English: A lesion of the pyramidal tract abolishes fine grasping movements.

A. A monkey is normally able to make individuated movements of the wrist, fingers, and thumb in order to pick up food in a small well. B. After bilateral sectioning of the pyramidal tract the monkey can remove the food only by grabbing it clumsily with the whole hand. This change results mainly from the loss of direct inputs from cortico-motoneurons onto spinal motor neurons. A pyramidal tract transection is not equivalent to a motor cortex

lesion, however, because not all pyramidal tract axons terminate in the spinal cord. The axons that do project to the spinal cord originate in several cortical areas, including the motor cortex, and the corticospinal tract is only one of several parallel output pathways of the motor cortex.