Plexus Stretch lesion?

Young gentlemen who fell out of a moving vehicle and hit his shoulder first and then his neck (ie., bringing both apart). Pt noticed tingling for a 24-48 hours after the accident. The weakness in the right arm wasn't appreciated until almost a 12-14 months later. The subjective weakness was in the right forearm and hand. Everything in his forearm and hand would go numb. No neck pain was referred by the pt.

Physical Exam:
The AC joint was more prominent in the right shoulder...

Plexus Stretch lesion?