Mobile data nonfunctional after impact

My Nexus 4 received a reasonable impact while in my pocket, I suspect the impact was to it's front face. I have successfully replaced the screen, but it appears there was additional damage somewhere as the device has been unable to establish a 2g/3g mobile data connection ever since (4g has never been supported in my case). Voice and SMS work just fine, as do wifi and bluetooth. I haven't been able to test NFC, wireless charging or GPS.

I am assuming due to the timing that this is a hardware issue but have no idea how to go about tracking down what specifically might be damaged. During screen placement no damage to the rear of the device was obvious but due to the nature of the impact it is possible that damage was sustained to the rear as the phone was in my pocket between me and what I hit.

The settings -> about -> status menu merely indicates the status of "mobile data disconnected" and power usage has been surprisingly low the last few days which suggests to me it hasn't even been trying to connect.

My main questions are relating to the antennae - the teardown guide suggests there are multiple cellular antennae but do they have divided responsibilities in terms of the features they supply, how can I determine if one is damaged?