Clinical anatomy of the human Achilles subtendons twist - meta-analysis.

PURPOSE: This study aimed to provide a comprehensive and current overview of the anatomy of the Achilles tendon (AT) twisted structure, as there is a discrepancy in the literature regarding its rotating morphology. METHODS: An extensive literature search was conducted across multiple databases to identify all studies that reported relevant data on the AT torsion, with no date or language restrictions applied. Data was extracted and assessed for this meta-analysis following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The quality of the included articles was examined using the anatomical quality assessment (AQUA) tool. RESULTS: Seven articles (n=690 limbs) were pooled into this meta-analysis. The prevalence of Achilles tendon torsion types was as follows: type II was the most common (46.7%, 95% CI: 31.6-60.9%), followed by type I (44.7%, 95% CI: 29.8-59.0%), and least commonly, type III (8.6%, 95% CI: 1.8-18.8%). Additionally, morphometric analysis, utilizing the method described by van Gils et al., revealed a mean Achilles tendon torsion of 46.5° (95% CI: 25.1-67.9°). CONCLUSIONS: This meta-analysis underscores the prominent and variable twist within the Achilles tendon among individuals, emphasizing the inherent diversity in AT morphology. Furthermore, the study highlights the importance of considering torsion angle as a potential factor influencing AT pathologies and biomechanical function.

Evolution of staining methods in neuroanatomy: Impetus for emanation of neuron doctrine during the turn of 20th century.

The nervous system is distinctive as compared to other tissue systems in human body owing to intricate structural organization. Histological studies played a key role in unveiling complex details of nervous tissue. However, the process of developing suitable staining method for nerve cells was arduous and spanned across almost half a century. The present study explored details of the journey involving quest for propitious staining method in neuroanatomy culminating in promulgation of neuron doctrine at the onset of 20th century. Initial efforts involving hematoxylin (including its diverse modifications) and subsequent adoption of analogous dye-based stains (like Nissl's method) had limited success in visualization of different parts of a nerve cell and structural details of nervous tissue. This was due to inability of dye-based stains to penetrate the connective tissue sheath of nervous tissue. Eventually, advent of metallic stains in form of silver impregnation method (Golgi stain), reduced silver impregnation method with gold stain (Cajal's stain) and silver carbonate staining method of Río-Hortega unraveled the structure of nervous tissue. The evolution of staining methods catalyzed the refinement of theories pertinent to constitution of nervous tissue. Golgi's staining led to emergence of reticular theory (neurons exist as a network) and Nissl's staining was the basis of the concept of Nervösen Grau (nerve cells and glial cells are embedded in mass of gray matter). Finally, Cajal's staining method successfully elucidated the complex anatomy of nerve terminals and resulted in emanation of neuron doctrine (neurons exists as individual units with adjacent connections).

Clinical anatomy of the popliteal artery and its implications in total knee arthroplasty: a systematic review and meta-analysis.

The popliteal artery (PA) is a lower extremity arterial vessel, a continuation of the superficial femoral artery. PA may be injured in the majority of total knee arthroplasty (TKA), as well as arthroscopic surgeries which may lead to acute ischemic injury. Our objective was analyzing morphometry of PA in relation to other structures both in flexion and extension of the knee, highlighting discrepancies in the PA's location in varying positions. Literature was reviewed in regards to morphological qualities, prevalence rates, and variants of PA were pooled. Five cadaveric and 14 radiological studies were included, totalling 1473 lower limbs. We found that PA, when nearing bone, was more predictable and fixed as seen in axial plane one and two centimeters distal to joint line at 0 degrees flexion. The distance between PA and posterior tibial cortex was estimated at 3.3 mm with 95% confidence interval (CI) 2.6-4.1 and 7.8 mm (95% CI 5.1-10.5) respectively. Once PA passed over and nearing the joint it had larger discrepancies with distance comparing the knee in 0 vs 90 degree flexion. Due to rise of TKA, arthroscopic surgeries and connected vascular complications PA has been investigated more frequently, and while majority of publications describes relationships between vessels of popliteal area and specific landmarks conducted with knee in extension, our study also implemented data regarding knee flexion thus encompassing the problem in a more dynamic manner. We believe this provides superior data for identification of PA, especially during knee surgery.

The twisted Achilles tendon microvasculature.

The Achilles tendon (AT) is reportedly the most vulnerable to rupture at the midportion, a section of relative hypovascularity. It has been postulated that the twisted structure of this tendon may constitute a critical factor contributing to increased propensity to vascular compromise, decreased regenerative capacity, and rupture in the midsection of the AT. In this review, we will give an overview of the most relevant research on AT vasculature and twist, and delve into the interplay between the two elements in the context of AT disorders. The pertinent body of research suggests a considerable variability in tendon twist among individuals, which likely constitutes a determining factor in the extent to which vessels coursing along and between AT fibers are compressed during contraction-induced elongation of the tendon. Consequently, further research is necessary to investigate the precise association between tendon torsion and blood flow within the AT.

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.

Responsible research in the practice of anatomy: Attributes relevant to body donors and human tissues sourced from them.

Responsible Research involves setting moral examples before fellow academicians and the society as a whole. The concept of Responsible Research applies appropriately to ethical sourcing and handling of human tissues. The present study was undertaken to analyze present situation regarding implementation of attributes of Relevant Research in relation to body donors in anatomical research. A literature search of relevant, peer-reviewed, published articles was undertaken from indexed databases (Medline & PubMed, Scopus, Embase, CINAHL Plus, Web of Science and Google Scholar) for this study. The following attributes of Responsible Research were identified for possible intervention: the fact that research was conducted on human tissues from body donors and details regarding ethical handling thereof may be explicitly mentioned in method section; expression of gratitude towards body donors by authors may be included in acknowledgement section; editor's and publisher's note in support of adoption of attributes of Responsible Research may be included in published research. Adherence to best practices in terms of ethical guidelines requires anatomists to embrace a responsible approach in research from an inclusive perspective. Accordingly, practice of acknowledging the body donors may be nurtured and augmented to include the anonymised dead (human tissues from unclaimed bodies and unknown source) provided the research protocol received clearance from authorities concerned with ethical scrutiny. Moreover, adoption of the practice in review articles will enhance the boundaries of Responsible Research in anatomical science. Thus, few recommendations are proposed as epilogue for effectual implementation of the notion floated in present study.

Superior mesenteric artery clinical classification and morphometrical analysis.

BACKGROUND: The superior mesenteric artery is one of the most important arteries in the abdominal cavity, which is of great clinical importance, especially in surgical procedures and fatal ischemic complications. The aim of this study was to develop a clinical classification of the superior mesenteric artery. MATERIALS AND METHODS: Postmortem contrast-enhanced computed tomography of 104 (29.8% female, age 50.7±18.7) human bodies were analyzed. Based on anatomic predisposition to ischemic and iatrogenic complications, a three-tiered clinical classification of the superior mesenteric artery was developed. Type 0 was defined as standard risk for ischemic and iatrogenic complications. Type 1 was defined as increased thromboembolic risk with decreased risk of iatrogenic bleeding, and type 2 was defined as decreased ischemic risk with increased risk of iatrogenic bleeding. The supply area of the superior mesenteric artery was divided into 4 regions: pancreas, caecum, ascending colon, and transverse colon. RESULTS: Type 0 (standard risk) was found in 62.5% of cases. Type 1 was most frequently observed in the ascending colon region (15.4%). Type 2 was most frequently observed in the pancreatic region (17.3%). Regarding type, most abnormalities were found in the region of the ascending colon (18.3%), pancreas region (17.3%), and transverse colon (16.3%). CONCLUSIONS: The proposed clinical classification of SMA links anatomic variations in morphology with their clinical significance. A simple, three-level classification can be easily applied in daily practice and serve as a great support for preoperative evaluation and recognition of patients at risk of iatrogenic or thromboembolic complications.

Reappraisal of the variational anatomy of the vermiform appendix and their possible clinical applicability: a cadaveric analysis.

BACKGROUND: The anatomical variations in the position, length, arterial supply and extension of mesoappendix of the vermiform appendix (VA) are pivotal to establishing a standard pattern in the study population of known ethnicity and their clinical applicability. MATERIALS AND METHODS: The present study was conducted on 47 adult human cadavers, thirty-five males and twelve female subjects of North Indian ethnicity. RESULTS: Retrocaecal appendix was found in 23 cases (48.9%) followed by pelvic in 13 (27.7%), three cases each of pre-ileal, post-ileal, and promontoric (6.4%), one case (2.1%) each of paracaecal and subcaecal reported. The length of VA varied from three to ten centimetres, averaging about 7.37±1.67 cm, both the shortest (2.9 cm) (female) and longest (10 cm) (male) were of retrocaecal type. The main appendicular artery (MAA) showed a widely varied branching pattern within the mesoappendix, ranging from three to seven. Fourteen cases (29.78%) showed the accessory appendicular artery (AAA) or dual arterial supply, arising from the ileocolic artery in ten (21%) and in four from the post-caecal (9%). In the specimens with dual arterial supply, the estimated portions of the VA supplied by the MAA also vary with distal ¾th being supplied in 57.14%. In ten cases (21%), the mesoappendix failed to reach the tip of the VF. CONCLUSIONS: Knowledge of anatomical diversities in position, length, course, arterial supply, branching pattern, and mesoappendix is potentially crucial in avoiding surgical catastrophes. Atypical positions of the organ can cause diagnostic confusion and result in delayed treatment. VF supplied by an end artery is one of the causes of the occurrence of appendicitis and mesoappendix not reaching the tip making the organ more vulnerable to necrosis. Vascular variations and anomalies involving the main or accessory appendicular artery are critical to prevent haemorrhage or faulty ligatures.

Systematic review and meta-analysis of the prevalence of the retrotransverse foramen of the atlas.

The retrotransverse foramen (RTF) is a nonmetric variant of the atlas vertebra that can accommodate an anastomotic vertebral vein and occipital nerve. An understanding of this variation and its occurrence is crucial, as it could aid in explanation of the unidentified cause of the high prevalence of variability in this region. The aim of this meta-analysis was to obtain data on the prevalence of the RTF and its variations according to anatomy, sex, and ethnicity. A large-scale search was conducted through the major online databases to establish and determine the pool of studies reporting data relevant to the RTF. No date or language restrictions were applied. The data collection was categorized by prevalence, type (incomplete/complete), side, sex, ethnicity, laterality, and diameter. A total of 17 studies (n = 1979 subjects) were incorporated into our analysis. The overall pooled prevalence for a complete RTF was 11.4% and the overall pooled prevalence of an incomplete (partial) RTF was 9.6%. A complete RTF was most prevalent in Africa (Sub-Saharan population) (12.1%), followed by Europe (11.8%) and Asia (9.7%). As this variant occurs in a significant number of patients in all of the aforementioned populations, recognition, and awareness, especially with thorough investigation with computer tomography angiography (CTA) should be implemented, as it is the only possible way to visualize the possible contents of RTF.

Duplication of the Hypoglossal Nerve Branch to the Thyrohyoid Muscle: A Case Report.

The motor fibers to the thyrohyoid muscle are provided by the anterior ramus of C1 via the hypoglossal nerve rather than via the ansa cervicalis. Knowledge of possible variations in the branching patterns of the nerves attached to the hypoglossal nerve is necessary to minimize iatrogenic injury to these structures during surgical procedures. We describe a rare anatomical variant of the nerve branch to the thyrohyoid muscle. To our knowledge, this particular variant has not been previously reported.

Prevalence, Laterality, and Classification of Ossified Petroclival Ligaments: An Anatomical and Histological Study With Application to Skull Base Surgery.

Background The petroclival ligament (PL) forms the roof of Dorello's canal (DC). In humans, partial and complete ossification of this ligament have been reported. When completely ossified, DC is transformed into a bony foramen for the abducens nerve and accompanying vascular structures. As this osteological finding might have an impact on skull base surgery, this anatomical study was performed. Methodology Using 100 adult human skulls, the presence of an ossified PL was noted and classified. The diameter of the resultant bony foramen and laterality were documented. Additionally, PL was evaluated histologically in 10 heads. Results Overall, 8% of the sides were found to have partial or complete ossification of the PL. Partial ossification (type I) was noted on 3% of the sides. Completely ossified PL was identified on 5% of the sides. Some ossified ligaments (2.5%) were seen as an ossified bridge (type II), and others (2.5%) were converted into small foramina (type III). Three skulls (3%) were found to have a completely ossified ligament bilaterally. The mean diameter of the underlying DC was 0.8 mm. Partially ossified ligaments were statistically more likely to be on the right sides, and the diameter of the underlying DC was statistically smaller in type III. Histologically, the PL was found to have bone within it on three skull sides. Conclusions An ossified ligament can be found on imaging of the skull base. Moreover, during surgical approaches to the petroclival region and, specifically, DC, skull base surgeons should be cognizant of this anatomical variation.

The clinical anatomy of the accessory submandibular gland: a comprehensive review.

An accessory submandibular gland is a rare variation. As such, there is limited literature regarding the embryology, anatomy, variations, clinical imaging, and pathology of the accessory submandibular gland. In this article, we review the existing literature on the accessory submandibular gland from clinical and anatomical perspectives. The goal of this review is to provide comprehensive knowledge of this variation which can be useful for oral and maxillofacial/head and neck surgeons, radiologists, and anatomists. Within this review, the embryologic origin as well as the anatomy of the accessory submandibular gland is detailed. Several imaging modalities which can be used to visualize the accessory submandibular gland are outlined as well as its variations. Lastly, this review investigates several reported clinical considerations regarding the accessory submandibular gland including sialoliths, Wharton's duct obstruction, and pleomorphic adenoma.

Identification of PDGFRα+ cells in uterine fibroids - link between angiogenesis and uterine telocytes.

Introduction: Telocytes (TCs), also called interstitial Cajal-like cells (ICLC), CD34+ cells or PDGFRα+ cells (platelet-derived growth factor receptor α positive cells), a new type of cell of mesenchymal origin, were described over one decade ago. The unique nature of these cells still deserves attention from the scientific community. Telocytes make homo- and heterocellular contact with myocytes, immunocytes and nerves, have their own immunohistochemical and secretome profiles and thus might regulate local regenerative processes including angiogenesis and fibrosis. The aim of our study was to observe the missing link between angiogenesis and telocytes in leiomyoma, the most common benign tumors affecting women of reproductive age. Material and methods: We observed uterine tissue samples from leiomyoma, adjacent myometrium and unchanged tissue from patients with leiomyoma and control subjects using routine histology, histochemistry, immunofluorescence (CD117, CD31, CD34, PDGFRα, tryptase, sFlt-1) and image analysis methods. Results: The decline of the telocyte density in the foci of fibroids correlated with poor vascularization inside the leiomyoma. Moreover, the expression of sFlt-1 (anti-angiogenic-related factor) significantly increased inside a fibroid. In leiomyoma the decrease of telocyte and blood micro-vessel density was accompanied by prevalence of collagen deposits, unlike the unchanged myometrium. Conclusions: Our results demonstrate TCs in human uterine fibroids and highlight their possible involvement in the pathogenesis of myometrial pathology in the context of angiogenesis.

The place of ethics in practice of anatomical sciences: have we left our dark past behind and looking towards a bright future?

INTRODUCTION: Anatomical sciences involve handling of human tissues and, therefore, application of principles of bioethics is central to anatomical practice. For a considerable period of time, anatomy was practiced without ethical norms as concept of ethics developed during second half of twentieth century. Hence, possible glimpse into contrast in ethical standards between anatomy in the past and present was deemed as an intriguing research theme. METHODS: A literature search was undertaken from indexed databases (Medline and Pubmed, Scopus, Embase, CINAHL Plus, Web of Science and Google Scholar). Relevant data were extracted from 37 articles that were selected from an initial pool of 752 articles based on search criteria set for the study. RESULTS: Prevalent anatomical practices in the past such as dissection of executed criminals, acts of vivisection, illegal procurement of human remains, use of human tissues obtained as part of war crimes and dissection of human fetuses as well as their archival were analyzed through prism of established ethical norms in present day. The observations from past were presented vis-à-vis ethical practices undertaken in present times such as use of donated bodies and/or body parts procured through legal means for dissection, adherence to ethical norms during dissection, archival of human tissues mandating stringent regulation and dignified disposal of human remains. Existing loop holes were identified and future prospects regarding ethical standards in anatomy were highlighted based on rational judgment of existing trends. CONCLUSION: The article concludes with defense on future prospects of ethics in anatomy based on documented arguments.

The middle anorectal artery: A systematic review and meta-analysis of 880 patients/1905 pelvic sides.

The middle anorectal artery (MAA) is considered to supply the middle and lower parts of the rectum, however, its prevalence and point of origin vary across the literature. Clinical importance of the MAA becomes evident in the total mesorectal excision during the colorectal surgery of rectal cancer in both sexes, as well as interventional radiology procedures utilizing the prostatic vasculature in males. Major electronic medical databases were investigated for terms pertaining to the MAA and its associated variations. Compatible data regarding the artery's prevalence, laterality, origin, and distribution in both sexes was acquired. The risk of bias within the studies was assessed utilizing the AQUA tool. In total, 28 works (n = 880 patients/1905 pelvic sides) were included in this systematic review and meta-analysis, and their publication date ranged from 1897 until 2021. The overall pooled prevalence estimate for the MAA was 59.8% of the patients, and 55.2% of the pelvic sides studied. The vessel was identified more frequently in cadaveric pelvic sides evaluations (79.3%). The artery was found bilaterally more often (56.7%), and most commonly originated from the internal pudendal artery (50.3%). Anastomoses between the MAA and the other anorectal arteries were reported in 78.1%. The MAA is predominantly a present vessel, with various point of origin. Its direct clinical significance is yet to be discovered in larger study samples, providing more detailed and unified reports of its anatomical features, especially regarding its branches.

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.

Duplication and Fenestration of the Inferior Petrosal Sinus: Cadaveric Study with Application to Imaging, Skull Base Surgery, and Neurointerventional Procedures.

BACKGROUND: Reports of a duplicated or fenestrated inferior petrosal sinus (IPS) are scarce or not found in the literature, respectively. To our knowledge, there are no cadaveric reports of the latter. METHODS: This study used 20 adult cadaveric heads (40 sides). After removal of the brain, the IPS was dissected using a surgical microscope. Specimens with duplication or fenestration of the IPS anywhere along its course were photographed and measured. RESULTS: On 2 (5%) left sides, a fenestration was identified in the IPS. One of these was found to have 2 fenestrations. The mean length and width of the 3 fenestrations were 2.3 mm and 0.95 mm, respectively. The 3 fenestrations were located at the middle to terminal parts of the IPS. On 2 (5%) left sides and 1 (2.5%) right side, the IPS was duplicated over a part of its course. The mean length and width of the duplicated parts of the IPS were 25.9 mm and 3.1 mm, respectively. No statistical significance was found for fenestrations or duplications comparing males versus females, but fenestrations were statistically significant (P < 0.05) for occurring on left sides. CONCLUSIONS: Unfamiliarity with a duplicated or fenestrated IPS could increase risk of iatrogenic injury and misinterpretation of imaging. Further radiological imaging studies are required to substantiate more accurately the mechanisms by which a duplicated or fenestrated IPS affects clinical outcomes. Nonetheless, anatomical awareness of such lesser known variations of the IPS is crucial for promoting safe and effective interventional approaches at the skull base.

Standardized statement for the ethical use of human cadaveric tissues in anatomy research papers: Recommendations from Anatomical Journal Editors-in-Chief.

Human cadaveric donors are essential for research in the anatomical sciences. However, many research papers in the anatomical sciences often omit a statement regarding the ethical use of the donor cadavers or, as no current standardized versions exist, use language that is extremely varied. To rectify this issue, 22 editors-in-chief of anatomical journals, representing 17 different countries, developed standardized and simplified language that can be used by authors of studies that use human cadaveric tissues. The goal of these editor recommendations is to standardize the writing approach by which the ethical use of cadaveric donors is acknowledged in anatomical studies that use donor human cadavers. Such sections in anatomical papers will help elevate our discipline and promote standardized language use in others non anatomy journals and also other media outlets that use cadaveric tissues.

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.

Retrospective analysis of a case report of a left ovarian ectopic pregnancy after the former tubal.

Up to 2% of pregnancies may be extrauterine. Despite reproductive problems, they might increase the risk of serious complications. We present a case report of a 31-year-old woman with two extrauterine pregnancies - tubal and ovarian, which occurred at the same side with little time difference. In addition, we aimed to examine possible reasons underlying this rare pathology. Thus, surgically removed tissue specimens were morphologically assessed and further compared with specimens from healthy control patients. Telocytes were analysed in detail due to their pivotal role in the female reproductive system. Our study had observational character and obvious limitations typical for a clinical case. Yet, such a clinical case of two ectopic pregnancies has not been previously reported in the literature.