永存舌下動脈

2019-02-18 09:00:04

永存的舌下動脈(persistent hypoglossal artery,PHA)是第二個最常見的頸動脈-基底動脈吻合(最常見的是三叉動脈),發生率約為0.027%~0.26%。此異常永存的胚胎血管起源於頸內動脈頸段,一般在C1~2水平,向後內彎曲走向並穿過擴大的舌下神經管而與基底動脈連合。後交通動脈缺如。

黃色箭頭:永存的舌下動脈;白色箭頭:椎動脈纖細;藍色箭頭:頸內動脈

頸內動脈與基底動脈異常交通,其血流動力學改變造成相交處動脈壁的損傷,加之原始動脈壁發育不全,故常伴有動脈瘤發生,亦可伴發動靜脈畸形、頸內動脈發育不良或閉塞、椎動脈發育不良和狹窄、煙霧病等.

備註:

在胚胎期顱腦發育階段,原始頸內動脈與後腦循環之間存在一時性的連通。除顱外段寰前節間動脈以外,這些血管是根據它們伴行的顱神經而命名的。由上而下它們是:(1)原始三叉動脈;(2)原始耳動脈;(3)原始舌下動脈。正常情況下這些胚胎吻合血管在後交通動脈發育後即消失。如果一個節段吻合支不消失而持續存在至成人,即成為頸動脈-基底動脈吻合。其中的兩支(原始舌下動脈及寰前節間動脈)將頸段頸內動脈與椎基底動脈系統連線起來。

Persistent hypoglossal artery (PHA) (yellow arrows), after persistent trigeminal artery, is the second most common vascular anomaly of the persistent carotid-vertebrobasilar anastomosis. PHA typically arises from the cervical internal carotid artery (blue arrows) from C1-C3 and courses through the hypoglossal canal (white arrow in Aindicates the contralateral normal canal) to join the basilar artery. The vertebral arteries are typically very hypoplastic (white arrows in C). Intracranial vascular anomalies, such as aneurysms, have been associated with PHA. Note that another similar vascular anomaly, persistent proatlantal intersegmental artery, courses through foramen magnum to join basilar artery.

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