Clinical diagnosis
Case 34
Hippocampus, parahipppocampal gyrus, amygdala and cingulate gyrus are main components of limbic system (1, 2).
Hippocampus seems to be involved in learning and memory. It is engaged in recollection of facts and in forming spatial memories (3). The hippocampal artery derived from posterior cerebral artery provides blood supply of the hippocampus. The hippocampal artery is known to communicate with anterior choroidal artery.
Parahippocampal gyrus plays an important role in encoding and recognizing landscape, places and situations (4-6). Further, it is known to remind of visual scenes when stimulating by electrodes stimulation (4-6). Furthermore, the volume decrease of hippocampal gyrus is more relevant with impair of cognition than that of hippocampas (6). Parahippocampal gyrus is provided by blood supply from unco-parahippocampal branches from internal carotid artery, middle cerebral artery and hippocampal artery derived from posterior cerebral artery.
Amygdala is a gray matter located in the medial temporal lobe. Amygdala is involved in anger, fear, sorrow and affection. It is also involved in regulating endocrine activity (adrenalin, cortisone), sexual behavior and food and water intake possibly by regulating hypothalamic activity (7-9). The anterior choloidal artery derived from internal carotid artery provides blood supply of amygdala. The anterior choroidal artery is known to communicate with the posterior choroidal artery derived from posterior cerebral artery.
Because of the existence of dual or tripple blood supply and fine network communications, the ischemic damages of hippocampus, hippocampal gyrus and amygdala least occur.
Anterior cingulate gyrus is involved in a number of functions including coordination of emotion, regulation of anger, emotional bonding such as mother and child or master and pupil, communication of speech structure, motivation and decision making (1, 2). Posterior cingulated gyrus plays a role of influencing functions related to movement, spatial orientation, and navigation (10-13). Cingulate gyrus is not supplied by an independent arterial system. Anterior cingulate gyrus is provided by the first and second cortical branches of the pericallosal artery (11). Posterior cingulate is supplied by small branches of the medial branch of the posterior cerebral artery (12). These small branch arteries frequently anastomose with the terminal branches of the pericallosal artery (11, 12). Infarction of anterior cerebral artery is rare, comprising less than 2% of ischemic strokes (13). The main cause of the stroke of anterior cerebral artery is embolism (13). The stroke mainly presents as speech disturbance (dysarthria, aphasia) (13). In our case, aneurysm rupture of right anterior cerebral artery caused hemorrhage, inducing extensive damage of anterior cingulate gyrus and leading to speech disturbance.
【Summary】
We present a rare case with hemorrhagic at cingulated gyrus due to aneurysm rupture of anterior cerebral artery. An ischemic change of anterior cingulate gyrus is rare because of the dual supply of anterior and posterior cerebral arteries. The case report of this week was initiated with the questioning why limbic system stroke is rarely encountered in the clinical situation. As discussed above, the components of limbic system are supplied by dual or tipple blood supply with abundant vascular nets contributing to least ischemia of limbic system.
【References】
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2016.11.30
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