外頸動脈欠損症の3症例

Unilateral Abscence of the External Carotid Artery:Three Case Reports

Ⅰ．はじめに

　先天的な外頸動脈欠損症は珍しく，文献を渉猟できたかぎりではFranklinら^4）の1例のみで，その発生要因においては症例も少なく十分に検討されているとはいえない．

　最近，外頸動脈欠損症の3症例を経験し，その内の2症例については，脳梗塞との関連をうかがわせる頸動脈病変として，特徴的な内膜の肥厚thickening of intima-media complex（以後intima-media complexをIMC）と潰瘍形成を超音波検査から認めたため，同部位の内膜剥離術を施行し，術野にて病変部位を観察することができた．それらの所見を含め，発生要因について若干の文献考察を加え，報告する．

We encountered three cases of unilateral absence of the external carotid artery. We were able to find only Frank-lin's case reported in the literature published to date. The absence of the external carotid artery has been explained as due to the fact that the development of the external carotid artery arising from the ventral aorta was disturbed by unkown factors in the early embryonic stage. In the process of embryonal development, the internal carotid artery and branchial arteries (that are to be components of the external carotid artery) have remained without connection and without development of the ECA trunk.