The pyramidal system is a major motor system comprised of the axons that run through the corticospinal and corticobulbar tracts.  The corticospinal neurons are involved with the movement of fingers, hands, arms torso, legs, and feet.  The corticobulbar neurons are involved with the movement of the neck, face, oral cavity, and larynx.  Damage to either the corticospinal or corticobulbar tracts above the level of efferent cranial nerve nuclei will result in problems with the motor activity on the opposite side.  For instance, if there is damage to the lateral area of one precentral gyrus, the muscle function of the face and oral cavities on the opposite side could be affected.  For a diagram of affected areas due to damage of certain parts of the pyramidal system click here. 


The topographical layout of the pyramidal cells and axons helps to explain the distribution of spasticity of muscles in children with cerebral palsy.


Diagram of pyramidal system


Diagram of topographical distribution