Anterior corticospinal tract

The anterior corticospinal tract is formed at the level of the of the medullary pyramids, where the majority (90%) of descending corticospinal tract fibres decussate to form the lateral corticospinal tract. The majority of the remaining non-decussating 10% of fibres form the much smaller anterior corticospinal tract 1,2

It descends in the anterior funiculus of the spinal cord, lying close to the anterior median fissure. At each relevant level, fibres cross the anterior commissure of the spinal cord to synapse with ventral horn motor neurones.  The anterior corticospinal tract thus becomes smaller as it descends, ending at the level of the mid-thoracic cord. 

In some cases, the anterior corticospinal tract is absent. In rare cases, this tract may contain all corticospinal fibres.

The anterior corticospinal tract is primarily responsible for gross and postural movement of the trunk and proximal musculature 3

Spinal anatomy
Neuroanatomy
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Article information

rID: 47408
Section: Anatomy
Synonyms or Alternate Spellings:

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Cases and figures

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    Fig 1: corticospinal tracts
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    Fig 2: spinal cord tracts
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