my sister has a split nipple, which sounds like what you are talking about with the crack down the middle, and she didn't have problems with actually feeding from them - she ended up not being able to produce any milk, but nothing to do with her nipples.

Some OB's will check your breasts at your 1st appointment, if they don't do this, then ask them to check them for you. and trust me sweetie, they have seen all kinds, so I am sure yours won't shock them!! Also don't place too much pressure on yourself, if you can't breastfeed, you can't breastfeed, bottle or boob, you will be feeding your baby with love, and formulas have come such a long way that your baby would get all the nourishment it needed.