前大脳動脈・前交通動脈の正常解剖と正常変異

Normal Anatomy and Variants of the Anterior Cerebral and Anterior Communicating Arteries

Point

・前大脳動脈は他の脳動脈よりも発生学的に古く，そのため中・後大脳動脈にはない特徴的な正常変異がある．

・前交通動脈はその発生学的背景から窓形成を多く認める．

・正常変異のいくつかは動脈瘤の合併を認めることがある．

　The anterior cerebral artery（ACA）and anterior communicating artery（AcomA）, two important arteries of the cerebral hemisphere, are involved in various disorders, including aneurysms, steno-occlusive diseases, and arteriovenous shunts, among other such conditions. Additionally, these vessels contain normal variants associated with their embryology and development. The ACA particularly shows characteristic variants such as a persistent primitive olfactory artery and an infraoptic course, among other such variations, which is attributable to the fact that it is embryologically older than the middle and posterior cerebral arteries. Aneurysm formation is associated with these variants. Therefore, knowledge of the normal anatomy and variants is important for diagnosis and treatment of conditions involving these arteries. In this article, we describe the normal anatomy and variants of the ACA and AcomA, focused on their embryological development.