A Cadaveric Study of Anatomical Variations in the Limbic System

PURPOSE The limbic system is a collection of brain structures responsible for affective processing, spatial coding, and certain types of memory. A comprehensive investigation of numerous limbic system components is necessary to thoroughly understand anatomical and pathological differences in individuals with related disorders (e.g., Alzheimer’s, depression, etc.). This study examines anatomical variations of limbic system structures including the hippocampus, dentate gyrus, amygdala, and cingulate gyrus. METHODS This cadaveric study includes the dissection of 47 formalin-fixed brain hemispheres and measurements of pertinent structures. The dentate gyrus, hippocampus, and amygdala were given categorical results: ill-defined, moderately defined, and well-defined; additionally, quantitative measurements were taken for all structures. RESULTS Our results indicate variations in the classification of the dentate gyrus (36% well-defined, 51% moderately defined, and 13% ill-defined) and amygdala (58% well-defined, 40% moderately defined, and 2% ill-defined). All hippocampus samples were well-defined (100%). CONCLUSION The knowledge of typical anatomy and morphology furthers our understanding of the limbic system and could be used to better understand clinical presentations. Future studies may be able to link anatomical variations and any potential relationships reported in this study to observed behavior. In summary, a thorough understanding of these variations will be useful for diagnostic purposes and future research.