Localization of hand sensory function to the pli de passage moyen of Broca

Object. The goal of this study was to identify a reliable landmark for hand sensory function in the central area. Methods. Hand sensory activation on positron emission tomography (PET) scans was analyzed in 27 patients. Each PET study was coregistered with the patient's magnetic resonance image and analyzed in two-dimensional and three-dimensional cortical surface reconstructions to define anatomicofunctional relationships. Conclusions. The substratum of hand sensory function is a prominent fold of cortex elevating the floor of the central sulcus and connecting the pre- and postcentral gyri. Broca named this cortical fold the pli de passage moyen, and hand motor function has been localized to the precentral component of this structure. In this study the authors demonstrate that hand sensory function is highly correlated with the postcentral component of the pli de passage moyen, and that this structure is a reliable cortical landmark for identifying the aforementioned function.