Final answer:
Methylprednisolone is the medication used to control edema of the spinal cord in a client with limited movement of the upper extremities due to a spinal cord injury at the level of T12.
Step-by-step explanation:
When a client is admitted with a spinal cord injury at the level of T12 and has limited movement of the upper extremities, the medication used to control edema of the spinal cord is Methylprednisolone (Solu-Medrol). Methylprednisolone is a corticosteroid that helps reduce inflammation and edema in the spinal cord. It is commonly used in the treatment of spinal cord injuries to minimize secondary damage and improve neurological recovery.