Unsuccessful ultrasound/curved cervix

[Poodlemom4now]

Hi, I was supposed to have my saline solution ultrasound today so the Dr would know where to implant the embryos in the future.  It didn't go well and the Dr was unable to get the catheter through my cervix.  She ended up stopping and deciding to wait until I'm under sedation during egg retrieval.  At that point she will dialate my cervix (or uterus, I'm really unsure) for a more clear picture.   My question is why was this not an issue at my HSG?  The HSG wasn't a party but it certainly wasn't this bad and all was well with results.  Why would the curved cervix not have inhibited the HSG like it did today?

I start my first injections for IVF on Saturday- I can tell it's going to be a heck of a ride :)

Thanks in advance.