Search Results (254)

Background/Objectives: The abductor pollicis longus (APL) muscle exhibits a high degree of anatomical variation, particularly in the number and configuration of its tendons. Understanding these variants is crucial in surgical contexts, especially for tendon transfer and reconstruction procedures. This study aimed to determine the prevalence and morphometric characteristics of the accessory abductor pollicis longus (AAPL) muscle in a Bolivian cadaveric population. Methods: A descriptive, cross-sectional study was performed on 16 forearms from eight adult cadavers (six males and two females) preserved in 10% formalin. Cadaveric dissection was conducted following the AQUA guidelines, with measurements obtained for the AAPL proximal tendon length (PTL), distal tendon length (DTL), muscle length (ML), and transverse muscle length (TML) using a digital caliper. Statistical analysis was carried out using SPSS v26. Results: The AAPL muscle was present in 50% of forearms. Most were unilateral, with one bilateral case. The muscle exhibited a fusiform shape, with fibers aligned longitudinally. Morphometric analysis revealed a mean PTL of 1.20 ± 0.08 cm, DTL of 3.91 ± 0.52 cm, ML of 5.30 ± 0.45 cm, and TML of 0.55 ± 0.056 cm. One case (6.25%) exhibited a multicaudal APL with an additional tendon measuring 6.23 cm. No significant correlations were found between muscle and tendon measurements. Conclusions: AAPL muscles are relatively common and demonstrate notable morphometric variation. While the proximal tendon may be inadequate for grafting due to its short length, the distal tendon offers a viable alternative for reconstructive procedures. Recognition of such variants is clinically relevant, as they may contribute to pathologies like De Quervain’s tenosynovitis or serve as graft sources in surgical interventions. Full article

Background: Squamous cell carcinoma (SCC) of the nail unit, known as the subungual region, and of the plantar foot is rare but often misdiagnosed due to its similar appearance to verruca, a common wart. The delayed diagnosis and treatment of SCC in the subungual and plantar foot leads to poorer outcomes. Human papillomavirus (HPV), and specifically the oncogenic potential of particular strains, influences SCC pathogenesis, progression, and treatment response. Methods: This review aims to address the current state of knowledge as well as deficits associated with clinical treatment of SCC in two anatomically challenging locations: verrucous carcinoma (VC), a variant of SCC that affects the plantar foot, and subungual SCC. Articles reviewed were evaluated based on date of publication, quality, and originality. Additionally, articles published after 2015 were given preferential consideration. Results: This review highlights considerations to reduce diagnostic delays and improve patient outcomes when considering two uncommon cutaneous malignancies. Conclusions: We recognize that misdiagnosis poses a barrier in the treatment of both plantar VC and subungual SCC. As such, we identify pertinent clinical pearls to assist in accurate identification and treatment of SCC in these locations. Lastly, we address the role of HPV and the microbiome in the pathogenesis of SCC to improve treatment efficacy. Full article

Duchenne muscular dystrophy (DMD) is a severe neuromuscular disease caused by mutations in the DMD gene, leading to muscle degeneration and shortened life expectancy. Beyond motor symptoms, DMD patients frequently exhibit brain co-morbidities, linked to loss of brain-expressed dystrophin isoforms: most frequently Dp427 and Dp140, and occasionally Dp71 and Dp40. DMD mouse models, including mdx^5cv and mdx52, replicate key aspects of the human cognitive phenotype and recapitulate the main genotypic categories of brain phenotype. However, the spatio-temporal expression of brain dystrophin in mice remains poorly defined, limiting insights into how its deficiency disrupts brain development and function. We systematically mapped RNA and protein expression of brain dystrophin isoforms (Dp427 variants, Dp140, Dp71, and Dp40) across brain regions and developmental stages in wild-type mice. Dp427 isoforms were differentially expressed in the adult brain, with Dp427c enriched in the cortex, Dp427p1/p2 in the cerebellum, and Dp427m was also detected across specific brain regions. Dp140 was expressed at lower levels than Dp427; Dp71 was the most abundant isoform in adulthood. Dp140 and Dp71 displayed dynamic developmental changes, from E15 to P60, suggesting stage-specific roles. We also analysed mdx^5cv mice lacking Dp427 and mdx52 mice lacking both Dp427 and Dp140. Both models had minimal Dp427 transcript levels, likely due to the nonsense-mediated decay, and neither expressed Dp427 protein. As expected, mdx52 mice lacked Dp140, confirming their genotypic relevance to human DMD. Our study provides the first atlas of dystrophin expression in the wild-type mouse brain, aiding understanding of the anatomical basis of behavioural and cognitive comorbidities in DMD. Full article

Background/Objectives: The peroneus quartus (PQ) muscle is a supernumerary muscle in the lateral compartment of the leg. Although frequently asymptomatic, it may contribute to peroneal tendon (PT) disorders due to mechanical crowding in the retromalleolar groove. This study aimed to determine the prevalence of the PQ muscle on MRI and assess its association with PT pathologies. Materials and Methods: This retrospective study evaluated 1160 ankle MRI scans from 1073 patients (mean age, 42.7 ± 14.5 years; 643 females, 430 males). The presence of the PQ muscle and associated PT pathologies, including tenosynovitis, tendinitis, and tendon tears of the peroneus brevis tendon (PBT) and peroneus longus tendon (PLT), was recorded. Statistical analyses were performed using chi-square tests, and associations were expressed as odds ratios (OR) with 95% confidence intervals (CI). Results: The PQ muscle was identified in 123 of 1160 ankles, corresponding to a prevalence of 10.6%. Its incidence was significantly higher in males (12.7%) than in females (9.2%) (p = 0.018), while the side distribution showed no statistically significant difference. PQ presence was associated with PBT pathology, particularly tendinitis and longitudinal tears, and with PLT tendinitis, whereas no clear association was observed with tenosynovitis or PLT tears. Conclusions: The PQ muscle is a relatively common anatomical variant, present in 10.6% of ankles on MRI scans. Its presence is significantly associated with PT abnormalities, especially PBT tendinitis and tears. Awareness of PQ may aid clinicians and radiologists in assessing lateral ankle pain and peroneal tendon disorders. 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

The renal vessels are known to exhibit variations in different populations. The present retrospective cross-sectional study aimed to evaluate the radiological anatomy of renal arteries and veins in the Omani population. Computed tomography angiography scans were used to assess diameter, laterality, and vascular branching patterns in adults (aged ≥ 18 years) who underwent contrast-enhanced CT angiography of the abdomen and pelvis between 1 January 2023, and 31 December 2024. Normal CT angiograms of cases performed for vascular pathology screening, renal transplant workup, or trauma evaluation with normal findings were included. Measurements included diameters, anatomical course, and vascular variations in the renal arteries and veins. Accessory renal arteries were defined as any additional arteries arising from the aorta supplying the kidney, regardless of the entry point. The mean diameters of the right and left renal arteries were significantly higher in males (p = 0.020 and 0.026, respectively). The right renal vein was significantly larger in females (p = 0.020). Accessory renal arteries were identified in 24.22% (n = 31 patients), including two cases with unilateral double accessory arteries. The right and left RA diameters were 4.51 ± 0.91 mm and 4.95 ± 0.98 mm, respectively, both significantly larger in males (p = 0.020 and 0.026). Supernumerary renal veins were observed in 21 patients; retroaortic and circumaortic left RVs were found in seven and one case(s), respectively. Venous variations were present in 17.2% of the Omani subjects. The findings may enhance preoperative planning, especially in renal transplantation and urologic surgery, by increasing awareness of anatomical variants. This region-specific dataset supports the development of optimized imaging protocols and surgical strategies for better patient care. Full article

The anatomical and physiological similarities between human and canine eyes suggest that dogs may serve as a valuable model for studying retinopathies and developing future gene therapies. This study aims to evaluate the similarities and differences between humans with GUCY2D gene variants causing Leber’s congenital amaurosis (LCA) and a group of German Spitz dogs with hereditary retinopathy due to variants in the same gene, to assess their potential as an animal model for gene therapy research. A review of medical records, genetic testing, and ophthalmological examinations was conducted, including data such as age, genotyping, fundus photography, visual acuity (VA), fundus autofluorescence, optical coherence tomography (OCT), and electroretinography (ERG). Both groups presented subtle fundus abnormalities and severely reduced or absent ERG responses. In humans, OCT scans revealed decreased retinal thickness and structural alterations in the outer retinal layers. Similarly, the affected dogs exhibited focal neurosensory retinal detachments. The German Spitz model with GUCY2D variants shows significant parallels in retinal structure and functional impairment and may represent a promising candidate for preclinical gene therapy studies for LCA. Full article

Background: Unilateral lung agenesis (ULA) is a rare congenital anomaly characterized by the complete absence of one lung, often accompanied by cardiovascular, skeletal, or gastrointestinal malformations. Despite its clinical significance, evidence of prevalence, anatomical variants, and outcomes remain fragmented. This systematic review aimed to synthesize existing data on ULA’s prevalence, anatomical classifications, diagnostic approaches, and clinical implications. Methods: Following PRISMA 2020 guidelines, five databases (MEDLINE, Web of Science, CINAHL, Scopus, and EMBASE) were searched from inception to January 2024. Inclusion criteria encompassed case reports, case series, and observational studies on ULA in humans. Risk of bias was assessed using the Joanna Briggs Institute (JBI) checklist. Narrative synthesis was performed due to methodological heterogeneity. Results: Thirty-two studies (137 participants) were included. Right-sided ULA predominated (58%), with poorer prognoses due to mediastinal distortion. Cardiovascular anomalies (40%) were the most common comorbidity. Diagnostic modalities included chest radiography (85%), CT (70%), and bronchoscopy (25%). Schneider-Boyden scale was used to classify the included studies. Risk of bias assessment revealed 65% of studies as low risk, 28% as moderate, and 7% as high risk. Conclusions: ULA necessitates multidisciplinary management, particularly in cases with associated anomalies. Left-sided ULA correlates with better outcomes, emphasizing the role of early imaging. Limitations include reliance on case reports and inconsistent reporting of anatomical variants. Future research should adopt standardized classifications and longitudinal designs to improve evidence quality. Open science framework (OSF): 10.17605/OSF.IO/XVQSP. Full article

Hemorrhagic complications during pleural interventions—such as thoracentesis and chest tube insertion—remain a significant clinical concern, primarily due to inadvertent injury of the intercostal artery (ICA). The highly variable ICA anatomy is frequently not visualized on conventional imaging, limiting the reliability of landmark-based techniques. Color Doppler thoracic ultrasound (CDUS) has emerged as a non-invasive, real-time modality capable of identifying ICAs and their anatomical variants prior to pleural access. This narrative review synthesizes current evidence on CDUS-guided ICA screening, focusing on its technical principles, diagnostic performance, and clinical applicability. While feasibility and utility are supported by multiple observational studies, robust evidence demonstrating a reduction in bleeding complications is still lacking. Barriers to widespread implementation include heterogeneous scanning protocols, operator dependency, and the absence of standardized training. We discuss the anatomical rationale for pre-procedural vascular mapping and highlight emerging protocols aimed at standardizing ICA visualization. Although not yet incorporated into major clinical guidelines, CDUS represents a promising tool to enhance procedural safety. Emerging AI applications may further improve vessel detection by reducing operator dependency and enhancing reproducibility. High-quality prospective studies are essential to validate potential clinical benefits, optimize implementation strategies, and support integration into routine pleural practice. Full article

Purpose: This review aims to synthesize current knowledge of anatomical variations of the popliteofibular ligament (PFL) and evaluate the clinical relevance of the classification system proposed by Olewnik et al. in the context of the diagnosis, surgical treatment, and rehabilitation of posterolateral corner (PLC) injuries. Methods: A comprehensive analysis of anatomical, surgical, and radiological studies concerning the PFL was conducted. The implications of PFL morphological variants were examined across clinical applications, with an emphasis on reconstructive strategies, imaging interpretation, and rehabilitation planning. Emerging research directions, including AI-supported imaging and personalized algorithms, were also explored. Results: Olewnik’s classification identifies three distinct types of PFL, each with unique structural and biomechanical properties. Recognizing these variants enhances intraoperative orientation, facilitates tailored surgical techniques, and supports individualized rehabilitation protocols. Variant-specific biomechanics, identified via cadaveric studies and imaging, are essential for optimizing functional outcomes and minimizing postoperative instability. Furthermore, the classification offers a platform for developing future diagnostic and decision-support tools using artificial intelligence. Conclusions: The Olewnik et al. classification system should be adopted as a modern anatomical standard for the PFL. Its integration into clinical practice has the potential to improve surgical precision, reduce complication rates, and enhance patient-specific treatment planning. This framework also supports future advancements in orthopedic imaging, education, and AI-driven diagnostics. Beyond descriptive anatomy, we provide a pragmatic surgical algorithm for PLC repair/reconstruction that accounts for scar- and fibrosis-dominated fields and the limited bone stock of the fibular head. Full article

Background: The presence of multiple renal arteries (MRAs) is a common anatomical variant in living kidney donors. While MRAs are not considered a contraindication to donation, it remains uncertain whether leaving the donor with a kidney containing MRAs affects long-term outcomes. This study aimed to evaluate renal and clinical outcomes in donors based on the vascular anatomy of the remnant kidney. Methods: We conducted a retrospective cohort study of living kidney donors who underwent nephrectomy at our institution between 2011 and 2016. Donors were categorized according to the vascular anatomy of the remaining kidney: single renal artery (SRA) vs. multiple renal arteries (MRAs). Data on renal function, hypertension, diabetes mellitus, and cardiovascular events were collected at baseline and follow-up. The primary outcome was long-term renal function, which was measured by the estimated glomerular filtration rate (eGFR). Secondary outcomes included clinical comorbidities and postoperative complications. Results: Among 190 donors, 132 had a remaining kidney with a single artery and 58 had MRAs. Over a median follow-up of 89.5 months (SRA) and 74.5 months (MRA), there were no significant differences in eGFR (SRA: 66 mL/min vs. MRA: 65 mL/min, p = 0.60), serum creatinine (p = 0.86), or the incidence of hypertension (31.8% vs. 34.5%, p = 0.35). Rates of diabetes mellitus and cardiovascular events were similarly low and comparable between groups. Conclusions: Living kidney donors left with a remnant kidney containing multiple renal arteries have similar long-term renal function and clinical outcomes as those with a single renal artery. These findings support the feasibility of MRA retention in donor selection and contribute to evidence-based surgical planning and donor counseling. Full article

Purpose: The popliteus tendon (PT), though often overlooked, plays a vital role in the functional and mechanical stability of the posterolateral corner (PLC) of the knee. This narrative review consolidates the current anatomical, biomechanical, imaging, clinical, and surgical data on the PT, with an emphasis on its morphological variability and relevance in orthopedic sports medicine. Methods: A comprehensive review of the literature was conducted, including classical anatomical studies, recent classification systems, biomechanical evaluations, imaging protocols, and rehabilitation strategies. Particular focus was given to the anatomical classification proposed by Olewnik et al. and its implications in surgical and diagnostic contexts. Results: Anatomical investigations have demonstrated considerable variability in the PT, including bifid tendons and accessory fascicles. These variants have a measurable impact on preoperative planning, diagnostic imaging interpretation, and outcomes of surgical procedures, such as anterior cruciate ligament (ACL) and PLC reconstructions. The PT also contributes significantly to knee rotational control and meniscal stabilization, particularly in athletic populations. Imaging modalities, such as MRI and dynamic ultrasound, show high diagnostic utility, while arthroscopy remains the definitive diagnostic and therapeutic modality. Rehabilitation should emphasize neuromuscular re-education and progressive control of tibial rotation. A phase-based rehabilitation framework and clinical action table are proposed. Conclusions: The PT should be recognized as a critical structure in both the conservative and the surgical management of posterolateral and rotational knee instability. Enhanced awareness of its anatomical variability and functional importance can improve diagnostic accuracy, surgical precision, and clinical outcomes. In particular, MRI and high-resolution ultrasound can aid in identifying accessory fascicles and bifid tendons, while arthroscopy benefits from preoperative knowledge of PT variants to avoid misidentification and iatrogenic injury. Surgical planning for ACL and PLC reconstructions may be refined by applying the classification system described. Future research should focus on refining diagnostic algorithms, developing PT-specific functional tests, and integrating popliteus evaluation into high-level clinical decision-making and surgical navigation systems. Full article

The coracobrachialis muscle (CB) is a phylogenetically conserved component of the anterior compartment of the upper limb, offering critical insights into evolutionary anatomy, developmental biology, and human morphological variation. This mini review synthesizes findings from comparative anatomical studies, embryological data, cadaveric dissections, and clinical reports to explore the CB’s morphology, ontogeny, and medical relevance. Among tetrapods, the CB consistently originates from the coracoid process and inserts into the humerus, with interspecies morphological adaptations reflecting specific locomotor functions such as climbing, grasping, or digging. In humans, embryological studies confirm a common developmental origin with the biceps brachii, accounting for the frequent occurrence of variant configurations, including multiple heads and accessory slips such as the coracobrachialis longus (CBL) and brevis (CBB). These variants may contribute to clinical conditions such as musculocutaneous nerve entrapment+ or subcoracoid impingement. They may also be employed in reconstructive surgical procedures. A deeper understanding of CB morphology within an evolutionary framework improves anatomical interpretation, enhances clinical safety, and reduces diagnostic ambiguity. This review highlights the significance of integrating evolutionary and developmental perspectives in the study of human muscle variation. Full article

The human sphenoid bone (SB), centrally located at the cranial base, is structurally and developmentally complex. It arises from multiple cartilaginous precursors and undergoes both endochondral and intramembranous ossification, forming essential elements such as the sella, orbital walls, and numerous foramina. This review integrates embryological, anatomical, and radiological findings to present a comprehensive view of SB development and variation. Embryological studies reveal a layered ossification sequence, with accessory centers in the presphenoid and basisphenoid that influence adult morphology and variants, such as the caroticoclinoid foramen. In adulthood, the SB consists of a central body, paired greater and lesser wings, and the pterygoid processes, which articulate with key craniofacial bones and transmit vital neurovascular structures. Notable variants include duplication or absence of foramina, ossification of ligaments such as the pterygoid and pterygospinous ligaments, and the formation of bony bridges among the clinoid processes. These variants may affect cranial nerve trajectories and surgical access, posing potential risks during neurosurgical, endoscopic, and dental interventions. Emissary structures such as the sphenoidal emissary foramen and the newly described sphenopterygoid canal underscore the region’s vascular complexity. Additionally, variations in the optic and Vidian canals, as well as the superior orbital fissure, can also impact surgical approaches to the orbit, sinuses, and skull base. Understanding the full spectrum of sphenoid bone embryogenesis and morphology is essential for safe clinical practice and practical radiological imaging. Full article

Background: Hypospadias is a common congenital anomaly in boys, marked by ectopic urethral meatus and a wide range of anatomical variants such as chordee and atypical glans morphology. Despite advancements in surgical techniques, complication rates remain high and unpredictable due to heterogeneity in anatomy and a lack of standardized preoperative assessments. Retrospective studies suggest associations between specific anatomical features and postoperative complications; however, high-quality prospective, multicenter evidence is currently lacking. Methods: The PREDICT-H (Prospective Research on Essential Determinants Influencing Complication Trends in Hypospadias) study is a multicenter, prospective cohort study aiming to enroll approximately 1450 boys aged 1–12 years undergoing primary hypospadias repair at ten or more tertiary pediatric urology centers. A standardized preoperative assessment protocol will document detailed anatomical parameters, including urethral plate width and length, glans size, meatal location, chordee severity, and GMS score. Intraoperative variables and surgical techniques will be recorded. Postoperative outcomes, including urethrocutaneous fistula, meatal stenosis, and recurrent chordee, will be assessed at ≥6 months follow-up. Statistical analyses will include multivariate logistic regression and advanced modeling to identify independent predictors and develop a validated risk prediction nomogram. Interobserver reliability of anatomical assessments will also be evaluated. Results: As this is a study protocol, results are not yet available. Data collection is ongoing and will be analyzed upon completion of the planned follow-up period. The primary outcome will be the incidence of postoperative complications and the development of a predictive nomogram for individualized risk estimation. Conclusions: The PREDICT-H study is designed to provide robust, prospective evidence on the anatomical determinants of postoperative complications in hypospadias surgery. The development of a validated, clinically applicable risk prediction tool could standardize preoperative assessment and enhance individualized surgical planning. Findings from this study are expected to support evidence-based practice and inform future clinical guidelines. Full article