<P> The primary motor cortex or precentral gyrus , is one of the most important areas in the frontal lobe . The precentral gyrus is the most posterior gyrus of the frontal lobe and it lies anterior to the central sulcus . The pyramidal cells of the precentral gyrus are also called upper motor neurons . The fibers of the upper motor neurons project out of the precentral gyrus ending in the brainstem , where they will decussate ( intersect ) within the lower medulla oblongata to form the lateral corticospinal tract on each side of the spinal cord . The fibers that do not decussate will pass through the medulla and continue on to form the anterior corticospinal tracts . The upper motor neuron descends in the spinal cord to the level of the appropriate spinal nerve root . At this point , the upper motor neuron synapses with the lower motor neuron , each of whose axons innervate a fiber of skeletal muscle . </P>
<P> The primary motor cortex or precentral gyrus , is one of the most important areas in the frontal lobe . The precentral gyrus is the most posterior gyrus of the frontal lobe and it lies anterior to the central sulcus . The pyramidal cells of the precentral gyrus are also called upper motor neurons . The fibers of the upper motor neurons project out of the precentral gyrus ending in the brainstem , where they will decussate ( intersect ) within the lower medulla oblongata to form the lateral corticospinal tract on each side of the spinal cord . The fibers that do not decussate will pass through the medulla and continue on to form the anterior corticospinal tracts . The upper motor neuron descends in the spinal cord to the level of the appropriate spinal nerve root . At this point , the upper motor neuron synapses with the lower motor neuron , each of whose axons innervate a fiber of skeletal muscle . </P>
where are the upper motor neurons that control skeletal muscles found
where are the upper motor neurons that control skeletal muscles found
the precentral gyrus
the precentral gyrus