頭蓋底のX線学的観察—特に本邦人頭蓋底の計測について

RADIOLOGICAL EXAMINATIONS OF THE BASE OF THE SKULL:ON MEASUREMENT IN CASES OF JAPANESE ADULTS

Ⅰ．まえがき

　頭蓋骨の奇形は種類が多いが，近年注目されはじめたものに，頭蓋底，ことに大後頭孔周辺の奇形と変形がある。これらのうちでも，platybasia， basilar impression, Arnold-Chiari malforma—tionについては，なおしばしば，その成因および異同についての討論が行なわれて，清水教授のごとく，総括的な「大後頭孔症」という名称を提唱する人さえあるくらいである。

　さて，この際，まず問題として取りあげられるものは頭蓋のレ線像である。後述のようにその病的限界を決めるために，Boogard, Chamberlain McGregor, Fishgoldらによつて各種の計測法が行なわれている。しかし，本邦人の頭蓋形態の特殊性からみて，そのいずれをとるべきか，またそれらの計測法で十分であろうか。これらの疑問に答えるために，われわれは正常頭蓋像1,000例中から，検討の目的にかなつたもの250例を選んで，諸種の計測を試みた。

More attention are being paid recently on the morphology of the baseof the skull, par-ticularly anomalies and malformations about the foramen occipitale magnum. Platybasia, basilar impression and Arnold-Chiari malfor-mation among them are described briefly, and criteria and results of the radiological diagnosis according to the western workers are introduced.

We examined 250 skull films of the Japanese adults and found normal values for Japanese as basal angle (108.5-137°) Boogard's angle (110-139°) and distance of dens from the Chamberlain's line (~9mm~+5mm).

These values are compared with results re-ported by the western authors, and consequ-ently no significant difference is found in the morphology about the base of the skull between Japanese and foreigners.

Interrelationship between basal angle, Boo-gard's angle and Chamberlain's line is studied in order to elucidate correlation between pla-tybasia and basilar impression, and it is con-cluded that platybasia and basilar impression are separate disease entities respectively. As various methods of mesurement have merits and demerits of its own, it is necessary to reach systematic judgement by use of multi-ple methods of mesurement.