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40505-Functional Anatomy of the Spinal Cord

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European Course in Neuroradiology Module 1 - Anatomy and Embryology Dubrovnik, October 2018 Overview Spinal Anatomy Spaces & Meninges Spinal Cord • spinal meninges & spaces Johan Van Goethem • spinal cord Anatomy of the spinal Anatomy of the spinal meninges meninges • three layers (outer to inner) • dura mater (also known as theca or pachymeninx) • arachnoid mater • pia mater • collectively the arachnoid and pia mater together are known as the leptomeninges • there are two actual spaces: epidural and subarachnoid Anatomy of the dura Anatomy of the arachnoid • stratum periostale • stratum meningeale: • separated from the dura • extension of the dura mater from by a thin film of lymph the posterior cranial fossa • lies free apart from attachments to • thin avascular membrane the tectorial membrane and lining the dural sac and posterior longitudinal ligament on the body of the axis nerve root sheaths • stabilised by anterior and posterior spinal nerve roots, which pierce it segmentally • a posterior median septum lies over the spinal cord, formed by web-like arachnoid processes • in between: a layer of fat containing the internal vertebral venous plexus Anatomy of the pia Epidural space • space between the dura mater and the periosteum and • invests the spinal cord and ligaments of the vertebral canal the spinal nerve roots, • blending in with the superiorly bounded by the fusion of the dura with the foramen magnum epineurium • content • continuous with the ligamentum denticulatum, • fat which at its lateral border has a series of • internal vertebral venous plexus triangular processes that are fixed to the dura mater • spinal nerve roots below S2 Subarachnoid space • thin cell layer between the closely apposed arachnoid and pia mater • content: • arachnoid trabeculae • CSF • veins • arteries: radicular, segmental, medullary and spinal Cranium Space Typical? Example traumatic Epidural Potential No hematoma (arterial) traumatic Subdural Potential Yes hematoma (bridging veins) haemorrhage Subarachnoid Actual Yes (aneurysm, CAA), infection Cranium Spine Myelography Space Typical? Example Space Typical? Example • occasional direct puncture of epidural or hematoma, subdural space traumatic Epidural Potential No Actual Yes infection, neoplasia, hematoma (arterial) disc herniation • leakage after subarachnoid puncture traumatic Subdural Potential Yes hematoma Potential No - (bridging veins) • 35% in epidural space haemorrhage continuous w/ Subarachnoid Actual Yes (aneurysm, CAA), Actual Yes • 2% in subdural space cranium infection Myelography Myelography Milants et al. European Journal of Radiology 1993 Milants et al. European Journal of Radiology 1993 Epidural space Spinal Cord • vertebral canal • conus medullaris: adult Th12- L1 • filum terminale • cauda equina • gray matter: anterior and posterior horns • white matter: anterior, lateral and posterior tracts Spinal nerves • ventral and dorsal roots • intervertebral foramen • each pair (31) innervates a body segment: dermatomes • cervical (8 p.), thoracic (12 p.), lumbar (5 p.), sacral (5 p.) and coccygeal (1 p.) 40-year-old woman So what is this? • gradual and uniform onset of • Lichtheim's disease • diminished pressure, vibration and touch sense • Lou Gehrig's disease • tingling and numbness of legs, arms and trunk that progressively worsens • Lyme disease • pain and temperature sense are normal • Devic’s disease • motor function is preserved, but slight ataxia And the answer is ... Let’s go back ... • gradual and uniform onset of • Lichtheim's disease • diminished pressure, vibration and touch sense • Lou Gehrig's disease • tingling and numbness of legs, arms and trunk that progressively worsens • Lyme disease • pain and temperature sense are normal • Devic’s disease • motor function is preserved, but slight ataxia Some anatomy Spinothalamic tract • anterior • coarse touch and pressure • lateral • pain • temperature Source: Prometheus • itch Anatomical atlas • 3 ascending pathways • sexual • 2 descending pathways Source: Prometheus Anatomical atlas Spinocerebellar tract Fasciculus gracilis & cuneatus • posterior or dorsal columns • unconscious • tracts of Goll and proprioception Burdach • walking • running • conscious proprioception • biking • fine touch, fine • ... pressure and vibration • 2-point discrimination Source: Prometheus Source: Prometheus Anatomical atlas Anatomical atlas Fasciculus gracilis & cuneatus Fasciculus gracilis & cuneatus Source: Prometheus Source: Prometheus Anatomical atlas Anatomical atlas Fasciculus gracilis & cuneatus Subacute combined degeneration • degeneration of the posterior (and lateral) columns as a result of vitamin B12 deficiency • dietary deficiency of B12, malabsorption of B12 in the terminal ileum, lack of intrinsic factor So what is this? 52-year-old woman • unable to move her legs after abdominal procedure •• Lichtheim'ssubacute combined disease degeneration • areflexic in the lower extremities with negative •• Louamyotrophic Gehrig's diseaselateral sclerosis Babinski testing bilaterally •• Lymeneuroborreliosis disease •• Devic’sneuromyelitis disease optica • sensory level to pain and temperature extended up to Th10 • other intact Corticospinal tract Extrapyramidal tracts • unconscious motor • automated • lateral • lateral • rubrospinalis • conscious motor • arm and hands fine • anterior motor • 20% • medial • reticulospinalis anterior, • cervical tectospinalis, vestibulospinalis Source: Prometheus Source: Prometheus • legs and trunk Anatomical atlas Anatomical atlas Back to our case Back to our case • lesions of pyramid tracts or extrapyramid tracts are always combined due to their close proximity • lesions of these tracts may cause Babinski sign • no reflex = no α-motorneuron function Source: Prometheus Source: Prometheus Anatomical atlas Anatomical atlas Back to our case Spinal cord infarction Source: Prometheus Anatomical atlas 9-year-old girl Anatomy revisited • acute flaccid paresis • AFP is the most common sign of acute polio, and used for surveillance during polio outbreaks Source: Wikipedia What is all the other stuff? What is all the other stuff? • interneuron coordination (reflexes, proprioception) Source: Prometheus Anatomical atlas • autonomic nervous system • mostly diffuse Conclusion • spinal meninges & spaces • spinal cord anatomy revisited.
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