I was on a school board in a comfortable suburb, and this kind of thing sadly does happen to teachers all the time. What is disgusting is that administrations often do not support the teachers in these altercations. Both these girls should be expelled and face serious felony charges.
When I was on the board, our high school principal exited a stairwell into a single loaded class hallway, and a student plowed into him with his shoulder and knocked this principal off his feet into the lockers along the wall. The principal said, 'watch it son', and the kid said 'F *&) You!'. The idiot principal wanted to let the altercation go, and I told the superintendent, you have only one choice, suspend the kid for one week or else. His parents squaked, and the Admin wanted to end the suspension. I told the superintendent one week. I had to force him to suspend the punk.
Subsequent to this event, we issued a school policy that clearly stated zero tolerance for bad behavior, and every student signed the policy acknowledging their comprehension of the policy. A lot of kids were expelled because of the policy, including students with very influential parents.