THE FORNIX OF THE HUMAN BRAIN - EVIDENCE OF LEFT RIGHT ASYMMETRY ON AXIAL MRI SCANS/

This article reports the observation that there is a left/right asymme try of the anterior columns of the fornix in the human brain. This asy mmetry is present in the position of the two columns of the fornix in relation to the septum pellucidum. The left columna fornicis was found to be located caudal to the right, and this can be readily visualized on axial MRI scans. This difference was seen in most of the subjects, but in some subjects there was no left/right-difference and in a few the asymmetry was inverse. The asymmetry of the fornix with respect to the anterior-posterior axis was independent of the well-known dissimi lar lateral ventricular volumes. However, the left/right difference in the position of the fornix was evident in subjects with or without di fferences in ventricular volumes. This suggests that the mechanism und erlying the development of asymmetry of the fornix is independent of t he mechanism leading to ventricular asymmetry. So far, no functional r elevance has been ascribed to such differences in location. The findin g is gaining interest in connection with recent reports of asymmetries in hippocampal subfields. Studies of fornical lesions should therefor e give attention to possible side-to-side differences.