Facial muscles are often affected first. Trismus or lockjaw is most common. This condition results from spasms of the jaw muscles that are responsible for chewing. Muscle spasms are progressive and may include a characteristic arching of the back known as opisthotonus. Muscle spasms may be intense enough to cause your bones to break and your joints to dislocate.
Severe cases can involve spasms of the vocal cords or muscles involved in breathing.
If this happens, death is likely, unless medical help is readily available. In cephalic tetanus, in addition to lockjaw, weakness of at least 1 other facial muscle occurs. In two-thirds of these cases, generalized tetanus will develop. In localized tetanus, muscle spasms occur at or near the site of your injury. This condition rarely progresses to generalized tetanus.