Anatomia

What is known today as the triangle of Koch (the triangular locus of the atrioventricular node, TLAVN) is bordered by the fibrous attachment of the septal cusp of tricuspid valve, the opening of the coronary sinus and tendon of valve of inferior vena cava (TIVCV). This is a concept developed cumulatively by several exceptional anatomists. The literature was reviewed with a focus on the discovery of the atrioventricular node by Sunao Tawara (January 1906), its previous announcement by Tawara’s mentor Ludwig Aschoff (1905), and the contributions of the authors who described the other components of the triangular locus. Francesco Todaro discovered the TIVCV (1865); Tawara described the atrioventricular node and its relationship with the fibrous attachment of the septal cusp of tricuspid valve and the opening of the coronary sinus. The first description of assembling all components was provided by Arthur Keith (March 1906). Keith was also the first to consider the triangular locus as a useful landmark for identifying the atrial structures of the conduction system discovered by Tawara and Wilhelm His Jr. (1893). Julius Tandler named the TLAVN as Koch’s triangle (1913). Keith’s contributions to this topic have been particularly overlooked. The “triangular locus of the atrioventricular node” or “triangle of the atrioventricular node” are more instructive and impartial names. Full article

While performing a routine anatomical dissection on a male donor, undergraduate medical students observed an uncommon vascular anomaly: a persistent left superior vena cava (LSVC). Prior to the anatomical dissection, computed tomography (CT) images were obtained in an embalmed condition. Relevant anatomical structures were measured using the JiveX DICOM Viewer. The left brachiocephalic vein (LBV) was present as a communicating vessel with a markedly reduced diameter between the LSVC and the right superior vena cava (RSVC). The diameters of RSVC and LSVC averaged 19.4 mm and 15.2 mm, respectively. The LSVC drained into a dilated coronary sinus (CS), which measured 22.7 mm in diameter. In addition, the left accessory hemiazygos vein collected the 2nd to 5th left intercostal veins, forming a small-caliber venous arch (2.1 mm in diameter) at the T5 vertebral level, which crossed anterior to the thoracic aorta, before draining into the LSVC. In comparison, the azygos venous arch on the right side is connected to the RSVC at T4. Knowledge of such venous variations through preoperative imaging—such as CT, MRI, or echocardiography—can be essential for procedural planning and for minimizing inadvertent complications. This case also highlights a dual approach, combining anatomical dissection with detailed CT analysis of the same specimen, which can both enhance undergraduate anatomical education and contribute to high-quality morphological research. Full article

Background/Objectives: Zenker’s diverticulum (ZD) is a rare but clinically relevant condition. It is a false, pulsion-type diverticulum due to the protrusion of mucosal and submucosal layers through the Killian’s Triangle. Its pathogenesis is multifactorial and entails cricopharyngeus muscle dysfunction and age-related tissue degeneration. This review addresses the current evidence regarding the anatomy, pathophysiology, clinical presentation, diagnostic approach, and therapeutic management of ZD. Methods: For this literature review, we searched the PubMed and Scopus databases using combinations of keywords relevant to Zenker’s diverticulum, including “Zenker’s diverticulum,” “esophageal diverticula,” “diagnosis,” “endoscopic treatment,” and “surgery”. We included articles published in recent decades, with a focus on most recent ones regarding clinical studies, systematic reviews, meta-analyses, and descriptions of new diagnostic and therapeutic techniques. Results: Characteristic symptoms comprise progressive dysphagia, regurgitation of undigested food, halitosis, and, in advanced cases, aspiration-related respiratory complications. Diagnosis of ZD is primarily based on barium swallow esophagography and endoscopic evaluation, complemented by other imaging techniques. Current therapeutic options include traditional open surgery and endoscopic procedures, including newer minimally invasive techniques. Conclusions: ZD is the most common type of esophageal diverticulum and can have a disabling impact on a patient’s quality of life. It is commonly underdiagnosed or misdiagnosed as another condition, and prevalence is expected to increase with the growing population ageing. Improved understanding of its pathophysiology is needed to refine diagnostic and therapeutic strategies and minimize recurrences and risks. Full article

Background/Objectives: The relationship between occlusion and temporomandibular joint is controversial in the scientific literature. The aim of this study is to evaluate the bone changes in the temporomandibular joint and surrounding bone structures and to determine the effect of malocclusions on the temporomandibular joint by making morphometric measurements in different skeletal classes using three-dimensional cone beam computed tomography images. Methods: A total of 90 patients (30 class I, 30 class II and 30 class III) were included in the study. In each skeletal pattern, condylar osseous changes were evaluated and articular eminence inclination and height, condylar diameters were measured. It was also divided into two age groups: 18–29 and 30 and over. Results: Articular eminence inclination measured with the best-fit line method was significantly higher in Class II compared with class I and III, and in individuals aged ≥30 years. Among osseous changes, only condylar flattening showed a significant age-related increase. The mediolateral condylar diameter was greater in males than females, while the anteroposterior diameter was higher in the ≥30-year age group. Conclusions: Temporomandibular joint morphology demonstrates age- and function-related adaptive remodeling, particularly in articular eminence inclination and condylar dimensions. CBCT-based assessment of these morphological features may assist clinicians in diagnosis and treatment planning, although further studies with larger prospective cohorts are warranted. Full article

Background/Objectives: Understanding anatomical variations in the abdominal vasculature, particularly of the inferior phrenic arteries (IPAs) and renal arteries (RAs), is essential in surgery and radiology, as such variations directly influence preoperative planning and therapeutic strategies. Although IPAs most commonly arise from the abdominal aorta (AA) or the celiac trunk, and RAs from the AA, anomalous origins have clinical significance, notably the emergence of the IPA from the RA. This study reports the concomitant occurrence of a triple right renal artery and the atypical origin of the ipsilateral inferior phrenic artery. Case Report: During a routine cadaveric dissection, three right renal arteries (superior, middle, and inferior) were identified in an adult male specimen, along with an anomalous origin of the right inferior phrenic artery (RIPA). The RIPA originated from the superior renal artery (SRA), ascended superolaterally to the inferior vena cava and bifurcated at the diaphragmatic dome. The SRA also gave rise to two right inferior suprarenal arteries. Conclusions: The coexistence of a triple renal artery and anomalous origin of the IPA represents an exceptionally uncommon and scarcely reported vascular configuration. This finding underscores the importance of meticulous preoperative vascular mapping, crucial for preventing intraoperative and iatrogenic complications. Broader anatomical and radiological studies are warranted to better elucidate the prevalence, developmental basis, and clinical implications of such variations. Full article

Background/Objectives: This study explores the evolution and morphology of the human mandible, focusing on recent changes and adaptations over the last 2000 years. It aims to examine how functional, genetic, and environmental factors influence mandibular size, shape, and sexual dimorphism by analyzing key anatomical landmarks—the horizontal ramus (HR), ascending ramus (AR), and mandibular angle (MA). Methods: A retrospective approach was employed using computed tomography (CT) scans of 39 mandibular samples from various historical periods, ranging from the Roman Imperial Age to the present day. Imaging was conducted using a 64-slice multislice computed tomography (MSCT) scanner, and the resulting data were processed to generate detailed 3D reconstructions for morphological assessment. Results: The analysis reveals that present-day samples exhibit significantly less variation in AR and MA compared to archaeological specimens, suggesting a trend of gracilization over time. Statistically significant differences were found in MA, likely influenced by environmental, dietary, and cultural factors. Correlation analysis showed moderate to weak relationships between AR, HR, and MA across sample groups, with significant sexual dimorphism in AR within the archaeological sample. Principal Component Analysis (PCA) further supported these findings, demonstrating a clear distinction between gracile modern mandibles and more robust ancient ones. Conclusions: These findings provide insights into the evolutionary trajectory of the human mandible, underscoring the influence of dietary and cultural shifts on mandibular structure over the past two millennia. Full article

The mental eminence (chin) is a uniquely human anatomical feature with critical relevance across multiple domains of biomedical and anthropological research. This transdisciplinary review aims to synthesize current knowledge regarding its morphology, population variability, evolutionary origin, and surgical relevance. A comprehensive scoping review aims to map how the mental eminence has been defined and evaluated in anthropological, forensic research, identifying the main methodological approaches, anatomical landmarks, and sources of morphological variability, as well as the reliability and applicability of current assessment methods in clinical–forensic contexts. The search strategy was performed in October 2025. The authors initially identified 3125 records, and 26 studies were finally included and assessed for qualitative analysis. Moreover, the analysis integrates data from osteological collections, radiographic imaging, and modern morphometric studies. The mental eminence exhibits significant variability across human populations, with pronounced sexual dimorphism and evolutionary distinction from non-human primates. Its emergence in Homo sapiens is a key taxonomic trait. Clinically, the chin serves as a landmark in surgical procedures involving genioplasty, trauma reconstruction, and dental implantology. Recent advances in imaging and biometrics have refined its analysis in both anthropological and diagnostic contexts. Though often overlooked, mental eminence plays a vital role in craniofacial morphology and human evolution. Its study bridges osteology, anthropology, and surgery, offering insight into both phylogenetic development and applied anatomical practice. A multidisciplinary understanding of this structure enhances its diagnostic and therapeutic utility. Full article

Background: Social networking platforms offer promising educational value, particularly for undergraduate students whose daily lives are deeply embedded in online spaces. Yet in most courses, instructional technologies remain limited to institutional learning management systems (LMSs), which often do not foster informal interaction or community. This study examined whether supplementing LMSs with a Facebook group could enhance academic outcomes and retention in undergraduate Anatomy and Physiology (A&P) courses. Methods: Over two semesters, two student cohorts (n = 39) were taught by the same instructor using identical materials; one cohort also used a closed Facebook group for course-related engagement. Results: While final course grades were not significantly different between groups (p = 0.186), students in the Facebook cohort scored significantly higher on mid-semester unit exams (p < 0.001 to p = 0.006). Regression analysis revealed a 9.4% higher mean final course grade among Facebook users. Importantly, the pass rate in the Facebook cohort was 94.7% compared to 45.0% in the control group, with dropout rates significantly lower (5.3% vs. 55%, p = 0.001). Conclusions: These findings suggest that incorporating social media into undergraduate science instruction may promote academic success and retention by providing a familiar, collaborative space for active learning and peer support. Full article

Background/Objectives: This article discusses the clinical–surgical relevance of vascular anatomical variations, such as fenestrations—the division of a vessel into multiple channels that subsequently rejoin distally. Although rare in peripheral veins, these variations, which originate from the incomplete condensation of the embryonic capillary plexus, can predispose thrombosis and necessitate preoperative recognition to avert complications during routine procedures. This study aims to report a rare case of dual origin and double fenestration of the cephalic vein. Methods: During a cadaveric dissection, a variation of the cephalic vein was identified. Results: In this case, an origin of the cephalic vein was observed arising from the dorsal venous network of the hand. It exhibited a double fenestration in the forearm, where a branch of the medial cutaneous nerve of the forearm perforated it before draining into the brachial vein. The second, a proximal origin, arose from the convergence of two tributaries—one originating from the subcutaneous tissue lateral to the brachial muscle and the other from the biceps brachii muscle, forming a single trunk that drained into the subclavian vein. Conclusions: This rare variation of the cephalic vein (dual origin and fenestration) carries significant hemodynamic implications, including an increased risk of turbulence and thrombosis. The atypical anatomical relationship between the nerve and the fenestrated vein also heightens the potential for iatrogenic injuries. In-depth knowledge of such anomalies is crucial for healthcare professionals to minimize complications and optimize the success of procedures like venous access and arteriovenous fistulas, ultimately ensuring patient safety. Full article

Background: Larger brains are believed to rely more heavily on intra-hemispheric than inter-hemispheric processing, which may lead to a proportionally reduced callosal size. Methods: To test this hypothesis, we used T1-weighted magnetic resonance images from a large population sample (n = 38,034). The sample was drawn from the UK Biobank and included 19,947 females and 18,087 males, aged between 44 and 83 years (mean ± SD: 64 ± 7.72 years). Linear modelling was used to assess the relationship between proportional callosal volume and total intracranial volume, with sex, age, and handedness included as covariates and interaction terms. Results: We observed a significant negative relationship between proportional callosal volume and total brain volume, such that larger brains had proportionally smaller corpora callosa. Conclusion: These findings support the hypothesis that increasing brain size is associated with reduced inter-hemispheric connectivity, potentially due to conduction constraints that promote greater intra-hemispheric processing in larger brains. Full article

The azygos lobe (AL), an additional lung lobe most commonly found in the right apical lung region, is a rare anatomical variant present in approximately 1% of the population. It is embryological in origin and may form if the azygos vein fails to migrate medially over the lung. While it is normally clinically silent, it can have surgical and clinical implications. An AL can be the source of infection or disease, such as squamous cell carcinoma, and can also compress the upper lobe and lead to obstruction, infarction, and necrotic tissue. Additionally, it can present as an unforeseen surgical obstacle, specifically during a thoracotomy, and can be mistaken for a thoracic mass on radiographic imaging, potentially leading to unnecessary interventions. In this case report, a 38-year-old male donor with a history of Ogilvie’s syndrome, multiple traumatic brain injuries (TBIs), and chronic respiratory failure presented with an AL during routine donor dissection. The cause of death was listed as prostate cancer, hypertension, atrial fibrillation, and type II diabetes mellitus. The AL, located on the posterior apical surface of the right lung, measured 5 cm in width and 8 cm in length. The left lung showed signs of atrophy and discoloration, possibly the result of pollution exposure or smoking earlier in life. In this article, we describe the incidence, historical classification, embryology, and physiology associated with an AL and its clinical implication for this donor. Full article

Background: Lower phylogenetic species are known to rebuild cut-off caudal parts with regeneration of the central nervous system (CNS). In contrast, CNS regeneration in higher vertebrates is often attributed to immaturity, although this has never been conclusively demonstrated. The emergence of stem cells and their effective medical applications has intensified research into spinal cord regeneration. However, despite these advances, the impact of clinical trials involving spinal cord-injured (SCI) patients remains disappointingly low. Long-distance regeneration has yet to be proven. Methods: Our study involved a microsurgical dorsal myelotomy in fetal rats. The development of pioneering long primary afferent axons during early gestation was examined long after birth. Results: A single cut triggered the intrinsic ability of the dorsal root ganglion (DRG) neurons to reprogram. Susceptibility to hypoxia caused the axons to stop developing. However, the residual axonal outgrowth sheds light on the intriguing temporal and spatial events that reveal long-distance CNS regeneration. The altered phenotypes displayed axons of varying lengths and different features, which remained visible throughout life. The previously designed developmental blueprint was crucial for interpreting these enigmatic features. Conclusions: This research into immaturity enabled the exploration of the previously impenetrable domain of early life and the identification of a potential missing link in CNS regeneration research. Central axon regeneration appeared to occur much faster than is generally believed. The paradigm provides a challenging approach for exhaustive intrauterine reprogramming. When the results demonstrate pre-clinical effectiveness in CNS regeneration research, the transformational impact may ultimately lead to improved outcomes for patients with spinal cord injuries. Full article

Objective: The aim of this study was to determine whether preoperative MRI has an impact on surgical planning in breast cancer patients. Tumor extent and molecular breast cancer subtypes were evaluated. Methods: This was a single-center study including 137 female patients with a first diagnosis of invasive breast cancer. Each patient had a standard clinical preoperative workup and an additional breast MRI. The interdisciplinary tumor board made written recommendations regarding the surgical therapy of each patient with and without the knowledge of the MRI findings. Results: The addition of MRI led to changes in surgical recommendations in 32 (23%) of the 137 patients. The highest rate of change in surgical therapy recommendations was observed in patients with multifocal tumors (53%). Molecular subtype had no influence on the changes in surgical therapy recommendations (p = 0.8). Conclusions: Patients with multifocal breast tumors were more likely to have a change in surgical therapy following MRI. Full article

Background/Objectives: This study explores the ocular anatomy and glandular components of domestic dogs compared to their ancestor, the wolf, with the aim of identifying evolutionary changes due to domestication and their implications for ocular pathologies. Methods: Utilizing histological and histochemical techniques, including hematoxylin–eosin, Periodic Acid–Schiff, Alcian Blue, and lectins, this research conducts a detailed analysis of the canine and wolf ocular systems, focusing on the eyelids, tarsal glands, and conjunctival tissues. Results: There are marked histological differences between the two species, particularly in the thickness and secretion levels of the conjunctival epithelia and the structure of the tarsal glands. Dogs exhibit a thicker epithelium with greater Periodic Acid–Schiff and Alcian Blue positive secretion, suggesting enhanced ocular protection and lubrication adapted to domestic environments. Conversely, wolves display more concentrated glandular secretions and a predominance of acidic mucopolysaccharides, aligning with their adaptation to natural habitats. Conclusions: Although this study is constrained by the limited number of samples, the use of mixed dog breeds, and the focus on the Iberian wolf, it nonetheless suggests histological and evolutionary differences between domestic dogs and wolves, particularly in structures related to ocular surface protection and lubrication. These differences likely reflect adaptive responses to domestication in dogs and environmental demands in wolves. Importantly, the findings emphasize the clinical and translational potential of using dogs as comparative models for human ocular surface disorders, given their anatomical proximity to humans. Full article

Anatomy education has long served as a cornerstone of medical training, equipping healthcare professionals with the foundational knowledge necessary for clinical practice. However, the discipline has undergone significant transformations in response to evolving curricula, ethical considerations, and technological advancements. This paper explores the historical development, current state, and future trajectory of anatomy education, focusing on challenges such as ethical concerns regarding cadaveric dissection, and the need for cost-effective alternatives. The study examines innovative teaching methods, including virtual reality, augmented reality and artificial intelligence, which enhance anatomical learning by providing interactive, scalable educational experiences. Additionally, it discusses the integration of anatomy with clinical practice through imaging technologies, competency-based education, and evidence-based approaches. While modern innovations offer valuable learning tools, they cannot entirely replace the hands-on experience and professional identity formation fostered by cadaveric dissection. A balanced approach that combines traditional methodologies with digital advancements is essential for optimizing anatomy education. By leveraging both physical and virtual resources, educators can enhance anatomical comprehension, improve clinical preparedness, and ensure that future healthcare professionals develop both technical expertise and ethical awareness. This paper underscores the need for continued adaptation in anatomy education to align with the demands of modern medicine while preserving its core educational values. Full article

Peripheral nerve injuries (PNIs) commonly result from trauma, compression, or iatrogenic causes, leading to functional deficits. Despite the peripheral nervous system’s regenerative capacity, current treatments yield inconsistent outcomes. Basic science and translational research supporting nerve repair remain underdeveloped, partly due to the absence of standardized protocols, limiting reproducibility. Animal models are essential for studying injury mechanisms, repair strategies, and therapeutic development. This review examines commonly used animal models in PNI research, from non-mammalian species to rodents and large mammals. We discuss the relevance of injury types, experimental variables (i.e., age, sex, nerve type), and study design elements (i.e., nerve gap size, injury induction methods). Assessing these models’ strengths and limitations, this review aims to guide researchers in selecting appropriate models that enhance preclinical relevance. It also addresses the need for standardized protocols and future directions for improving PNI research and patient outcomes. Various PNI treatments—including microsurgery, nerve grafts, scaffolds, stem cells, immunomodulators, nerve augmentation strategies, and polyethylene glycol-mediated fusion—have been developed using animal models. These models are essential for driving innovation and translating emerging therapies to improve outcomes across a broad range of peripheral nerve injuries. Full article

Background: The brachial plexus is a network of nerves responsible for the motor and sensory innervation of the upper limb. Variations in the formation and course of the brachial plexus are well documented, though combinations of multiple unilateral abnormalities are rare. The complex pathology of this structure nerve may result in clinical consequences. We present a unique set of brachial plexus abnormalities involving the C4–C6 nerve roots, superior and middle trunks, additional communicating branches, and delayed median nerve union. Case Presentation: During the routine dissection of a 70-year-old female cadaver, several unique variations in the brachial plexus anatomy were identified. The C4 root contributed to C5 before the superior trunk formed, resulting in a superior trunk composed of C4–C6. The C5 root was located anterior to the anterior scalene muscle, whereas C6 maintained its usual posterior position. Additionally, an anterior communicating branch from the middle trunk to the posterior cord was observed. A communicating branch between the lateral and medial cords split into two terminal branches: one merged with the ulnar nerve, and the other joined the medial contribution of the median nerve. The median nerve contributions from the lateral and medial cords merged approximately two inches above the elbow. Conclusions: This rare combination of brachial plexus anomalies has not been previously described in the literature and is of significant clinical relevance. The additional anterior communicating branch from the middle trunk may suggest potential flexor muscle innervation by the posterior cord, which typically innervates extensor muscles. Additionally, the delayed convergence of the median nerve may provide a protective mechanism in cases of midshaft humeral fracture. Awareness of these peripheral nerve abnormalities is important for diagnostic imaging, surgery, or peripheral nerve blocks. Knowledge of such variations is critical for clinicians managing upper limb pathologies. Full article

Background/Objectives: The hypoglossal nerve plays a crucial role in cervical surgery, requiring precise anatomical knowledge to prevent iatrogenic injury. This study examined its position relative to key structures using cadaveric dissections and assessed ChatGPT-4’s reliability in providing anatomical insights. Methods: Ten cadavers were dissected to identify the hypoglossal nerve’s course in relation to the internal jugular vein, carotid arteries, thyro-linguo-facial trunk, hyoid bone, and digastric muscle. Measurements were taken, and ChatGPT was queried for anatomical guidance and surgical recommendations. Results: The hypoglossal nerve was consistently medial to the internal jugular vein and lateral to the carotid arteries. The measured distances to the surrounding structures showed notable variability, particularly with the thyro-linguo-facial trunk. ChatGPT accurately described major landmarks but overlooked lesser-known anatomical triangles and provided no additional dissection guidance. It primarily suggested intraoperative monitoring and preoperative imaging. Conclusions: The carotid and submandibular triangles serve as reliable landmarks for identifying the hypoglossal nerve. This study highlights an unreported variability in its relationship with the thyro-linguo-facial trunk. ChatGPT, while informative, lacked detailed surgical applicability for dissection. Full article

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