Absent posterior arch of the atlas.
D000063:Accidents, Traffic; D000293:Adolescent; D000328:Adult; D001859:Bone Neoplasms / Q000000981:diagnostic imaging; D002528:Cerebellar Neoplasms / Q000000981:diagnostic imaging; D001270:Cervical Atlas / Q000002:abnormalities* / Q000000981:diagnostic imaging; D002574:Cervical Vertebrae / Q000293:injuries; D002648:Child; D005260:Female; D005909:Glioblastoma / Q000000981:diagnostic imaging; D006801:Humans; D008297:Male; D008875:Middle Aged; D011859:Radiography; D012509:Sarcoma / Q000000981:diagnostic imaging