Why do corticospinal tracts cross over?

Corticospinal tracts cross over, or decussate, primarily to allow for the control of the opposite side of the body by the brain. This crossing occurs at the junction of the medulla oblongata and the spinal cord, enabling motor signals from the left hemisphere of the brain to influence movement on the right side of the body and vice versa. This anatomical design contributes to coordinated movement and motor function, facilitating complex motor tasks.