Innervation of the distal part of the vastus medialis muscle is endangered by splitting its muscle fibers during total knee replacement: an anatomical study using modified Sihler's technique.

Background and purpose - The distal part of the vastus medialis muscle is an important stabilizer for the patella. Thus, knowledge of the intramuscular nerve course and branching pattern is important to estimate whether the muscle's innervation is at risk if splitting the muscle. We determined the intramuscular course of the nerve branches supplying the distal part of the vastus medialis muscle to identify the surgical approach that best preserves its innervation.Material and methods - 8 vastus medialis muscles from embalmed anatomic specimens underwent Sihler's procedure to make soft tissue translucent while staining the nerves to study their intramuscular course. After dissection under transillumination using magnification glasses all nerve branches were evaluated.Results - The terminal nerve branches were located in different layers of the muscle and ran mostly parallel but also transverse to the muscle fibers. In half of the cases, the latter formed 1 to 3 anastomoses and coursed close to the myotendinous junction. Additionally, most of the branches extended into the ventromedial part of the knee joint capsule.Interpretation - To preserve the innervation of the distal part of the vastus medialis muscle, any split of the muscle during surgical approaches to the knee joint should be avoided.

A Rare Case of Facial Artery Branching-A Review of the Literature and a Case Report with Clinical Implications.

Background and Objectives: Vascular variations appear as morphologically distinct patterns of blood diverging from the most commonly observed vessel patterns. The facial artery is considered to be the main vessel for supplying blood to the anterior part of the face. An anatomical understanding of the facial artery, its course, its topography, and its branches is important in medical and dental practice (especially in neck and face surgery), and is also essential for radiologists to be able to interpret vascular imaging in the face following angiography of the region. A profound knowledge of the arteries in the region will aid in minimizing the risks to the patient. Materials and Methods: In our publication a narrative literature review and a case report are presented. Results: A rare case of a facial artery pattern has been described anatomically for the first time with respect to its course and branching. This variation was found on the left side of a 60-year-old male corpse during anatomical dissection. The anterior branch of the facial artery arched in the direction of the labial angle, and there divided into the inferior and superior labial arteries. At the same time, the posterior branch coursed vertically and superficially to the masseter muscle. It here gave off the premasseteric branch, and continued towards the nose, where it ran below the levator labii superioris and the levator labii superioris alaeque nasi muscles and terminated at the dorsum nasi. Conclusions: Our review of the literature and the case report add to knowledge on the facial artery with respect to its topographical anatomy and its branching and termination patterns, as well as the areas of supply. An exact knowledge of individual facial artery anatomy may play an important role in the planning of flaps or tumor excisions due to the differing vascularization and can also help to prevent artery injuries during aesthetic procedures such as filler and botulinum toxin injections.

There are no safe areas for avoiding the perforating arteries along the proximal part of the femur: A word of caution.

Knowledge about the variable course of the perforating arteries near the body of the femur is essential during surgical procedures (e.g., percutaneous cerclage wiring, plate osteosynthesis, Ilizarov technique). Our aims were to determine the number of perforating arteries, and to identify safe zones along the body of the femur within which perforating arteries are unlikely to pass toward the back of the thigh. The number of perforating arteries was determined in both legs of 100 formalin-fixed anatomic specimens of both sexes. The level of passage of perforating arteries near the body of the femur was measured in reference to a line from the anterior superior iliac spine to the medial femoral condyle. In each leg, two to seven perforating arteries were present. In 64% of legs, at least one artery divided into two to four branches before entering the back of the thigh. Thus, the total number of branches passing near the body of the femur varied between two to nine. Perforating arteries passed to the back of the thigh at every level between 14.0 and 36.5 cm from the anterior superior iliac spine (16-39% of the leg length). Within this distance, no safe zones along the body of the femur could be identified. The present study shows the high variability regarding number and course of the perforating arteries. Surgeons can be faced with an artery at every level on the posteromedial aspect of the body of the femur between 14.0 and 36.5 cm distally to the anterior superior iliac spine. Clin. Anat. 33:507-515, 2020. © 2019 Wiley Periodicals, Inc.

A Phylogenetic and Ontogenetic Perspective of the Unique Accumulation of Arterial Variations in One Human Anatomic Specimen.

Background and objectives: Anatomical dissection is an indispensable means of acquiring knowledge about the variability of the human body. We detected the co-existence of several arterial variations within one female anatomic specimen during routine anatomical dissection. The aim of this study was to evaluate if this status is a regular pattern in any of other vertebrates. Materials and Methods: Besides of a meticulous anatomic dissection, we performed a literature review concerning the frequency, the phylogenesis, and ontogenesis of all of these variations. Results: Exceptionally, the middle colic artery arose from an extraordinarily divided celiac trunk. The kidneys received three polar arteries. On the left side, a corona mortis replaced the obturator artery. The aortic arch gave rise to a bicarotid trunk, and the right subclavian artery originated and coursed as a typical lusorial artery leading to a non-recurrent laryngeal nerve on the right side. Furthermore, variations of the branches of the thyrocervical trunk were found to be present. Extraordinarily, in their cervical portion both internal carotid arteries gave rise to two arteries each. All of these variations developed within two to three weeks, around the sixth week of gestation. It was not possible to ascribe all or even one of the variations to a singular species of vertebrates. Conclusion: Apparently, arterial variations are frequently a result of random development. Medical professionals must always be aware of anatomical variations; the absence of such awareness would create major difficulties during surgery. The present case confirms the relevance of anatomical dissection, particularly for medical students.

Paget's Disease of Long Bones: Microstructural Analyses of Historical Bone Samples.

Although Paget's disease of bone (PDB) is the second most common metabolic bone disease, there is only limited information about the microarchitecture of affected bones. Therefore, the aim of this study was to determine cortical and trabecular bone properties in clinically relevant locations by microcomputed tomography (µCT). Ten femora and ten tibiae affected by Paget's disease taken from the Natural History Museum Vienna were compared to 13 femora and 10 tibiae of non-affected body donors. Digitization of the cortical and trabecular bone microarchitecture was performed with an X-ray-based µCT scanner. Additionally, semi-quantitative gradings of trabecular and cortical architectural parameters of the femora and the tibiae were generated. Microcomputed tomography images showed changes in the thickness of cortices, cortical porosity, and trabecularization of cortical structures. Moreover, severe disorganization of trabecular structures, trabecular defects, and thickening of (remaining) trabeculae were detected. Numerical cortical analyses showed lower total bone volume (BV) and lower BV in the outer region (66-100%) (- 36%, p = 0.004, and - 50%, p < 0.001, respectively), lower total volume (TV) in the outer region (66-100%) (- 42%, p < 0.001), lower total bone volume fraction (BV/TV) and BV/TV in the outer region (66-100%) (- 23%, and - 12%, p < 0.001, respectively), higher BV and TV in the middle region (33-66%) and higher BV/TV in the inner region (0-33%) (123%, p = 0.011, 147%, p = 0.010, and 33%, p = 0.025, respectively) in Pagetic compared to non-affected bones. Trabecular analyses showed higher BV/TV (96%, p = 0.008) and Tb.Th (43%, p = 0.004) in Pagetic compared to non-affected bones. There is a major and consistent structural alteration of PDB at cortical and trabecular sites in weight-bearing long bones. Our findings are relevant for the differential diagnosis of PDB and for the pathogenesis of associated complications, since the disorder produces abnormalities in the structure that might lead to bone fragility.

Comparison of mesh fixation devices for laparoscopic ventral hernia repair: an experimental study on human anatomic specimens.

BACKGROUND: As there is a lack of clarity in terms of the tensile strength of mesh fixation for laparoscopic ventral hernia repair (LVHR), our aim was to investigate the immediate tensile strength of currently available mesh fixation devices on human anatomic specimens. METHODS: Sixteen recently deceased body donators (mean body mass index of 24.4 kg/m2) were used to test the immediate tensile strength (Newton) of 11 different LVHR mesh fixation devices. RESULTS: Each of the 11 different laparoscopic fixation devices was tested 44 times. Non-articulating tackers provided higher fixation resistance to tensile stress in comparison to articulating tackers (5.1-mm ReliaTack™: 16.9 ± 8.7 N vs. 12.2 ± 5.6 N, p = 0.013; 7-mm ReliaTack™: 19.8 ± 9.4 N vs. 15.0 ± 7.0 N, p = 0.007). Absorbable tacks with a greater length, i.e. ≥6 mm (7-mm ReliaTack™, 6-mm SorbaFix™ and 7.2-mm SecureStrap™) had significantly higher fixation tensile strength than tacks with a shorter length, i.e. < 6 mm (5.1-mm ReliaTack™ and 5.1-mm AbsorbaTack™) (p < 0.001). Furthermore, transfascial sutures (PDS 2-0 sutures 26.3 ± 5.6 N) provided superior fixation tensile strength than 5.1-mm AbsorbaTack™ (13.6 ± 7.3 N) and cyanoacrylate glues such as LiquiBand FIX8™ (3.5 ± 2.4 N) (p < 0.001, respectively). There was a significant deterioration in fixation capacity in obese body donators with a body mass index > 30 kg/m2 (13.8 ± 8.0 vs. 17.9 ± 9.7 N, p = 0.044). CONCLUSIONS: Although articulating laparoscopic tackers improve accessibility and facilitate the utilization of tacks within the fixation weak spot adjacent to the trocar placement, an articulating shaft that is not ergonomic to use may limit mechanisms of force transmission. For mesh fixation in LVHR, transfascial sutures and tacks with a longer length provide better immediate fixation tensile strength results.

Congenital Bilateral Absence of the Radial Artery: A Very Rare Variation in Humans - Phylogenetic and Ontogenetic Aspects.

In an 80-year-old Caucasian woman, both radial arteries were found to be replaced by an enlarged anterior interosseous artery. Additionally, the right forearm revealed a persistent median artery which formed the superficial palmar arch together with the ulnar artery. In both hands, the replaced radial artery was connected only to the deep but not the superficial palmar arch. In clinical practice, lack of an arterial pulse on the radial aspect of the wrist joint may indicate the presence of this anatomic variation. In this case, arterial blood sample collections, application of contrast media, invasive measurements of blood pressure, and several angiographic interventions cannot be performed via the radial artery. As this is the fourth reported case since 1830, bilateral aplasia of the radial artery appears to be an exceptional variation in humans. Thus, the phylo- and ontogenetic aspects of this anomaly are discussed.

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.

Reliability of radiographic landmarks in medial patello-femoral ligament reconstruction in relation to the anatomical femoral torsion.

PURPOSE: Anatomically correct graft positioning at the femoral insertion site is a key factor in surgical reconstruction of the medial patello-femoral ligament (MPFL). Basically there are two techniques to define this point in fluoroscopy during surgery. The role of the anatomical femoral torsion on the accuracy and reproducibility of both procedures has not been clarified. METHODS: Twenty human anatomical leg specimens were dissected. The femoral insertion of the MPFL was marked by two K-wires. The position of the ligament insertion was determined fluoroscopically in the true lateral view as used in routine clinical practice. The anatomical MPFL insertion was compared to the radiographic landmarks which were recommended by two previous studies. The anatomical femoral torsion of the specimens was assessed by computed tomography scans. RESULTS: In true lateral view fluoroscopy, the mean distance of the femoral MPFL insertion was -0.2 mm distal to the vertical reference line intersecting the posterior point of Blumensaat's line. In the anteroposterior direction, the mean distance was -2.0 mm posterior to the femoral cortex reference line. There was no correlation between anatomical femoral torsion and the distance of the femoral MPFL insertion to the posterior cortex. CONCLUSIONS: The results of this study strongly recommend use of a vertical line intersecting the most posterior point of Blumensaat's line as a reference to identify the MPFL insertion in the craniocaudal direction. In the anteroposterior direction, the femoral MPFL insertion showed distinctive variation and was found -2.0 mm posterior to the femoral cortex reference line without being influenced by the anatomical femoral torsion.

High-resolution ultrasound visualization of the subcutaneous nerves of the forearm: a feasibility study in anatomic specimens.

INTRODUCTION: The aim of this ultrasound-anatomical study was to evaluate the ability of high-resolution ultrasound (HRUS) to visualize and infiltrate small subcutaneous nerves of the forearm in anatomic specimens. METHODS: Seven nonembalmed human bodies (4 men, 3 women; mean age at death, 60 years) were included in the study. Two investigators scanned the anatomic specimens using 15-MHz and 18-MHz HRUS transducers. The lateral, medial, and posterior antebrachial cutaneous nerves were scanned and interventionally marked with ink using HRUS-guidance. Subsequently, dissections were performed to assess the anatomical correlation of HRUS findings. RESULTS: All 3 nerves were identified consistently using HRUS. The precision of the ink-markings was excellent, with good correlation with the small peripheral branches of all 3 nerves. CONCLUSIONS: HRUS can identify precisely the small subcutaneous nerves of the forearm and may aid in both diagnosis and therapy in cases of neuropathy.

Finite element based nonlinear normalization of human lumbar intervertebral disc stiffness to account for its morphology.

Disc degeneration, usually associated with low back pain and changes of intervertebral stiffness, represents a major health issue. As the intervertebral disc (IVD) morphology influences its stiffness, the link between mechanical properties and degenerative grade is partially lost without an efficient normalization of the stiffness with respect to the morphology. Moreover, although the behavior of soft tissues is highly nonlinear, only linear normalization protocols have been defined so far for the disc stiffness. Thus, the aim of this work is to propose a nonlinear normalization based on finite elements (FE) simulations and evaluate its impact on the stiffness of human anatomical specimens of lumbar IVD. First, a parameter study involving simulations of biomechanical tests (compression, flexion/extension, bilateral torsion and bending) on 20 FE models of IVDs with various dimensions was carried out to evaluate the effect of the disc's geometry on its compliance and establish stiffness/morphology relations necessary to the nonlinear normalization. The computed stiffness was then normalized by height (H), cross-sectional area (CSA), polar moment of inertia (J) or moments of inertia (Ixx, Iyy) to quantify the effect of both linear and nonlinear normalizations. In the second part of the study, T1-weighted MRI images were acquired to determine H, CSA, J, Ixx and Iyy of 14 human lumbar IVDs. Based on the measured morphology and pre-established relation with stiffness, linear and nonlinear normalization routines were then applied to the compliance of the specimens for each quasi-static biomechanical test. The variability of the stiffness prior to and after normalization was assessed via coefficient of variation (CV). The FE study confirmed that larger and thinner IVDs were stiffer while the normalization strongly attenuated the effect of the disc geometry on its stiffness. Yet, notwithstanding the results of the FE study, the experimental stiffness showed consistently higher CV after normalization. Assuming that geometry and material properties affect the mechanical response, they can also compensate for one another. Therefore, the larger CV after normalization can be interpreted as a strong variability of the material properties, previously hidden by the geometry's own influence. In conclusion, a new normalization protocol for the intervertebral disc stiffness in compression, flexion, extension, bilateral torsion and bending was proposed, with the possible use of MRI and FE to acquire the discs' anatomy and determine the nonlinear relations between stiffness and morphology. Such protocol may be useful to relate the disc's mechanical properties to its degree of degeneration.

Nomina anatomica-unde venient et quo vaditis?

As the title indicates, this article deals with the origins of anatomic terminology and its development up to the present day. The first attempt to name anatomical structures in animals and humans date back to Alkmaion, i.e. to the fifth century BC. Further work has been done at the same time by the Hippocratics and about 100 years later by Aristotle. As the Alexandrians Erasistratos and Herophilos first in history dissected human bodies, they expanded the anatomical terms. Until Celsus (around Christ's birth) and even later on, anatomical terminology was almost exclusively based on the Greek language. Thus, Celsus and not-as frequently done-Galenos has to be called the father of Latin-based anatomical terminology. Due to several translations including Arabic, first periods of proverbial Bable resulted. Return to systematic order was achieved finally by Andreas Vesal (1514/15-1564) and Caspar Bauhin (1560-1624). But again due to translations into several national languages, the uniformity of the anatomical nomenclature was undermined. Thus, by the end of the nineteenth century, in 1895 the newly founded Anatomische Gesellschaft created a uniform terminology, the Basle Nomina Anatomica (BNA). Although it has been revised several times, it is still the very basic of human anatomical terminology. Recently, an attempt was made to replace it by English translations of the original Latin (and also still Greek) terms to mainly get machine-readable denominations. As this will result again in non-uniformity of terminology, the Anatomische Gesellschaft proposes a version of the latest, generally accepted terminology, based on the Latin terms but incorporating recent developments.

Bone collagen tensile properties of the aging human proximal femur.

Despite the dominant role of bone mass in osteoporotic fractures, aging bone tissue properties must be thoroughly understood to improve osteoporosis management. In this context, collagen content and integrity are considered important factors, although limited research has been conducted on the tensile behavior of demineralized compact bone in relation to its porosity and elastic properties in the native mineralized state. Therefore, this study aims (i) at examining the age-dependency of mineralized bone and collagen micromechanical properties; (ii) to test whether, and if so to which extent, collagen properties contribute to mineralized bone mechanical properties. Two cylindrical cortical bone samples from fresh frozen human anatomic donor material were extracted from 80 proximal diaphyseal sections from a cohort of 24 female and 19 male donors (57 to 96 years at death). One sample per section was tested in uniaxial tension under hydrated conditions. First, the native sample was tested elastically (0.25 % strain), and after demineralization, up to failure. Morphology and composition of the second specimen was assessed using micro-computed tomography, Raman spectroscopy, and gravimetric methods. Simple and multiple linear regression were employed to relate morphological, compositional, and mechanical variables with age and sex. Macro-tensile properties revealed that only elastic modulus of native samples was age dependent whereas apparent elastic modulus was sex dependent (p < 0.01). Compositional and morphological analysis detected a weak but significant age and sex dependency of relative mineral weight (r = -0.24, p < 0.05) and collagen disorder ratio (I∼1670/I∼1640, r = 0.25, p < 0.05) and a strong sex dependency of bone volume fraction while generally showing consistent results in mineral content assessment. Young's modulus of demineralized bone was significantly related to tissue mineral density and Young's modulus of native bone. The results indicate that mechanical properties of the organic phase, that include collagen and non-collagenous proteins, are independent of donor age. The observed reduction in relative mineral weight and corresponding overall stiffer response of the collagen network may be caused by a reduced number of mineral-collagen connections and a lack of extrafibrillar and intrafibrillar mineralization that induces a loss of waviness and a collagen fiber pre-stretch.

Homogenized finite element analysis of distal tibia sections: Achievements and limitations.

High-resolution peripheral quantitative computed tomography (HR-pQCT) based micro-finite element (µFE) analysis allows accurate prediction of stiffness and ultimate load of standardised (∼1 cm) distal radius and tibia sections. An alternative homogenized finite element method (hFE) was recently validated to compute the ultimate load of larger (∼2 cm) distal radius sections that include Colles' fracture sites. Since the mechanical integrity of the weight-bearing distal tibia is gaining clinical interest, it has been shown that the same properties can be used to predict the strength of both distal segments of the radius and the tibia. Despite the capacity of hFE to predict structural properties of distal segments of the radius and the tibia, the limitations of such homogenization scheme remain unclear. Therefore, the objective of this study is to build a complete mechanical data set of the compressive behavior of distal segments of the tibia and to compare quantitatively the structural properties with the hFE predictions. As a further aim, it is intended to verify whether hFE is also able to capture the post-yield strain localisation or fracture zones in such a bone section, despite the absence of strain softening in the constitutive model. Twenty-five fresh-frozen distal parts of tibias of human donors were used in this study. Sections were cut corresponding to an in-house triple-stack protocol HR-pQCT scan, lapped, and scanned using micro computed tomography (µCT). The sections were tested in compression until failure, unloaded and scanned again in µCT. Volumetric bone mineral density (vBMD) and bone mineral content (BMC) were correlated to compression test results. hFE analysis was performed in order to compare computational predictions (stiffness, yield load and plastic deformation field pattern) with the compressive experiment. Namely, strain localization was assessed based on digital volume correlation (DVC) results and qualitatively compared to hFE predictions by comparing mid-slices patterns. Bone mineral content (BMC) showed a good correlation with stiffness (R2 = 0.92) and yield (R2 = 0.88). Structural parameters also showed good agreement between the experiment and hFE for both stiffness (R2 = 0.96, slope = 1.05 with 95 % CI [0.97, 1.14]) and yield (R2 = 0.95, slope = 1.04 [0.94, 1.13]). The qualitative comparison between hFE and DVC strain localization patterns allowed the classification of the samples into 3 categories: bad (15 sections), semi (8), and good agreement (2). The good correlations between BMC or hFE and experiment for structural parameters were similar to those obtained previously for the distal part of the radius. The failure zones determined by hFE corresponded to registration only in 8 % of the cases. We attribute these discrepancies to local elastic/plastic buckling effects that are not captured by the continuum-based FE approach exempt from strain softening. A way to improve strain localization hFE prediction would be to use longer distal segments with intact cortical shells, as done for the radius. To conclude, the used hFE scheme captures the elastic and yield response of the tibia sections reliably but not the subsequent failure process.

Injury of the gluteal aponeurotic fascia and proximal iliotibial band: anatomy, pathologic conditions, and MR imaging.

The fascia lata, or deep fascia of the thigh, is a complex anatomic structure that has not been emphasized as a potential source of pelvic and hip pain. This structure represents a broad continuum of fibrous tissue about the buttock, hip, and thigh that receives contributions from the posteriorly located aponeurotic fascia covering the gluteus medius muscle and from the more laterally located iliotibial band (ITB). At the pelvis and hip, the ITB consists of three layers that merge at the lower portion of the tensor fasciae latae muscle. The gluteal aponeurotic fascia and ITB merge at the buttock and hip before extending inferiorly to the Gerdy tubercle at the anterolateral tibia. Injuries to these anatomic structures are an underdiagnosed cause of pain and disability and may clinically mimic more common processes affecting the hip and proximal thigh. Categories of disease include overuse injuries, traumatic injuries, degenerative lesions, and inflammatory lesions. Familiarity with the anatomy and pathologic conditions of the fascia lata and its components is important in their recognition as a potential source of symptoms. This article illustrates the anatomy of this complex fascia through anatomic-pathologic correlation and describes the magnetic resonance imaging appearances of the pathologic conditions involving it.

The Corona mortis is similar in size to the regular obturator artery, but is highly variable at the level of origin: an anatomical study.

An enlarged anastomosis connecting the vascular territory of the external iliac and the obturator artery may replace most or all of the latter. This relatively common vascular variation, known as Corona mortis, can lead to death in the worst-case scenario if injured. Despite being well-known, exact anthropometric data are lacking. The purpose of this study was to determine diameters of the regular obturator artery, the Corona mortis and the inferior epigastric artery. In addition, the level of origin of the Corona mortis was quantified. The obturator artery and its norm variants were dissected bilaterally in 75 specimens (37 females, 38 males) and measured using two different methods. The Corona mortis was present in 36 of the 150 hemipelves (24%), presenting in one third of all cases bilaterally. Its level of origin measured from the commencement of the inferior epigastric artery was subject to high variability (4.4-28.3 mm). The mean diameters of the Corona mortis (mean 2.5 and 2.1 mm, respectively) and the regular obturator artery (mean 2.4 and 2.0 mm, respectively) were similar for both methods. There were no significant sex nor side differences. The diameter of the inferior epigastric artery was significantly smaller distal to the origin of the Corona mortis. The high incidence, non-predictable level of origin of the Corona mortis and its size similar to the regular obturator artery support its clinical relevance even to date. Clinicians should always be aware of an additional arterial vessel close to the pelvic brim.

Topographical Anatomy of the Adductor Muscle Group in the Albino Rat (Rattus norvegicus).

In comparative anatomy, the adductor muscles are said to be quite variable and to often cause difficulty in separation. The arrangement of these muscles and the possible occurrence of the adductor minimus and obturator intermedius muscles in the albino rat has not been investigated. The aim of this study was to accurately describe the adductor muscles in the albino rat (Rattus norvegicus). We hypothesized that all adductor muscles are constantly present and can be separated in a constant manner, and that the adductor minimus and obturator intermedius muscles are constant structures. Both pelvic limbs of 30 formalin-embalmed male albino rats were carefully dissected. The identification of the individual muscles was made based on their position in relation to the two branches of the obturator nerve and by comparing our results with previous findings in other species including humans. All examined rats had two gracilis muscles. The adductor longus muscle was the most superficial and smallest individual. The adductor brevis split into two parts of insertion-the femoral and genicular parts. The adductor magnus and minimus muscles could be separated constantly. The obturator intermedius muscle was a constant structure next to the obturator externus muscle. The adductor muscles of the albino rat were constantly separable and could be clearly assigned to their names. Further research is needed to investigate these muscles, especially the obturator intermedius muscle, in other species including humans.

2D-3D reconstruction of the proximal femur from DXA scans: Evaluation of the 3D-Shaper software.

Introduction: Osteoporosis is currently diagnosed based on areal bone mineral density (aBMD) computed from 2D DXA scans. However, aBMD is a limited surrogate for femoral strength since it does not account for 3D bone geometry and density distribution. QCT scans combined with finite element (FE) analysis can deliver improved femoral strength predictions. However, non-negligible radiation dose and high costs prevent a systematic usage of this technique for screening purposes. As an alternative, the 3D-Shaper software (3D-Shaper Medical, Spain) reconstructs the 3D shape and density distribution of the femur from 2D DXA scans. This approach could deliver a more accurate estimation of femoral strength than aBMD by using FE analysis on the reconstructed 3D DXA. Methods: Here we present the first independent evaluation of the software, using a dataset of 77 ex vivo femora. We extend a prior evaluation by including the density distribution differences, the spatial correlation of density values and an FE analysis. Yet, cortical thickness is left out of this evaluation, since the cortex is not resolved in our FE models. Results: We found an average surface distance of 1.16 mm between 3D DXA and QCT images, which shows a good reconstruction of the bone geometry. Although BMD values obtained from 3D DXA and QCT correlated well (r 2 = 0.92), the 3D DXA BMD were systematically lower. The average BMD difference amounted to 64 mg/cm3, more than one-third of the 3D DXA BMD. Furthermore, the low correlation (r 2 = 0.48) between density values of both images indicates a limited reconstruction of the 3D density distribution. FE results were in good agreement between QCT and 3D DXA images, with a high coefficient of determination (r 2 = 0.88). However, this correlation was not statistically different from a direct prediction by aBMD. Moreover, we found differences in the fracture patterns between the two image types. QCT-based FE analysis resulted mostly in femoral neck fractures and 3D DXA-based FE in subcapital or pertrochanteric fractures. Discussion: In conclusion, 3D-Shaper generates an altered BMD distribution compared to QCT but, after careful density calibration, shows an interesting potential for deriving a standardized femoral strength from a DXA scan.

Phrenic Nerve Transfer to Musculocutaneous Nerve: An Anatomical and Histological Study.

BACKGROUND: To restore elbow flexor muscle function in case of traumatic brachial plexus avulsion, the phrenic nerve transfer to the musculocutaneous nerve has become part of clinical practice. The nerve transfer can be done by means of video-assisted thoracic surgery without nerve graft or via supraclavicular approach in combination with an autograft. This study focuses on a detailed microscopic and macroscopic examination of the phrenic nerve. It will allow a better interpretation of existing clinical results and, thus, serve as a basis for future clinical studies. MATERIAL AND METHODS: An anatomical study was conducted on 28 body donors of Caucasian origin (female n = 14, male n = 14). A sliding caliper and measuring tape were used to measure the diameter and length of the nerves. Sudan black staining was performed on 15 µm thick cryostat sections mounted on glass slides and the number of axons was determined by the ImageJ counting tool. In 23 individuals, the phrenic nerve could be examined on both sides. In 5 individuals, however, only one side was examined. Thus, a total of 51 nerves were examined. RESULTS: The mean length of the left phrenic nerves (33 cm (29-38 cm)) was significantly longer compared to the mean length of the right phrenic nerves (30 cm (24-33 cm)) (p < 0.001). Accessory phrenic nerves were present in 9 of 51 (18%) phrenic nerves. The mean number of phrenic nerves axons at the level of the first intercostal space in body donors with a right accessory phrenic nerve was significantly greater compared to the mean number of phrenic nerves axons at the same level in body donors without a right accessory phrenic nerve (3145 (range, 2688-3877) vs. 2278 (range, 1558-3276)), p = 0.034. A negative correlation was registered between age and the nerve number of axons in left (0.742, p < 0.001) and right (-0.273, p = 0.197) phrenic nerves. The mean distance from the upper edge of the ventral ramus of the fourth cervical spinal nerve to the point of entrance of the musculocutaneous nerve between the two parts of the coracobrachialis muscle was 19 cm (range, 15-24 cm) for the right and 20 cm (range, 15-25 cm) for the left arm. CONCLUSIONS: If an accessory phrenic nerve is available, it presumably should be spared. Thus, in that case, a supraclavicular approach in combination with a nerve graft would probably be of advantage.

Undergraduate medical student perceptions and learning outcomes related to anatomy training using Thiel- and ethanol-glycerin-embalmed tissues.

Anatomical dissection is known to serve as an integral tool in teaching gross anatomy, including postgraduate training. A variety of embalming techniques exist, resulting in different haptic and optical tissue properties. This study aimed to objectify learning outcomes and medical student perceptions related to the use of two widely used embalming techniques, namely Thiel and ethanol-glycerin embalming. Between 2020 and 2022, first- and second-year medical students enrolled in the course on topographic anatomy participated in this study. Objective structured practical examinations were carried out for the head, neck, thorax, abdomen, pelvis, and extremity regions following regional dissection just before the oral examinations began. Six to ten numbered tags were marked in prosections of each region in Thiel- and ethanol-glycerin-embalmed specimens. Following the examinations, the students were surveyed regarding the suitability of the two embalming techniques with respect to preservation, colorfastness, tissue pliability, and the suitability in preparing for their anatomy examinations. Consistently higher scores were achieved for the thoracic and abdominal regions in ethanol-glycerin-embalmed specimens when compared to Thiel. No benefit was found for Thiel-embalmed upper or lower extremities. Tissues embalmed with ethanol-glycerin were rated higher for preservation and suitability to achieve the learning objectives, tissue pliability was rated higher for Thiel-embalmed tissues. Ethanol-glycerin embalming appears to offer certain advantages for undergraduate students in recognizing visceral structures, which may align with students' ideas on tissue suitability for their learning. Consequently, the benefits reported for Thiel embalming for postgraduate study unlikely reflect its suitability for novices.