Three-Dimensional Topographic Fiber Tract Anatomy of the Cerebrum

BACKGROUND: The fiber tracts of the cerebrum may be a more important determinant of resection limits than the cortex. Better knowledge of the 3-dimensional (3-D) anatomic organization of the fiber pathways is important in planning safe and accurate surgery for lesions within the cerebrum. OBJECTIVE: To examine the topographic anatomy of fiber tracts and subcortical gray matter of the human cerebrum and their relationships with consistent cortical, ventricular, and nuclear landmarks. METHODS: Twenty-five formalin-fixed human brains and 4 whole cadaveric heads were examined by fiber dissection technique and x6 to x40 magnification. The fiber tracts and central core structures, including the insula and basal ganglia, were examined and their relationships captured in 3-D photography. The depth between the surface of the cortical gyri and selected fiber tracts was measured. RESULTS: The topographic relationships of the important association, projection, and commissural fasciculi within the cerebrum and superficial cortical landmarks were identified. Important landmarks with consistent relationships to the fiber tracts were the cortical gyri and sulci, limiting sulci of the insula, nuclear masses in the central core, and lateral ventricles. The fiber tracts were also organized in a consistent pattern in relation to each other. The anatomic findings are briefly compared with functional data from clinicoradiological analysis and intraoperative stimulation of fiber tracts. CONCLUSION: An understanding of the 3-D anatomic organization of the fiber tracts of the brain is essential in planning safe and accurate cerebral surgery.