Tetanus is an acute, often fatal, disease caused by an exotoxin produced by the bacterium Clostridium tetani. It is characterized by generalized rigidity and convulsive spasms of skeletal muscles. The muscle stiffness usually involves the jaw and neck and then becomes generalized. Clostridium tetani is a slender, gram-positive, anaerobic rod that may develop a terminal spore. The organism is sensitive to heat and cannot survive in the presence of oxygen. The spores; however, are very resistant to heat and the usual antiseptics.