脳血管障害の合併により発見された arteria primitiva hypoglossicaの2例

ARTERIA PRIMITIVA HYPOGLOSSICA REVEALED BY AN ASSOCIATED CEREBROVASCULAR ACCIDENT REPORT OF 2 CASES

Ｉ．緒言

　胎生期初期には内頸動脈系と椎脳底動脈系との間にいくつかの吻合枝がみられる。これらが吸収されずに残つたものを総称して，内頸動脈・椎骨脳底動脈吻合遺残血管という。これらを頭側から尾側に順に列挙すると，persistent primitive trigeminal artery （P．T．A．），pe—rsistent primitiv otic artery （P．O．A．），persistent pri—mitive hypoglossal artery （P．H．A．），persistent pri—mitive proatlantal artery （P．P．A．）である。P．T．A．は1884年Quainにより，P．O．A．は1947年Altmannにより，P．H．A．は1889年Batujeffにより，P．P．A．は1885年Gottschawによりそれぞれ剖検により発見された。しかし近年脳血管撮影法の普及により臨床的に発見されるものが多くなり，P．T．A．は既に150例以上，P．0．A．が4例，P．H．A．が71例，P．P．A．が5例報告されている。P．T．A．の脳血管撮影での発見頻度はO．1％〜0.3％，P．H．A．の発見頻度は0.014％〜0.045％である。我々の経験したP．H．A．　2例は脳血管撮影上2／743例に当り0.13％に相当する。我々はこの2例を報告し若干の考察を試みたい。

1) 2 cases of A. hypoglossica primitiva were re-ported. The one case, a 60-year old female, was associated with episodes of syncopal attack. In CAG, an A. hypogloss. prim. was found on the left side. The other case, a 58-year old female, was associated with an attack of subarachnoid hemor-rhage. In CAG, an A. hypoglass. prim. and an aneurysm of the A. cerebri post. were found on the right side.

2) Whereas most cases of Internal Carotid Ver-tebro-Basilar Anastomosis (IC･V-BA) were foundaccidentally, in both of our cases the abnormal vessels were found in CAG performed on account of cerebral vascular accidents, i. e. a syncopal attack and a subarachnoid hemorrhage, respectively, which are supposed to have eventuated in relation to the primitive abnormality.

3) Cases of IC･V-BA associated woth aneurysmor subarachnoid hemorrhage, or with syncopal attack, found in literature were studied and the relations of these associations with ICC･V-BA werediscussed from embriological, pathological, phsio-logical points of view. The authors examined EEG under a mild pressure on IC and opthalmic pressures, for second case, considering by-passing of blood flow. The results of these examinations, however, were found to be within normal ranges.