| Anterior corticospinal tract | |
|---|---|
 Anterior corticospinal tract seen in red at bottom center in figure (text tag found at upper-left). | |
 Decussation ofpyramids. Scheme showing passage of variousfasciculi frommedulla spinalis tomedulla oblongata. a.Pons. b.Medulla oblongata. c. Decussation of the pyramids. d. Section of cervical part ofmedulla spinalis. 1. Anterior cerebrospinal fasciculus (in red). 2.Lateral cerebrospinal fasciculus (in red). 3.Dorsal column tracts (gracile fasciculus andcuneate fasciculus) (in blue). 3’.Gracile andcuneate nuclei. 4.Anterolateral corticospinal tract (in dotted line). 5.Pyramid. 6.Lemniscus. 7.Medial longitudinal fasciculus. 8.Ventral spinocerebellar fasciculus (in blue). 9.Dorsal spinocerebellar fasciculus (in yellow). | |
| Details | |
| Identifiers | |
| Latin | tractus corticospinalis anterior, fasciculus cerebrospinalis anterior |
| NeuroLex ID | birnlex_1618 |
| TA98 | A14.1.02.205 |
| TA2 | 6112 |
| FMA | 72636 |
| Anatomical terminology | |
Theanterior corticospinal tract (also called theventral corticospinal tract,medial corticospinal tract,direct pyramidal tract, oranterior cerebrospinal fasciculus) is a small bundle ofdescending fibers that connect thecerebral cortex to thespinal cord. Descending tracts are pathways by which motor signals are sent fromupper motor neurons in the brain tolower motor neurons which then directly innervate muscle to produce movement. The anterior corticospinal tract is usually small, varying inversely in size with thelateral corticospinal tract, which is the main part of thecorticospinal tract.
It lies close to theanterior median fissure, and is present only in the upper part of the spinal cord; gradually diminishing in size as it descends, it ends about the middle of the thoracic region.
It consists of descending fibers that arise from cells in the motor area of the ipsilateral cerebral hemisphere. The impulse travels from these upper motor neurons (located in the pre-central gyrus of the brain) through the anterior column. In contrast to the fibers for the lateral corticospinal tract, the fibers for the anterior corticospinal tract do not decussate at the level of themedulla oblongata, although they do cross over in the spinal level they innervate.[1] They then synapse at the anterior horn with the lower motor neuron which then synapses with the target muscle at the motor end plate. In contrast to the lateral corticospinal tract which controls the movement of the limbs, the anterior corticospinal tract controls the movements of axial muscles (of the trunk).
A few of its fibers pass to thelateral column of the same side and to the gray matter at the base of theposterior grey column.[citation needed]
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This article incorporates text in thepublic domain frompage 759 of the 20th edition ofGray's Anatomy(1918)
