So, some information is beginning to leak out in MSM articles on FG's injuries.
BBM
http://www.msn.com/en-us/news/us/fr...-in-back-of-police-van-say-reports/ar-BBiXIAC
So, what is being described in this article, and by commentators such as Dr. Kobilinsky (ME) of CNN, is that there was indeed a serious head injury. I think it's entirely possible the cervical fracture damage is as a result of that head injury-- axial loading, resulting in a specific kind of fracture called a "burst fracture." Burst fractures are a result of high velocity axial impact.
http://en.wikipedia.org/wiki/Burst_fracture
There have also been comments that he may have been in a full cardiac arrest at the van scene-- IDK yet if that's been confirmed.
Keep in mind that the head injury could have been intentional (slamming him into the van while handcuffed and unable to break his fall), or as a result of him struggling and breaking free and falling while being placed in the van, or due to rough driving (intentional, or accidental) and his head impacting the bolt.
So while we know a little more, we still don't know what caused the head impact.
And no one is talking about laryngeal damage today. There is also no mention of FG being "beaten", as some posters have speculated. That will be in the autopsy if there are signs-- but remember, FG was in the hospital a week before he died.