Papez circuit: An anatomical study by cadaveric dissection

ABSTRACT

This study was done to completely the Papez circuit by cadaveric dissection and it's relation to ventricles and other related anatomical structures. Eight formalin fixed cerebral hemispheres were microscopically dissected for Papez circuit. Klingler's technique of fibre dissection was adopted. The circuit was dissected from medial and superior-lateral cerebral surfaces. Bilateral hemispheric dissection was done simultaneously in intact brain from superior-lateral surface in two brains [4 hemispheres]. During and after dissection it's relation with lateral ventricles and other related structures were studied. Papez circuit was demonstrated by total dissection. Fibres leave the hippocampal formation and proceed through the fomix; most of these fibres have been shown to terminate in the mammillary nuclei of the hypothalamus. From here, the mammillothalamic tract ascends to the anterior group of thalamic nuclei. This group of nuclei projects to the cingulated gyrus through the anterior limb of internal capsule to anterior cingulated gyrus. From the cingulated gyrus there is an association bundle; the cingulum, which connects the cingulated gyrus with the parahippocampal gyrus part of the limbic lobe. The parahippocampal gyrus projects to the hippocampal formation and circuit is completed. Relation of different parts of the circuit with surrounding structures were also clearly seen. Knowledge of the microsurgical anatomy of the Papez circuit is not only important for understanding memory mechanism and other limbic functions but also very important in management of lateral and third ventricular lesions, in transcallosal, transventricular, supraseller and temporal lobe surgery, and for psycho-neurosurgery