Final answer:
The lateral corticospinal tract is responsible for controlling the muscles of the limbs by crossing over at the pyramidal decussation and synapsing on lower motor neurons in the spinal cord's ventral horn. The anterior corticospinal tract controls trunk muscles and decussates at the spinal level before synapsing with lower motor neurons.
Step-by-step explanation:
The lateral corticospinal tract plays a critical role in the control of appendicular muscles, which include the muscles of the arms and legs. This tract is part of the major descending motor pathway known as the corticospinal tract. The axons of this tract originate in the primary motor cortex, descend through the brain, and cross the midline at the pyramidal decussation in the medulla. After decussation, these axons enter the lateral column of the spinal cord before synapsing on lower motor neurons in the ventral horn. These lower motor neurons ultimately project to and control the appendicular muscles.
On the other hand, the anterior corticospinal tract controls the muscles of the body trunk. These axons do not cross at the pyramids but instead remain in an anterior position down the brain stem and into the spinal cord, where they eventually decussate at the appropriate spinal level and synapse with lower motor neurons located in the medial regions of the ventral horn, controlling the axial muscles of the trunk.