No bullet path through back and neck was confirmed through dissection of JFK.
Sure, cutting JFK's neck halfway off would have pleased the Kennedy family upstairs, who wanted no unnecessary mutilation. While they're at it, why not dissect his face and ears into slices looking for potential fragment tracks?
When everything between the neck in-shoot and out-shoot signaled damage, it was obvious the wounds connected, but only after Humes learned there had been a bullet hole seen at the throat.