Align Vertices's

I’m trying to define the central line of my model. I wish to ensure that the centre vertices’s on my model are all lined up along only the Z axis.
I know you can snap vertices’s to the 3D cursor, but that groups them all together in one place.

select the vertises and scale them to 0 along the z-axis (‘s -> z -> 0’)

Aha! Thank you that’s perfect!