The medullary pyramid is a structure located in the brainstem, specifically within the medulla oblongata. It plays a crucial role in the central nervous system by containing motor fibers that originate from the cerebral cortex. These fibers are responsible for voluntary movement and descend to the spinal cord. In the medullary pyramid, the majority of these motor fibers cross over to the opposite side of the body, a process known as decussation. This crossing is significant because it means that each side of the brain controls the opposite side of the body, influencing motor function and coordination.