The central canal.
D000293:Adolescent; D000328:Adult; D014695:Cerebral Ventriculography; D005260:Female; D005471:Fluoroscopy; D006801:Humans; D006849:Hydrocephalus / Q000150:complications; D008297:Male; D009192:Myelography; D013118:Spinal Cord Diseases / Q000000981:diagnostic imaging*; D013595:Syringomyelia / Q000000981:diagnostic imaging* / Q000209:etiology