A car accident is possibly the most common cause of a C5-C6 disc or vertebrae injury. In even the most minor crashes, drivers can suffer from whiplash, which primarily injures the cervical spine due to the forceful whipping motion of the head. Other common causes of C5-C6 disc or vertebral injuries include general wear and tear, slipping and falling, sports injuries, motorcycle accidents, truck accidents, violent assaults, and even poor posture.