xq28 duplications, in which the patients presented with cerebellar ataxia, severe constipation, and small feet, in addition to the common clinical features. The 488-kb duplication spanned from L1CAM to EMD and contained 17 genes, two pseudo genes, and three microRNA-coding genes. FISH and nucleotide sequence analyses demonstrated that the duplication was tandem and in a forward orientation, and the duplication breakpoints were located in AluSc at the EMD side, with a 32-bp deletion, and LTR50 at the L1CAM side, with "tc" and "gc" microhomologies at the duplication breakpoints, respectively. The duplicated segment was completely segregated from the grandmother to the patients. These results suggest that the duplication was generated by fork-stalling and template-switching at the AluSc and LTR50 sites. This is the first report to determine the size and nucleotide sequences of the duplicated segments at Xq28 of three generations of a family and provides the genotype-phenotype correlation of the patients harboring the specific duplicated segment.

The anatomy of the coracohumeral ligament and its relation to the subscapularis muscle.

BACKGROUND: Only a few reports describe the extension of the coracohumeral ligament to the subscapularis muscle. The purposes of this study were to histo-anatomically examine the structure between the ligament and subscapularis and to discuss the function of the ligament. METHODS: Nineteen intact embalmed shoulders were used. In 9 shoulders, the expansion of the ligament was anatomically observed, and in 6 of these 9, the muscular tissue of the supraspinatus and subscapularis was removed to carefully examine the attachments to the tendons of these muscles. Five shoulders were frozen and sagittally sectioned into 3-mm-thick slices. After observation, histologic analysis was performed on 3 of these shoulders. In the remaining 5 shoulders, the coracoid process was harvested to investigate the ligament origin. RESULTS: The coracohumeral ligament originated from the horizontal limb and base of the coracoid process and enveloped the cranial part of the subscapularis muscle. The superficial layer of the ligament covered a broad area of the anterior surface of the muscle. Laterally, it protruded between the long head of the biceps tendon and subscapularis and attached to the tendinous floor, which extended from the subscapularis insertion. Histologically, the ligament consisted of irregular and sparse fibers abundant in type III collagen. CONCLUSION: The coracohumeral ligament envelops the whole subscapularis muscle and insertion and seems to function as a kind of holder for the subscapularis and supraspinatus muscles. The ligament is composed of irregular and sparse fibers and contains relatively rich type III collagen, which would suggest flexibility.

Dynamic intersection of the longitudinal muscle and external anal sphincter in the layered structure of the anal canal posterior wall.

PURPOSE: The minute details of the structure of the anal canal are still not well understood. The complex structural configuration of the muscles, ligaments and raphes remains unclarified. This study was undertaken to determine the precise structure of the posterior part of the anal canal and to facilitate an understanding of previous studies. METHODS: For macroscopic examination, 14 right pelvic halves from 14 Japanese cadavers were used. Observation and dissection were performed from the median plane. In the histological examination, six left pelvic halves were used. The sections of the posterior parts of the anal canal were stained with hematoxylin and eosin, Elastic van Gieson, anti-smooth actin antibody and anti-skeletal myosin antibody. RESULTS: We identified the following muscles arranged from the internal side to the external side: internal anal sphincter, longitudinal muscle (LM), external anal sphincter (EAS) and levator ani muscle (LAM). Two different types of conformation of the posterior part of the anal canal were found, each bearing a different shape of EAS. In both types, LM penetrated the inferior part of EAS. After penetrating EAS, some fibers of LM ran posterosuperiorly and attached to the "the posterior fibers" which reach the dorsal side of the coccyx. CONCLUSIONS: We defined and labeled the connective tissues between the anal canal and coccyx on the basis of their relative position to LAM. Based on a comparison of the two types of the posterior part of the anal canal, we propose that there are two phases due to constriction and relaxation of LM.

Association between grit and depressive symptoms among medical students, moderated by academic performance.

Depression amongst medical students is a crucial matter. Grit, which is a potentially modifiable psychological factor, has been inversely linked to depressive symptoms. However, it remains unclear how grit is associated with depression. This study aims to examine the relationship between grit and depressive symptoms and to further investigate the potential effect modification by academic performance on the association between grit and depression among medical students. We focus on the total grit score and its subscales, namely perseverance of effort and consistency of interest. A cross-sectional study was conducted using data from second-year medical students at Tokyo Medical and Dental University in Japan from 2020 to 2023. The participants responded to questionnaire surveys comprising the Center for Epidemiologic Studies Depression Scale and the Short Grit Scale. Linear regression analysis was performed to assess the association between grit and depressive symptoms. We also tested for effect modification by first-year Grade Point Average (GPA) on the association between grit and depression. The total grit score and its subscales, perseverance of effort and consistency of interest, were all inversely associated with depressive symptoms (b = -4.7 [95%CI - 6.7 to - 2.6], b = -3.7 [95%CI - 5.3 to - 2.1], b = -1.8 [95%CI - 3.5 to - 0.2], respectively). While the interaction term for the total grit score and GPA was not significant, the interaction term for perseverance of effort and GPA was significant, indicating that the association between perseverance of effort and depression was stronger among the higher-achieving students. The interaction term for consistency of interest and GPA was also significant, indicating that the association was stronger among the lower-achieving students. We reveal a novel aspect of the association between grit and depressive symptoms in light of academic performance. The findings will contribute to future research on depression amongst medical students.

Anatomic study of the attachment of the medial patellofemoral ligament and its characteristic relationships to the vastus intermedius.

PURPOSE: The aim of this study was to investigate the attachment of the medial patellofemoral ligament (MPFL) using cadaver specimens and establish an anatomic basis for optimal MPFL reconstruction to achieve better patella stability. METHODS: Sixteen knees of eight cadavers were used in this study. The relationship of the MPFL with quadriceps muscles was investigated from outside after removal of the distal part of the vastus medialis and the rectus femoris and then evaluated from intra-articular side after release of lateral margin of the vastus lateralis muscle, patella and patella tendon. RESULTS: The proximal fibres of MPFL were mainly attached to the vastus intermedius tendon, without tight adhesion to the vastus medialis. The distal fibres of MPFL were interdigitated with the deep layer of the medial retinaculum that was attached to the medial margin of the patella tendon. CONCLUSION: These findings imply that MPFL, which was directly attached to the vastus intermedius and patella and indirectly continued to the patella tendon, could keep pulling them medially as one unit and consequently make the patella move smoothly on the trochlea during whole movement of the knee. Clinically, dysfunction of both proximal and distal MPFL fibres should be considered in the diagnosis and treatment of patella instability after traumatic patella dislocation. MPFL reconstruction with both fibres has a possibility to lead ideal function of MPFL and better instability of the patella.

Attachments of separate small bundles of human posterior cruciate ligament: an anatomic study.

PURPOSE: To date, there is no consensus on the detailed anatomy of the posterior cruciate ligament (PCL) and the most appropriate PCL reconstruction method. The purpose of this study is the detailed observation of separate small PCL bundles for better comprehension of detailed PCL anatomy to facilitate the design of anatomic PCL reconstruction. METHODS: Twelve cadaveric knees were used in this study. PCL was divided into anterolateral and posteromedial (PM) sections and then separated into about 20 small bundles of 1 mm in diameter while maintaining preservation of their attachment sites marked with fine coloured marker pens. The positional relationship between the femoral and tibial attachments of each small bundle was investigated. RESULTS: The small bundles of tibial and femoral attachments showed a topographical correlation. The anterior-posterior aligned bundles in the tibia corresponded to the bundles aligned in a low-high direction in flexion in the femur. The femoral attachment pattern was relatively similar in each specimen. However, the tibial attachment showed two patterns of small bundle footprint location: a parabolic type (6 of 12) and a transverse type (6 of 12). The posterior portion of the PM bundle was separately attached to the medial and lateral portions in the tibial attachment. CONCLUSION: Small bundles of PCL showed a relatively layered arrangement between tibial and femoral attachments. Therefore, anatomic PCL reconstruction cannot be completed simply performed merely with straight bundles and circular bone tunnels.

Association between the social network of medical students and their academic performance on the anatomy written examination.

Although medical students learn human anatomy within a social network of friends/classmates, limited research has examined how social network structure is related to student's performance in human anatomy examinations. This study aimed to examine the association between centrality (i.e., the degree to which a student is connected to other students in class) before the start of the anatomy laboratory and changes in centrality owing to the start of the laboratory and failing the written examination taken on the last day of the course. Data included all 211 medical students at Tokyo Medical and Dental University who took anatomy classes in 2018 and 2019. The in-class social network before the laboratory was defined as "connected" if the student had more than one connection to the same individual in terms of the type of club activity, high school, and affiliation with an extracurricular program. The laboratory group adds the connection to the prelaboratory network, resulting in a postlaboratory network. Logistic regression models were used to estimate the association of degree and eigenvector centrality and changes in centrality after the laboratory with failing the written examination. Of the 211 students, 38 failed the examination. A one standard deviation increase in eigenvector centrality before the laboratory was significantly associated with a 44% decrease in odds of failing the examination (OR: 0.56, 95% CI: 0.34, 0.92). Changes in centrality measures were not associated with the performance of students in the examination. Higher in-class network centrality was associated with lower odds of failing the written examination.