You evaluate a patient whose right arm is markedly weak. Reflexes in the arm are diminished. However, you note that reflexes are rather brisk in the right leg and the patient has an up-going toe on...

You evaluate a patient whose right arm is markedly weak. Reflexes in the arm are diminished. However, you note that reflexes are rather brisk in the right leg and the patient has an up-going toe on the right. Reflexes are normal on the left. What structure is involved?

A. Peripheral nerves

B. Ventral roots

C. Spinal cord

D. Brainstem

E. Alpha motor neurons