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

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.