慢性硬膜下血腫症例における頭指数（Cephalic Index）の意義

Cephalic Index in the Case of Chronic Subdural Hematomas; A preliminary report

I．はじめに

　慢性硬膜下血肺症例の中に頭指数が小さい，すなわち長頭（dolichocephaly）のものがしばしばみられることに気付き，慢性硬膜下血腫の発生と頭指数の関係について検討した．

As a low cephalic index (cephalic index=breadth X 100/length) , also called “dolichocephaly” has often been observed in patients with chronic subdural hema-tomas, the relation between the occurrence of chronic subdural hematoma and the cephalic index was investi-gated. 62 patients (male: 51, female: 11) with chronic subdural hematomas who were admitted during the past 5 years, and 62 patients (male: 51, female: 11) aged 40 years and over who visited the hospital for head injury which caused no intracranial hematoma, randomly sampled, as a control group, a total of 124 pa-tients were studied for cephalic index on plain cranio-gram. The average cephalic index was 79.0 for males and 81.3 for females in the chronic subdural hematoma group, compared with 82.1 for males and 83.3 for females in the control group. The former index was lower than the latter for both sexes. Dolichocephaly was observed in 8 out of 51 males (15.7%) with chronic subdural hematomas while it was observed in only 1 out of 51 males (2.0%) in the control group. Since it has been reported that dolichocephaly depends on the development of arcus superciliaris and protuberantia occipitalis externa by the interaction between androgen and GH in males as well as time of closure of the cra-nial suture in childhood, and as androgen accelerates offensive behavior and GH stimulates the synthesis of collagen, the occurrence of chronic subdural hematoma is potentially related with sexual or individual variation in such endocrinic environments. On the other hand, since dolichocephaly appears to easily cause angular acceleration in the direction of the cranial axis accord-ing to the site of head injury, it may cause a traction of bridging veins. In adult patients of head trauma with hyperdolichocephaly on plain craniogram, the occur-rence of chronic subdural hematoma should be careful-ly expected and cared for.