What describes a tonic-clonic seizure?

A tonic-clonic seizure, previously known as a grand mal seizure, is characterized by a specific pattern of muscle activity. During this type of seizure, there is a sudden and intense contraction of all major muscle groups followed by rhythmic contractions and relaxations. This leads to a series of violent muscle contractions, which can result in the individual falling to the ground and may be accompanied by a loss of consciousness, making it distinct from other types of seizures.

The description of sudden cyclic tightening and loosening of all major muscle groups captures the essence of the tonic phase (sustained muscle contraction) followed by the clonic phase (alternating contractions and relaxations), thus accurately defining the behavior observed during a tonic-clonic seizure. Its physical manifestation, involving the entire body, is what sets it apart from the other types described.