An involuntary contraction of muscles, causing a clinching or twitching of that part of the body. In persons with spinal cord injuries, spasm of the paralyzed muscles is common and can interfere with daily activities and medical care. In addition, some people report pain from the spasms. Spasms can usually be controlled with drugs. When that does not work, doctors sometimes kill the nerves leading directly to those muscles (below the injury at the spinal cord) either with direct injections or, in extreme cases, with surgery.