For a few seconds after the convulsion has ceased, whilst the patient is cyanosed and the breathing forced, there is complete flaccidity of all the body muscles. The first sign of muscular activity is a contraction of the masseter muscle, which holds the mouth tightly closed. This is followed by rigidity of a definite pattern; in its complete form the neck is retracted, the mouth closed, the shoulder flexed and adducted, the elbow flexed and the forearm pronated, the hip, knee and ankle joint are extended. Wrists, fingers and toes are invariably flaccid, offering no resistance to passive movements. In the extreme forms of rigidity the extension in the lower limbs is so intense that it is impossible to overcome it by force.