Tetanus is a specific infection caused by Clostridium tetani. The incubation period of tetanus is generally seven to eight days, but it can be as short as 24 hours or as long as several months to years. Patients with shorter incubation periods have a worse prognosis. Tetanus occurs within two weeks after injury in 90% of patients, presenting symptoms such as general weakness, headache, dizziness, chewing difficulty, local muscle tightness, painful pulling, and increased reflexes. Typical symptoms include muscle tonic contraction, opisthotonus, and facial expressions characterized by lockjaw and a sardonic smile.