Spatial proteomics in three-dimensional intact specimens.

Spatial molecular profiling of complex tissues is essential to investigate cellular function in physiological and pathological states. However, methods for molecular analysis of large biological specimens imaged in 3D are lacking. Here, we present DISCO-MS, a technology that combines whole-organ/whole-organism clearing and imaging, deep-learning-based image analysis, robotic tissue extraction, and ultra-high-sensitivity mass spectrometry. DISCO-MS yielded proteome data indistinguishable from uncleared samples in both rodent and human tissues. We used DISCO-MS to investigate microglia activation along axonal tracts after brain injury and characterized early- and late-stage individual amyloid-beta plaques in a mouse model of Alzheimer's disease. DISCO-bot robotic sample extraction enabled us to study the regional heterogeneity of immune cells in intact mouse bodies and aortic plaques in a complete human heart. DISCO-MS enables unbiased proteome analysis of preclinical and clinical tissues after unbiased imaging of entire specimens in 3D, identifying diagnostic and therapeutic opportunities for complex diseases. VIDEO ABSTRACT.

Cellular and Molecular Probing of Intact Human Organs.

Optical tissue transparency permits scalable cellular and molecular investigation of complex tissues in 3D. Adult human organs are particularly challenging to render transparent because of the accumulation of dense and sturdy molecules in decades-aged tissues. To overcome these challenges, we developed SHANEL, a method based on a new tissue permeabilization approach to clear and label stiff human organs. We used SHANEL to render the intact adult human brain and kidney transparent and perform 3D histology with antibodies and dyes in centimeters-depth. Thereby, we revealed structural details of the intact human eye, human thyroid, human kidney, and transgenic pig pancreas at the cellular resolution. Furthermore, we developed a deep learning pipeline to analyze millions of cells in cleared human brain tissues within hours with standard lab computers. Overall, SHANEL is a robust and unbiased technology to chart the cellular and molecular architecture of large intact mammalian organs.

In vivo detection of the lumbar intraforaminal ligaments by MRI.

PURPOSE: Intraforaminal ligaments (IFL) are of great interest to anatomists and clinicians to fully understand the detailed anatomy of the neuroforamina and to diagnose unclear radicular symptoms. Studies published until now have described radiological imaging of the IFLs using magnetic resonance imaging (MRI) on donor bodies. In the present study, we investigated the detectability of lumbar IFLs in vivo in adults using the high spatial resolution of the constructive interference in steady state (CISS) sequence. METHODS: A total of 14 patients were studied using a 1.5 T MRI scanner. The lumbar spine was imaged using the parasagittal CISS sequence, and the detectability of the IFLs was assessed for each lumbar level. All image datasets were analyzed by a radiologist, an orthopedic surgeon, and an anatomist. Interrater reliability was expressed as Fleiss' Kappa. Using a single data set, a three-dimensional (3D) model was created to map the location of the IFLs within the intervertebral foramen (IF) and the immediate surrounding vessels. RESULTS: Overall, the radiologist was able to detect IFLs in 60% of all imaged IFs, the orthopedic surgeon in 62%, and the anatomist in 66%. Fleiss' Kappa for the various segments varies from 0.71 for L4/5 up to 0.90 for L3/4. CONCLUSION: Lumbar IFLs were successfully detected in vivo in every patient. The detection frequency varied from 42-86% per IF. We demonstrated reproducible imaging of the IFLs on MRI, with good interrater reliability. The present study was a launching point for further clinical studies investigating the potential impact of altered IFLs on radicular pain.

Sacroiliac innervation.

PURPOSE: To investigate the innervation pattern of the sacroiliac region, especially with regard to the sacroiliac joint (SIJ). Dorsal SIJ innervation was analyzed and described. Our main hypothesis was that nerves reach the SIJ dorsally, passing ligamental compartments, as this would explain dorsal SIJ pain. METHODS: To examine sacroiliac innervation, we followed the nerves in over 50 specimens over several years. Plastinated slices were evaluated, nerves in the region were stained histologically, and the data were summarized as 3D models. RESULTS: The Rami communicans and posterior branches of the spinal nerves and their branches that form a dorsal sacral plexus and communicating branches, together with corresponding vessels, were observed to form neurovascular bundles embedded by tiny fatty connectives in gaps and tunnels. Branches of L5-S1 pass the inner sacroiliac ligaments (the interosseous sacroiliac ligament and axial interosseous ligament). The outer sacroiliac ligaments (posterior sacroiliac ligaments, long posterior sacroiliac ligament, sacrotuberal ligament, thoracolumbar fascia) are passed by the S1-S4 branches. However, although the paths of these nerves are in the direction of the SIJ, they do not reach it. It is possible that impingement of the neurovascular bundles may result in pain. Moreover, the gaps and tunnels connect to the open dorsal SIJ. CONCLUSION: Our findings suggest that Bogduk's term "sacroiliac pain" correlates to "sacroiliac innervation", which consists of "inner-" and "outer sacroiliac ligament innervation", and to ventral "SIJ pain". The watery gaps and tunnels observed could play a significant role in innervation and thus in the origins of SIJ pain. LEVEL OF EVIDENCE: Individual cross-sectional studies with consistently applied reference standard and blinding.

Topography and evidence of a separate "fascia plate" for the femoral nerve inside the iliopsoas - A dorsal approach.

The femoral nerve stretch test is an essential part of clinical neurological examinations. This test is performed alongside Magnetic Resonance Imaging (MRI) to determine if there is any evidence of nerve root irritation, usually as a consequence of disc prolapse. The test occasionally gives false positive results. Why such false positives can occur, is subject to continued research, however, no obvious reason has yet emerged. We hypothesize that connectives of the femoral nerve may explain such a phenomenon. To see these connectives, we approached the femoral nerve from dorsal in 12 cases. With the use of ink injection into the subparaneural compartment of the femoral nerve and dissections, a thin transparent structure can clearly be seen that is separate from the epineurium, perineurium, and a paraneural sheath. A continuation of the paraneural sheath produces a fascia plate approximately 1.5 cm in width and with a thickness of around 3 mm, which not only circumnavigates the nerve but projects into the surrounding tissues. Our qualitative observations show that not only does this femoral nerve fascia plate exists, but it also contains nerves and vessels. Furthermore, we show that the femoral nerve is connected to the myofascial complex of the iliopsoas, and in a separate fascia plate from the iliopsoas fascia. This plate is a hitherto neglected connective which extends as far as the spinal dura mater. Evidence from our plastinates and histological sections suggests that when tension is applied to the femoral nerve during the femoral nerve stretch test, tension is also applied to the femoral nerve fascia plate. The femoral nerve fascia plate could be a specific factor that contributes to pain resulting in a false positive femoral nerve stretch test.

Integrity of the pectineal ligament in MRI correlates with radiographic superior pubic ramus fracture displacement.

BACKGROUND: Estimating the stability of pelvic lateral compression fractures solely by static radiographs can be difficult. In this context, the role of anterior pelvic soft tissues as potential secondary stabilizer of the pelvic ring has hardly been investigated. PURPOSE: To correlate the initial radiographic appearance of the pubic ramus fracture with the integrity of the pectineal ligament, a strong ligament along the pecten pubis. MATERIAL AND METHODS: In total, 31 patients with a pelvic lateral compression fracture (AO/OTA 61- B1.1/B2.1) with 33 superior pubic ramus fractures and available post-traumatic radiographs (pelvis anteroposterior, inlet, outlet) and magnetic resonance imaging (MRI) of the pelvis with fat-suppressed coronal images were reviewed retrospectively. Radiographic superior pubic ramus fracture displacement was measured and correlated to the degree of MR-morphologic alterations of the pectineal ligament (grade 0 = intact, grade 3 = rupture). RESULTS: In the majority of fractures (72.7%), associated MR-morphologic alterations of the pectineal ligament were present. Radiographic displacement and MRI grading showed a strong positive correlation (Spearman rho = 0.783, P < 0.001). The sensitivity and specificity for a radiographic displacement of >3 mm on plain radiographs to detect a structural ligament lesion on MRI (grade 2 and higher) were 73% and 100%, respectively. CONCLUSION: Radiographic displacement of superior pubic ramus fractures >3 mm is a strong indicator for a structural lesion of the pectineal ligament. Future studies should investigate the potential biomechanical importance of this ligament for pelvic ring stability.

On the importance of the innervation of the human cervical longitudinal ligaments at vertebral level.

PURPOSE: In our aging society, the prevalence of degenerative spinal diseases rose drastically within the last years. However, up till now, the origin of cervical pain is incompletely understood. While animal and small cadaver studies indicate that a complex system of sensory and nociceptive nerve fibers in the anterior (ALL) and posterior longitudinal ligament (PLL) at the level of the intervertebral disc might be involved, there is a lack of data exploring whether such a network exists and is equally distributed within the cervical vertebrae (VB). We, therefore, aimed to investigate the spatial distribution of the mentioned nerve networks in human tissue. METHODS: We performed macroscopic (Sihler staining, Spalteholz technique, and Plastination) and microscopic (immunohistochemistry for PGP 9.5 and CGRP) studies to characterize spatial differences in sensory and nociceptive innervation patterns. Therefore, 23 human body donors were dissected from level C3-C6. RESULTS: We could show that there is a focal increase in sensory and nociceptive nerve fibers at the level of C4 and C5 for both ALL and PLL, while we observed less nerve fiber density at the level of C3 and C6. An anatomical vicinity between nerve and vessels was observed. CONCLUSION: To our knowledge, these findings for the first time report spatial differences in sensory and nociceptive nerve fibers in the human cervical spine at VB level. The interconnection between nerves and vessels supports the importance of the perivascular plexus. These findings might be of special interest for clinical practice as many patients suffer from pain after cervical spine surgery.

Ligamental compartments and their relation to the passing spinal nerves are detectable with MRI inside the lumbar neural foramina.

PURPOSE: Intraforaminal ligaments (IFL) in lumbar neural foramina (NF) and their relation to the lumbar spinal nerves (SN) are addressed. METHOD: Giemsa- and PAS-stained plastinated body slices of 15 lumbar spines were made and compared to MRI and CT data acquired of the same fresh specimens. We dissected one fixed lumbar spine to discuss our results with previous literature. Macroscopic pathophysiological changes and operational interventions at these lumbar spines were excluded. RESULTS: In the NF, thin medial IFL touch the SN. As a second compartment, intermedial vertical IFL are seen. A third lateral horizontal compartment of IFL is formed by thick cranial and caudal ligaments. Ligaments of the second and third compartments have no direct contact with the SN. From medial to lateral, the IFL thicken. All compartments are 3D reconstructed. If compartments of the IFL have no direct contact with the SN seen in the slices, a connection was noticed after dissection. CONCLUSION: Manual dissection seems to be inappropriate for a detailed study of the IFL. The lateral and intermedial compartments being free of the SN may transmit power and protect the SN, while the thin medial IFL may lead the SN passing the NF under physiological conditions. We conclude from the close topographical relation that the IFL may be relevant in foraminal stenosis. Any herniation in the NF presses IFL to the SN. Therefore, we think the IFL themselves could cause neurogenic claudication in case of their non-physiological turnover. Visualisation of IFL seems to be possible by using MRI. These slides can be retrieved under Electronic Supplementary Material.

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.

Sex hormones in association with general joint laxity and hypermobility in the temporomandibular joint in adolescents-results of the epidemiologic LIFE child study.

OBJECTIVES: The aim of this cross-sectional study was to investigate whether sex hormones (testosterone, oestradiol, sex-hormone-binding globulin = SHBG) are associated with general joint laxity (GJL) and hypermobility or derangements of the temporomandibular joint (TMJ) in adolescents. METHODS: Within the LIFE Child study, 970 adolescents (10-18 years) were included. GJL was assessed using the Beighton test. Maximum mouth opening (MMO) and clinical clicking sounds as signs of disc displacement (DD) in the TMJ were assessed according to the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD). Serum levels of sex hormones were assessed using standardised laboratory analyses. RESULTS: Hypermobile joints were found in 54.9% (N = 532) of the sample; females were more affected than males (61.4% vs. 51.8%, P < 0.001). Using logistic regression analyses, the odds ratio (OR) for having >1 hypermobile joints increased to 1.15 (95% confidence interval [CI]: 1.04-1.27) in males and 1.09 (95% CI: 1.02-1.17) in females per 10 units of the SHBG serum level, compared to those without hypermobile joints-after controlling for the effect of age, adjusted BMI, pubertal development (Tanner scale), testosterone as well as oestradiol levels. Female subjects with >1 hypermobile joints showed a higher OR (1.89; 95% CI: 1.05-3.43) for having clinical clicking sounds in the TMJ and a 3.28 times higher OR (95% CI: 1.44-7.44) for MMO ≥ 55 mm. CONCLUSIONS: We observed age- and gender-independent associations of higher SHBG serum levels with GJL in adolescents. Moreover, hypermobile female adolescents show a more frequent hypermobility of the TMJ and clinical signs of DD.

Third primary branch of the posterior ramus of the spinal nerve at the thoracolumbar region: a cadaveric study.

PURPOSE: Spinal column procedures require an accurate understanding of neural pathways relative to the anatomic structure. Since Bogduk's report in 1982, it has been known that the human lumbar posterior ramus of the spinal nerve (PRSN) comprise not two but three primary branches at least in some lumbar segments. The purpose of the current study was to examine the existence of the three primary branches in the thoracic and lumbar segments. METHODS: In this study, we investigated the anatomy of the human PRSN in the thoracic and lumbar segments. Ventral dissection was performed in eight cadavers to determine the anatomy of the PRSN between T1 and L5. RESULTS: At the distal end of a given PRSN, the PRSN divided into three primary branches-medial, intermediate and lateral-in 196 out of 272 segments in the thoracic and lumbar regions in eight cadavers. The medial branch supplied the spinalis compartment, and reached the skin. The lateral branch supplied the iliocostalis muscle compartment, and reached skin. The intermediate branch supplied the longissimus muscle and the area between the medial and the lateral branch, which was a seemingly shorter branch. CONCLUSION: The triplication of the primary branch of the PRSN is considered not uncommon. The third branch should be recognized in the literature and in textbooks.

Accessory Spleen in the Greater Omentum: Embryology and Revisited Prevalence Rates.

PURPOSE: To investigate in a large sample the prevalence rates of accessory spleens located in the greater omentum and to explain the embryological background and the vascular supply of this rare congenital disorder. METHODS: Evaluation of the presence of accessory spleens located in the greater omentum was performed in 5 different international anatomical centers investigating a total of 1,045 body donors. Arterial and venous blood supply and the precise location of the respective vasculature within the splenic ligaments are described based on dissection of this rare condition in a male specimen. RESULTS: The reported prevalence rates from 5 different centers were: 0.5% (out of 380 body donors), 0% (out of 230 donors), 0% (out of 200 donors), 2% (out of 200 donors), and 0% (out of 35 donors). The cumulative prevalence rate obtained from 1,045 anatomical dissections was 0.6%. The identified accessory spleen measured 3 × 3 × 2.5 cm and was located in the left upper abdominal quadrant. A vascular stag 7.5 cm in length was identified within the gastro-splenic ligament, containing an artery and a vein piercing the greater omentum from posterior. CONCLUSION: An accessory spleen located in the greater omentum is a rare congenital disorder. Physicians should be aware of the fact that in patients without any representative symptom history a nodular mass located within the greater omentum could be an accessory spleen.

The bicipital groove as a landmark for reconstruction of complex proximal humeral fractures with hybrid double plate osteosynthesis.

BACKGROUND: Complex proximal humerus fractures with metaphyseal comminution remain challenging regarding reduction and stability. In most fracture patterns the hard bone of the bicipital groove remains intact. In this case series, we describe a novel technique of hybrid double plate osteosynthesis of complex proximal humerus fractures with metaphyseal comminution. METHODS: In randomly chosen shoulder specimens and synthetic bones, pilot studies for evaluation of the feasibility of the technique were performed. Between 4/2010 and 1/2012 10 patients underwent hybrid double plate osteosynthesis. Seven patients (4 male, 3 female, mean age was 50 years (range 27-73)) were available for retrospective analysis. Based on plain radiographs (anterior-posterior and axial view), the fractures were classified according to the Orthopaedic Trauma Association classification (OTA) and by descriptive means (head-split variant (HS), diaphyseal extension or comminution (DE)). RESULTS: Follow-up radiographs demonstrated complete fracture healing in six patients and one incomplete avascular necrosis. None of the patients sustained loss of reduction. Three patients where reoperated. The medium, not adapted, Constant score was 80 Points (58-94). Patients subjective satisfaction was graded mean 3 (range: 0-6) in the visual analog scoring system (VAS). CONCLUSION: The technique of hybrid double plate osteosynthesis using the bicipital groove as anatomic landmark may re-establish shoulder function after complex proximal humerus fractures in two dimensions. Firstly the anatomy is restored due to a proper reduction based on intraoperative landmarks. Secondly additional support by the second plate may provide a higher stability in complex fractures with metaphyseal comminution.

The Facial Adipose Tissue: A Revision.

Recent advantages in the anatomical understanding of the face have turned the focus toward the subcutaneous and deep facial fat compartments. During facial aging, these fat-filled compartments undergo substantial changes along with other structures in the face. Soft tissue filler and fat grafting are valid methods to fight the signs of facial aging, but little is known about their precise effect on the facial fat. This narrative review summarizes the current knowledge about the facial fat compartments in terms of anatomical location, histologic appearance, immune-histochemical characteristics, cellular interactions, and therapeutic options. Three different types of facial adipose tissue can be identified, which are located either superficially (dermal white adipose tissue) or deep (subcutaneous white adipose tissue): fibrous (perioral locations), structural (major parts of the midface), and deposit (buccal fat pad and deep temporal fat pad). These various fat types differ in the size of the adipocytes and the collagenous composition of their extracellular matrix and thus in their mechanical properties. Minimal invasive (e.g., soft tissue fillers or fat grafting) and surgical interventions aiming to restore the youthful face have to account for the different fat properties in various facial areas. However, little is known about the macro- and microscopic characteristics of the facial fat tissue in different compartments and future studies are needed to reveal new insights to better understand the process of aging and how to fight its signs best.

Reference data on muscle volumes of healthy human pelvis and lower extremity muscles: an in vivo magnetic resonance imaging feasibility study.

PURPOSE: Muscle volumes are of crucial interest when attempting to analyze individual physical performance and disease- or age-related alterations in muscle morphology. However, very little reference data are available in the literature on pelvis and lower extremity muscle volumes originating from healthy and young individuals. Furthermore, it is of interest if representative muscle volumes, covering large anatomical regions, can be obtained using magnetic resonance imaging (MRI) in a setting similar to the clinical routine. Our objective was therefore to provide encompassing, bilateral, 3-T MRI-based datasets on muscle volumes of the pelvis and the lower limb muscles. METHODS: T1-weighted 3-T MRI records were obtained bilaterally from six young and healthy participants. Three-dimensional volumes were compiled from 28 muscles and muscle groups of each participant before the muscle volumes were computed. RESULTS: Muscle volumes were obtained from 28 muscles and muscle groups of the pelvis and lower extremity. Volumes were larger in male than in female participants. Volumes of the dominant and non-dominant sides were similar in both genders. The obtained results were in line with volumetric data obtained from smaller anatomical areas, thus extending the available datasets. CONCLUSIONS: This study provides an encompassing and feasible approach to obtain data on the muscle volumes of pelvic and limb muscles of healthy, young, and physically active individuals. The respective data form a basis to determine effects of therapeutic approaches, progression of diseases, or technical applications like automated segmentation algorithms applied to different populations.

Teaching surgical exposures to undergraduate medical students: an integration concept for anatomical and surgical education.

BACKGROUND: Decreasing numbers of students are interested in starting a surgical career, posing substantial challenges to patient care in the next years. The anatomy course is one of the key subjects in medical training, especially in surgical disciplines. Innovative teaching concepts that integrate surgically relevant anatomy and manual dexterity might help boost student interest in surgery. METHODS: A preclinical workshop entitled "Surgical exposures" was developed. A team of anatomists and surgeons introduced the surgical exposures, demonstrating the procedures on Thiel-fixed body donors. Following this introduction, students practiced the exposures in an operating room-like manner. A six-point Likert scale was used to evaluate the workshop and to compare it to the first-year dissection course. RESULTS: The overall evaluation result for the surgical exposures was excellent, proving to be a significantly better result when compared to the first-year dissection course. The students were more satisfied with the teaching time invested by the peers and regarded the workshop as clinically highly relevant. Furthermore, they felt that questions were addressed better and that the overall atmosphere was better than in the gross anatomy course. Subject to criticism was the course size and practicing time in both cases. DISCUSSION: The surgical exposures workshop provides preclinical students with clinically relevant anatomy and manual dexterity. It may positively influence the decision to follow a surgical career. This course, however, requires extensive teaching resources. The given concept may help implement practical medical skills in the preclinical curriculum, strengthening the professional identity of surgeons and anatomists.

Ligament-induced sacral fractures of the pelvis are possible.

Pelvic ring stability is maintained passively by both the osseous and the ligamentous apparatus. Therapeutic approaches focus mainly on fracture patterns, so ligaments are often neglected. When they rupture along with the bone after pelvic ring fractures, disrupting stability, ligaments need to be considered during reconstruction and rehabilitation. Our aim was to determine the influence of ligaments on open-book injury using two experimental models with body donors. Mechanisms of bone avulsion related to open-book injury were investigated. Open-book injuries were induced in human pelves and subsequently investigated by anatomical dissection and endoscopy. The findings were compared to CT and MRI scans of open-book injuries. Relevant structures were further analyzed using plastinated cross-sections of the posterior pelvic ring. A fragment of the distal sacrum was observed, related to open-book injury. Two ligaments were found to be responsible for this avulsion phenomenon: the caudal portion of the anterior sacroiliac ligament and another ligament running along the ventral surface of the third sacral vertebra. The sacral fragment remained attached to the coxal bone by this second ligament after open-book injury. These results were validated using plastination and the structures were identified. Pelvic ligaments are probably involved in sacral avulsion caused by lateral traction. Therefore, ligaments should to be taken into account in diagnosis of open-book injury and subsequent therapy.

Presenting embryologically defined peripancreatic compartments and fusion planes in the search for pancreatic cancer fields.

BACKGROUND: Clinical progress in form of "total mesometrial resection" (TMMR) in cervical cancer and "total mesorectal excision" (TME) in rectal cancer can be traced to a paradigm-shift regarding the extent and range of resection. More significance is bestowed upon embryologically defined borders which define compartments, "morphogenetic units" and "cancer fields", that have to be addressed in order to avoid incomplete tumor resection. We want to transfer this rationale on the pancreas and define such borders for pancreatic compartments. MATERIAL AND METHODS: We used 26 unfixed body donors (16 male, 10 female) ranging in age from 64 to 98 years. Manual preparation consisted of performing the Cattell-Braasch maneuver to restore embryologic anatomy and define fascial remnants of the borders of the dorsal and ventral mesogastrium with focus on the pancreatic fusion fasciae and peripancreatic spaces. RESULTS: We tracked what used to be the dorsal and ventral mesogastrium and assigned their remnants to the bowel and pancreas. Following avascular embryologic fascial fusion planes along the mesogastria we could demonstrate peripancreatic spaces, which were sealed off from bordering surfaces of presumably different morphogenetic units and possible cancer fields. Reverting embryologic development also seemed possible within the pancreas, demonstrating the embryologic fusion plane between the ventral and dorsal pancreatic buds as two distinct compartments. CONCLUSIONS: Following pancreatic fusion fasciae by separating embryologic fusion planes enables to define the pancreatic compartments which might play a major role in applying the success of TMMR and TME on pancreatic resection and define pancreatic cancer fields.

Drying irreversibly affects the elastic behavior of pelvic cortical bone.

Various studies have shown that the water content affects the elastic behavior of cortical bone. However, there is disagreement regarding the reversibility of the elastic behavior with rewetting. This study investigates this issue using an intrinsic approach, i.e., moisture manipulation and material testing were always carried out on the same specimen. The test results were then evaluated separately for each of several specimens. In total, 24 specimens of human cortical bone from the ischiopubic ramus were examined. The water content was varied in 11 steps, and the corresponding elastic moduli were determined using three-point bending tests within the elastic range. Moisture adjustment was achieved mainly using desiccators, accelerated by forced convection. Reference samples stored in the same manner were evaluated microscopically. The experiments confirmed the known correlation between water content reduction and stiffness increase of cortical bone. Complete drying increased the elastic modulus by about 83 %. By rewetting, the stiffness was significantly reduced again, though not only to the initial state, but even about 24 % below this. Thus, an irreversible alteration of the elastic behavior was observed. Decay of the reference samples was not observed. Therefore, decay is not the main reason for the significant loss of stiffness. In terms of the storage conditions for cortical bone specimens, an environment with 100 % relative humidity yielded the best match with the initial state. This storage method can therefore be recommended for biomechanical specimens used to determine in-vivo-like material parameters.

The median nerve´s system of connective tissue distal to the pronator teres to the carpal tunnel.

BACKGROUND: Connective tissue serves a role beyond mere spatial filling. Furthermore, there is increasing evidence that connective tissue plays an important role in the pathogenesis of conditions such as carpal tunnel syndrome (CTS). According to our hypothesis, the median nerve (MN) is surrounded by a system of connective tissue distal to the pronator teres and extending up to, and including, the carpal tunnel. METHODS: To visualize the connective tissue surrounding the median nerve, we dissected the forearms of 15 body donors from pronator teres to the carpal tunnel, created plastination slices stained with Periodic Acid-Schiff (PAS), and injected ink into the seen spaces. We verified our findings with a segmentational analysis of radiological data of 10 healthy individuals. RESULTS: We macroscopically describe the median nerve´s system of connective tissue (MC) distal to the pronator teres and up to and including the carpal tunnel. This system creates, connects, and separates spaces. At least from the pronator teres to the carpal tunnel it also creates subspaces from proximal to distal. For the MC, we established a mean cross-sectional area of 153.1 mm2 (SD=37.15) in the carpal tunnel. The median nerve consistently resides at the center of this MC, which further connects to flexor muscles of the forearm, and to the radius bone. In the carpal tunnel, the MC creates subspaces inside. There, it also acts as the outermost internal layer enveloping flexor tendons, and the MN. DISCUSSION: The term MC does not negate but orders the existence of other "connectives", like subsynovial connective tissue, endo-, epi- or perineuria, epimysia, periostea, or peritendinea, to a hierarchy related to the median nerve. Diseases of the MN are common. Knowing the anatomy of the MC and how it relates to MN function may help clinicians recognize and understand conditions like CTS.