Correlation Between the Foramen of Monro and the Pars Opercularis: A Morphometric Analysis

Correlation Between the Foramen of Monro and the Pars Opercularis: A Morphometric Analysis | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Correlation Between the Foramen of Monro and the Pars Opercularis: A Morphometric Analysis Teófilo Dorneles Claro dos Santos Silva, Esequiel José Felipe de Medeiros Neto, and 8 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7060320/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 24 Feb, 2026 Read the published version in Surgical and Radiologic Anatomy → Version 1 posted 7 You are reading this latest preprint version Abstract Purpose : To evaluate morphometric correlation between the foramen of Monro and pars opercularis through MRI. Methods : This retrospective, cross-sectional, and observational study analyzed 90 cerebral hemispheres from patients treated at Ophir Loyola Hospital. Volumetric T1-weighted MRI sequences (1-mm slices) were processed in 3D Slicer. Distances between the Foramen of Monro and Pars Opercularis were measured along the X (mediolateral), Y (anteroposterior), and Z (superoinferior) axes. Pearson’s correlation and t-tests were applied for statistical analysis. Results : The Pars Opercularis was predominantly anterior (9.96 mm) and superior (2.62 mm) to the Foramen of Monro, with a mean linear distance of 45.21 mm. Significant lateral differences were observed: the right hemisphere exhibited a greater linear distance (46.52 mm) than the left (43.90 mm). Age showed a moderate negative correlation exclusively in depth (Z-axis), indicating progressive reduction in this measurement over time. Conclusion : The Foramen of Monro maintains a consistent spatial relationship with the Pars Opercularis , with stable positioning and subtle hemispheric differences. These findings refine anatomical knowledge and contribute to neurosurgical planning, particularly in procedures requiring precise anatomical references, such as ventricular surgeries and resections near eloquent cortical areas. Foramen of Monro Pars Opercularis Neuroanatomy Neuroimaging Brain Morphology Neurosurgical Planning Figures Figure 1 Figure 2 Figure 3 INTRODUCTION Human anatomy serves as the foundation of health sciences, providing an essential understanding of the structure and function of the human body while offering the necessary support for the diagnosis and treatment of pathological conditions. In the field of neuroanatomy, the study of intracranial structures plays a pivotal role in planning neurosurgical interventions, particularly in eloquent areas where precision is crucial for preserving motor and cognitive functions [ 12 , 3 ]. Among intracranial structures, the foramen of Monro and the pars opercularis of the inferior frontal gyrus play fundamental roles in both clinical and surgical contexts. The foramen of Monro is widely recognized as a key anatomical landmark in ventricular interventions, such as cerebrospinal fluid shunting and accessing the lateral or third ventricles for the treatment of hydrocephalus and intraventricular tumors [ 13 , 17 ] . On the other hand, the pars opercularis , located near motor and language-related areas, is of clinical interest due to its functional relevance and the challenges it presents during neurosurgical procedures, where its preservation is essential to prevent permanent deficits [ 14 , 8 ] Although direct neurosurgical interventions connecting the foramen of Monro and the pars opercularis are uncommon, the spatial relationship between these structures has significant practical implications. A detailed topographic understanding of this relationship can facilitate the planning of safer surgical trajectories, particularly for lesions involving the inferior frontal gyrus or ventricular procedures requiring precise localization of eloquent structures. Furthermore, identifying reproducible anatomical patterns is essential for minimizing complications and optimizing clinical outcomes [ 7 ]. Despite its clinical importance, the literature still lacks systematic studies analyzing the precise topographic correlation between the foramen of Monro and the pars opercularis using high-resolution magnetic resonance imaging (MRI). This data gap limits neurosurgeons' ability to plan interventions more safely in critical brain regions. Multiplanar MRI reconstructions have proven to be a powerful tool for exploring these relationships, enabling detailed morphometric analyses and recognizing individual variations that may directly impact neurosurgical practice [ 1 , 1 0 ] This study aims to explore the morphometric relationship between foramen of Monro and pars opercularis using magnetic resonance imaging. METHODOLOGY Study Location and Desi gn The present retrospective, cross-sectional, and observational study was conducted based on the analysis of imaging exams from patients treated by the neurosurgery team at Ophir Loyola Hospital (OLH), located in Belém, Pará, Brazil. Data Collection Data were collected from imaging exams available between January 2022 and December 2023, with organization and analysis carried out in October and November 2024. To be included in the study, MRI scans had to meet the following inclusion criteria: volumetric T1-weighted sequences, multislice volumetric studies, 1 mm slice thickness, and patients undergoing MRI due to suspected neurosurgical or neurological conditions such as hydrocephalus, brain tumors, or epilepsy. Exclusion criteria were based on incomplete or low-quality exams, as well as those showing significant anatomical alterations, including congenital malformations or extensive lesions. Anatomical landmarks The analysis focused on measuring distances between two anatomical landmarks in both cerebral hemispheres: the foramen of Monro, clearly defined as the space located below and medial to the column of the fornix and the thalamus, and specific areas of the inferior frontal gyrus, with emphasis on the pars opercularis . The identification of these points was performed using 3D-reconstructed images processed with 3D Slicer software, version 4.11.20210226 (Brigham and Women’s Hospital - BWH). This software enabled multiplanar visualization of T1-weighted MRI images in sagittal, coronal, and axial planes. The software was configured to automatically detect structural margins using standardized and validated segmentation algorithms, including “GrowCut,” a region-growing algorithm based on competitive cellular automata, selected for its ability to handle complex margins and low-contrast tissues [ 5 ]. Additionally, the “Segment Editor” module was employed for manual adjustments of automatic markings, ensuring greater accuracy and reliability. The literature highlights 3D Slicer as a reliable tool for medical image segmentation and analysis. Studies such as Egger et al. (2013) [ 1 8 ] validate its application in precise measurements, such as glioblastoma volumetry, demonstrating high reproducibility and accuracy. The combination of automatic algorithms like "GrowCut" with manual refinements enhances segmentation quality [ 11 ]. To ensure accuracy in the markings, segmentations were reviewed by two independent specialists, who analyzed the delineations by comparing them with previously established standards in the literature and reference studies. For better visualization, an illustrative image highlighting anatomical locations and applied demarcations was included, as shown in Figures 1 and 2. The marking of anatomical landmarks followed the parameters established for each point, described as follows: the pars opercularis was identified from the first slice displaying visible gray matter in the caudal portion, immediately posterior to the ascending branch of the lateral sulcus, based on T1-weighted volumetric sagittal sequences, as illustrated in Figure 1. The foramen of Monro was determined in the coronal plane as the space immediately below and medial to the fornical column and the thalamus, and in the sagittal plane as the beginning of the medullary stria of the thalamus, as shown in Figure 2. The distances were measured considering the following axes: X (latero-lateral), from the center of the foramen of Monro to the lateralmost point of the pars opercularis; Y (antero-posterior), from the foramen of Monro to the anterior limit of the pars opercularis; and Z (supero-inferior or depth), from the foramen of Monro to the inferiormost extremity of the pars opercularis. The distance analysis was conducted based on the demarcations obtained from the software, ensuring precision and reproducibility of the measurements. A three-dimensional visualization demonstrating the spatial relationship between the two points was included to facilitate understanding, as illustrated in Figure 3. Statistical Analysis The distances between anatomical structures along the X, Y, and Z axes were automatically calculated by the 3D Slicer software and expressed in millimeters (mm). The generated data were exported for descriptive statistical analysis, including measures of central tendency (mean, median, and mode), dispersion measures (variance and standard deviation), and frequency distributions. These analyses were conducted using the BioEstat 5.0 software. Additionally, D’Agostino and Pearson normality tests were applied to assess data distribution. Results were considered statistically significant for p -values < 0.05. Ethical Statement The study was approved by the Research Ethics Committee under protocol CAAE: 82368124.0.0000.5550, approval number 7.024.391. A waiver of the Informed Consent Form (ICF) was granted, given that the research was limited to the analysis of previously acquired radiological images for clinical purposes. RESULTS Following the application of exclusion criteria to a database of 216 patients who met the inclusion criteria, 90 samples (hemispheres) remained available for morphological analysis and comparative evaluation. As shown in Table 1, the mean distances between the pars opercularis and the foramen of Monro (POF) revealed that, along the anteroposterior axis, the pars opercularis was located an average of 9.96 mm anterior to the foramen of Monro, with a range from -10 mm to 21 mm. Along the superoinferior axis, the pars opercularis was positioned an average of 2.62 mm superior to the foramen of Monro, ranging from -10.84 mm to 49.88 mm, predominantly situated above the foramen. In terms of depth, the mean distance between the foramen of Monro and the pars opercularis was 43.54 mm, ranging from 35.98 mm to 53.75 mm. The direct linear distance between the two structures was estimated at 45.21 mm, with a range of 37.13 mm to 54.27 mm. Statistical analysis of the distributions indicated that the assumption of normality was not met, with a p-value < 0.05 for all examined variables. Table 1 : Descriptive statistics of the distances between the Pars Opercularis and the Foramen of Monro. Results POF Z-Axis (Latero lateral) POF X-Axis (Anteroposterior) POF Y-Axis (Superoinferior) Linear Distance POF Sample Size 90 90 90 90 Minimum 35,983 -10,451 -10,847 37,137 Maximum 53,758 21,256 49,881 54,273 Mean 43,5402 9,9613 2,6287 45,2121 Variance 12,977 29,2468 42,7554 12,1007 Standard Deviation 3,6024 5,408 6,5388 3,4786 Legend: POF (Distance from Pars Opercularis to the Foramen of Monro) The projection of the pars opercularis and the foramen of Monro onto the Cartesian plane revealed statistically significant differences in their spatial distribution along both the X and Y axes, as shown in Table 2. On the X-axis, the mean distance to the foramen of Monro was 32.12 mm, while the mean distance to the pars opercularis was 42.12 mm (p < 0.0001). On the Y-axis, the means were 36.40 mm for the foramen and 39.03 mm for the pars opercularis (p < 0.0001). The 99% confidence interval demonstrated that the foramen of Monro was consistently located posterior to the pars opercularis, with a variation from -11.47 mm to -8.44 mm. Although the two points did not occupy equivalent positions, a safe distance was consistently maintained between them, with the foramen of Monro located, on average, between 4 mm and -0.8 mm below the pars opercularis. Table 2: Morphological Reference on the X and Y Axes between the Foramen of Monro and the Opercular Gyrus. Foramen of Monro X-Axis (Anteroposterior) Pars Opercular X-Axis (Anteroposterior) Foramen of Monro Y-Axis (Superoinferior) Pars Opercular Y-Axis (Superoinferior) Individuals 90 90 90 90 Mean 32,1622 42,1235 36,4069 39,0355 Standard Deviation 9,0188 9,4994 17,2144 16,7244 Mean of Differences -9,9613 --- -2,6287 --- (p) one-tailed < 0.0001 --- < 0.0001 --- (p) two-tailed < 0.0001 --- < 0.0001 --- CI (95%) -11.0986 to - 8.8241 --- -4.0037 to - 1.2536 --- CI (99%) -11.4735 to -8.4492 --- -4.4570 to - 0.8004 --- Legenda : CI (Confidence interval). Depth exhibited a statistically significant difference between hemispheres, with a mean of 42.35 mm on the left side and 44.73 mm on the right. The t-test yielded t = -3.9045 and a two-tailed p-value < 0.0001, indicating that depth was significantly lower on the left (99% CI: -4.02 to -0.74 mm), as shown in Table 3. In addition to depth, the total linear distance between the foramen of Monro and the operculum also differed significantly between hemispheres. The mean linear distance was 43.90 mm on the left and 46.52 mm on the right, indicating a greater separation on the right side (Table 4). Table 3: Depth Comparison Between Left and Right Sides for the Foramen of Monro and the Opercular Gyrus. POF Z-Axis (Laterolateral) POF X-Axis (Anteroposterior) POF Y-Axis (Superoinferior) L R L R L R Individuals 45 45 45 45 45 45 Mean 42,3498 44,7306 9,4174 10,5053 3,6332 1,6241 Mean of Differences -2,3808 --- -1,0879 --- 2,0091 --- (t) -3,9045 --- -1,225 --- 1,5613 --- (p) one-tailed < 0.0001 --- 0,1135 --- 0,0628 --- (p) two-tailed < 0.0001 --- 0,227 --- 0,1255 --- CI (95%) -3.6093 to - 1.1523 --- -2.8771 to 0.7014 --- -0.5836 to 4.6019 --- CI (99%) -4.0215 to - 0.7401 --- -3.4773 to 1.3016 --- -1.4533 to 5.4716 --- Legend: POF (Distance from Pars Opercularis to the Foramen of Monro), CI (Confidence Interval), L (Left), R (Right).. Table 4 : Linear Distance Comparison Between Left and Right Sides for the Foramen of Monro and the Pars Opercularis. Linear Distance POF Left Right Individuals 45 45 Mean 43,9002 46,5241 Mean of Differences -2,624 --- (t) -4,2508 --- (p) one-tailed < 0.0001 --- (p) two-tailed < 0.0001 --- CI (95%) -3.8677 a - 1.3803 --- CI (99%) -4.2849 a - 0.9631 Legend: POF (Distance from Pars Opercularis to the Foramen of Monro), CI (Confidence Interval). Along the anteroposterior axis, the difference between sides was not statistically significant (p = 0.227), with means of 9.42 mm on the left and 10.51 mm on the right. The 99% confidence interval for the difference between sides ranged from -3.48 mm to 1.30 mm, suggesting only minor variation without statistical significance. On the superoinferior axis, the mean distance was slightly greater on the left (3.63 mm) than on the right (1.62 mm); however, this difference was also not statistically significant (two-tailed p = 0.1255; 99% CI: -1.45 to 5.47 mm). Patient age did not significantly influence most of the distances analyzed. Only the Z-axis (depth) distance showed a moderate negative correlation with age (Pearson's r = -0.4326, p < 0.0001), indicating a progressive decrease in the distance between the structures with increasing age. Distances along the other axes showed minimal variation with age, with Pearson's coefficients of -0.0805 (p = 0.5015) for the anteroposterior axis and -0.0579 (p = 0.6289) for the superoinferior axis. However, age had a final significant effect on the linear distance between the structures, as shown in Table 5. Table 5: Pearson Correlation Between Patient Age and Distances on the X, Y, and Z Axes. Results POF Z-Axis (Latero lateral) POF X-Axis (Anteroposterior) POF Y-Axis (Superoinferior) Linear Distance POF N 90 90 90 90 r (Pearson) -0,0747 -0,0892 0,166 -0,0718 CI 95% -0.28 a 0.13 -0.29 a 0.12 -0.04 a 0.36 -0.27 a 0.14 CI 99% -0.34 a 0.20 -0.35 a 0.19 -0.11 a 0.42 -0.34 a 0.20 (p) 0,4841 0,4031 0,1178 0,501 Legenda : POF (Distance from Pars Opercularis to the Foramen of Monro), CI (Confidence Interval). DISCUSSION This study examined the anatomical relationships between the foramen of Monro and the pars opercularis, providing precise measurements that underscore the relevance of these structures in neurosurgical planning . Although a direct connection between these areas is neither practical nor functional, the analysis of their spatial orientation yields valuable data for neuroanatomical understanding and surgical approaches to adjacent regions [ 1 , 1 5 ]. The analyses revealed that, along the anteroposterior axis, the pars opercularis is, on average, 9.96 mm anterior to the foramen of Monro, with variations ranging from -10 mm to 21 mm. This distance reflects relative anterior plane stability, which may be relevant in surgeries involving lesions affecting the ventricular regions or the inferior frontal gyrus [ 1 5 ]. On the superoinferior axis, the mean position of the pars opercularis was 2.62 mm superior to the foramen of Monro (range: -10.84 mm to 49.88 mm), indicating that the pars opercularis is predominantly located above the foramen, although individual variability is substantial. The mean depth (Z-axis) was 43.54 mm, ranging from 35.98 mm to 53.75 mm, and the direct linear distance between the two structures was estimated at 45.21 mm. These values serve as consistent quantitative parameters for anatomical modeling and may aid in delineating critical areas during surgical approaches. One of the most notable findings was the depth asymmetry between hemispheres, with the right side exhibiting a greater mean distance (44.73 mm) compared to the left (42.35 mm), as shown in Table 3. This anatomical asymmetry may reflect widely documented cerebral lateralization differences [ 6 , 9 ]. However, no statistically significant differences were found between sides along the anteroposterior and superoinferior axes, suggesting greater topographical consistency in these planes. Furthermore, a moderate negative correlation was observed between age and depth (Pearson’s r = -0.4326, p < 0.0001), indicating a progressive reduction in distance with advancing age. This change may reflect age-related cerebral atrophy, which should be considered when planning procedures in older populations [ 9 ]. In contrast, variables such as sex did not significantly influence the measured distances. The identified spatial orientation has potential applications in various clinical contexts. In ventricular procedures, such as cerebrospinal fluid shunting or endoscopic resection of intraventricular tumors, the foramen of Monro serves as a critical landmark to guide surgical trajectories. Although not functionally linked, the relationship with the pars opercularis may offer an additional anatomical reference to avoid injury to adjacent eloquent areas, such as motor and language regions [ 2 , 4 ]. These data may also be valuable for mapping alterations in specific pathological conditions, including hydrocephalus, ventricular malformations, or infiltrative tumors. The study’s findings lay the groundwork for future investigations, such as analyzing these anatomical relationships in populations with specific pathologies or conditions that alter brain morphology. Additionally, the results may be integrated into surgical navigation systems, 3D anatomical guides, and educational atlases, enhancing both neurosurgical training and safety during intracranial procedures [ 1 6 ] . Despite its contributions, this study has limitations. The absence of detailed clinical data prevents direct correlation between the measured distances and neurological conditions. Moreover, the lack of comparative studies in the literature restricts external validation of the findings. Further research is needed to explore how these spatial relationships can be applied in more complex clinical scenarios. CONCLUSION This study demonstrated that the foramen of Monro is consistently positioned posterior, inferior, and medial to the pars opercularis, with significant bilateral variations—particularly in depth, where the right hemisphere exhibited a greater distance. These differences, combined with the topographical stability observed along the anteroposterior and superoinferior axes, highlight the importance of accounting for individual anatomical variability during neurosurgical procedures near the ventricular system. Additionally, the negative correlation between age and depth suggests that aging influences intracranial morphometry—an important consideration when planning surgeries in elderly patients. The findings of this study have direct implications for procedures requiring precise localization of the foramen of Monro, such as ventricular shunting and tumor resections, where detailed spatial orientation may enhance surgical safety. Furthermore, the data may be incorporated into 3D anatomical models, supporting neurosurgical training and the refinement of minimally invasive techniques. Future studies should explore the clinical applicability of these measurements in populations with specific pathologies, thereby broadening the impact of these findings on modern neurosurgical practice. Declarations CONFLICT OF INTEREST Not applicable. AUTHOR’s CONTRIBUTIONS Protocol development: Silva TDCS, Medeiros Neto EJF, Christino MG, Lima NMS, Monteiro AM, Brito JRN, Reghin Neto M and Correa ACS. Conception and design: Silva TDCS and Medeiros Neto EJF. Data collection: Silva TDCS, Medeiros Neto EJF, Christino MG, Lima NMS, Monteiro AM, Nascimento Neto AFC, Brito JRN, Reghin Neto M and Correa ACS. Data analysis: Figueiredo Filho LC and Correa ACS. Manuscript editing: Silva TDCS and Medeiros Neto EJF and Figueiredo Filho LC. Manuscript writing: Figueiredo Filho LC, Monteiro AM, Silva TDCS and Medeiros Neto EJF. DATA AVAILABILITY No datasets were generated or analysed during the current study. FUNDING Not applicable. ACKNOWLEDGEMENTS Not applicable. References Anagnostopoulou S, Mavridis I (2015) Stereotactic localization of the Monro foramen and the safest stereotactic interforniceal approach to the third ventricle: a neuroanatomical study. J Neurol Surg A Cent Eur Neurosurg 77:102–110. https://doi.org/10.1055/s-0035-1558406 Brusius CV, Bianchin MM, Mira JM, Frigeri T, Kruger M, Grudtner MC, Lenhardt R, Maschke S, Wolfsberger S (2021) Single burr-hole extended transforaminal approach for concurrent endoscopic surgery in the third ventricle posterior to the foramen of Monro and ventriculostomy: clinical series and planning steps. World Neurosurg 150:e1–e11. https://doi.org/10.1016/j.wneu.2021.01.067 Curley LB, Newman E, Thompson WK, Brown TT, Hagler DJ Jr, Akshoomoff N, Reuter C, Dale AM, Jernigan TL (2018) Cortical morphology of the pars opercularis and its relationship to motor-inhibitory performance in a longitudinal, developing cohort. Brain Struct Funct 223:211–220. https://doi.org/10.1007/s00429-017-1480-5 Duffau H (2012) The challenge to remove diffuse low-grade gliomas while preserving brain functions. Acta Neurochir (Wien) 154:569–574. https://doi.org/10.1007/s00701-012-1275-7 Egger J, Kapur T, Fedorov A, Pieper S, Miller JV, Veeraraghavan H, Freisleben B, Golby AJ, Nimsky C, Kikinis R (2013) GBM volumetry using the 3D Slicer medical image computing platform. Sci Rep 3. https://doi.org/10.1038/srep01364 Hoch MJ, Bruno MT, Faustin A, Cruz N, Mogilner AY, Crandall L, Wisniewski T, Devinsky O, Shepherd TM (2019) 3T MRI whole-brain microscopy discrimination of subcortical anatomy, part 2: basal forebrain. AJNR Am J Neuroradiol 40:1095–1105. https://doi.org/10.3174/ajnr.a6088 Jean WC, Tai AX, Hogan E, Herur-Raman A, Felbaum DR, Leonardo J, Syed HR (2019) An anatomical study of the foramen of Monro: implications in management of pineal tumors presenting with hydrocephalus. Acta Neurochir (Wien) 161:975–983. https://doi.org/10.1007/s00701-019-03887-4 Lawrence A, Carvajal M, Ormsby J (2023) Beyond Broca’s and Wernicke’s: functional mapping of ancillary language centers prior to brain tumor surgery. Tomography 9:1254–1275. https://doi.org/10.3390/tomography9040100 Lubben N, Ensink E, Coetzee GA, Labrie V (2021) The enigma and implications of brain hemispheric asymmetry in neurodegenerative diseases. Brain Commun 3:fcab211. https://doi.org/10.1093/braincomms/fcab211 Matys T, Brown FS, Zaccagna F, Kirollos RW, Massoud TF (2020) A critical appraisal of Monro’s erroneous description of the cerebral interventricular foramina: age-related magnetic resonance imaging spatial morphometry and a proposed new terminology. Clin Anat 33:446–457. https://doi.org/10.1002/ca.23560 Nardelli P, Jaeger A, O’Shea C, Khan KA, Kennedy MP, Cantillon-Murphy P (2017) Pre-clinical validation of virtual bronchoscopy using 3D Slicer. Int J Comput Assist Radiol Surg 12:25–38. https://doi.org/10.1007/s11548-016-1447-7 Oliveira RCE, Tinôco JDST, Delgado MF, Isadora ICA, Cícera CMBS, Ana Luisa ALBCL (2018) Estratégia educativa no ensino de anatomia humana aplicada à enfermagem. Av Enferm 36. https://doi.org/10.15446/av.enferm.v36n1.61034 Pereira KF, Santos FF, Minuzzo LG, Salles VER (2023) Dissecação anatômica como estratégia para o estudo do sistema neural em fetos humanos. Arq Ciênc Saúde UNIPAR 27. https://doi.org/10.25110/arqsaude.v27i1.2023.8919 Singh K, Bharatha A, Sa B, Adams OP, Majumder MAA (2019) Teaching anatomy using an active and engaging learning strategy. BMC Med Educ 19. https://doi.org/10.1186/s12909-019-1590-2 Sprung-Much T, Petrides M (2018) Morphological patterns and spatial probability maps of two defining sulci of the posterior ventrolateral frontal cortex of the human brain: the sulcus diagonalis and the anterior ascending ramus of the lateral fissure. Brain Struct Funct 223:4125–4152. https://doi.org/10.1007/s00429-018-1733-y Tawk RG, Akinduro OO, Grewal SS, Brasiliense L, Grand W, Grotenhuis A (2020) Endoscopic transforaminal transchoroidal approach to the third ventricle for cystic and solid tumors. World Neurosurg 134:e453–e459. https://doi.org/10.1016/j.wneu.2019.10.099 Tubbs RS, Oakes P, Maran IS, Salib C, Loukas M (2014) The foramen of Monro: a review of its anatomy, history, pathology, and surgery. Childs Nerv Syst 30:1645–1649. https://doi.org/10.1007/s00381-014-2512-6 Wang Y, Li Y, Shi H, Du Y, Guo W, Shi H, Qian T (2024) The value of multimodal imaging fusion in preoperative visualization assessment of neurovascular relationship in hemifacial spasm: a single-center retrospective study. Neurosurg Rev 47:605. https://doi.org/10.1007/s10143-024-02872-5 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 24 Feb, 2026 Read the published version in Surgical and Radiologic Anatomy → Version 1 posted Editorial decision: Revision requested 19 Sep, 2025 Reviews received at journal 04 Sep, 2025 Reviewers agreed at journal 01 Aug, 2025 Reviewers invited by journal 30 Jul, 2025 Editor assigned by journal 08 Jul, 2025 Submission checks completed at journal 07 Jul, 2025 First submitted to journal 06 Jul, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7060320","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":494117237,"identity":"bed9fcc4-630b-4435-bcdd-0e3a15392553","order_by":0,"name":"Teófilo Dorneles Claro dos Santos Silva","email":"","orcid":"","institution":"Ophir Loyola Hospital","correspondingAuthor":false,"prefix":"","firstName":"Teófilo","middleName":"Dorneles Claro dos Santos","lastName":"Silva","suffix":""},{"id":494117238,"identity":"ff8c198c-c0c6-4174-819f-adba6518735a","order_by":1,"name":"Esequiel José Felipe de Medeiros Neto","email":"","orcid":"","institution":"Ophir Loyola Hospital","correspondingAuthor":false,"prefix":"","firstName":"Esequiel","middleName":"José Felipe de Medeiros","lastName":"Neto","suffix":""},{"id":494117239,"identity":"dcd6aef8-17d3-4be8-9515-2f47bf62ae47","order_by":2,"name":"Luiz Carlos Figueiredo Filho","email":"data:image/png;base64,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","orcid":"","institution":"Pará State University","correspondingAuthor":true,"prefix":"","firstName":"Luiz","middleName":"Carlos Figueiredo","lastName":"Filho","suffix":""},{"id":494117241,"identity":"835fe7ea-71a3-4e47-b50f-161e7d7cce60","order_by":3,"name":"Matheus Gondim Christino","email":"","orcid":"","institution":"Ophir Loyola Hospital","correspondingAuthor":false,"prefix":"","firstName":"Matheus","middleName":"Gondim","lastName":"Christino","suffix":""},{"id":494117243,"identity":"2a0b1f61-eb55-41bd-afab-25b2bd78623a","order_by":4,"name":"Nelson Machado da Silva de Lima","email":"","orcid":"","institution":"Ophir Loyola Hospital","correspondingAuthor":false,"prefix":"","firstName":"Nelson","middleName":"Machado da Silva","lastName":"de Lima","suffix":""},{"id":494117246,"identity":"0576e627-dbf6-4e13-9280-5df55ac3a58c","order_by":5,"name":"Artur Francisco da Conceição Nascimento Neto","email":"","orcid":"","institution":"Ophir Loyola Hospital","correspondingAuthor":false,"prefix":"","firstName":"Artur","middleName":"Francisco da Conceição Nascimento","lastName":"Neto","suffix":""},{"id":494117247,"identity":"3d234d3d-4c9c-49eb-8581-49d7e08317df","order_by":6,"name":"Andrew Moraes Monteiro","email":"","orcid":"","institution":"Ophir Loyola Hospital","correspondingAuthor":false,"prefix":"","firstName":"Andrew","middleName":"Moraes","lastName":"Monteiro","suffix":""},{"id":494117248,"identity":"28563c31-a453-460e-855e-76f9a14049c3","order_by":7,"name":"José Reginaldo Nascimento Brito","email":"","orcid":"","institution":"Ophir Loyola Hospital","correspondingAuthor":false,"prefix":"","firstName":"José","middleName":"Reginaldo Nascimento","lastName":"Brito","suffix":""},{"id":494117250,"identity":"cdc67823-aad2-4fda-a0f1-bb17e4172c8c","order_by":8,"name":"Mateus Reghin Neto","email":"","orcid":"","institution":"Instituto de Assistência Médica ao Servidor Público Estadual","correspondingAuthor":false,"prefix":"","firstName":"Mateus","middleName":"Reghin","lastName":"Neto","suffix":""},{"id":494117252,"identity":"7b586eb3-78d4-4423-a6b9-a037193a12b9","order_by":9,"name":"Antônio Carlos de Souza Correa","email":"","orcid":"","institution":"Ophir Loyola Hospital","correspondingAuthor":false,"prefix":"","firstName":"Antônio","middleName":"Carlos de Souza","lastName":"Correa","suffix":""}],"badges":[],"createdAt":"2025-07-07 01:38:06","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7060320/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7060320/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s00276-026-03833-x","type":"published","date":"2026-02-24T15:58:23+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":88306566,"identity":"b53665a4-ebc0-4fbe-bfc9-ce51b7952578","added_by":"auto","created_at":"2025-08-05 06:06:02","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":489000,"visible":true,"origin":"","legend":"\u003cp\u003eDelineation of the \u003cem\u003epars opercularis\u003c/em\u003e using the 3D Slicer platform. A fiducial point was placed in the right hemisphere to mark the most inferior and immediately posterior aspect of the anterior ascending ramus of the lateral fissure, corresponding to the anatomical location of the \u003cem\u003epars opercularis\u003c/em\u003e. In panel (a), the point is shown in the axial plane; panel (b) provides a tridimensional reconstruction demonstrating its intersection across the axial, coronal, and sagittal planes; panel (c) shows the point in the coronal plane; and panel (d) depicts the sagittal view\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-7060320/v1/47bfcdeca080a2f1255268d4.png"},{"id":88306562,"identity":"44d098c9-111c-4882-b99a-18f333679b0a","added_by":"auto","created_at":"2025-08-05 06:06:02","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":488809,"visible":true,"origin":"","legend":"\u003cp\u003eSpatial projection of the foramen of Monro in 3D Slicer. A fiducial marker was placed in the right hemisphere to indicate the anatomical location of the foramen. Panel (a) shows the axial view, while panel (b) presents the tridimensional reconstruction intersected by the three standard planes, providing spatial confirmation of the point’s location. In panel (c), the coronal section demonstrates the marker at the interface between the fornicial column medially and the thalamus laterally. Panel (d) displays the sagittal plane, where the point aligns with the anterior end of the thalamic stria medullaris, confirming its placement at the anterior aspect of the third ventricle.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-7060320/v1/9af39983d1c77a216a01a375.png"},{"id":88306559,"identity":"c0077e35-bd4d-4311-b3f7-e65eed3005fb","added_by":"auto","created_at":"2025-08-05 06:06:02","extension":"jpeg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":27352,"visible":true,"origin":"","legend":"\u003cp\u003eThree-dimensional reconstruction between the Foramen of Monro and the Pars Opercularis. 3D visualization showing the spatial relationship between the Foramen of Monro and the Pars Opercularis, highlighting the distances measured and the axes used (lateral-lateral, antero-posterior and superior-inferior).\u003c/p\u003e","description":"","filename":"floatimage3.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7060320/v1/7eea3d352b37fa32cfaa349d.jpeg"},{"id":103765862,"identity":"9a150255-e0c3-4768-8c1d-342a7721d67a","added_by":"auto","created_at":"2026-03-02 16:10:39","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2145386,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7060320/v1/0b2b1826-e0e5-4dce-925f-f68f6f123d66.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003eCorrelation Between the Foramen of Monro and the Pars Opercularis: A Morphometric Analysis\u003c/p\u003e","fulltext":[{"header":"INTRODUCTION","content":"\u003cp\u003eHuman anatomy serves as the foundation of health sciences, providing an essential understanding of the structure and function of the human body while offering the necessary support for the diagnosis and treatment of pathological conditions. In the field of neuroanatomy, the study of intracranial structures\u0026nbsp;plays a pivotal role in planning neurosurgical interventions, particularly in eloquent areas where precision is crucial for preserving motor and cognitive functions [\u003cstrong\u003e12\u003c/strong\u003e,\u003cstrong\u003e3\u003c/strong\u003e].\u003c/p\u003e\n\u003cp\u003eAmong intracranial structures, the foramen of Monro and the \u003cem\u003epars opercularis\u003c/em\u003e of the inferior frontal gyrus play fundamental roles in both clinical and surgical contexts. The foramen of Monro is widely recognized as a key anatomical landmark in ventricular interventions, such as cerebrospinal fluid shunting and accessing the lateral or third ventricles for the treatment of hydrocephalus and intraventricular tumors [\u003cstrong\u003e13\u003c/strong\u003e,\u003cstrong\u003e17\u003c/strong\u003e] . On the other hand, the \u003cem\u003epars opercularis\u003c/em\u003e, located near motor and language-related areas, is of clinical interest due to its functional relevance and the challenges it presents during neurosurgical procedures, where its preservation is essential to prevent permanent deficits [\u003cstrong\u003e14\u003c/strong\u003e,\u003cstrong\u003e8\u003c/strong\u003e]\u003c/p\u003e\n\u003cp\u003eAlthough direct neurosurgical interventions connecting the foramen of Monro and the \u003cem\u003epars opercularis\u003c/em\u003e are uncommon, the spatial relationship between these structures has significant practical implications. A detailed topographic understanding of this relationship can facilitate the planning of safer surgical trajectories, particularly for lesions involving the inferior frontal gyrus or ventricular procedures requiring precise localization of eloquent structures. Furthermore, identifying reproducible anatomical patterns is essential for minimizing complications and optimizing clinical outcomes\u0026nbsp;[\u003cstrong\u003e7\u003c/strong\u003e].\u003c/p\u003e\n\u003cp\u003eDespite its clinical importance, the literature still lacks systematic studies analyzing the precise topographic correlation between the foramen of Monro and the \u003cem\u003epars opercularis\u003c/em\u003e using high-resolution magnetic resonance imaging (MRI). This data gap limits neurosurgeons' ability to plan interventions more safely in critical brain regions. Multiplanar MRI reconstructions have proven to be a powerful tool for exploring these relationships, enabling detailed morphometric analyses and recognizing individual variations that may directly impact neurosurgical practice [\u003cstrong\u003e1\u003c/strong\u003e,\u003cstrong\u003e1\u003c/strong\u003e\u003cstrong\u003e0\u003c/strong\u003e]\u003c/p\u003e\n\u003cp\u003eThis study aims to explore the morphometric relationship between foramen of Monro and \u003cem\u003epars opercularis\u003c/em\u003e using magnetic resonance imaging.\u003c/p\u003e"},{"header":"METHODOLOGY","content":"\u003cp\u003e\u003cstrong\u003eStudy Location and Desi\u003c/strong\u003e\u003cstrong\u003egn\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe present retrospective, cross-sectional, and observational study was conducted based on the analysis of imaging exams from patients treated by the neurosurgery team at Ophir Loyola Hospital (OLH), located in Bel\u0026eacute;m, Par\u0026aacute;, Brazil.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData Collection\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eData were collected from imaging exams available between January 2022 and December 2023, with organization and analysis carried out in October and November 2024. To be included in the study, MRI scans had to meet the following inclusion criteria: volumetric T1-weighted sequences, multislice volumetric studies, 1 mm slice thickness, and patients undergoing MRI due to suspected neurosurgical or neurological conditions such as hydrocephalus, brain tumors, or epilepsy. Exclusion criteria were based on incomplete or low-quality exams, as well as those showing significant anatomical alterations, including congenital malformations or extensive lesions.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAnatomical landmarks\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe analysis focused on measuring distances between two anatomical landmarks in both cerebral hemispheres: the foramen of Monro, clearly defined as the space located below and medial to the column of the fornix and the thalamus, and specific areas of the inferior frontal gyrus, with emphasis on the \u003cem\u003epars opercularis\u003c/em\u003e. The identification of these points was performed using 3D-reconstructed images processed with 3D Slicer software, version 4.11.20210226 (Brigham and Women\u0026rsquo;s Hospital - BWH). This software enabled multiplanar visualization of T1-weighted MRI images in sagittal, coronal, and axial planes.\u003c/p\u003e\n\u003cp\u003eThe software was configured to automatically detect structural margins using standardized and validated segmentation algorithms, including \u0026ldquo;GrowCut,\u0026rdquo; a region-growing algorithm based on competitive cellular automata, selected for its ability to handle complex margins and low-contrast tissues [\u003cstrong\u003e5\u003c/strong\u003e]. Additionally, the \u0026ldquo;Segment Editor\u0026rdquo; module was employed for manual adjustments of automatic markings, ensuring greater accuracy and reliability. The literature highlights 3D Slicer as a reliable tool for medical image segmentation and analysis. Studies such as Egger et al. (2013) [\u003cstrong\u003e1\u003c/strong\u003e\u003cstrong\u003e8\u003c/strong\u003e] validate its application in precise measurements, such as glioblastoma volumetry, demonstrating high reproducibility and accuracy. The combination of automatic algorithms like \u0026quot;GrowCut\u0026quot; with manual refinements enhances segmentation quality [\u003cstrong\u003e11\u003c/strong\u003e].\u003c/p\u003e\n\u003cp\u003eTo ensure accuracy in the markings, segmentations were reviewed by two independent specialists, who analyzed the delineations by comparing them with previously established standards in the literature and reference studies. For better visualization, an illustrative image highlighting anatomical locations and applied demarcations was included, as shown in Figures 1 and 2. The marking of anatomical landmarks followed the parameters established for each point, described as follows: the \u003cem\u003epars opercularis\u003c/em\u003e was identified from the first slice displaying visible gray matter in the caudal portion, immediately posterior to the ascending branch of the lateral sulcus, based on T1-weighted volumetric sagittal sequences, as illustrated in Figure 1. The foramen of Monro was determined in the coronal plane as the space immediately below and medial to the fornical column and the thalamus, and in the sagittal plane as the beginning of the medullary stria of the thalamus, as shown in Figure 2.\u003c/p\u003e\n\u003cp\u003eThe distances were measured considering the following axes: X (latero-lateral), from the center of the foramen of Monro to the lateralmost point of the pars opercularis; Y (antero-posterior), from the foramen of Monro to the anterior limit of the pars opercularis; and Z (supero-inferior or depth), from the foramen of Monro to the inferiormost extremity of the pars opercularis. The distance analysis was conducted based on the demarcations obtained from the software, ensuring precision and reproducibility of the measurements. A three-dimensional visualization demonstrating the spatial relationship between the two points was included to facilitate understanding, as illustrated in Figure 3.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStatistical Analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe distances between anatomical structures along the X, Y, and Z axes were automatically calculated by the 3D Slicer software and expressed in millimeters (mm). The generated data were exported for descriptive statistical analysis, including measures of central tendency (mean, median, and mode), dispersion measures (variance and standard deviation), and frequency distributions. These analyses were conducted using the BioEstat 5.0 software. Additionally, D\u0026rsquo;Agostino and Pearson normality tests were applied to assess data distribution. Results were considered statistically significant for \u003cem\u003ep\u003c/em\u003e-values\u0026nbsp;\u0026lt; 0.05.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthical Statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe study was approved by the Research Ethics Committee under protocol CAAE: 82368124.0.0000.5550, approval number 7.024.391. A waiver of the Informed Consent Form (ICF) was granted, given that the research was limited to the analysis of previously acquired radiological images for clinical purposes.\u003c/p\u003e"},{"header":"RESULTS","content":"\u003cp\u003eFollowing the application of exclusion criteria to a database of 216 patients who met the inclusion criteria, 90 samples (hemispheres) remained available for morphological analysis and comparative evaluation.\u003c/p\u003e\n\u003cp\u003eAs shown in Table 1, the mean distances between the pars opercularis and the foramen of Monro (POF) revealed that, along the anteroposterior axis, the pars opercularis was located an average of 9.96 mm anterior to the foramen of Monro, with a range from -10 mm to 21 mm. Along the superoinferior axis, the pars opercularis was positioned an average of 2.62 mm superior to the foramen of Monro, ranging from -10.84 mm to 49.88 mm, predominantly situated above the foramen. In terms of depth, the mean distance between the foramen of Monro and the pars opercularis was 43.54 mm, ranging from 35.98 mm to 53.75 mm. The direct linear distance between the two structures was estimated at 45.21 mm, with a range of 37.13 mm to 54.27 mm. Statistical analysis of the distributions indicated that the assumption of normality was not met, with a p-value \u0026lt; 0.05 for all examined variables.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 1\u003c/strong\u003e: Descriptive statistics of the distances between the Pars Opercularis and the Foramen of Monro.\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"605\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 162px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eResults\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 105px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePOF Z-Axis (Latero lateral)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 128px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePOF X-Axis (Anteroposterior)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 113px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePOF\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eY-Axis (Superoinferior)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eLinear Distance POF\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 162px;\"\u003e\n \u003cp\u003eSample Size\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 105px;\"\u003e\n \u003cp\u003e90\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 128px;\"\u003e\n \u003cp\u003e90\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 113px;\"\u003e\n \u003cp\u003e90\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e90\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 162px;\"\u003e\n \u003cp\u003eMinimum\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 105px;\"\u003e\n \u003cp\u003e35,983\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 128px;\"\u003e\n \u003cp\u003e-10,451\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 113px;\"\u003e\n \u003cp\u003e-10,847\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e37,137\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 162px;\"\u003e\n \u003cp\u003eMaximum\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 105px;\"\u003e\n \u003cp\u003e53,758\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 128px;\"\u003e\n \u003cp\u003e21,256\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 113px;\"\u003e\n \u003cp\u003e49,881\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e54,273\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 162px;\"\u003e\n \u003cp\u003eMean\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 105px;\"\u003e\n \u003cp\u003e43,5402\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 128px;\"\u003e\n \u003cp\u003e9,9613\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 113px;\"\u003e\n \u003cp\u003e2,6287\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e45,2121\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 162px;\"\u003e\n \u003cp\u003eVariance\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 105px;\"\u003e\n \u003cp\u003e12,977\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 128px;\"\u003e\n \u003cp\u003e29,2468\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 113px;\"\u003e\n \u003cp\u003e42,7554\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e12,1007\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 162px;\"\u003e\n \u003cp\u003eStandard Deviation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 105px;\"\u003e\n \u003cp\u003e3,6024\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 128px;\"\u003e\n \u003cp\u003e5,408\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 113px;\"\u003e\n \u003cp\u003e6,5388\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 98px;\"\u003e\n \u003cp\u003e3,4786\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003eLegend:\u003c/strong\u003e POF (Distance from Pars Opercularis to the Foramen of Monro)\u003c/p\u003e\n\u003cp\u003eThe projection of the pars opercularis and the foramen of Monro onto the Cartesian plane revealed statistically significant differences in their spatial distribution along both the X and Y axes, as shown in Table 2. On the X-axis, the mean distance to the foramen of Monro was 32.12 mm, while the mean distance to the pars opercularis was 42.12 mm (p \u0026lt; 0.0001). On the Y-axis, the means were 36.40 mm for the foramen and 39.03 mm for the pars opercularis (p \u0026lt; 0.0001). The 99% confidence interval demonstrated that the foramen of Monro was consistently located posterior to the pars opercularis, with a variation from -11.47 mm to -8.44 mm. Although the two points did not occupy equivalent positions, a safe distance was consistently maintained between them, with the foramen of Monro located, on average, between 4 mm and -0.8 mm below the pars opercularis.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 2:\u0026nbsp;\u003c/strong\u003eMorphological Reference on the X and Y Axes between the Foramen of Monro and the Opercular Gyrus.\u003c/p\u003e\n\u003cdiv\u003e\n \u003ctable class=\"MsoNormalTable\" border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"605\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 144px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cstrong\u003e\u003cspan lang=\"EN-US\"\u003eForamen of Monro\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cstrong\u003e\u003cspan lang=\"EN-US\"\u003eX-Axis\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cstrong\u003e\u003cspan lang=\"EN-US\"\u003e(Anteroposterior)\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 127px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cstrong\u003e\u003cspan lang=\"EN-US\"\u003ePars Opercular\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cstrong\u003e\u003cspan lang=\"EN-US\"\u003eX-Axis\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cstrong\u003e\u003cspan lang=\"EN-US\"\u003e(Anteroposterior)\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 116px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cstrong\u003e\u003cspan lang=\"EN-US\"\u003eForamen of Monro Y-Axis\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cstrong\u003e\u003cspan lang=\"EN-US\"\u003e(Superoinferior)\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 125px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cstrong\u003e\u003cspan lang=\"EN-US\"\u003ePars Opercular\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cstrong\u003e\u003cspan lang=\"EN-US\"\u003eY-Axis (Superoinferior)\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003eIndividuals\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 144px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e90\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 127px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e90\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 116px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e90\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 125px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e90\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003eMean\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 144px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e32,1622\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 127px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e42,1235\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 116px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e36,4069\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 125px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e39,0355\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003eStandard Deviation\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 144px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e9,0188\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 127px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e9,4994\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 116px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e17,2144\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 125px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e16,7244\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003eMean of Differences\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 144px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e-9,9613\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 127px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e---\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 116px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e-2,6287\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 125px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e---\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e(p) one-tailed\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 144px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e\u0026lt; 0.0001\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 127px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e---\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 116px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e\u0026lt; 0.0001\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 125px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e---\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e(p) two-tailed\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 144px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e\u0026lt; 0.0001\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 127px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e---\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 116px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e\u0026lt; 0.0001\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 125px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e---\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003eCI (95%)\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 144px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e-11.0986 to - 8.8241\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 127px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e---\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 116px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e-4.0037 to - 1.2536\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 125px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e---\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003eCI (99%)\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 144px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e-11.4735 to -8.4492\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 127px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e---\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 116px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e-4.4570 to - 0.8004\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 125px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e---\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e\u003cstrong\u003eLegenda\u003c/strong\u003e: CI (Confidence interval).\u003c/p\u003e\n\u003cp\u003eDepth exhibited a statistically significant difference between hemispheres, with a mean of 42.35 mm on the left side and 44.73 mm on the right. The t-test yielded t = -3.9045 and a two-tailed p-value \u0026lt; 0.0001, indicating that depth was significantly lower on the left (99% CI: -4.02 to -0.74 mm), as shown in Table 3. In addition to depth, the total linear distance between the foramen of Monro and the operculum also differed significantly between hemispheres. The mean linear distance was 43.90 mm on the left and 46.52 mm on the right, indicating a greater separation on the right side (Table 4).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 3:\u0026nbsp;\u003c/strong\u003eDepth Comparison Between Left and Right Sides for the Foramen of Monro and the Opercular Gyrus.\u003c/p\u003e\n\u003cdiv\u003e\n \u003ctable class=\"MsoNormalTable\" border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"613\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" style=\"width: 138px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 162px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cstrong\u003e\u003cspan lang=\"EN-US\"\u003ePOF Z-Axis\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cstrong\u003e\u003cspan lang=\"EN-US\"\u003e(Laterolateral)\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 159px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cstrong\u003e\u003cspan lang=\"EN-US\"\u003ePOF X-Axis\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cstrong\u003e\u003cspan lang=\"EN-US\"\u003e(Anteroposterior)\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 154px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cstrong\u003e\u003cspan lang=\"EN-US\"\u003ePOF Y-Axis\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cstrong\u003e\u003cspan lang=\"EN-US\"\u003e(Superoinferior)\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003eL\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 65px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003eR\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003eL\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 65px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003eR\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003eL\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003eR\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 138px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003eIndividuals\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e45\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 65px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e45\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e45\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 65px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e45\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e45\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e45\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 138px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003eMean\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e42,3498\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 65px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e44,7306\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e9,4174\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 65px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e10,5053\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e3,6332\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e1,6241\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 138px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003eMean of Differences\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e-2,3808\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 65px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e---\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e-1,0879\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 65px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e---\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e2,0091\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e---\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 138px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e(t)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e-3,9045\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 65px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e---\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e-1,225\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 65px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e---\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e1,5613\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e---\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 138px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e(p) one-tailed\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e\u0026lt; 0.0001\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 65px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e---\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e0,1135\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 65px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e---\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e0,0628\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e---\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 138px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e(p) two-tailed\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e\u0026lt; 0.0001\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 65px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e---\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e0,227\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 65px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e---\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e0,1255\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e---\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 138px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003eCI (95%)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e-3.6093 to - 1.1523\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 65px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e---\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e-2.8771 to 0.7014\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 65px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e---\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e-0.5836 to 4.6019\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e---\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 138px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003eCI (99%)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e-4.0215 to - 0.7401\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 65px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e---\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e-3.4773 to 1.3016\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 65px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e---\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e-1.4533 to 5.4716\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e---\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e\u003cstrong\u003eLegend:\u0026nbsp;\u003c/strong\u003ePOF (Distance from Pars Opercularis to the Foramen of Monro), CI (Confidence Interval), L (Left), R (Right)..\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 4\u003c/strong\u003e: Linear Distance Comparison Between Left and Right Sides for the Foramen of Monro and the Pars Opercularis.\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"605\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"3\" style=\"width: 605px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eLinear Distance POF\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 221px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 193px;\"\u003e\n \u003cp\u003eLeft\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 191px;\"\u003e\n \u003cp\u003eRight\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 221px;\"\u003e\n \u003cp\u003eIndividuals\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 193px;\"\u003e\n \u003cp\u003e45\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 191px;\"\u003e\n \u003cp\u003e45\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 221px;\"\u003e\n \u003cp\u003eMean\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 193px;\"\u003e\n \u003cp\u003e43,9002\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 191px;\"\u003e\n \u003cp\u003e46,5241\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 221px;\"\u003e\n \u003cp\u003eMean of Differences\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 193px;\"\u003e\n \u003cp\u003e-2,624\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 191px;\"\u003e\n \u003cp\u003e---\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 221px;\"\u003e\n \u003cp\u003e(t)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 193px;\"\u003e\n \u003cp\u003e-4,2508\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 191px;\"\u003e\n \u003cp\u003e---\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 221px;\"\u003e\n \u003cp\u003e(p) one-tailed\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 193px;\"\u003e\n \u003cp\u003e\u0026lt; 0.0001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 191px;\"\u003e\n \u003cp\u003e---\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 221px;\"\u003e\n \u003cp\u003e(p) two-tailed\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 193px;\"\u003e\n \u003cp\u003e\u0026lt; 0.0001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 191px;\"\u003e\n \u003cp\u003e---\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 221px;\"\u003e\n \u003cp\u003eCI (95%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 193px;\"\u003e\n \u003cp\u003e-3.8677 a - 1.3803\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 191px;\"\u003e\n \u003cp\u003e---\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 221px;\"\u003e\n \u003cp\u003eCI (99%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 193px;\"\u003e\n \u003cp\u003e-4.2849 a - 0.9631\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 191px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003eLegend:\u0026nbsp;\u003c/strong\u003ePOF (Distance from Pars Opercularis to the Foramen of Monro), CI (Confidence Interval).\u003c/p\u003e\n\u003cp\u003eAlong the anteroposterior axis, the difference between sides was not statistically significant (p = 0.227), with means of 9.42 mm on the left and 10.51 mm on the right. The 99% confidence interval for the difference between sides ranged from -3.48 mm to 1.30 mm, suggesting only minor variation without statistical significance.\u003c/p\u003e\n\u003cp\u003eOn the superoinferior axis, the mean distance was slightly greater on the left (3.63 mm) than on the right (1.62 mm); however, this difference was also not statistically significant (two-tailed p = 0.1255; 99% CI: -1.45 to 5.47 mm).\u003c/p\u003e\n\u003cp\u003ePatient age did not significantly influence most of the distances analyzed. Only the Z-axis (depth) distance showed a moderate negative correlation with age (Pearson\u0026apos;s r = -0.4326, p \u0026lt; 0.0001), indicating a progressive decrease in the distance between the structures with increasing age. Distances along the other axes showed minimal variation with age, with Pearson\u0026apos;s coefficients of -0.0805 (p = 0.5015) for the anteroposterior axis and -0.0579 (p = 0.6289) for the superoinferior axis. However, age had a final significant effect on the linear distance between the structures, as shown in Table 5.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 5:\u0026nbsp;\u003c/strong\u003ePearson Correlation Between Patient Age and Distances on the X, Y, and Z Axes.\u003c/p\u003e\n\u003cdiv\u003e\n \u003ctable class=\"MsoNormalTable\" border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"605\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 95px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cstrong\u003e\u003cspan lang=\"EN-US\"\u003eResults\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 129px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cstrong\u003e\u003cspan lang=\"EN-US\"\u003ePOF Z-Axis (Latero lateral)\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 144px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cstrong\u003e\u003cspan lang=\"EN-US\"\u003ePOF X-Axis (Anteroposterior)\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 133px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cstrong\u003e\u003cspan lang=\"EN-US\"\u003ePOF\u0026nbsp;\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cstrong\u003e\u003cspan lang=\"EN-US\"\u003eY-Axis (Superoinferior)\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 104px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cstrong\u003e\u003cspan lang=\"EN-US\"\u003eLinear Distance POF\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 95px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003eN\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 129px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e90\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 144px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e90\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 133px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e90\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 104px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e90\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 95px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003er (Pearson)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 129px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e-0,0747\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 144px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e-0,0892\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 133px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e0,166\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 104px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e-0,0718\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 95px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003eCI 95%\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 129px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e-0.28 a 0.13\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 144px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e-0.29 a 0.12\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 133px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e-0.04 a 0.36\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 104px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e-0.27 a 0.14\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 95px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003eCI 99%\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 129px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e-0.34 a 0.20\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 144px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e-0.35 a 0.19\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 133px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e-0.11 a 0.42\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 104px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e-0.34 a 0.20\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 95px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e(p)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 129px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e0,4841\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 144px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e0,4031\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 133px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e0,1178\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 104px;\"\u003e\n \u003cp class=\"MsoNormal\" align=\"center\"\u003e\u003cspan lang=\"EN-US\"\u003e0,501\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e\u003cstrong\u003eLegenda\u003c/strong\u003e: POF (Distance from Pars Opercularis to the Foramen of Monro), CI (Confidence Interval).\u0026nbsp;\u003c/p\u003e"},{"header":"DISCUSSION","content":"\u003cp\u003eThis study examined the anatomical relationships between the foramen of Monro and the pars opercularis, providing precise measurements that underscore the relevance of these structures in neurosurgical planning\u003cstrong\u003e.\u003c/strong\u003e Although a direct connection between these areas is neither practical nor functional, the analysis of their spatial orientation yields valuable data for neuroanatomical understanding and surgical approaches to adjacent regions [\u003cstrong\u003e1\u003c/strong\u003e,\u003cstrong\u003e1\u003c/strong\u003e\u003cstrong\u003e5\u003c/strong\u003e].\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe analyses revealed that, along the anteroposterior axis, the pars opercularis is, on average, 9.96 mm anterior to the foramen of Monro, with variations ranging from -10 mm to 21 mm. This distance reflects relative anterior plane stability, which may be relevant in surgeries involving lesions affecting the ventricular regions or the inferior frontal gyrus [\u003cstrong\u003e1\u003c/strong\u003e\u003cstrong\u003e5\u003c/strong\u003e]. On the superoinferior axis, the mean position of the pars opercularis was 2.62 mm superior to the foramen of Monro (range: -10.84 mm to 49.88 mm), indicating that the pars opercularis is predominantly located above the foramen, although individual variability is substantial. The mean depth (Z-axis) was 43.54 mm, ranging from 35.98 mm to 53.75 mm, and the direct linear distance between the two structures was estimated at 45.21 mm. These values serve as consistent quantitative parameters for anatomical modeling and may aid in delineating critical areas during surgical approaches.\u003c/p\u003e\n\u003cp\u003eOne of the most notable findings was the depth asymmetry between hemispheres, with the right side exhibiting a greater mean distance (44.73 mm) compared to the left (42.35 mm), as shown in Table 3. This anatomical asymmetry may reflect widely documented cerebral lateralization differences [\u003cstrong\u003e6\u003c/strong\u003e,\u003cstrong\u003e9\u003c/strong\u003e]. However, no statistically significant differences were found between sides along the anteroposterior and superoinferior axes, suggesting greater topographical consistency in these planes.\u003c/p\u003e\n\u003cp\u003eFurthermore, a moderate negative correlation was observed between age and depth (Pearson’s r = -0.4326, p \u0026lt; 0.0001), indicating a progressive reduction in distance with advancing age. This change may reflect age-related cerebral atrophy, which should be considered when planning procedures in older populations\u0026nbsp;[\u003cstrong\u003e9\u003c/strong\u003e]. In contrast, variables such as sex did not significantly influence the measured distances.\u003c/p\u003e\n\u003cp\u003eThe identified spatial orientation has potential applications in various clinical contexts. In ventricular procedures, such as cerebrospinal fluid shunting or endoscopic resection of intraventricular tumors, the foramen of Monro serves as a critical landmark to guide surgical trajectories. Although not functionally linked, the relationship with the pars opercularis may offer an additional anatomical reference to avoid injury to adjacent eloquent areas, such as motor and language regions [\u003cstrong\u003e2\u003c/strong\u003e,\u003cstrong\u003e4\u003c/strong\u003e]. These data may also be valuable for mapping alterations in specific pathological conditions, including hydrocephalus, ventricular malformations, or infiltrative tumors.\u003c/p\u003e\n\u003cp\u003eThe study’s findings lay the groundwork for future investigations, such as analyzing these anatomical relationships in populations with specific pathologies or conditions that alter brain morphology. Additionally, the results may be integrated into surgical navigation systems, 3D anatomical guides, and educational atlases, enhancing both neurosurgical training and safety during intracranial procedures [\u003cstrong\u003e1\u003c/strong\u003e\u003cstrong\u003e6\u003c/strong\u003e] .\u003c/p\u003e\n\u003cp\u003eDespite its contributions, this study has limitations. The absence of detailed clinical data prevents direct correlation between the measured distances and neurological conditions. Moreover, the lack of comparative studies in the literature restricts external validation of the findings. Further research is needed to explore how these spatial relationships can be applied in more complex clinical scenarios.\u003c/p\u003e"},{"header":"CONCLUSION","content":"\u003cp\u003eThis study demonstrated that the foramen of Monro is consistently positioned posterior, inferior, and medial to the pars opercularis, with significant bilateral variations—particularly in depth, where the right hemisphere exhibited a greater distance. These differences, combined with the topographical stability observed along the anteroposterior and superoinferior axes, highlight the importance of accounting for individual anatomical variability during neurosurgical procedures near the ventricular system. Additionally, the negative correlation between age and depth suggests that aging influences intracranial morphometry—an important consideration when planning surgeries in elderly patients.\u003c/p\u003e\n\u003cp\u003eThe findings of this study have direct implications for procedures requiring precise localization of the foramen of Monro, such as ventricular shunting and tumor resections, where detailed spatial orientation may enhance surgical safety. Furthermore, the data may be incorporated into 3D anatomical models, supporting neurosurgical training and the refinement of minimally invasive techniques. Future studies should explore the clinical applicability of these measurements in populations with specific pathologies, thereby broadening the impact of these findings on modern neurosurgical practice.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eCONFLICT OF INTEREST\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAUTHOR’s CONTRIBUTIONS\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eProtocol development:\u003c/strong\u003e Silva TDCS, Medeiros Neto EJF, Christino MG, Lima NMS, Monteiro AM, Brito JRN, Reghin Neto M and Correa ACS. \u003cstrong\u003eConception and design:\u003c/strong\u003e Silva TDCS and Medeiros Neto EJF. \u003cstrong\u003eData collection:\u003c/strong\u003e Silva TDCS, Medeiros Neto EJF, Christino MG, Lima NMS, Monteiro AM, Nascimento Neto AFC, Brito JRN, Reghin Neto M and Correa ACS. \u003cstrong\u003eData analysis:\u003c/strong\u003e Figueiredo Filho LC and Correa ACS. \u003cstrong\u003eManuscript editing:\u003c/strong\u003e Silva TDCS and Medeiros Neto EJF and Figueiredo Filho LC. \u003cstrong\u003eManuscript writing:\u003c/strong\u003e Figueiredo Filho LC, Monteiro AM, Silva TDCS and Medeiros Neto EJF.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDATA AVAILABILITY\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNo datasets were generated or analysed during the current study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFUNDING\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eACKNOWLEDGEMENTS\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eAnagnostopoulou S, Mavridis I (2015) Stereotactic localization of the Monro foramen and the safest stereotactic interforniceal approach to the third ventricle: a neuroanatomical study. J Neurol Surg A Cent Eur Neurosurg 77:102\u0026ndash;110. https://doi.org/10.1055/s-0035-1558406\u003c/li\u003e\n\u003cli\u003eBrusius CV, Bianchin MM, Mira JM, Frigeri T, Kruger M, Grudtner MC, Lenhardt R, Maschke S, Wolfsberger S (2021) Single burr-hole extended transforaminal approach for concurrent endoscopic surgery in the third ventricle posterior to the foramen of Monro and ventriculostomy: clinical series and planning steps. World Neurosurg 150:e1\u0026ndash;e11. https://doi.org/10.1016/j.wneu.2021.01.067\u003c/li\u003e\n\u003cli\u003eCurley LB, Newman E, Thompson WK, Brown TT, Hagler DJ Jr, Akshoomoff N, Reuter C, Dale AM, Jernigan TL (2018) Cortical morphology of the pars opercularis and its relationship to motor-inhibitory performance in a longitudinal, developing cohort. Brain Struct Funct 223:211\u0026ndash;220. https://doi.org/10.1007/s00429-017-1480-5\u003c/li\u003e\n\u003cli\u003eDuffau H (2012) The challenge to remove diffuse low-grade gliomas while preserving brain functions. Acta Neurochir (Wien) 154:569\u0026ndash;574. https://doi.org/10.1007/s00701-012-1275-7\u003c/li\u003e\n\u003cli\u003eEgger J, Kapur T, Fedorov A, Pieper S, Miller JV, Veeraraghavan H, Freisleben B, Golby AJ, Nimsky C, Kikinis R (2013) GBM volumetry using the 3D Slicer medical image computing platform. Sci Rep 3. https://doi.org/10.1038/srep01364\u003c/li\u003e\n\u003cli\u003eHoch MJ, Bruno MT, Faustin A, Cruz N, Mogilner AY, Crandall L, Wisniewski T, Devinsky O, Shepherd TM (2019) 3T MRI whole-brain microscopy discrimination of subcortical anatomy, part 2: basal forebrain. AJNR Am J Neuroradiol 40:1095\u0026ndash;1105. https://doi.org/10.3174/ajnr.a6088\u003c/li\u003e\n\u003cli\u003eJean WC, Tai AX, Hogan E, Herur-Raman A, Felbaum DR, Leonardo J, Syed HR (2019) An anatomical study of the foramen of Monro: implications in management of pineal tumors presenting with hydrocephalus. Acta Neurochir (Wien) 161:975\u0026ndash;983. https://doi.org/10.1007/s00701-019-03887-4\u003c/li\u003e\n\u003cli\u003eLawrence A, Carvajal M, Ormsby J (2023) Beyond Broca\u0026rsquo;s and Wernicke\u0026rsquo;s: functional mapping of ancillary language centers prior to brain tumor surgery. Tomography 9:1254\u0026ndash;1275. https://doi.org/10.3390/tomography9040100\u003c/li\u003e\n\u003cli\u003eLubben N, Ensink E, Coetzee GA, Labrie V (2021) The enigma and implications of brain hemispheric asymmetry in neurodegenerative diseases. Brain Commun 3:fcab211. https://doi.org/10.1093/braincomms/fcab211\u003c/li\u003e\n\u003cli\u003eMatys T, Brown FS, Zaccagna F, Kirollos RW, Massoud TF (2020) A critical appraisal of Monro\u0026rsquo;s erroneous description of the cerebral interventricular foramina: age-related magnetic resonance imaging spatial morphometry and a proposed new terminology. Clin Anat 33:446\u0026ndash;457. https://doi.org/10.1002/ca.23560\u003c/li\u003e\n\u003cli\u003eNardelli P, Jaeger A, O\u0026rsquo;Shea C, Khan KA, Kennedy MP, Cantillon-Murphy P (2017) Pre-clinical validation of virtual bronchoscopy using 3D Slicer. Int J Comput Assist Radiol Surg 12:25\u0026ndash;38. https://doi.org/10.1007/s11548-016-1447-7\u003c/li\u003e\n\u003cli\u003eOliveira RCE, Tin\u0026ocirc;co JDST, Delgado MF, Isadora ICA, C\u0026iacute;cera CMBS, Ana Luisa ALBCL (2018) Estrat\u0026eacute;gia educativa no ensino de anatomia humana aplicada \u0026agrave; enfermagem. Av Enferm 36. https://doi.org/10.15446/av.enferm.v36n1.61034\u003c/li\u003e\n\u003cli\u003ePereira KF, Santos FF, Minuzzo LG, Salles VER (2023) Disseca\u0026ccedil;\u0026atilde;o anat\u0026ocirc;mica como estrat\u0026eacute;gia para o estudo do sistema neural em fetos humanos. Arq Ci\u0026ecirc;nc Sa\u0026uacute;de UNIPAR 27. https://doi.org/10.25110/arqsaude.v27i1.2023.8919\u003c/li\u003e\n\u003cli\u003eSingh K, Bharatha A, Sa B, Adams OP, Majumder MAA (2019) Teaching anatomy using an active and engaging learning strategy. BMC Med Educ 19. https://doi.org/10.1186/s12909-019-1590-2\u003c/li\u003e\n\u003cli\u003eSprung-Much T, Petrides M (2018) Morphological patterns and spatial probability maps of two defining sulci of the posterior ventrolateral frontal cortex of the human brain: the sulcus diagonalis and the anterior ascending ramus of the lateral fissure. Brain Struct Funct 223:4125\u0026ndash;4152. https://doi.org/10.1007/s00429-018-1733-y\u003c/li\u003e\n\u003cli\u003eTawk RG, Akinduro OO, Grewal SS, Brasiliense L, Grand W, Grotenhuis A (2020) Endoscopic transforaminal transchoroidal approach to the third ventricle for cystic and solid tumors. World Neurosurg 134:e453\u0026ndash;e459. https://doi.org/10.1016/j.wneu.2019.10.099\u003c/li\u003e\n\u003cli\u003eTubbs RS, Oakes P, Maran IS, Salib C, Loukas M (2014) The foramen of Monro: a review of its anatomy, history, pathology, and surgery. Childs Nerv Syst 30:1645\u0026ndash;1649. https://doi.org/10.1007/s00381-014-2512-6\u003c/li\u003e\n\u003cli\u003eWang Y, Li Y, Shi H, Du Y, Guo W, Shi H, Qian T (2024) The value of multimodal imaging fusion in preoperative visualization assessment of neurovascular relationship in hemifacial spasm: a single-center retrospective study. Neurosurg Rev 47:605. https://doi.org/10.1007/s10143-024-02872-5\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"surgical-and-radiologic-anatomy","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"sara","sideBox":"Learn more about [Surgical and Radiologic Anatomy](http://link.springer.com/journal/276)","snPcode":"276","submissionUrl":"https://submission.nature.com/new-submission/276/3","title":"Surgical and Radiologic Anatomy","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Foramen of Monro, Pars Opercularis, Neuroanatomy, Neuroimaging, Brain Morphology, Neurosurgical Planning","lastPublishedDoi":"10.21203/rs.3.rs-7060320/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7060320/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003ePurpose\u003c/strong\u003e: To evaluate morphometric correlation between the foramen of Monro and pars opercularis through MRI.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods\u003c/strong\u003e: This retrospective, cross-sectional, and observational study analyzed 90 cerebral hemispheres from patients treated at Ophir Loyola Hospital. Volumetric T1-weighted MRI sequences (1-mm slices) were processed in 3D Slicer. Distances between the Foramen of Monro and \u003cem\u003ePars Opercularis\u003c/em\u003e were measured along the X (mediolateral), Y (anteroposterior), and Z (superoinferior) axes. Pearson’s correlation and t-tests were applied for statistical analysis.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults\u003c/strong\u003e: The \u003cem\u003ePars Opercularis\u003c/em\u003e was predominantly anterior (9.96 mm) and superior (2.62 mm) to the Foramen of Monro, with a mean linear distance of 45.21 mm. Significant lateral differences were observed: the right hemisphere exhibited a greater linear distance (46.52 mm) than the left (43.90 mm). Age showed a moderate negative correlation exclusively in depth (Z-axis), indicating progressive reduction in this measurement over time.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion\u003c/strong\u003e: The Foramen of Monro maintains a consistent spatial relationship with the \u003cem\u003ePars Opercularis\u003c/em\u003e, with stable positioning and subtle hemispheric differences. These findings refine anatomical knowledge and contribute to neurosurgical planning, particularly in procedures requiring precise anatomical references, such as ventricular surgeries and resections near eloquent cortical areas.\u003c/p\u003e","manuscriptTitle":"Correlation Between the Foramen of Monro and the Pars Opercularis: A Morphometric Analysis","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-08-05 06:05:57","doi":"10.21203/rs.3.rs-7060320/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-09-19T08:37:57+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-09-04T09:02:35+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"61340955004207442060711159528305554173","date":"2025-08-01T06:47:23+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-07-30T06:21:06+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-07-08T06:43:34+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-07-07T14:55:05+00:00","index":"","fulltext":""},{"type":"submitted","content":"Surgical and Radiologic Anatomy","date":"2025-07-07T01:26:09+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"surgical-and-radiologic-anatomy","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"sara","sideBox":"Learn more about [Surgical and Radiologic Anatomy](http://link.springer.com/journal/276)","snPcode":"276","submissionUrl":"https://submission.nature.com/new-submission/276/3","title":"Surgical and Radiologic Anatomy","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"ed422aee-a241-4340-98ff-f0673e14c645","owner":[],"postedDate":"August 5th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2026-03-02T16:07:47+00:00","versionOfRecord":{"articleIdentity":"rs-7060320","link":"https://doi.org/10.1007/s00276-026-03833-x","journal":{"identity":"surgical-and-radiologic-anatomy","isVorOnly":false,"title":"Surgical and Radiologic Anatomy"},"publishedOn":"2026-02-24 15:58:23","publishedOnDateReadable":"February 24th, 2026"},"versionCreatedAt":"2025-08-05 06:05:57","video":"","vorDoi":"10.1007/s00276-026-03833-x","vorDoiUrl":"https://doi.org/10.1007/s00276-026-03833-x","workflowStages":[]},"version":"v1","identity":"rs-7060320","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7060320","identity":"rs-7060320","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}