Ligament injuries are common in whiplash.  Think of ligaments like duct tape; they hold bones together.  Ligaments also play a key role in telling the bones how much to move and protecting the joints and nerves.  When these structures are injured, thy usually heal.  However, sometimes they can't heal and instability occurs.  When this happens, deep supporting muscles get weak, nerves get irritated (causing more muscle weakness), and joints get inflamed and painful.  Ligament injuries after whiplash are usually accompanied by lots of popping and cracking.  While these symptoms are common after whiplash, this is usually caused by tight muscles and bad posture.  How can you tell the difference?  When the popping and cracking feels good or relives pressure, it's almost always due to tight muscles and bad posture.  However, when the popping causes more pain, numbness, or other symptoms; it may be due to instability.  Flexion-extension views should be done to rule-out any type of instability.