Corticospinal tract
Updates to Article Attributes
The corticospinal tract (or(also known as the pyramidal tract) is a descending white matter tract primarily concerned with motor function extendingthat extends caudally from the motor cortex down to synapse with motor neurones of the spinal cord in the anterior horns.
Gross anatomy
Centralconnections
Corticospinal fibres are axons from upper motor neurones in the cerebral cortex. Over half of these arise in the primary motor cortex with additional contributions from the premotor cortex, supplementary motor cortex and even the sensory cortex. In the primary motor cortex, fibres arise specifically from Betz cells 1-2,2,4.
Intracranial course
Organised somatotopically, these fibres descend through subcortical white matter and form the anterior two-thirds of the posterior limb of the internal capsule. They pass through the ventral midbrain, specifically the central and lateral portions of the inner crus, and continue through the pons. In the medulla oblongata, corticospinal fibres collect into a discrete bundle forming the pyramid 1-2,2.
The pyramid is a discrete triangular column on the ventral medulla oblongata next to the midline. This is why the corticospinal tract is also called the pyramidal tract. Within the pyramids approximately 90% of the corticospinal fibres decussate, forming the lateral corticospinal tract. The remaining 10% fibres remain ipsilateral (i.e. do not decussate) and form the anterior corticospinal tract 1-4.
The anterior and lateral tracts are discussed separately.
Related pathology
-<p>The<strong> corticospinal tract (or pyramidal tract)</strong> is a descending white matter tract primarily concerned with motor function extending from the motor cortex down to synapse with motor neurones of the <a href="/articles/spinal-cord">spinal cord</a> in the anterior horns. </p><h4>Gross anatomy</h4><h5>Central<strong> </strong>connections</h5><p>Corticospinal fibres are axons from upper motor neurones in the cerebral cortex. Over half of these arise in the <a href="/articles/precentral-gyrus">primary motor cortex</a> with additional contributions from the <a href="/articles/premotor-cortex">premotor cortex</a>, <a href="/articles/supplementary-motor-area">supplementary motor cortex</a> and even the sensory cortex. In the <a href="/articles/precentral-gyrus">primary motor cortex</a>, fibres arise specifically from <a href="/articles/betz-cells">Betz cells</a> <sup>1-2,4</sup>.</p><h5>Intracranial course</h5><p>Organised somatotopically, these fibres descend through subcortical white matter and form the anterior two-thirds of the posterior limb of the <a href="/articles/internal-capsule">internal capsule</a>. They pass through the ventral <a href="/articles/midbrain">midbrain</a>, specifically the central and lateral portions of the inner crus, and continue through the <a href="/articles/pons">pons</a>. In the <a href="/articles/medulla-oblongata">medulla oblongata</a>, corticospinal fibres collect into a discrete bundle forming the pyramid <sup>1-2</sup>.</p><p>The pyramid is a discrete triangular column on the ventral medulla oblongata next to the midline. This is why the corticospinal tract is also called the pyramidal tract. Within the pyramids approximately 90% of the corticospinal fibres decussate, forming the <a href="/articles/lateral-corticospinal-tract">lateral corticospinal tract</a>. The remaining 10% fibres remain ipsilateral (i.e. do not decussate) and form the <a href="/articles/anterior-corticospinal-tract">anterior corticospinal tract</a> <sup>1-4</sup>.</p><p>The anterior and lateral tracts are discussed separately. </p><ul>-<li><a href="/articles/anterior-corticospinal-tract">anterior corticospinal tract</a></li>-<li><a href="/articles/lateral-corticospinal-tract">lateral corticospinal tract</a></li>- +<p>The<strong> corticospinal tract </strong>(also known as the<strong> pyramidal tract</strong>) is a descending white matter tract primarily concerned with motor function that extends caudally from the motor cortex to synapse with motor neurones of the <a href="/articles/spinal-cord">spinal cord</a> in the anterior horns. </p><h4>Gross anatomy</h4><h5>Central<strong> </strong>connections</h5><p>Corticospinal fibres are axons from upper motor neurones in the cerebral cortex. Over half of these arise in the <a href="/articles/precentral-gyrus">primary motor cortex</a> with additional contributions from the <a href="/articles/premotor-cortex">premotor cortex</a>, <a href="/articles/supplementary-motor-area">supplementary motor cortex</a> and even the sensory cortex. In the <a href="/articles/precentral-gyrus">primary motor cortex</a>, fibres arise specifically from <a href="/articles/betz-cells">Betz cells</a> <sup>1,2,4</sup>.</p><h5>Intracranial course</h5><p>Organised somatotopically, these fibres descend through subcortical white matter and form the anterior two-thirds of the posterior limb of the <a href="/articles/internal-capsule">internal capsule</a>. They pass through the ventral <a href="/articles/midbrain">midbrain</a>, specifically the central and lateral portions of the inner crus, and continue through the <a href="/articles/pons">pons</a>. In the <a href="/articles/medulla-oblongata">medulla oblongata</a>, corticospinal fibres collect into a discrete bundle forming the pyramid <sup>1,2</sup>.</p><p>The pyramid is a discrete triangular column on the ventral medulla oblongata next to the midline. This is why the corticospinal tract is also called the pyramidal tract. Within the pyramids approximately 90% of the corticospinal fibres decussate, forming the <a href="/articles/lateral-corticospinal-tract">lateral corticospinal tract</a>. The remaining 10% fibres remain ipsilateral (i.e. do not decussate) and form the <a href="/articles/anterior-corticospinal-tract">anterior corticospinal tract</a> <sup>1-4</sup>.</p><p>The anterior and lateral tracts are discussed separately. </p><ul>
- +<li><p><a href="/articles/anterior-corticospinal-tract">anterior corticospinal tract</a></p></li>
- +<li><p><a href="/articles/lateral-corticospinal-tract">lateral corticospinal tract</a></p></li>
-<li><a title="Amyotrophic lateral sclerosis" href="/articles/amyotrophic-lateral-sclerosis-3">amyotrophic lateral sclerosis</a></li>-<li>-<a title="MOG antibody-associated disease" href="/articles/mog-antibody-associated-disease">MOG antibody-associated disease</a> <sup>5</sup>-</li>-<li>-<a title="Neuromyelitis optica spectrum disorder" href="/articles/neuromyelitis-optica-spectrum-disorder">neuromyelitis optica</a> <sup>6</sup>-</li>- +<li><p><a href="/articles/amyotrophic-lateral-sclerosis-3" title="Amyotrophic lateral sclerosis">amyotrophic lateral sclerosis</a></p></li>
- +<li><p><a href="/articles/myelin-oligodendrocyte-glycoprotein-antibody-associated-disease-mogad" title="Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD)">MOG antibody-associated disease (MOGAD)</a> <sup>5</sup></p></li>
- +<li><p><a href="/articles/neuromyelitis-optica-spectrum-disorder" title="Neuromyelitis optica spectrum disorder">neuromyelitis optica</a> <sup>6</sup></p></li>
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