Renal vein valves: a prevalence, microanatomical and histological study.

PURPOSE: In the modern era of robotic renal procedures and diagnostics, an even more detailed anatomical understanding than hitherto is necessary. Valves of the renal veins (RVV) have been underemphasized and have been disputed by some authors, and few textbooks describe them. The current anatomical study was performed to address such shortcomings in the literature. METHODS: One hundred renal veins were studied in fifty adult formalin-fixed cadavers. Renal veins were removed from the abdomen after sectioning them flush with their entrance to the renal hilum. The inferior vena cava was then incised longitudinally and opened, and RVV were examined grossly and histologically. A classification scheme was developed and applied to our findings. RESULTS: Nineteen RVVs were observed in the fifty cadavers (38%). Four (8%) valves were found on right sides and fifteen (30%) on left sides. The valves were seen as cord/band-like, folds, and single and double leaflets. Histologically, they were all extensions of the tunica intima. CONCLUSION: On the basis of our study, RVV are not uncommon. They were more common on left sides, and on both sides, they were found within approximately one centimeter of the junction of the inferior vena cava and renal vein. Although the function of such valves cannot be inferred from this anatomical study, the structures of the Single leaflet valve (TS2) and Double leaflet valve (TS3) valves suggest they could prevent venous reflux from the IVC into the kidney.

The anterior communicating artery variants: a meta-analysis with a proposed classification system.

Morphological and morphometric variants of the anterior communicating artery (AComA) have been described by multiple studies; however, a complete classification system of all possible morphological variants with their prevalence is lacking. The current systematic review with meta-analysis combines data from different databases, concerning the AComA morphological and morphometric variants (length and diameter). Emphasis was given to the related clinical implications to highlight the clinical value of their knowledge. The typical AComA morphology occurs with a pooled prevalence (PP) of 67.3%, while the PP of atypical AComA is 32.7%. The identified AComA morphological variants (artery's hypoplasia, absence, duplication, triplication, differed shape, fenestration, and the persistence of a median artery of the corpus callosum- MACC) were classified in order of frequency. The commonest presented variants were the AComA hypoplasia (8%) and the anterior cerebral artery (ACA) fusion (5.9%), and the rarest ones were the MACC persistence (2.3%), and the AComA triplication (0.7%). The knowledge of those variants is essential, especially for neurosurgeons operating in the area. Given the high prevalence of AComA aneurysms, an adequate and complete classification of those variants is of utmost importance.

Are the Ethmoidal Foramina Through the Frontal Bone, Ethmoid Bone, or Frontoethmoidal Suture?

INTRODUCTION: To investigate the locations of the anterior, middle, and posterior ethmoidal foramina and their relationships to the frontoethmoidal suture. METHODS: One hundred twenty sides from sixty adult human skulls were used. Specimens with significant damage to the medial orbit wall were excluded. The number of ethmoidal foramina (anterior, middle, and posterior) on the medial orbital wall and the relationship of each foramen to the frontoethmoidal suture were recorded and classified as follows: Type I: superior to the frontoethmoidal suture; Type II: on the frontoethmoidal suture; Type III: inferior to the frontoethmoidal suture. RESULTS: Of the ninety-four sides, fourteen (14.9%) had one foramen, sixty-two (66.0%) had two , and eighteen (19.1%) had three. In total, 192 ethmoidal foramina were observed. Among the fourteen sides with one foramen, eight foramina were anterior and six were posterior. Among the 192 ethmoidal foramina, 162 were eligible for fur ther classification (74 anterior, 14 middle, and 74 posterior). Types I, II, and III ethmoidal foramina were found in 38.3% (62/162), 61.7% (100/162), and 0% (0/162), respectively. CONCLUSIONS: Our current study found a higher incidence of type I than previously reported. It is important to be aware of the significant incidence of foramen variations when the medial orbit wall is manipulated during surgery. Unless caution is observed, an inadvertent surgical injury can occur and lead to life-threatening complications. Therefore, a good understanding of orbital anatomy and its potential variations is critical for improving patient out comes.

Transcription factor support for the dual embryological origin of the sternocleidomastoid and trapezius muscles.

The embryological origin of the trapezius and sternocleidomastoid muscles has been debated for over a century. To shed light on this issue, the present anatomical study was performed. Five fresh frozen human cadavers, three males and two females, were used for this study. Samples from each specimen's trapezius and sternocleidomastoid were fixed in 10% formalin and placed in paraffin blocks. As Paired like homeodomain 2 (Pitx2) and T-box factor 1(Tbx1) have been implicated in the region and muscle type regulation, we performed Tbx1 and Pitx2 Immunohistochemistry (IHC) on these muscle tissue samples to identify the origin of the trapezius and sternocleidomastoid muscles. We have used the latest version of QuPath, v0.4.3, software to quantify the Tbx and Pitx2 staining. For the sternocleidomastoid muscle, for evaluated samples, the average amount of positively stained Tbx1 and Pitx2 was 25% (range 16%-30%) and 18% (range 12%-23%), respectively. For the trapezius muscles, for evaluated samples, the average amount of positively stained Tbx1 and Pitx2 parts of the samples was 17% (range 15%-20%) and 15% (14%-17%), respectively. Our anatomical findings suggest dual origins of both the trapezius and sternocleidomastoid muscles. Additionally, as neither Pitx2 nor Tbx1 made up all the staining observed for each muscle, other contributions to these structures are likely. Future studies with larger samples are now necessary to confirm these findings.

A histological study of the adult ligamentum arteriosum: Novel findings with application to a patent ductus arteriosus.

The ligamentum arteriosum (LA) is the vestigial fibrous remnant of the ductus arteriosus (DA), a fetal vessel arising from the left dorsal segment of the sixth aortic arch that connects the left pulmonary artery to the aortic arch. Incomplete obliteration of the DA results in a patent ductus arteriosus (PDA), causing the shunting of oxygen-rich blood to recirculate to the lungs, which can lead to pulmonary hypertension. The current study aims to further elucidate the structural characteristics of the LA via histological analysis with data gathered from adult cadaveric specimens. The LA was harvested and histologically observed with Hematoxylin and Eosin, van Gieson, and Masson's trichrome staining. Fibrous and muscle tissues were observed in all 25 specimens. The LA was categorized into three types based on the morphological features of the LA. Type I (vessel-like structure), type II (fibrotic tissue with duct-like structure), and type III (no duct-like structure) were found in 4.0%, 80.0%, and 16.0%, respectively. Finally, the remnant of a valve in the LA was also observed at the junction between the AA and LA. We suggest that this valve be called the "pulmonary-aortic valve." In the majority of the adult LAs, a duct-like structure was still present. These data could better elucidate our understanding of the pathology and etiology of a PDA.

Cardiac ventricular false tendons: A meta-analysis.

Ventricular false tendons are fibromuscular structures that travel across the ventricular cavity. Left ventricular false tendons (LVFTs) have been examined through gross dissection and echocardiography. This study aimed to comprehensively evaluate the prevalence, morphology, and clinical importance of ventricular false tendons using a systematic review. In multiple studies, these structures have had a wide reported prevalence ranging from less than 1% to 100% of cases. This meta-analysis found the overall pooled prevalence of LVFTs to be 30.2%. Subgroup analysis indicated the prevalence to be 55.1% in cadaveric studies and 24.5% in living patients predominantly studied by echocardiography. Morphologically, left and right ventricular false tendons have been classified into several types based on their location and attachments. Studies have demonstrated false tendons have important clinical implications involving innocent murmurs, premature ventricular contractions, early repolarization, and impairment of systolic and diastolic function. Despite these potential complications, there is evidence demonstrating that the presence of false tendons can lead to positive clinical outcomes.

Musculus pterygoideus proprius: A meta-analysis.

The pterygoideus proprius muscle can be found incidentally in the infratemporal fossa, where it is spatially associated with the muscles of mastication, the maxillary artery, and the trigeminal nerve and its branches. Anatomists have described the muscle in various ways over the past 160 years, chiefly as a musculotendinous structure that originates from the infratemporal crest of the sphenoid bone and inserts into the lateral pterygoid plate and the lateral pterygoid muscle. It is present in non-human primates, albeit rarely, with similar anatomical findings. Embryologically, the pterygoideus proprius is thought to have developed from the first pharyngeal arch mesenchyme along with other muscles of mastication. Its close association with the maxillary artery and trigeminal nerve suggests possible clinical significance in trigeminal neuralgia and temporomandibular joint disorders. The literature was reviewed systematically to detail the historical background of research on the pterygoideus proprius muscle and explain its morphology, prevalence, embryology, and potential clinical significance. Despite its rarity, we propose that it is important to recognize its presence when the infratemporal fossa is approached.

Quadricuspid Pulmonary Valve With Fenestration: Cadaveric Findings.

Quadricuspid pulmonary valves (QPV) are rare entities. Such valves can be associated with other cardiac anatomical anomalies. In this report, we present a case of a quadricuspid valve with an additional variant and discuss the morphometrics of this anatomical variation. During the routine dissection of an adult male body, two anatomical variations were found within the pulmonary trunk. This individual had a QPV. In addition, one of the leaflets of this valve contained fenestrations. No additional cardiac anomalies were identified. Clinicians who review imaging of the heart or treat patients with cardiac conditions should be well-informed about QPV.

An Extremely Rare Case of a Sciatic Nerve Variant.

The sciatic nerve (SN) is the nerve of the posterior compartment of the thigh and typically traverses beneath the piriformis muscle (PM) before continuing along a vertical course deep to the gluteus maximus and biceps femoris. However, cadaveric studies have often revealed significant variations in the structural features of the SN in relation to the piriformis. Knowledge of such variations is not only useful for clinicians treating pathophysiologies such as piriformis syndrome and sciatica but is also essential for surgeons carrying out procedures involving the hip and sacroiliac joints to avoid iatrogenic injury to the SN. During routine cadaveric dissection, one such anatomical variant was identified with the SN passing over the superior border of the piriformis muscle. To our knowledge, such a variant is exceedingly rare.

A Review of Crucial Radiological Investigations in the Management of COVID-19 Cases.

Chest X-ray, chest CT, and lung ultrasound are the most common radiological interventions used in the diagnosis and management of coronavirus disease 2019 (COVID-19) patients. The purpose of this literature review, which was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, is to determine which radiological investigation is crucial for that purpose. PubMed, Medline, American Journal of Radiology (AJR), Public Library of Science (PLOS), Elsevier, National Center for Biotechnology Information (NCBI), and ScienceDirect were explored. Seventy-two articles were reviewed for potential inclusion, including 50 discussing chest CT, 15 discussing chest X-ray, five discussing lung ultrasound, and two discussing COVID-19 epidemiology. The reported sensitivities and specificities for chest CT ranged from 64 to 98% and 25 to 88%, respectively. The reported sensitivities and specificities for chest X-rays ranged from 33 to 89% and 11.1 to 88.9%, respectively. The reported sensitivities and specificities for lung ultrasound ranged from 93 to 96.8% and 21.3 to 95%, respectively. The most common findings on chest CT include ground glass opacities and consolidation. The most common findings on chest X-rays include opacities, consolidation, and pleural effusion. The data indicate that chest CT is the most effective radiological tool for the diagnosis and management of COVID-19 patients. The authors support the continued use of reverse transcription polymerase chain reaction (RT-PCR), along with physical examination and contact history, for such diagnosis. Chest CT could be more appropriate in emergency situations when quick triage of patients is necessary before RT-PCR results are available. CT can also be used to visualize the progression of COVID-19 pneumonia and to identify potential false positive RT-PCR results. Chest X-ray and lung ultrasound are acceptable in situations where chest CT is unavailable or contraindicated.

The transversoclasiotome: a novel instrument for examining the vertebral artery.

Opening the foramen transversarium of the cervical vertebrae is necessary for accessing the vertebral vessels. There are no specialist tools for cutting the anterior lamina of the transverse processes, and alternatives lead to questionable results. A novel tool, the transversoclasiotome, is described and tested. The literature and patent databases were systematically reviewed. A blueprint of the transversoclasiotome was created, and the prototype was tested through autopsy on ten fresh-frozen cadavers within our Body Donation Program. The transversoclasiotome consists of two delicate branches mounted as a scissor, one a cutting jaw and the other a knocker with a rounded tip, both angled 30° to the principal axis. The jaws shut, facing each other in parallel. The cutting jaw corresponds to a slit on the knocker profile without protruding beyond it even when entirely closed. It acts by cutting and wedging. The testing autopsies demonstrated its suitability for its purpose, with an adequate response to the pressure exerted on the bone lamina. The section cut cleanly, without sliding off while closing on the bone. The vertebral vessels were not injured either during instrument insertion or cutting. Their morphological features are described. The transversoclasiotome has been proven appropriate for sectioning the anterior lamina of transverse processes of the cervical vertebrae. It meets the needs of clinical anatomy in teaching and training clinicians or surgeons, forensic clinical anatomy during medico-legal investigation, and research.

Endoscopically-Assisted Percutaneous Trigeminal Rhizotomy for Trigeminal Neuralgia: A Cadaveric Feasibility Study.

Objective Trigeminal neuralgia (TN) is a debilitating syndrome characterized by paroxysmal facial pain in one or more divisions of the trigeminal nerve. The etiology and treatment paradigms are still controversial. The endoscopically-assisted procedure has not yet been described in percutaneous procedures for TN. The aim of this study was to assess the utility and feasibility of endoscopic-assisted percutaneous approaches for trigeminal rhizotomy in TN. Methods This study comprised eight cadaveric sides heads that underwent an endoscopically assisted percutaneous approach using Hakanson's anterior puncture method for targeting the foramen ovale. Results V3 exiting the foramen ovale was easily visualized with the endoscope on all sides. While approaching the foramen ovale, distal branches of V3 such as the lingual and inferior alveolar nerves were first identified as they traveled between the medial and lateral pterygoid muscles. These branches were then traced proximally to the V3 trunk deep to the lateral pterygoid. Large arteries and veins were easily visualized and avoided in the trajectory to the foramen ovale. No gross injury to any neurovascular structure along the course of the needle insertion was identified. Conclusion We found that endoscopic-assisted percutaneous approach to the foramen ovale is feasible and allows for accurate canalization and anatomical identification of the precise location for rhizotomy under direct visualization. Such a procedure, after it is confirmed in patients, could offer a new technique for reducing unsuccessful canalization and could improve outcomes.

Anatomical Study of the Atrioventricular Nodal Branch of the Heart.

Background The atrioventricular (AV) node is a relay station for electrical signals passing between the atria and ventricles. The artery supplying the AV node is functionally important, and its anatomical topography is relevant during invasive procedures. Therefore, the aim of this study was to identify and understand the variations of the origin of the AV nodal branch (AVNb) and its variations. Materials and methods We dissected 31 adult human hearts to evaluate their AVNb and its variations. A classification scheme was used to detail the morphology found for each of these arteries. Results We identified five distinct origins of the AVNb: AVNb originating from the right coronary artery (RCA) proximal to the inferior interventricular branch (IVb) (type I, 3.2%), AVNb originating from the junction of the RCA and IVb (type II, 19.4%), AVNb originating from the RCA distal to the IVb (type III, 64.5%), AVNb originating from the IVb (type IV, 6.5%), and AVNb originating from the circumflex branch of the left coronary artery (LCA) (type V, 6.5%). Conclusions Our study provides data on the morphology and variations of the AVNb. Such information can assist in better diagnoses based on imaging, better guide invasive procedures, and provide the cardiac surgeon with an improved method of classifying the AVNb and its branches during procedures of the coronary arteries and their branches.

Who really needs a Metaverse in anatomy education? A review with preliminary survey results.

The term Metaverse ("meta" defined as beyond, transcendence or virtuality, and "verse" meaning universe or world) denotes a "virtual reality space" for anatomy teaching. To ascertain how many anatomists are familiar or are using this adjunct in teaching, we conducted a short survey at the 2022 annual meeting of the American Association of Clinical Anatomists (AACA). Interestingly, only six respondents (9.4%) had used a Metaverse for teaching anatomy. Moreover, the vast majority of attendees were anatomy educators or basic science faculty, but not practicing physicians/surgeons or other actively practicing health care professionals; a group where this technology has been used much more commonly. The present manuscript was authored by anatomy educators, practicing physicians and other actively practicing health care professionals with backgrounds in diverse medical fields, that is, anatomists, medical doctors, physician assistants, dentists, occupational therapists, physical therapists, chiropractors, veterinarians, and medical students. Many of these authors have used or have been exposed to a Metaverse in the clinical realm. Therefore, the aim of the paper is to better understand those who are knowledgeable of a Metaverse and its use in anatomy education, and to provide ways forward for using such technology in this discipline.

A Unique Foramen Magnum with a Posterior Notch.

The foramen magnum is an important structure of the skull base. A unique foramen magnum with posterior notching was found in an adult male skull, around 60 years old at death. The posterior notch was roughly V-shaped and resulted in posterior elongation of the foramen magnum. Variants such as described herein should be kept in mind when interpreting radiological imaging or operating on patients.

Clinical Anatomy and Medical Malpractice-A Narrative Review with Methodological Implications.

Anatomical issues are intrinsically included in medico-legal methodology, however, higher awareness would be needed about the relevance of anatomy in addressing medico-legal questions in clinical/surgical contexts. Forensic Clinical Anatomy has been defined as "the practical application of Clinical Anatomy to the ascertainment and evaluation of medico-legal problems". The so-called individual anatomy (normal anatomy, anatomical variations, or anatomical modifications due to development, aging, para-physiological conditions, diseases, or surgery) may acquire specific relevance in medico-legal ascertainment and evaluation of cases of supposed medical malpractice. Here, we reviewed the literature on the relationships between anatomy, clinics/surgery, and legal medicine. Some methodological considerations were also proposed concerning the following issues: (1) relevant aspects of individual anatomy may arise from the application of methods of ascertainment, and they may be furtherly ascertained through specific anatomical methodology; (2) data about individual anatomy may help in the objective application of the criteria of evaluation (physio-pathological pathway, identification-evaluation of errors, causal value, damage estimation) and in final judgment about medical responsibility/liability. Awareness of the relevance of individual anatomy (risk of iatrogenic lesions, need for preoperative diagnostic procedures) should be one of the principles guiding the clinician; medico-legal analyses can also take advantage of its contribution in terms of ascertainment/evaluation.

Simultaneous Posterior Femoral Cutaneous Nerve and Sciatic Nerve Variations: A Case Report.

During the routine dissection of a formalin fixed Caucasian cadaver, a previously unreported variation of the sacral plexus was found in the right gluteal region. The posterior femoral cutaneous nerve was found to pierce the piriformis muscle as opposed to running along its more common course below the muscle. At the same level of the posterior femoral cutaneous nerve, the common fibular nerve also pierced the piriformis muscle, while the tibial nerve passed inferior to the piriformis muscle. No other anatomical variations were found.

A comprehensive study of the abdominal ganglia part 2: Aorticorenal ganglia.

Investigation into reports of pain treatment for abdominal cancer and abdominal pain syndromes revealed the lack of human studies on some of the abdominal sympathetic ganglia. Recent studies on renal artery denervation therapy as treatment for resistant hypertension has made the aorticorenal ganglia of particular importance. The aim of this study was to investigate the location, morphology, interconnections, and histological nature of aorticorenal ganglia. We dissected nine abdominal cavities and harvested 37 aorticorenal ganglia. Hematoxylin and Eosin, and Masson's staining techniques were used to study the histological structure. Additionally, ganglia harvested from five individuals were stained with immunohistochemical techniques to test for tyrosine hydroxylase activity. All aorticorenal ganglia were located in proximity to the renal artery, and the majority were close to the vessel origin. Identification of multiple aorticorenal ganglia was the norm, and ranged from 2 to 4 on the left and 1 to 3 on the right. While the pattern of aorticorenal ganglia seemed to be unique in each individual case, the interconnections between these and other ganglia were vast. The aorticorenal ganglia shared direct connections with the celiac, gonadal, inferior mesenteric, and first lumbar sympathetic trunk ganglion. Contributions from the greater, lesser, and least thoracic splanchnic nerves were also observed. While the results of our study may not have direct clinical implications in isolation, the vast number of interconnections with the other abdominal ganglia may cause complications in procedures such as celiac ganglion block. In addition, aorticorenal innervation interruption may lead to hypotension.

A comprehensive study of the abdominal ganglia part 3: An overview of the most commonly observed ganglion patterns.

Chronic pain from untreatable abdominal cancers or pancreatitis can severely decrease an individual's quality of life due to accompanying neuropathic pain, the most difficult pain mechanism to treat. Current treatment modalities focus on peripheral block or neurolysis procedures of the sympathetic ganglia in an attempt to curb the pain and improve quality of life. Reports indicated that these treatments are ineffective with patients either experiencing no relief or return the pain in a few weeks. The aim of this study was to investigate the location, macro- and microscopic morphology, and interconnections of the abdominal ganglia. The abdominal sympathetic ganglia of nine adult cadavers were investigated. The locations, morphology, interconnections, and microscopic structure were studied in 108 potential abdominal ganglia. Particular emphasis was placed on direct interconnectivity between the ganglia and histological morphology. A total of 100 ganglia were confirmed histologically to contain ganglion cells. The number and locations of most of the ganglia identified in our study does not correspond to that described by previous reports. Numerous interconnections between the different ganglia, as well as direct communications with the lumbar sympathetic chain ganglia were observed. The interconnections and presence of ganglion cells the nerves connecting the ganglia lead to the belief that the system should be considered as a unit and that pain fibers may be transmitted via alternative previously undiscovered pathways. If the pain treatments are to be reassessed with this information in mind, we believe that greater success could be achieved.

Postprandial Referred Shoulder Pain: A Case Report.

The precise mechanism of referred pain is not well understood; however, diaphragmatic irritation is a well-known etiology of referred pain. Left side referred pain due to diaphragmatic irritation is most commonly attributed to splenic laceration i.e. Kerr's sign. Here, we report an unusual case of left-sided referred pain that followed eating. An adult male presented vague and chronic left shoulder pain that followed eating. The pain was described as a deep boring type of discomfort that was poorly localized to the region deep to the acromion and extended superomedially along the upper fibers of the trapezius muscle. The pain was present immediately after eating heavy meals and always abated approximately 30 minutes later. There was no history of previous surgery and physical examination was unremarkable. CT examination of the abdomen and thorax did not show any pathology or anatomical variations that would result in such referred pain. Although the exact etiology of this case is unclear, the most likely cause would be left-sided diaphragmatic irritation from the stomach after eating. The current literature does not enclose reports pertaining to similar findings. Although unusual and seemingly rare, postprandial referred shoulder pain should be considered by clinicians alongside other causes of referred shoulder pain when presented with shoulder pain without an obvious musculoskeletal or neural etiology.