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.

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.

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.

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.

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.

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.

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.

C6 and not C5 nerve fibers more commonly contribute most to deltoid muscle innervation: anatomical study with application to better diagnosing cervical nerve injuries.

Most anatomical textbooks list both the C5 and C6 spinal nerves as contributing to the deltoid muscle's innervation via the axillary nerve. To our knowledge, no previous study has detailed the exact spinal nerve components of the axillary nerve terminating in the deltoid via cadaveric dissection. Twenty formalin-fixed cadavers (40 sides) underwent dissection of the brachial plexus. The fascicles making up the axillary nerve branch that specifically terminated in the deltoid muscle were traced proximally. The axillary nerve branch to the deltoid muscle was most commonly (70%) made up of three spinal nerve segments and less commonly (30%) by two spinal nerve segments. For all axillary nerve branches to the deltoid muscle, C4 spinal nerves contributed 0-5%, C5 spinal nerves contributed 1-80%, C6 spinal nerve contributed 15-99%, C7 spinal nerves contributed 0-30%, and C8 and T1 spinal nerves were not found to contribute any fibers to any deltoid muscle branches. The nerve to the deltoid muscle was contributed to equally by C5 and C6 nerve fibers on 10% of sides. On 16% of sides, C5 contributed the most nerve fibers to this muscle. On 35% of sides, C6 contributed the majority fibers found in the axillary nerve branches to the deltoid. Based on our anatomical study, C6 is more often than not the main level of innervation. C5 was never the sole component of the axillary nerve branches to the deltoid muscle. Such anatomical data will now need to be reconciled with clinical studies.

Ligaments stabilizing the sacrum and sacroiliac joint: a comprehensive review.

The sacroiliac joint is a diarthrodial synovial joint in the pelvis. Anatomically, it is described as a symphysis, its synovial joint characteristics being limited to the distal cartilaginous portion on the iliac side. It is a continuous ligamentous stocking comprising interconnecting ligamentous structures and surrounding fascia. Its ligaments, the primary source of its stability, include the anterior, interosseous and dorsal sacroiliac, the iliolumbar, sacrotuberous, and sacrospinous. Structural reinforcement is also provided by neighboring fascia and muscles. Lower back pain is a common presentation of sacroiliac joint disease, the best-established treatments being corticosteroid injections, bipolar radiofrequency ablation, and sacroiliac joint fusion.

A comprehensive study of the abdominal ganglia part 1: Celiac, phrenic and superior mesenteric ganglia.

INTRODUCTION: Patients with pancreatic cancer, chronic pancreatitis and other abdominal pain syndromes may develop debilitating pain throughout the course of their illness with little to no relief by most conventional methods. While some form of relief is experienced by patients, not all benefit from these procedures and side effects, while transitory in most cases are severe and often not expected. Our aim was therefore to investigate the anatomy surrounding the abdominal sympathetic ganglia, the target for the invasive procedures in an attempt to understand the variations in results. MATERIALS AND METHODS: The abdominal cavities of nine individuals were dissected and the ganglia investigated, harvested and histologically and immunochemical stained. RESULTS: The phrenic ganglion was found inconsistently and more often in the left than the right. If present it was located in association with the inferior phrenic artery and often connected to the celiac ganglion. The celiac ganglion was located anterior to the diaphragmatic crus on both sides and specifically posteromedial to the suprarenal gland and superior to the renal artery on the left. On the right it was located posterior to the suprarenal gland and inferior vena cava also superior to the renal vessels. The superior mesenteric ganglion was only positively identified in one individual and was located on the left lateral aspect of the superior mesenteric artery. CONCLUSION: The blockade procedures for treatment of pain are developed to target the area around the celiac artery where the ganglion is commonly described to be located. However, based on our results of its location and interconnections the ganglion is not located in the targeted area.

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.

A comprehensive review of the "supracondylar process" with translation of Adachi.

The supracondylar process is a nonpathological projection from the distal humerus that in some patients, can result in compression of regional neurovascular structures, for example, median nerve. Since the first description of the supracondylar process in 1818, it has also been a focus of anthropological study because of its possible relevance to human origins and relationships to other species. Although its overall incidence is low, it is more common in races of European descent. It is particularly interesting for anatomists and anthropologists, but knowledge of its anatomical relationships and effect on pathological processes helps in the diagnosis and treatment of supracondylar process syndrome. One of the most detailed descriptions of this variant process stems from the work of Buntaro Adachi. Herein, a translation of his findings is provided and a review of the supracondylar process and its potential pathological presentations presented.

Top 100 most cited journal articles in anatomy.

The number of citations a journal article receives can be used to represent its impact on its field. The aim of the current study was to identify and characterize the top 100 cited articles in journals related to anatomy. The Journal Citation Report database was searched to identify journals categorized as anatomy and morphology. The top 15 most highly cited journals were selected for review. The articles from these journals were then sorted by "Times Cited". The timeline used was 1976-2001. The top 100 most cited articles were extracted for analysis. Articles were excluded if they focused on basic scientific research or animal studies. Fifteen journals were identified based on our criteria using the Journal Citation Report database and the articles were sorted by most cited; 916 anatomy articles were screened to select the top 100 cited since 1976. Among the selected articles, 46 were published in Journal of Anatomy, 13 in Clinical Anatomy, 12 in Microscopy Research and Technique, 11 in Surgical and Radiologic Anatomy, seven in Brain Structure & Function, five in Annals of Anatomy - AnatomischerAnzeiger, three in Anatomical Record - Advances in Integrative Anatomy and Evolutionary Biology, two in Cells Tissues Organs, and one in Developmental Dynamics. Our study identified the top 100 journal articles in anatomy with a clinical and surgical focus. This compilation of articles could help anatomists and clinicians familiarize themselves with impactful research included in terms of study type and field of anatomy, journal of publication, and recurring authors.

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.

The deep brachial artery-A meta-analysis of its origin and diameter with a review of the literature.

The deep brachial artery (DBA) is the first and largest branch of the brachial artery. Multiple variations of the DBA's origin, termination, and diameter have been reported in the literature. Major online medical databases such as PubMed, Scopus, Embase, Web of Science, and Google Scholar were searched in order to find all studies considering origin variations and the diameter of the DBA. The prevalence of the DBA originating directly from the axillary or brachial artery was shown to be 92.87%. DBA originating indirectly from the axillary or brachial artery, as a common trunk with other arteries, was found to be 7.13%. The mean diameter of the DBA was shown to be 2.05 mm. The authors of the present study believe that this is the most accurate and up-to-date meta-analysis considering origin patterns and the diameter of the DBA. Additionally, this study contains a comprehensive literature review in which current detailed anatomical knowledge concerning the DBA was gathered. The results of this study could provide a helpful tool for physicians, especially surgeons, dealing with an upper limb in their daily practice.

An anatomical study of the pharyngeal plexus: Application to avoiding postoperative dysphagia following anterior approaches to the cervical spine.

We aimed to localize the pharyngeal branches of the pharyngeal plexus to preclude postoperative complications such as dysphagia resulting from injury to those branches. Cranial nerves IX and X and the sympathetic trunk were dissected on 10 sides in the necks of embalmed adult cadavers of European descent to identify the pharyngeal branches so that anatomical landmarks could be identified and injury thereby avoided. In all sides, the pharyngeal branches originated from the glossopharyngeal and vagus nerves and the superior cervical ganglion and entered the posterior pharyngeal wall at the C2-C4 levels within 10 mm medial to the greater horn of the hyoid bone. All pharyngeal branches were anterior to the alar fascia. Based on our anatomical study, vagus nerve branches to the pharyngeal muscles enter at the C3/C4 vertebral levels. Such knowledge might help decrease or allow surgeons to predict which patients are more likely to develop dysphagia after cervical spine surgery.

Vitamin D receptor gene polymorphism influence on lumbar intervertebral disc degeneration.

Intervertebral disc (IVD) degeneration is a multifaceted pathology that is the main morphological cause of lower back pain. This study aimed to determine the link between the vitamin D receptor gene single nucleotide polymorphisms (SNPs) and degenerative processes of the lumbar spine. The complete lumbar spinal columns were collected from 100 Caucasian cadavers via ventral dissection. The specimens for the histological analysis were harvested from the L5/S1 IVDs and endplates. Then, the tissues were cut into slices, inserted into paraffin blocks, and stained. The histology was evaluated according to the Boos' protocol. Moreover, TaqI(rs731236), FokI(rs2228570), and ApaI(rs7975232) genotyping were performed. Lastly, the histological scores for different genotypes were analyzed. The overall Boos' score in the study group was 12.49. It consisted of a mean IVD score of 7.46 and endplate score of 5.39. The determination of the SNPs was successful in 99 specimens and had a distribution of all alleles in accordance with the Hardy-Weinberg equilibrium. No significant differences in overall histological degeneration scores were found between samples from donors with different genotypes. However, in subgroup analysis of specific regions on the IVD, the significant difference was found in posterior inner anulus fibrosus for ApaI. The results of this study suggest that one must be careful when interpreting the results of the clinical and/or radiological studies on vitamin D receptor gene polymorphisms and lumbar spine degeneration risk, because such a relationship, if present, is likely to be very subtle.

Ulnar nerve subluxation and dislocation: a review of the literature.

The pathogenesis of ulnar nerve subluxation and dislocation is widely debated. Upon elbow flexion, the ulnar nerve slips out of the groove for the ulnar nerve, relocates medial or anterior to the medial epicondyle, and returns to its correct anatomical position upon extension. This chronic condition can cause neuritis or neuropathy; however, it has also been suggested that it protects against neuropathy by reducing tension along the nerve. This article reviews the extant literature with the aim of bringing knowledge of the topic into perspective and standardizing terminology.

The proximal humeral attachment of the lateral head of the triceps brachii: a cadaveric study and potential site for radial nerve compression.

BACKGROUND: Knowledge of potential compression sites of peripheral nerves is important to the clinician and surgeon alike. One anatomical location for potential compression of the radial nerve, which is rarely mentioned in the literature, is at the proximal humeral attachment of the lateral head of the triceps brachii at the level of the proximal spiral groove. As no anatomical studies have been devoted to this band, the present study was conducted. METHODS: Ten adult fresh-frozen cadavers were dissected and the lateral head's attachment onto the posterior humerus evaluated for a band. This anatomy and its relation to the radial nerve during range of motion of the elbow and forearm were evaluated. RESULTS: A band was found on 15 of 20 arms. On five sides, the band was comprised of grossly muscle fibers of the lateral head of the triceps brachii and was not tendinous. The bands were crescent-shaped, straight, and duplicated on nine, five, and one arm, respectively. The length of the bands ranged from 1.1 to 2.2 cm (mean 1.54 cm). The width of the bands ranged from 0.5 to 1.1 cm (mean 0.8 cm). With elbow extension and the forearm in neutral, all bands were lax. With elbow extension and the forearm supinated, the bands became tauter less the muscular bands. In elbow extension and with the forearm in supination, the bands became most taut less the muscular bands. CONCLUSIONS: The presence of a fibrous band extending from the lateral head of the triceps brachii is common and should be among the differential diagnoses of anatomical sites for potential proximal radial nerve compression when other more common locations are ruled out.