生体脳における左右半球の解剖学的差異—特に側頭葉planumについて

HEMISPHERIC ASYMMETRY IN LIVING MAN

I．はじめに

　人の中枢神経系を扱うものにとり，左右大脳半球の機能的，解剖学的差異を知る事は重要である。機能的差異については周知の事であろう。解剖学的差異について現在までに明瞭な統計的有意差の認められる部位として，sylvius溝後部，側頭葉上面に位置する側頭葉平面pla—num temporale （以後planumと略す。）およびHeschlの横回が挙げられる。然し剖検脳に対して行なわれたこれらの研究成果は，生きている患者を目前にした時，臨床家にとり有用とはいえなかつた。

　著者はTalairach^12）により考案された定位脳血管撮影により，planum表面を通る血管を示標として，テンカン患者のplanumを中心とするsylvius溝後部の両半球の機能的左右差と結びついた，解剖学的左右差につき研究し，血管撮影で決定されるsylvius溝最終点（syl—vius溝がsupramarginal gyrusに移行する点）が両半球左右差の良い指標となる事を見い出し，臨床上有益と思われるのでここに報告したい。

Bilateral temporal planums in living man (39 epileptic patients, major pathology excluded) were calculated by the aid of arteriography using the system of stereotactic technic of Talairach.

The surface of planum temporale on the left was significantly larger than that of the right (P< 0.001). Mean value on the left was 8.55±0.27 cm² (mean±standard error) and on the right was 7.44 ±0.30 cm².

The inclination of the right planum to the superior insular line (Vlahovitch) was significantly bigger than that of the left (P<0.001). Mean value of the inclination on the left was 50.0±3.1ﾟ and on the right was 70.1±2.5ﾟ.

The distance of each landmark from vertical line of the AC-PC line (Talairach) at the level of the anterior margin of the posterior commissure and that from the AC-PC line were measured and analyzed statistically in both hemispheres. The sylvian fissure of the dominant hemisphere was significantly longer than that of the non-dominant hemisphere at its terminal portion.

Especially in the right handed or ambidexter group whose dominant hemisphere were considered to be on the left, end point of sylvian fissure on the left was situated postero-inferiorly than on the right.

Finally it can be said that the end point of sylvian fissure which can be determined by the aid of artery of planum is the best landmark to determine the dominant hemisphere in living man.

In conclusion, three dimensional reading of the angiogram reveals the form of the brain with an enormous amount of precise detailed information, and future research will reveal more and more functional correlations of the precise anatomical organization.