Are the wife's grandmothers (from the mother's or father's side) considered محرم (unmarriageable) to the husband, and are the husband's grandfathers (from the father's or mother's side) considered محرم to the wife?

The wife's grandmother is forbidden to the husband, and the husband's grandfather is forbidden to the wife, whether from both parents or from one of them. So, whoever marries a woman, her mothers become forbidden to him. And if any of his sons or grandsons, no matter how far down, marries her, she becomes forbidden to him.