Acute bacterial disease caused by Clostridium tetani (see clostridium). Spores of this organism are common, especially in soil; it thrives away from oxygen in deep wounds, especially punctures. Its toxin stimulates nerves, causing muscle rigidity with frequent spasms. This may occur around the site of the wound or, if the toxin reaches spinal motor ganglia via the bloodstream, throughout the body. The jaw muscles are almost always involved (lockjaw). Vaccination every few years is the best protection; an antitoxin prevents or delays symptoms in cases of suspect wounds but has limited value once they develop. Treatment usually includes antibiotics, sedatives, and muscle relaxants. Recovered patients are not immune.

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• trismus, a pathological condition in which the mouth is held shut by sustained spasm of the masseter (jaw) muscle, often observed in cases of tetanus
• tetanus, an infectious disease of the central nervous system
• Lockjaw (comics), a character from Marvel Comics' Inhumans
• Lockjaw (band), a UK punk rock band from the 1970s
• Eddie "Lockjaw" Davis, a jazz saxophonist (d. 1986)
• Locust Valley Lockjaw, an upper-class American accent