環椎後弓欠損の2例

Aplasia of Posterior Arch of Atlas: Report of two cases

I．はじめに

　頭蓋頸椎移行部は各種の奇形の好発部位であるが，これらのなかには無症状で偶然に発見される例も少なくない．環椎後弓欠損もその1つであるといえる．著者らはこの比較的稀な奇形を経験する機会を得たので文献的考察を加えて報告する

Two cases of aplasia of the posterior arch of the atlas incidentally found are reported.

Case 1: A 37-year-old man hit the forehead and the right mandible against the front glass at a head-on collision of his car and was brought to the emergency room. He was alert and neurologically normal except for multiple incision wounds with glass fragments in the face. CT, and cervical X-rays revealed total absence of the posterior arch of the atlas.

Case 2: A 73-year-old woman, who sustained whip lash injury at an automobile accident, was admitted several hours after injury, complaining of neck and occipital pain.