The Spinal Cord Is a Nerve Column That Passes Downward from Brain Into the Vertebral Canal

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The spinal cord is a nerve column that passes downward from brain into the vertebral canal. Recall that it is part of the CNS. Spinal nerves extend to/from the spinal cord and are part of the PNS. Length = about 17 inches Start = foramen magnum End = tapers to point (conus medullaris) st nd and terminates 1 –2 lumbar (L1-L2) vertebra Contains 31 segments à gives rise to 31 pairs of spinal nerves Note cervical and lumbar enlargements. cauda equina (“horse’s tail”) –collection of spinal nerves at inferior end of vertebral column (nerves coming off end of spinal cord) Meninges- cushion and protected by same 3 layers as brain. Extend past end of cord into vertebral canal à spinal tap because no cord A cross-section of the spinal cord resembles a butterfly with its wings outspread (gray matter) surrounded by white matter. GRAY MATTER or “butterfly” = bundles of cell bodies Posterior (dorsal) horns=association or interneurons (incoming somatosensory information) Lateral horns=autonomic neurons Anterior (ventral) horns=cell bodies of motor neurons Central canal-found within gray matter and filled with CSF White Matter: 3 Regions: Posterior (dorsal) white column or funiculi – contains only ASCENDING tracts à sensory only Lateral white column or funiculi – both ascending and descending tracts à sensory and motor Anterior (ventral) white column or funiculi – both ascending and descending tracts à sensory and motor All nerve tracts made of mylinated axons with same destination and function Associated Structures: Dorsal Roots = made of axons of sensory neurons Dorsal Root Ganglia = enlarged area of dorsal root that contains cell bodies of sensory neurons Ventral Roots = made of axons of motor neurons Spinal Nerve = area where dorsal and ventral roots combine à passes through intervertebral foraman *All these structures are paired – coming from each side of spinal cord Flaccid Paralysis Spastic Paralysis Caused by damage to Caused by a transected or ventral root crushed spinal cord Affected muscles healthy Because no nerve because still stimulated by impulse reaches the reflex arc – involuntary muscle there is no movements movement Loss of both sensory and Muscle atrophies motor functions Quadriplegic=4 limbs Paraplegic = only legs .

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Intramedullary Cystic Lesions Ofthe Conus Medullaris
J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.31.2.106 on 1 April 1968. Downloaded from J. Neurol. Neurosurg. Psychiat., 1968, 31, 106-109 Intramedullary cystic lesions of the conus medullaris SAMI I. NASSAR, JAMES W. CORRELL, AND EDGAR M. HOUSEPIAN From the Department of Neurosurgery, College ofPhysicians and Surgeons, Columbia University, and the Neurological Institute of the Columbia-Presbyterian Medical Center, New York, U.S.A. Intramedullary cystic lesions of the conus medullaris of the aetiology, these cysts may simulate the clinical are rare. Although an extensive literature describes picture of syringomyelia. syringomyelia as being a frequent basis for cystic The cases of cysts of the conus medullaris re- cervico-thoracic lesions it is apparent that this ported here simulated the clinical picture of does not occur frequently in the lumbosacral region syringomyelia, tumour, or lumbar disc disease. (Kirgis and Echols, 1949; Netsky, 1953; Rand and The radiographic findings in each case were inter- Rand, 1960; Love and Olafson, 1966). Poser (1956), preted as indicating the presence ofan intramedullary in a review of 234 cases of syringomyelia, found tumour. The correct diagnosis was made in each that the cavity extended into the lumbosacral region case only at operation. in only 12-6% and in only five cases were the Protected by copyright. cavities restricted to the lumbosacral segments. Some authors (Thevenard, 1942; Andre, 1951) CASE REPORTS question the occurrence of syringomyelia in the lower spinal cord. Nevertheless a high incidence CASE 1 (F.T., NO. 179 16 92) A 22-year-old negro male of constitutional defects has been noted among was admitted complaining of weakness and pain in the syringomyelia patients and members of their legs for three years.
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