Spinal cord
Updates to Article Attributes
The spinal cord is the part of the central nervous system that is found within the spinal canal of the vertebral column. It is contained by the thecal sac, a continuation of the intracranial dura matter, and extends from the corticomedullary junction at the foramen magnum of the skull down to the tip of the conus medullaris.
Gross anatomy
ItThe spinal cord measures approximately 42-45 cm in length, ~1 cm in diameter and 35 g in weight.
ItLike the brain, it is composed of grey and white matter, however, opposite to the brain, the grey matter is on the internal aspect of the cord and the white matter tracts are external. Throughout its length paired dorsal and ventral nerve roots enter its dorsolateral and ventrolateral surface respectively.
The spinal cord is divided into cervical, thoracic and lumbar parts and terminates at the conus medullaris at approximately the T12/L1L1 vertebral body level in adults.
The spinal cord is segmented by the nerve roots that emerge from it. There are 31 nerve roots in total:
- 8 cervical
- 12 thoracic
- 5 lumbar
- 5 sacral
- 1 coccygeal
Like the brain, there is grey and white matter, however, opposite to the brain, the grey matter is on the internal aspect of the cord and the white matter tracts are external.
Internal structure
A transverse section of the spinal cord shows a peripheral mass of white matter enclosing asurrounding an ‘H’ or butterfly-shaped central mass of grey matter with a small ependyma-lined central canal filled with CSF 2. The central canal is lined by a single layer of ependymal cells. Surrounding this canal is the ‘H’ or butterfly shaped grey matter. The The central limb of the ‘H’ connects the left and right halves of the grey matter, known as the grey commissure. Anterior to the grey matter, the white commissure connects both halves of the white matter.
Grey matter
The grey matter contains the cell bodies of neurons and glia, and is divided into anterior, dorsal and lateral horns 3:
the anterior horn contains motor neurons for skeletal musclethe lateral horn contains autonomic neurons for pelvic and visceral organsthe dorsal horns receive somatosensory information from the posterior roots of the spinal nerves
The grey matter is enlarged in the cervical and lumbosacral regions to provide fibres to the large nerve plexuses. It is divided into anterior, dorsal and lateral horns and periependymal grey matter 3,5:
-
anterior horns
- contain motor neurons for skeletal muscle
- send efferent fibres via the ventral nerve roots
-
lateral horns
- contain autonomic neurons for pelvic and visceral organs
- only present in the thoracic region
-
dorsal horns
- contains somatosensory neurons
- receive primary afferents from the dorsal roots of the spinal nerves
-
periependymal grey matter
- divided into ventral and dorsal grey matter commissures
White matter
The white matter contains nerve fibres or tracts, and is divided into anterior, dorsal orand lateral columns (also known as funiculi) as well as the anterior spinal commissure 3,5.
-
columns
- anterior columns primarily contain the spinothalamic tracts which are responsible for pain, temperature, coarse (non-discriminative) touch and pressure sensations
- dorsal columns contain ascending fibres which are responsible for vibration, conscious proprioception, and fine (discriminative) touch sensations
-
thelateral columns primarilycontainscontain the corticospinal tracts which are the principal motor pathway connecting the cerebral cortex to spinal motor neurons
-
anterior spinal commissure is located between the posterior-most extent of the anterior
columns primarily containsmedian fissure anteriorly and thespinothalamic tractswhich are responsible for pain, temperature, coarse (non-discriminative) touch, and pressure sensations
In general, neuronsfibres found posteriorly process and relay sensory information, neurons roundfibres found laterally are preganglionic visceral motor neurons and somatic motor neuronsfibres are found anteriorly 4.
Blood supply
Blood supply is discussed separately. See spinal cord blood supply.
-<p>The <strong>spinal cord</strong> is the part of the central nervous system that is found within the <a href="/articles/spinal-canal">spinal canal</a> of the <a href="/articles/spinal-anatomy-1">vertebral column</a>. </p><h4>Gross anatomy</h4><p>It measures approximately 42-45 cm in length, ~1 cm in diameter and 35 g in weight. </p><p>It is divided into cervical, thoracic and lumbar parts and terminates at the <a href="/articles/conus-medullaris">conus medullaris</a> at approximately the T12/L1 vertebral body level. </p><p>The spinal cord is segmented by the nerve roots that emerge from it. There are 31 nerve roots in total:</p><ul>- +<p>The <strong>spinal cord</strong> is the part of the central nervous system that is found within the <a href="/articles/spinal-canal">spinal canal</a> of the <a href="/articles/spinal-anatomy-1">vertebral column</a>. It is contained by the thecal sac, a continuation of the intracranial dura matter, and extends from the corticomedullary junction at the foramen magnum of the skull down to the tip of the conus medullaris. </p><h4>Gross anatomy</h4><p>The spinal cord measures approximately 42-45 cm in length, ~1 cm in diameter and 35 g in weight. </p><p>Like the <a href="/articles/brain">brain</a>, it is composed of <a href="/articles/grey-matter">grey</a> and <a href="/articles/white-matter">white matter</a>, however, opposite to the brain, the grey matter is on the internal aspect of the cord and the <a href="/articles/white-matter-tracts-of-the-spinal-cord">white matter tracts</a> are external. Throughout its length paired dorsal and ventral nerve roots enter its dorsolateral and ventrolateral surface respectively. </p><p>The spinal cord is divided into cervical, thoracic and lumbar parts and terminates at the <a href="/articles/conus-medullaris">conus medullaris</a> at approximately the L1 vertebral body level in adults. </p><p>The spinal cord is segmented by the nerve roots that emerge from it. There are 31 nerve roots in total:</p><ul>
-</ul><p>Like the <a href="/articles/brain">brain</a>, there is <a title="Grey matter" href="/articles/grey-matter">grey</a> and <a href="/articles/white-matter">white matter</a>, however, opposite to the brain, the grey matter is on the internal aspect of the cord and the <a href="/articles/white-matter-tracts-of-the-spinal-cord">white matter tracts</a> are external.</p><h4>Internal structure</h4><p>A transverse section of the spinal cord shows a peripheral mass of white matter enclosing a central mass of grey matter with a small central canal filled with <a href="/articles/cerebrospinal-fluid-1">CSF</a> <sup>2</sup>. The <a href="/articles/central-canal">central canal</a> is lined by a single layer of ependymal cells. Surrounding this canal is the ‘H’ or butterfly shaped grey matter. The cord is incompletely divided into left and right halves by the posterior median sulcus and the anterior median fissure. The central limb of the ‘H’ connects the left and right halves of the grey matter, known as the grey commissure. Anterior to the grey matter, the white commissure connects both halves of the white matter.</p><h6>Grey matter</h6><p>The grey matter contains the cell bodies of neurons and glia, and is divided into anterior, dorsal and lateral horns <sup>3</sup>:</p><ul>-<li>the anterior horn contains motor neurons for skeletal muscle</li>-<li>the lateral horn contains autonomic neurons for pelvic and visceral organs</li>-<li>the dorsal horns receive somatosensory information from the posterior roots of the spinal nerves</li>-</ul><p>The grey matter is enlarged in the cervical and lumbosacral regions to provide fibres to the large nerve plexuses.</p><h6>White matter</h6><p>The white matter contains nerve fibres or tracts, and is divided into anterior, dorsal or lateral columns <sup>3</sup>. </p><ul>-<li>the <a href="/articles/dorsal-columns">dorsal columns</a> contain ascending fibres which are responsible for vibration, conscious proprioception, and fine (discriminative) touch sensations</li>-<li>the lateral columns primarily contains the <a href="/articles/corticospinal-tract">corticospinal tracts</a> which are the principal motor pathway connecting the cerebral cortex to spinal motor neurons</li>-<li>the anterior columns primarily contains the <a href="/articles/anterior-spinothalamic-tract-1">spinothalamic tract</a><a href="/articles/spinothalamic-tracts">s</a> which are responsible for pain, temperature, coarse (non-discriminative) touch, and pressure sensations </li>-</ul><p>In general, neurons found posteriorly process and relay sensory information, neurons round laterally are preganglionic visceral motor neurons and somatic motor neurons are found anteriorly <sup>4</sup>. </p><h4>Blood supply</h4><p>See <a href="/articles/spinal-cord-blood-supply">spinal cord blood supply</a>.</p>- +</ul><h5>Internal structure</h5><p>A transverse section of the spinal cord shows a peripheral mass of white matter surrounding an ‘H’ or butterfly-shaped central mass of grey matter with a small ependyma-lined <a href="/articles/central-canal">central canal</a> filled with <a href="/articles/cerebrospinal-fluid-1">CSF</a> <sup>2</sup>. The cord is incompletely divided into left and right halves by the posterior median sulcus (shallow) and the anterior median fissure (deep) <sup>6</sup>. </p><h6>Grey matter</h6><p>The grey matter contains the cell bodies of neurons and glia and is enlarged in the cervical and lumbosacral regions to provide fibres to the large nerve plexuses. It is divided into anterior, dorsal and lateral horns and periependymal grey matter <sup>3,5</sup>:</p><ul>
- +<li>anterior horns<ul>
- +<li>contain motor neurons for skeletal muscle</li>
- +<li>send efferent fibres via the ventral nerve roots</li>
- +</ul>
- +</li>
- +<li>lateral horns<ul>
- +<li>contain autonomic neurons for pelvic and visceral organs</li>
- +<li>only present in the thoracic region</li>
- +</ul>
- +</li>
- +<li>dorsal horns<ul>
- +<li>contains somatosensory neurons</li>
- +<li>receive primary afferents from the dorsal roots of the spinal nerves</li>
- +</ul>
- +</li>
- +<li>periependymal grey matter<ul><li>divided into ventral and dorsal grey matter commissures</li></ul>
- +</li>
- +</ul><h6>White matter</h6><p>The white matter contains nerve fibres or tracts and is divided into anterior, dorsal and lateral columns (also known as funiculi) as well as the anterior spinal commissure <sup>3,5</sup>. </p><ul>
- +<li>columns<ul>
- +<li>anterior columns primarily contain the <a href="/articles/anterior-spinothalamic-tract-1">spinothalamic tract</a><a href="/articles/spinothalamic-tracts">s</a> which are responsible for pain, temperature, coarse (non-discriminative) touch and pressure sensations </li>
- +<li>
- +<a href="/articles/dorsal-columns">dorsal columns</a> contain ascending fibres which are responsible for vibration, conscious proprioception, and fine (discriminative) touch sensations</li>
- +<li>lateral columns primarily contain the <a href="/articles/corticospinal-tract">corticospinal tracts</a> which are the principal motor pathway connecting the cerebral cortex to spinal motor neurons</li>
- +</ul>
- +</li>
- +<li>
- +<a href="/articles/anterior-spinal-commissure">anterior spinal commissure</a> is located between the posterior-most extent of the anterior median fissure anteriorly and the ventral grey matter commissure posteriorly <sup>5</sup>. </li>
- +</ul><p>In general, fibres found posteriorly process and relay sensory information, fibres found laterally are preganglionic visceral motor neurons and somatic motor fibres are found anteriorly <sup>4</sup>. </p><h4>Blood supply</h4><p>Blood supply is discussed separately. See <a href="/articles/spinal-cord-blood-supply">spinal cord blood supply</a>.</p>
References changed:
- 5. Maria A. Patestas, Leslie P. Gartner. A Textbook of Neuroanatomy. (2016) ISBN: 9781118677353 - <a href="http://books.google.com/books?vid=ISBN9781118677353">Google Books</a>
- 6. Kunam V, Velayudhan V, Chaudhry Z, Bobinski M, Smoker W, Reede D. Incomplete Cord Syndromes: Clinical and Imaging Review. Radiographics. 2018;38(4):1201-22. <a href="https://doi.org/10.1148/rg.2018170178">doi:10.1148/rg.2018170178</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/29995620">Pubmed</a>
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