title: Caudal aperture of the central canal at the filum terminale in primates.
abstract: An aperture has been observed in the central canal at the filum terminale in some lower vertebrates and some mammals but not in the human. We examined 8 human spinal cords and 2 macaque monkey spinal cords and detected a caudal aperture in both human and monkey filum terminale. The ependymal lining of the human terminal ventricle was found to begin direct contact dorsally with the pia mater at 12.8 +/- 5.3 mm caudal from the most cranial root of the 5th sacral nerve (S5). In the human spinal cords the central canal was found to open into pia-arachnoid space at about 16.5 +/- 5.0 mm caudal from S5. Typical size of the caudal aperture was about 150 microns long x 130 microns wide. In the monkey filum terminale the caudal aperture appeared at about 45 mm caudal from S5. The opening was about 100 microns long x 65 microns wide. The cytoplasmic process of the pial fibroblast was contiguous to the ependymal cell at the site of opening.
authors.affiliation: College of Biomedical Technology, Osaka University, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Sakata
authors.forename: K
authors.initials: K
authors.lastname: Yashika
authors.forename: P H
authors.initials: PH
authors.lastname: Hashimoto
mesh_terms: D000818:Animals; D005260:Female; D006801:Humans; D008251:Macaca / Q000033:anatomy & histology*; D008297:Male; D008854:Microscopy, Electron; D013116:Spinal Cord / Q000033:anatomy & histology* / Q000166:cytology / Q000648:ultrastructure