Tetanus is a specific infection in which tetanus bacilli invade the body through skin or mucosal wounds, grow and multiply in a hypoxic environment, producing exotoxins that cause contractions and paroxysmal spasms of the transverse muscle. Wound contamination and hypoxic environment are the necessary conditions for the occurrence of this disease. All types and sizes of wounds may be contaminated, especially open fractures, wounds containing rust, puncture wounds with small and deep wounds, blind canal trauma, and firearm wounds, which are more susceptible to contamination by tetanus bacilli. If the outer wound opening is small, the wound is filled with necrotic tissue, blood clots, overfilling, local ischemia, etc., a hypoxic environment suitable for the growth and reproduction of the bacterium is formed. The disease is more likely to occur if there is also an aerobic bacterial infection, the latter further consuming the residual oxygen in the wound.