The DCML somatosensory pathways ascend in what manner?

• A. Contralateral from DRG
• B. Bilateral
• C. Discrete crossing
• D. Ipsilateral from the DRG (ascends on the same side as the receptor)

Answer: (D)

The system carrying fine touch, vibration, and proprioception travels up the body on the same side as the receptor. After entering the dorsal root ganglion, these fibers ascend in the dorsal columns (fasciculus gracilis for the lower body, fasciculus cuneatus for the upper body) without crossing, staying ipsilateral all the way to the medulla. There they synapse in the gracile and cuneate nuclei and cross over to form the contralateral medial lemniscus, which then continues to the thalamus and cortex. So describing the ascent as ipsilateral from the DRG captures the actual path up to the medullary crossing.