The motor system is _______ pathway.

• A. Spinothalamic
• B. Corticospinal
• C. Corticobulbospinal
• D. Column-medial lemniscus

Answer: (B)

Voluntary movement relies on descending motor pathways, with the corticospinal tract as the main route from the cortex to the spinal motor neurons. It starts in the primary motor cortex (and nearby motor areas), travels through the internal capsule and brainstem, and most fibers cross in the medullary pyramids to form the lateral corticospinal tract. This tract then descends in the spinal cord to synapse on alpha motor neurons in the ventral horn, enabling skilled, precise movements of the limbs. A smaller portion stays uncrossed to form the anterior corticospinal tract, influencing trunk muscles and crossing at the spinal level as needed. Spinothalamic and dorsal column–medial lemniscus pathways are sensory (pain/temperature and fine touch/vibration/proprioception, respectively), not motor. Corticobulbar tracts feed the cranial nerves for face and head movements, but the principal pathway for voluntary motor control to the spinal cord is corticospinal.