Thiébaud Picart1, Marc Barritault2, Emile Simon3, Philip Robinson4, Cédric Barrey5, David Meyronet6, Patrick Mertens7. 1. Department of Neurosurgery, Hospices Civils de Lyon, Hôpital Neurologique Pierre Wertheimer, Bron, France. Electronic address: thiebaud.picart@chu-lyon.fr. 2. Department of Molecular Biology, Hospices Civils de Lyon, Groupe Hospitalier Est, Bron, France; Faculty of Medicine Lyon Est, Claude Bernard University Lyon 1, Lyon, France. 3. Department of Neurosurgery, Hospices Civils de Lyon, Hôpital Neurologique Pierre Wertheimer, Bron, France; Laboratory of Anatomy, Faculty of Medicine Lyon Est, Claude Bernard University Lyon 1, Lyon, France. 4. Hospices Civils de Lyon, Direction de la Recherche Clinique et de l'Innovation, Lyon, France. 5. Department of Neurosurgery, Hospices Civils de Lyon, Hôpital Neurologique Pierre Wertheimer, Bron, France. 6. Department of Neuropathology, Hospices Civils de Lyon, Groupe Hospitalier Est, Bron, France; Faculty of Medicine Lyon Est, Claude Bernard University Lyon 1, Lyon, France. 7. Department of Neurosurgery, Hospices Civils de Lyon, Hôpital Neurologique Pierre Wertheimer, Bron, France; Faculty of Medicine Lyon Est, Claude Bernard University Lyon 1, Lyon, France; Laboratory of Anatomy, Faculty of Medicine Lyon Est, Claude Bernard University Lyon 1, Lyon, France.
Abstract
BACKGROUND: The intradural filum terminale (iFT) connects the conus medullaris (CM) with the dural sac (DS), and the extradural filum terminale (eFT) connects the DS to the coccyx. The aim of the present study was to update the description of the FT and integrate these data in a physiological and pathological context. METHODS: Anatomical measurements and histological investigations were performed on 10 human cadavers. RESULTS: The mean length of the iFT and eFT was 167.13 and 87.59 mm, respectively. The mean cranial diameter of the iFT was 1.84 mm. It was >2 mm in 2 specimens. The mean half and caudal diameter of the iFT was 0.71 and 0.74 mm, respectively. The cranial diameter of the eFT correlated with the caudal diameter of the eFT (ρ = 0.94; P = 0.02). The level of the CM-iFT junction correlated significantly with the iFT length (ρ = -0.67; P = 0.03). The mobilization of the iFT was not transmitted to the extradural elements and vice versa. The iFT contained axons and ependymal cells, which were dense in the first third and then randomly arranged caudally in islets. This could explain why ependymomas can occur all along the iFT. Ganglion cells were abundant around the junction with the DS. The eFT contained smooth muscle cells, adipocytes, and axons. A mechanoreceptor was identified in 1 specimen. CONCLUSIONS: Consistently with their common embryological origin, a real anatomical and histological continuum is present between the CM and FT. The FT should, therefore, no longer be considered a simple ligament but, rather, a complex fibrocellular structure.
BACKGROUND: The intradural filum terminale (iFT) connects the conus medullaris (CM) with the dural sac (DS), and the extradural filum terminale (eFT) connects the DS to the coccyx. The aim of the present study was to update the description of the FT and integrate these data in a physiological and pathological context. METHODS: Anatomical measurements and histological investigations were performed on 10 human cadavers. RESULTS: The mean length of the iFT and eFT was 167.13 and 87.59 mm, respectively. The mean cranial diameter of the iFT was 1.84 mm. It was >2 mm in 2 specimens. The mean half and caudal diameter of the iFT was 0.71 and 0.74 mm, respectively. The cranial diameter of the eFT correlated with the caudal diameter of the eFT (ρ = 0.94; P = 0.02). The level of the CM-iFT junction correlated significantly with the iFT length (ρ = -0.67; P = 0.03). The mobilization of the iFT was not transmitted to the extradural elements and vice versa. The iFT contained axons and ependymal cells, which were dense in the first third and then randomly arranged caudally in islets. This could explain why ependymomas can occur all along the iFT. Ganglion cells were abundant around the junction with the DS. The eFT contained smooth muscle cells, adipocytes, and axons. A mechanoreceptor was identified in 1 specimen. CONCLUSIONS: Consistently with their common embryological origin, a real anatomical and histological continuum is present between the CM and FT. The FT should, therefore, no longer be considered a simple ligament but, rather, a complex fibrocellular structure.