def get_ax_idx(orientation: str) -> int:
    """
        Given a named orientation get the idx
        of the axis orthogonal to the plane,
    """
    if orientation == "frontal":
        return 0
    elif orientation == "sagittal":
        return 2
    elif orientation == "horizontal":
        return 1
    else:
        raise ValueError(f'Orientation "{orientation}" not recognized')