The spinal cord begins to form in the second week of gestation, and remains suspended in the spinal canal, surrounded by a column of vertebrae. In adults, the spinal cord spans from the foramen magnum to the conus medullaris, which lies in the thoracolumbar region, while the cauda equina lies in the lumbar spine. Both the cord and cauda equina are encased within the dura mater with a layer of cerebrospinal fluid helping to keep the cord suspended. Dorsal sensory and ventral motor nerve roots, which emanate directly from the cord, combine into a single nerve that exits the spine via the neural foramen.
The interior anatomy of the spinal cord is organized to process both sensory information, as well as to effect motor responses in the trunk and extremities. The internal architecture of the spinal cord reveals a dichotomy of white and gray matter. Within the gray matter, different zones—or nuclei—mediate sensory or motor functions. White matter tracts further relay information as either ascending sensory or descending motor pathways.
KeywordsSpinal cord Anatomy Ascending sensory pathway Descending motor pathway White matter Gray matter Dura mater Cerebrospinal fluid Cauda Equina
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