The force of an accident can lead to very severe injuries.  At the time of the accident many whom are able to walk away, choose to  go at it alone.  Injured victims go as far as refusing medical treatment at the time of the accident.  Many of these individuals sadly make it home to find out the the sequela of symptoms just start their presentations.  There is much written of the delay in onset of these symptoms.  The main reason most individuals delay care is that during the periods following a motor vehicle accident is due to the naturally released large amounts of adrenaline.  Adrenaline, released by the adrenal cortex is released due to the large amount of  stress cause by the incident.  This natural release is so great at times that it limits the bodies ability to feel pain.  The body is just simply fooled into not feeling pain at that moment.  It is for this reason that a competent clinical evaluations be performed as soon as possible even though the apparent presenting physical findings appear transient or minimal.