Site of pyramidal decussation?

• A. Midbrain
• B. Medulla oblongata
• C. Spinal cord
• D. Cerebellum

Answer: (B)

The crossing of the corticospinal fibers happens at the pyramidal decussation in the medulla oblongata. From the motor cortex, these fibers travel through the internal capsule and cerebral peduncles, then reach the medullary pyramids. At the caudal end of the medulla, most fibers cross to the opposite side and continue down the spinal cord as the lateral corticospinal tract, ultimately reaching alpha motor neurons to produce contralateral voluntary movement. The midbrain contains parts of the tract before crossing but not the crossing point itself, the spinal cord is where the fibers descend after crossing, and the cerebellum is not where the decussation occurs.