Anterior white commissure

The anterior white commissure (ventral white commissure) is a bundle of nerve fibers which cross the midline of the spinal cord just anterior (in front of) to the gray commissure (Rexed lamina X). A δ fibers and C fibers carrying pain sensation in the spinothalamic tract contribute to this commissure, as do fibers of the anterior corticospinal tract, which carry motor signals from the primary motor cortex.

Two of the five sensory modalities, pain and temperature, cross sides at the anterior white commissure. Therefore, a pre-medullary lesion will result in contralateral (opposite sided) pain and temperature loss, whereas touch, pressure, and proprioception will be ipsilateral (same sided).