Can anyone translate this sweep jargon for me?

[MayimBialik]

Had a sweep today and it says the following things in my notes:

CX central - I presume CX is cervix? Is central good?
Effaced Os - I understand effaced, anyone know what Os is?
Ceph -2 fixed - I think ceph is referring to position of baby but what is -2 fixed?

Hope there are some knowledgable types out there that can help. Thanks!

Cervix central. Good.

Effaced os. Os is the hole. Effaced means nice and thinned out, not like a tube still. Good.

Ceph. Head down. Good

-2. 2cm above ischial spines (pelvis nobbly bits). Good. Not too high up.

Fixed. Nicely engaged and not floating around or bobbing up and away when prodded.

Ah brilliant. Thankyou