Extreme muscular rigidity is typically observed in which phase of a seizure?

Extreme muscular rigidity is typically observed in the tonic phase of a seizure. During this phase, the muscles become stiff, leading to a sustained contraction. This rigidity is a direct result of increased neuronal activity and abnormal electrical discharges in the brain. The tonic phase is often characterized by the person becoming suddenly stiff, which may be accompanied by a loss of consciousness.

The other phases, such as the clonic phase, involve rhythmic jerking movements rather than rigidity. The hypertonic phase, though it indicates increased tone, does not specifically relate to seizures in the same way as the tonic phase does. The postictal state refers to the period following a seizure, where the individual may experience confusion and fatigue, rather than muscular rigidity. Therefore, the tonic phase is definitively identified by the extreme muscular rigidity that occurs at the onset of a generalized seizure.