Anatomia

Background: The alignment of a person’s body segments depends on their innate anatomy and neuromuscular status. Sagittal posture assessments provide valuable information on correctable deficits, which can be used to prevent possible health issues or injuries. Methods: This article provides practical guidance on how to perform a basic photometric sagittal posture analysis in a reproducible manner, which reference points should be used, and which errors should be avoided. For this purpose, based on the current literature, four important evidence-based parameters for evaluation are defined, and literature-based reference values are given for the assessment of posture. Conclusions: When done correctly, the sagittal posture analysis is a valuable tool in the fields of medicine and sports. Full article

Background: The dorsal scapular nerve (DSN) and the long thoracic nerve (LTN) exhibit variable anatomical pathways, which may contribute to upper back pain and impaired scapular movement in affected patients. This study investigates these variations to enhance clinicians’ diagnostic and surgical approaches. Methods: The bilateral cervical regions of 32 formalin-embalmed donors (64 sides) were dissected to document the origin of the DSN, the relationship with the scalene muscles of the DSN, and anatomical connections between the DSN and LTN. Measurements of the distance between the mastoid process and the piercing point of the DSN to the scalene muscle were obtained with digital calipers. Additional measurements were obtained from the medial border of the scapula at two specific locations: the scapular spine (zone 1) and the midpoint between the scapular spine and the inferior angle of the scapula (zone 2). Results: The DSN demonstrated four distinct cervical spinal nerve root origins and five unique scalene muscle piercing patterns. The average distance between the DSNs’ scalene muscle piercing point and the mastoid process was 94.87 ± 10.09 mm, with significantly greater distances observed in male donors compared to female donors (p < 0.001). Connections between the DSN and LTN were identified in 65.2% of the examined cervical regions. The mean distance of the DSN from the medial border of the scapula at zone 2 was significantly greater than at zone 1 (p < 0.001). Conclusions: The anatomical variation findings and classification of the DSN provide valuable insights, offering guidance for conducting clinical procedures of the scalene and rhomboid musculature in a way that minimizes the risk of iatrogenic injury. The documented variations may also assist in the diagnosis and management of DSN-related pathologies such as DSN neuropathy. Full article

Background: Clinical-surgical procedures in the thoracic outlet can be challenging due to the proximity of neurovascular structures to the subclavian vein. Methods: During a routine anatomical dissection in an undergraduate medical study at Paracelsus Medical University, Nuremberg, a novel anatomical finding was observed in an ethanol–glycerin embalmed, 79-year-old female body. In addition to the standard measurements, hematoxylin eosin staining of relevant vessels was performed Results: A nerve branch separating from the brachial plexus at the C6 spinal nerve traversed inferiorly and passed through a fenestration of the subclavian vein in the lateral section, rejoining the lateral cord of the brachial plexus. In addition, hypoplasia of the right-sided internal carotid artery (ICA) and a left-sided internal jugular vein (IJV) hypoplasia were detected. At the left venous angle of the left IJV, a venous saccular aneurysm was found. The ectopic origin of the left ascending pharyngeal artery originated from the initial segment of the left ICA. Also, Langer’s axillary arches were observed bilaterally in the same subject. Conclusions: The anatomical findings in the specimen do not provide a direct symptomatic correlation or functional relevance comparable to clinical observations. Nevertheless, it is important to highlight this discovery as a potential clinical reference for future studies. Full article

Background: Endovascular treatment of venous disease is introducing new therapeutic options in neuroradiology. These procedures are technically challenging and require extensive physician training. Currently, training is mainly conducted on animal models, which presents drawbacks such as ethical concerns and anatomical differences from human vascular architecture. There is no training model that simulates treating intracranial venous disease using original instruments in a real angiography suite. Methods: This work presents the development of a venous system model for endovascular training simulations for integration into the existing Hamburg ANatomical NEurointerventional Simulator (HANNES) for arterial interventions. Results: The manufacturing process established at HANNES and the material used for the arterial vascular models were successfully transferred to the larger 3D-printed vein models. The application test was conducted in a real angiography suite with original instruments by an experienced neurointerventional physician to evaluate the system in terms of geometric mapping, flow, haptics and probing. Conclusion: This newly developed model provides a first approach to simulate an endovascular intervention in the venous system within the HANNES environment. Future expansions might include specific treatment simulations for conditions such as arteriovenous malformations, dural arteriovenous fistulas, sinus vein thrombosis and hydrocephalus. Full article

Background: Peripheral nerve surgeries require extensive practice to address anatomical variability and effectively manage neuropathy symptoms. While these procedures are increasingly performed by other surgical specialists, neurosurgeons bring unparalleled expertise in the central and peripheral nervous systems. Microscopic surgical techniques are essential for minimally invasive procedures, and cadaver-based education provides an invaluable medium for trainees to practice these techniques. However, few papers address these concepts in tandem. This study explores lesser-known peripheral nerve entrapments, highlights minimally invasive microscopic approaches, and advocates for cadaver-based training. Methods: Willed cadavers were embalmed through approved methods by the state anatomical board. For each decompression procedure, a 1–2 cm keyhole incision was made. Further methods are described in each nerve entrapment surgery below. Exploratory sessions with wider incisions were conducted either before or after the minimally invasive procedure to review anatomy or assess procedural success, respectively. Results: Neurosurgical medical education using cadavers allows trainees to practice techniques and enhance their skillset. Cadavers provide a valuable medium for exploring the relevant anatomy and visualizing the correct procedural steps after minimally invasive surgeries. Using microscopes for the procedures further facilitates detailed anatomical observation and technique refinement. Conclusions: Here, we show that cadaver-based medical education offers a realistic and controlled environment for exploring anatomical variability and refining surgical techniques. This method allows for a visual, mental, and tactile understanding, while performing minimally invasive procedures with a microscope on cadavers further enhances trainees’ proficiency, precision, and confidence, equipping them with the skills needed for improved surgical outcomes. Full article

This article explores the continuation of the pathological morphology research program at neuroscience-related institutes from the Kaiser Wilhelm Society after World War II. It covers the research tradition in the brain sciences, which can be described by an emphasis on gross anatomy, the functional implications of morphological substrates, and the analysis of neurohistological research paths of the human brain in comparative contexts. To enable examination of the assimilation processes of the Kaiser Wilhelm Society’s legacy, the decisions and developments of the newly created Max Planck Society in Germany and its early brain science facilities will be assessed for the time period from 1948 to 2002. Pertaining to these overall developments in the Max Planck Society, a persistence of the “morphological paradigm” (microanatomy, pathology, comparative anatomy, etc.) can be identified as lasting until the 1960s. The newer “functional paradigm” (neurophysiology, electroencephalography, cybernetics, and behavioral studies) only became more visible when the first generations of the scientific leaders left their positions in this national research society. It is of note that many directors and scientific members, including Detlev Ploog (1920–2005), Dieter Lux (1924–1995), Georg W. Kreutzberg (1932–2019), Otto Detlev Creutzfeldt (1927–1992), Hans Thönen (1928–2012), Manfred Eigen (1927–2019), Erwin Neher (b. 1944), Hartmut Wekerle (b. 1944), Albert Hertz (1921–2018), Bert Sakmann (b. 1942), and Wolf Singer (b. 1943) were part of the American Neuroscience Research Program as associates, members, conference chairs, or trainees. Likewise, they joined the Society for Neuroscience early on, after it had emerged from the Neuroscience Research Program’s steering committee in 1969. This article seeks to clarify the context of the reorganization of the brain research-related Max Planck Institutes during the postwar period after World War II. Its trajectory includes the location of the institutes, their previous involvement in applied research, and personal continuities in scientific leadership positions, contributing to debates during the first decades of the Max Planck Society. The lens of pathological brain research emerges here as an important viewpoint to aid the understanding of the continued impact and concerns over the dominant morphological approaches in postwar West German neurology and psychiatry. Full article

Disuse osteoporosis occurs due to rest and reduced mechanical stimulation. Under these conditions, bone resorption exceeds bone formation, leading to a decrease in bone density. Vector potential (VP) generators have been developed, and their ability to maintain cartilage thickness has been reported. However, their effects on bone tissue remain unstudied. In this study, experiments were conducted to test the effects of VP on bones that had undergone weight reduction due to hindlimb suspension as a model of disuse osteoporosis. Methods: In this study, 7-week-old male Wistar rats (N = 6 each) were classified into control (CO), hindlimb suspension (HS), and VP energization intervention groups. The tail was used to suspend the HS and VP to remove the load applied to the hindlimbs. The VP conditions were as follows: voltage, 67 mV; frequency, 20 kHz, 0.12 mA; experimental intervention, 30 min/day, 5 days/week, for 3 weeks. At the end of the experimental period, the rats were euthanized with carbon dioxide gas, and histological specimens were fixed in 4% paraformaldehyde (PFA) in the femur and analyzed by electron microscopy, bone morphometry, immunohistology, bone fracture testing, and gene expression analysis. Results: HS decreased trabecular bone density and strength. However, VP maintained a significantly higher bone mass than HS, and VP did not differ from CO in bone strength; more osteoclasts were observed on the bone surface in HS, but they were suppressed in VP, and gene expression of CTSK and MMP-9 was decreased. Conclusions: VP suppressed bone resorption by osteoclasts, suggesting that VP is useful in the treatment of disuse osteoporosis. Full article

The rhesus monkey (Macaca mulatta) is a non-human primate with a genome that is 93.5% identical to that of humans. Both species, therefore, have numerous phenotypical similarities in common. Consequently, this non-human primate is regularly studied in biomedical research. Not only does the rhesus monkey play an important role as an animal model for studying human disease, but it is also often featured in zoos, and there are substantial feral populations that live in Asia. Since they are exploited as research subjects, their appropriate housing and husbandry and the validation of obtained research data benefit from the comprehension of the rhesus monkey anatomy. Unexpectedly, the number of anatomical documents on the rhesus monkey are largely outnumbered by publications on the anatomy of domestic animals. In addition, the limited number of available anatomical books and atlases are, unfortunately, outdated, e.g., by presenting black-and-white photographs and using archaic nomenclature, or failing to cover the in-depth anatomy of various anatomical systems. Since state-of-the-art data on the rhesus monkey anatomy are requested by biomedical researchers and veterinarians responsible for the daily care of these captive animals, the present study describes the musculature of the foot of the rhesus monkey. It builds on a recently published manuscript on the topographical anatomy of the pelvic limb of this non-human primate. Full-color anatomical (stereomicroscopic) photographs are taken during layer-by-layer dissections of the feet of three rhesus monkeys. All the muscles, from the superficial to the deepest layer, are described using veterinary anatomical nomenclature and annotated on multipaneled figures. Although the foot musculature of the rhesus monkey largely parallels that of its human counterparts, the small number of dissimilarities should be recognized when extrapolating these research data. In addition, a solid understanding of the rhesus monkey anatomy by veterinarians can be valuable during medical interventions, such as surgery for foot injuries. Full article

Objective: The purpose of this cadaveric investigation was to provide a detailed morphologic description of the proximal gastrocnemius within the popliteal region of the knee and test the hypothesis that the gastrocnemius is anatomically positioned to function as an antagonist to the anterior cruciate ligament (ACL) of the knee. Methods: Twenty-two lower limbs from 11 embalmed cadavers underwent detailed dissection and anatomical analysis. Results: The results indicate that 63.3 ± 5.8% of the popliteal region is comprised of the hamstrings and the gastrocnemius, whereas 36.8 ± 5.7% is occupied by free space (fossa). Within the popliteal region, the gastrocnemius had a length crossing above the knee joint line of 5.4 ± 1.2 cm, which would likely result in a posterior pull on the femur during muscular contraction. Data provide an in-depth description of length and width morphology of the gastrocnemius and provide a detailed comparison between the medial and lateral heads of the muscle. Our results agree with earlier reports in the literature which suggest that the medial head is significantly longer and wider than the lateral head of the gastrocnemius. The medial head length was 23 ± 3.4 cm, compared to a lateral head length of 20.5 ± 2.9 cm. The medial head maximum width was 5.5 ± 1.6 cm, compared to a lateral head maximum width of 4.2 ± 1.1 cm. Conclusion: This research expands on past descriptions of the femoral origin of the gastrocnemius muscle’s medial head and confirms past descriptions of the lateral head origin on the femur. Our data clearly illustrate that the femoral attachment of the medial head of the gastrocnemius was much different (or more complex) than previously described and that it wraps around the posterior side of the medial femoral condyle and attaches more anteriorly. Further research should be directed at exploring the functional significance (if any) of these differences and examining the effect they may have on ACL function and knee joint kinematics. Full article

Pelvic organ prolapse impacts an increasing number of women in the United States. The standard approach to correcting apical pelvic organ prolapse uses the sacral anterior longitudinal ligament (SALL) to lift the vaginal apex; however, this approach may result in recurrent prolapse. A newer procedure utilizes the pectineal ligament (PL), which may be a more reliable anchor point. This study compares the biomechanical properties of these two ligaments to elucidate which can withstand more stress to provide long-term stability following prolapse. Seventeen formalin-embalmed donors were used (PL: 17 right, 16 left; SALL, 15). The PL was evaluated to better characterize the ligament’s properties within the pelvis using digital calipers and descriptive statistics. Mean values were statistically evaluated using an independent t test (p = 0.05) but no differences in laterality were appreciable. The PL and SALL samples were harvested and evaluated using a mechanical tester to determine their force at failure (N), toughness (Jm⁻²), and elastic modulus (MPa). The PL had increased values in the mean force at failure and toughness than the SALL when evaluated by each side as well as a combined mean value. These differences were statistically significant (p = 0.05) for toughness as evaluated using an independent t-test (right, p = 0.004; left, p = 0.005; combined, p = 0.002) and force at failure [right, p = 0.001 (independent t-test); left, p = 0.004 and combined, p = 0.005 (Mann–Whitney U test)], indicating that the PL may permit more deformation, but greater resistance to catastrophic failure as compared to the SALL. When evaluating any statistical differences in modulus, the individual and combined values were increased for the PL as compared to the SALL but were not significant (right, p = 0.290; left, p = 0.143; combined, p = 0.110) suggesting a stiffer material that may be more prone to catastrophic failure once a tear has begun. Collectively, these inherent biomechanical properties of the pectineal ligament indicate the ligament may be a more reliable anchor point for pelvic organ prolapse repair than the SALL. Full article

The fabella is a rare sesamoid bone found within the posterior aspect of the knee joint. Patients can suffer from fabella syndrome which is characterized as pain with extension of the knee, ultimately limiting motion and causing a clicking or catching sensation. There is debate in the literature regarding operative excision versus nonoperative management for patients with fabella syndrome. This review seeks to provide a comprehensive overview of fabella anatomy and fabella syndrome presentation, diagnosis, treatment, and outcomes. Full article

Introduction: Rabies remains a significant global threat, yet accurate estimations of its impact are hindered by the lack of confirmatory diagnoses. Postmortem diagnosis of rabies traditionally involves invasive brain tissue testing, a process met with resistance from deceased patients’ families, impeding consent. This paper presents and evaluates an innovative yet unpublished transnasal approach for postmortem brain tissue collection, offering a minimally invasive, easier, faster, and safer method. This method preserves the cadaver’s integrity, potentially easing family reluctance towards autopsies. The limited testing of both human and animal rabies in Ghana highlights the challenges in diagnosing this fatal disease. Scarce diagnostic resources and the complexity of obtaining brain tissue samples exacerbate the issue. Cultural and religious beliefs surrounding autopsies contribute to familial hesitation, as families view these procedures as disruptive and disfiguring, further complicating consent. Methodology: The transnasal technique involves approaching the brain tissue through the nostrils and cribriform plate without any superficial manipulation of the patient’s head and face, thereby preserving the aesthetics and natural features of the person. Results: Technological advancements and seamless One Health collaboration among governmental, non-governmental, and research entities locally and globally have culminated in Ghana’s first confirmed rabies diagnosis using this method of brain tissue collection. This success emphasizes the efficiency and feasibility of the transnasal brain collection approach and the invaluable role of the One Health approach and collaborative efforts in overcoming diagnostic challenges in rabies control. Full article

Several terminologies exist for a vestigial muscle connecting the clavicle to the cervical vertebrae; however, “levator claviculae muscle” and “cleidocervical muscle” are commonly found in the contemporary literature. The term “levator claviculae” does not determine the location of the superior insertion point, but rather describes a single function of the muscle. However, similar to the sternocleidomastoid muscle, the bilateral presence of this muscle could result not only in increased strength for elevating the clavicle, but also in enhanced neck flexion and greater neck stability. To provide anatomical precision, the muscle could be more accurately termed the cleidocervical muscle. This literature review was performed using “PubMed” as the search engine. Mesh terms such as levator AND claviculae, cleidocervicalis, cleidocervical, cleidoatlanticus, and cleidotrachelian were used. Our proposal for a precise methodology in addressing the terminology would be as follows: [Position 1: cleidocervical muscle] [Position 2: vertebra levels]. In this opinion paper, we advocate for the anatomical community to discontinue the use of the term “levator claviculae” and instead adopt the more appropriate “cleidocervical muscle” in academic discourse. Full article

During anatomical dissection of a female body donor at the Howard University College of Medicine, a rare renal anomaly was discovered. Detailed anatomical and histological analyses on this anomaly were compared to a normal kidney from another donor and previously published reports from a comprehensive literature review. Anatomical assessment confirmed the condition of pancake kidney, a rare form of completely fused, ectopic kidneys without an isthmus. Due to the lack of symptoms in patients with this condition and the limited number of published case reports, very little information is available regarding the anatomy, development, and histology of pancake kidneys, making it difficult to determine an accurate estimate of the number of individuals who are affected. In the case presented here, a single kidney was located in the pelvis, below the bifurcation of the abdominal aorta into the common iliac arteries. The histological analysis of the pancake kidney revealed focal segmental glomerulosclerosis, dilated renal tubules, and increased interstitial fluid, all common characteristics of renal disease and not present in the normal kidney of the other donor. Future studies are needed to compare the histology of pancake kidneys and typical kidneys in order to help determine potential pathologies. Full article

Limited reports have evaluated the utility of the popliteal vein (PV) specific to cannulation. The objective of this study was to characterize the diameter and length of the PV to evaluate this area as a potential cannulation site. The popliteal region in 23 formalin-embalmed, prosected donors was dissected, and the PV was exposed from the adductor hiatus (AH) superiorly to the small saphenous vein (SSV) inferiorly. The diameter of the popliteal vein was measured at the AH, SSV, and half of the distance from the AH to the SSV (MID) using a brass plumb bob. The length of the PV was measured to the AH, SSV, MID, and femoral condyles (FCs). Overall, the mean diameters and mean lengths for the combined population were calculated, as well as individual limbs (right, left) and anatomical sex. Univariate analysis used to evaluate differences in mean diameter and length measurements based on anatomical sex revealed significant differences (p < 0.05) for both diameter and length at all the landmarks evaluated. Multivariate analysis of PV diameter at the AH and SSV landmarks was statistically significant (p < 0.05) when laterally and anatomical comparing sex. These data provide full characterization of the PV in support of its utility in vascular access. Full article

Variations of the sciatic nerve and piriformis muscle (SN-PM) relationship must be considered when discussing orthopedic procedures within the region as they may cause increased risk of SN injuries. Thirty-one formalin-embalmed, prosected donors were evaluated using the Beaton and Anson (B&A) classification system (1939). Major landmarks of the SN-PM relationship were identified, including the posterior superior iliac spine (PSIS), ischial tuberosity (IT), greater trochanter (GT), and the middle of the SN as it exits under the PM (S1). Distances measured included: PSIS-IT, PSIS-GT, IT-GT, PSIS-S1, IT-S1, GT-S1, S1-Q (distance of perpendicular line connecting S1 to PSIS-IT), and S1-R (distance of perpendicular line connecting S1 to PSIS-GT). Measurements from 49 lower extremities were evaluated using a two-tailed t-test to compare by sex and laterality; a one-tailed t-test was utilized to compare groups based on anatomical sex. Six donors displayed asymmetric B&A classifications, demonstrating gross anatomical differences within a single individual; however, no measurements were significant when comparing extremities. Seven measurements were statistically significant (p < 0.05) between sexes, indicating notable sex-based differences. These data highlight sex-based differences in the SN-PM relationship, as well as consistencies within measurements among extremities, which can be utilized by clinicians when treating male and female patients needing unilateral or bilateral orthopedic procedures or injections within the gluteal region. Full article

The rhesus monkey (Macaca mulatta) is one of the most frequently used primate species in biomedical research. As a common animal model used to study human disease, the validation of the obtained research data depends on a solid understanding of rhesus monkey anatomy. Unfortunately, the number of anatomical studies on the rhesus monkey is low. Moreover, the available anatomical books and atlases are outdated. For example, no color photographs—only line drawings—are presented. Luckily, renewed interest in rhesus monkey anatomy has been observed. The present study builds upon a recently published manuscript on the topographical anatomy of the thoracic limb of the rhesus monkey. More specifically, the musculature of the rhesus monkey hand is described using full-color anatomical photographs taken during dissections of the hands of three rhesus monkeys. The structures that are visible in the different layers, from the superficial to the deepest layer, are described using veterinary anatomical nomenclature. As expected, the anatomy of the rhesus monkey hand largely parallels human anatomy, which supports the value of the rhesus monkey as animal model. However, some remarkable differences have been identified as well. The present publication could therefore be useful when modeling the human hand (e.g., surgical protocols) using the rhesus monkey. Full article

Congenital Adrenal Hyperplasia (CAH) has been reported to involve structural alterations in some brain regions. However, it remains to be established whether there is also an impact on the size of the brain as a whole. Here, we compiled the largest CAH sample to date (n = 53), matched pair-wise to a control group (n = 53) on sex, age, and verbal intelligence. Using T1-weighted brain scans, we calculated intracranial volume (ICV) as well as total brain volume (TBV), which are both common estimates for brain size. The statistical analysis was performed using a general linear model assessing the effects of CAH (CAH vs. controls), sex (women vs. men), and any CAH-by-sex interaction. The outcomes were comparable for ICV and TBV, i.e., there was no significant main effect of CAH and no significant CAH-by-sex interaction. However, there was a significant main effect of sex, with larger ICVs and TBVs in men than in women. Our findings contribute to an understudied field of research exploring brain anatomy in CAH. In contrast to some existing studies suggesting a smaller brain size in CAH, we did not observe such an effect. In other words, ICV and TBV in women and men with CAH did not differ significantly from those in controls. Notwithstanding, we observed the well-known sex difference in brain size (12.69% for ICV and 12.50% for TBV), with larger volumes in men than in women, which is in agreement with the existing literature. Full article

Veins of the lower extremity can be categorized into three hierarchically ordered groups: the epifascial, the interfascial, and the deep ones. In the past, the interfascial veins, e.g., the great saphenous vein, were categorized as superficial veins. But nowadays, experts recommend regarding these veins as a separate group because of their unique topography and clinical relevance. In order to better understand the venous anatomy of the lower limbs, which is highly variable, one should also comprehend their embryological development. Venous embryogenesis in the lower limb consists of three stages. During the first stage the primitive fibular vein is the main vein of the extremity. During the second stage it is replaced by the axial vein and finally by the femoral vein. In some adult individuals this embryonic or fetal venous anatomy is still present. Unfortunately, current anatomical textbooks and atlases, as well as traditional cadaver dissections, are not very useful regarding these issues. Therefore, undergraduate teaching of anatomy can be challenging. New educational tools, such as ultrasonography, seem indispensable to teach the anatomy of these veins properly. Full article