Which option contains the sensory fibers that transmit the sensation of light touch?

• A. Spinothalamic tract
• B. Posterior column
• C. Spinothalamic tract and posterior column
• D. Proprioception

Answer: (C)

Light touch can be carried by two main ascending pathways. The posterior column–medial lemniscus pathway transmits fine, discriminative touch (along with vibration and proprioception) from the body. The spinothalamic tract, particularly its anterior (ventral) portion, transmits crude touch and pressure signals. Because light touch can be perceived as either a precise tactile sensation or a more diffuse, crude sensation, signals can travel via either pathway. Thus, the sensation of light touch may be transmitted through both the spinothalamic tract and the posterior column, making that combined option the best choice. Proprioception is a separate modality primarily carried by the posterior column, so it alone isn’t the complete carrier for light touch.