Iwanaga, Joe

ABSTRACT Following the introduction of meta‐analytic methodology into anatomical research, anatomical meta‐analyses have increased substantially. However, extremely high statistical heterogeneity is frequently observed in these studies, while its implications remain insufficiently discussed within anatomical research. The present study investigated the current state and patterns of heterogeneity in anatomical meta‐analyses and explored the interpretive implications of heterogeneity in anatomical evidence synthesis. A PubMed search was performed on May 21, 2026, using the title‐based search strategy: ((meta‐analysis[Title]) OR (meta analysis[Title])) AND (anatomy[Title]). Anatomical meta‐analyses focused on human structural anatomy were included. Reported I 2 values were extracted and descriptively analyzed by overall distribution and anatomical category. A total of 132 studies were identified, of which 61 anatomical meta‐analyses with analyzable heterogeneity data were included. The mean reported I 2 value was 95.27% (range 41%–100%), with a median I 2 of 98.77%. Most studies demonstrated extreme heterogeneity, with 86.9% reporting I 2 values exceeding 90%. Category‐specific analysis demonstrated consistently elevated heterogeneity across anatomical systems, including skeletal structures (mean I 2 = 99%), peripheral nerves (mean I 2 = 95%), and vascular anatomy studies (mean I 2 = 94.56%). Despite this, pooled prevalence estimates were frequently reported with highly precise numerical values and narrow confidence intervals. Extreme statistical heterogeneity is highly prevalent across anatomical meta‐analyses and appears to represent a widespread characteristic of anatomical synthesis research rather than an isolated statistical phenomenon. Although such heterogeneity likely reflects genuine biological and methodological variability, pooled anatomical estimates should be interpreted with caution, particularly when highly precise numerical estimates are reported despite substantial interstudy inconsistency. These findings highlight the importance of transparent heterogeneity reporting and anatomically stratified approaches in future anatomical meta‐analyses.

ABSTRACT The term “clinical anatomy” is widely used in education and research, yet its conceptual boundaries continue to be interpreted in various ways. Prior consensus‐based efforts have emphasized integration, collaboration, and clinical relevance as central features of the field and have provided an important foundation for interdisciplinary engagement. At the same time, ongoing changes in academic structure, medical education, and interdisciplinary biomedical science raise important questions regarding how clinical anatomy can sustain its scientific identity and long‐term relevance. Building upon prior discussions, this article argues that the continued maturation of clinical anatomy depends on the integration of conceptual frameworks with the sustained production of rigorous, reproducible, and clinically meaningful scholarly contributions. Historical and contemporary examples alike demonstrate that the influence of clinical anatomy has been shaped through contributions that directly advanced clinical science and practice. Accordingly, continued emphasis on methodological rigor, reproducibility, clinically meaningful contribution, and educational accountability may be essential to the field's future development and relevance.

ABSTRACT At the 42nd Annual Meeting of the American Association of Clinical Anatomists (AACA) in Bellevue, Washington, June 2025, two inaugural events—the Clinical Anatomy Fireside Chat (CAFC) and the Clinical Anatomy Symposium: Head and Neck 2025 (CAS)—fostered rich dialogue on the evolving role and operational definition of clinical anatomy. Experts from various clinical and anatomical disciplines explored the meaning of clinical anatomy, highlighting the absence of a universal definition despite its frequent use in education and research. Through these interdisciplinary discussions, a consensus emerged: clinical anatomy is not defined solely by the possession of clinical credentials but by the integration of anatomical knowledge and clinical relevance, achieved most effectively through collaboration. Clinical anatomy education and research require different depths of clinical knowledge depending on the audience and objective, and meaningful collaboration can bridge gaps in expertise. The symposium further illustrated that high‐quality clinical anatomy emerges from mutual respect and reciprocal insight between clinicians and anatomists. This article presents a consensus statement developed by AACA representatives and invited speakers, affirming that collaboration is not only foundational to the practice of clinical anatomy but also fundamental to its definition. These conclusions aim to guide future educational models, research strategies, and interdisciplinary partnerships in the field of clinical anatomy.

ABSTRACT Determining an appropriate sample size in human cadaveric studies remains a long‐standing and unresolved challenge. Unlike other basic science fields, anatomical research is constrained by factors such as limited human donor availability, cultural considerations, and ethical restrictions. Despite these limitations, researchers are often asked to justify sample sizes, yet no standardized guidelines currently exist. To quantitatively assess sample sizes in recent human cadaveric studies and propose evidence‐based recommendations for future research, a PubMed search was conducted on February 26, 2024, using the term human cadaveric study . The articles published in 2023 and 2024 were screened, yielding 770 eligible studies. Data extracted included the total sample size, number of classified groups, and journal impact factor (IF). Descriptive statistics, linear regression, and correlation analyses were performed. Continuous variables were summarized using medians and interquartile ranges (IQR). The median sample size was 11.5 (IQR: 7–20), and 47.9% of studies used 10 or fewer specimens. The median number of classified groups was 3 (IQR: 2–4). Linear regression showed that studies dividing specimens into 2–6 groups often failed to meet the recommended sample size per group based on regression modeling. No significant correlation was found between sample size and journal IF ( r = −0.062, p = 0.115). Most cadaveric studies rely on small sample sizes due to inherent constraints, yet many still attempt a subgroup analysis without sufficient statistical power. Although flexibility is essential in anatomical research, we recommend a minimum total sample size of 10 for basic studies and at least five samples per group for those involving classification. Cadaveric sample size alone does not predict journal impact, highlighting the importance of methodological rigor over quantity.

ABSTRACTMost discussions about discrimination and bias in anatomical research papers have been limited to terminology relating to race/ethnicity and gender/sex. However, as editors of anatomical journals, the authors of this article have frequently observed broader instances of potential discrimination and bias within anatomical research. These often stem from differences among authors' backgrounds, traditions, cultures, religions, provenance/origins, and workplace affiliations. In view of the limited discourse on this topic, we seek in this article to establish a consensus among editors of anatomical journals and to propose new Guidelines Against Discrimination and Bias in Anatomical Research Papers (GDBARP). We have identified multiple factors that can contribute to discrimination and bias, underscoring the need for greater awareness and proactive measures. It is imperative in anatomical research to respect authors, reviewers, and editors regardless of their background, culture, traditions, sex, ethnicity, language, religion, or ethical perspectives.

ABSTRACT Anatomy education is a cornerstone of medical training and relies on cadaveric dissection and 2D illustrations. Technological advancements and integrated curricula have reduced the focus on detailed anatomy and challenged educators to engage Generation Z learners with interactive, tech‐driven methods. Advanced imaging and artificial intelligence (AI) offer a solution, providing virtual dissection simulations and personalized learning tools that mimic 3D anatomy and adapt to individual student needs. Machine learning, a subset of AI, enhances this process by enabling predictive analytics, adaptive feedback, and tailored learning pathways based on performance data, significantly improving anatomical comprehension. Despite its benefits, AI integration raises concerns about over‐reliance on technology, biases, and diminished human interaction in training. This review examines AI's transformative potential in anatomy education while emphasizing the need for balanced implementation and ethical oversight. A systematic review following PRISMA guidelines was conducted, utilizing PubMed and backward citation searches. The search yielded 56 studies, with 47 additional articles from citations, resulting in 61 included studies. These explored AI applications such as virtual dissection simulations, machine learning algorithms for adaptive feedback, and gamified learning experiences, which were shown to enhance engagement, personalize learning, and improve anatomical understanding. Concerns about over‐reliance on AI and the loss of human interaction were also raised. AI has the potential to enhance anatomy education, but careful consideration of ethical and practical implications is essential. A balanced approach combining traditional methods with AI and robust oversight is crucial for effective integration.

ABSTRACT The Lazarus sign is a well‐documented spinal reflex observed in brain‐dead patients, characterized by involuntary upper limb movements that can resemble voluntary gestures. Initially described during the 1980s, this phenomenon has contributed to ongoing discussions about the physiological basis of spinal reflexes and their role in assessing brain death. The Lazarus sign was once considered a diagnostic challenge, but recent research reports confirm that it originates solely from the spinal cord, independent of brainstem or cortical activity. However, recent studies also suggest that spinal reflexes in brain‐dead patients, including the Lazarus sign, can be more variable than previously thought, occurring in multiple limb regions beyond the upper limbs. Prolonged survival in brain‐dead patients exhibiting the Lazarus sign has also raised new questions about its physiological significance. Its recognition has helped refine brain death criteria, ensuring accurate diagnoses and minimizing misinterpretations in critical care and organ donation settings. PubMed‐indexed studies and backward citations were reviewed. Studies were included if they explicitly described spinal reflexes in brain‐dead patients, examined neurophysiological mechanisms, or provided clinical observations on the Lazarus sign. Exclusion criteria included studies focusing solely on brainstem activity without considering spinal reflexes or case reports lacking detailed methodology. These investigations explored the prevalence, neurophysiological mechanisms, and clinical significance of the Lazarus sign. Research highlights its variable presentation, its occurrence in up to 40% of brain‐dead patients, and its potential to be misunderstood by families and healthcare providers. The sign does not indicate residual brain function, but it reinforces the need for clear communication in end‐of‐life care. Future research should focus on standardizing diagnostic protocols, educating clinicians, and addressing ethical concerns. Integrating this knowledge into brain death assessments will enhance clinical decision‐making and patient management.

ABSTRACT Nowadays, consent to use donor bodies for medical education and research is obtained from the body donors and their families before the donation. Recently, the International Federation of Associations of Anatomists (IFAA) published guidelines that could restrict the appearance of cadaveric images in commercial anatomical resources such as textbooks and other educational products. These guidelines state that the donor must expressly consent to using such images for this purpose. Cadaveric photos and drawings made from dissections of cadavers have been used in anatomy textbooks and atlases for hundreds of years. They are invaluable for anatomy students and clinical/surgical practitioners. The IFAA guidelines should not restrict the use of those older books; to do so would infringe the rights of those seeking knowledge from these resources. As the images in such textbooks and atlases are anonymized and are used for teaching and research, and the donors and their families are informed about this before the donation, we believe no additional consent is needed. It is impossible to separate educational from “commercial” usage entirely in any situation, e.g., publications from publishers and the use of cadavers in medical schools. Therefore, our best efforts to avoid unethical use of cadaveric images by following traditional consent processes are still needed so that more people will reap the benefits from them. As senior textbook/atlas authors/editors from over 10 countries, we believe that using cadaveric images in anatomy textbooks is appropriate, and no additional consent should be necessary. Such usage falls within the good faith of professionals using these invaluable gifts.

AbstractAlthough superior gluteal nerve (SGN) injury can have significant morbidity, to date, surgical strategies for its repair are scant in the literature. Specifically, neurotization options have not been explored. To address this deficiency in the literature, the current cadaveric feasibility study was performed. Via a transgluteal approach on 16 cadaveric sides, the proximal sciatic nerve and the entrance of the SGN into the gluteus medius and minimus were identified. Additionally, branches from the sciatic nerve to the hamstring muscles were traced proximally to confirm their position in relation to the sciatic nerve as a whole. These branches were cut at the level of the ischial tuberosity and teased away from the sciatic nerve proximally to the greater sciatic foramen and transferred superolateral to the SGN. The diameter of each nerve branch was measured as well as its available length for reaching the SGN. All branches of the sciatic nerve to the hamstring muscles arose from the anteromedial part of the nerve. The mean diameters of the branches to the semimembranosus, semitendinosus, and biceps femoris muscles were 2.1, 1.9, and 1.5 mm, respectively. The mean diameter of the SGN was 3.1 mm and the mean distance from this entrance point to the ischial spine was 7.2 cm. The mean length of the donor nerve was 8.5 cm. Based on our study, use of a tibial‐innervated hamstring branch as a donor for nerve transfer to the SGN is feasible.

Ulnar neuropathy at the cubital tunnel is common. However, a rare form of ulnar neuropathy here is due to compression from an accessory muscle, the anconeus epitrochlearis. Reports in the literature regarding the details of this muscle's innervation are vague, so the aim of the present study was to characterize this anatomy more clearly. This was a combined review of magnetic resonance imaging (MRI) from patients with an anconeus epitrochlearis and ulnar neuropathy and cadaveric dissections to characterize the innervation of this variant muscle. A review of 11 patients and three reports of ulnar neuropathy and an anconeus epitrochlearis in the literature revealed no MRI changes consistent with acute denervation of this muscle. However, in two cases, there were signs of chronic denervation of the muscle. Dissection of five cadavers revealed that the nerve supply to the anconeus epitrochlearis originated proximal to the medial epicondyle, traveled parallel to the ulnar nerve, terminated on the deep aspect of this muscle, and had a mean length of 60 mm. This clinicoanatomical study provides evidence that the innervation of the anconeus epitrochlearis is proximal to the muscle and on its deep aspect. Clin. Anat. 32:218–223, 2019. © 2018 Wiley Periodicals, Inc.