def create_friedman_line(point0,point1):

    """
    Determines the second point needed to form the Friedman line

    :param point0: First point on glenoid line, anatomically defined as a
        point on the anterior margin of glenoid
    :param point1: Second point on glenoid line anatomically defined as a
        point on the posterior margin of glenoid

    :raises: Value Error if the z values of point0 and point1 are not equal

    :returns: The midpoint of the glenoid line, which is the second point of
        the Friedman line
    """

    if point0[2] != point1[2]:
        raise ValueError("For Friedman method points must have equal z values")

    midpoint_x = (point0[0] + point1[0])/2
    midpoint_y = (point0[1] + point1[1])/2
    midpoint = [midpoint_x, midpoint_y,point0[2]]
    return midpoint