The mechanism of a rear-end collision begins with the basic principles of physics set forth by Newton: A mass at rest remains at rest until acted upon by some external force; and a mass in motion remains in motion until acted upon by some external force. Physical laws dictate that rear-end collisions produce a sudden acceleration which is transmitted through the car seat to the victim’s body. The head, being a mass at rest, remains at rest until acted upon by the rear-ending force. The great flexibility of the neck, with the weight of the head (approximately 8 1/2 pounds) resting upon its otherwise free end, results in a forceful hyperextension of the neck as the body is accelerated forward. When the head hits the top of the back of the seat, or the headrest in most cars, this impact, together with the reflex contraction of the neck muscles, starts the head in forward motion. The head continues forward until it is acted upon by some external force, such as contact with the steering wheel, the windshield or the restraining action of the soft-tissue structures which hold the head and neck on the body. This type of injury tends to stretch and tear the soft tissues that limit extension and flexion.

Most insurance adjusters seem to focus upon the amount of damage done to the rear-ended vehicle. While the amount of force of the trauma is one factor to be considered, it is generally not the most significant. The plaintiff’s medical witnesses must be prepared to state that even a slight impact or force may cause varying degrees of serious injury to the spinal cord, depending upon such factors as the age of the patient, direction of the thrust, and position of the body at the time of impact. The plaintiff’s counsel needs to obtain information on the speed of both vehicles, road surface conditions, and use of seat and lap belts. It is also important to establish whether the injured person was aware that the accident was about to occur, the reason being that a person who sees the approach of a car and tenses for an impact will usually have a more severe injury than a person who is relaxed and unaware of what is happening. Likewise, the age of the individual is significant. The degree of force sufficient to cause a serious injury in a person of advanced years may cause no more than a slight sprain of the cervical ligaments in a younger person. The reason for this difference in vulnerability is attributed to the mobility and smooth function of the joints in the younger person, as contrasted with the naturally degenerated or aged condition of the older person.


The effects of hyperextension/hyperflexion injury of the cervical spine are dependent on many individual factors and circumstances, including the following.

  1. The physical status of the cervical spine. For example, persons previously injured or suffering from cervical disc disease or degeneration.
  2. The actual physical form of the person involved. Example: A person having a shorter neck generally has a lesser risk of serious injury compared to a person having a longer neck.
  3. The height of the person. Height is also a relative risk factor for injury to the cervical spine.
  4. The type of clothing being worn at the time of an accident. A tight collar could be significant since it could cause compression of the carotid vessels and cervical region.
  5. The presence of a headrest in the vehicle and its position at impact.
  6. The emotional state of the person at the time of injury.
  7. Various biomechanical factors associated with the acceleration and deceleration actually experienced by the head as it moves the cervical spine in extension and flexion. Acceleration and deceleration experienced by the spine during injury will be affected by: (a) The weights of the colliding vehicles and the disparity in their weights; (b) The relative positions of the vehicles; (c) The speeds of the vehicles—especially the degree of motion of the vehicle in which the injured person is seated; (d)The degree of motion and the direction of motion of the injured person at the time of impact; movement will be dependent on body position, position of the arms, legs and feet (The person may have turned his or her head while backing up, had a foot and leg extended on the accelerator, leaned forward, been the driver, front seat passenger, or back seat passenger); (e) The condition of the roadway, including wet or dry (Road surface affects how much acceleration force is transmitted through the car and how much is absorbed by the occupants); (f) Multiple impacts.

It is necessary to establish the extent of all of these factors to accurately calculate the severity of the biomechanical forces imposed on the cervical spine during Tampa rear-end accident.


There is no uniform or characteristic pattern of the effect of a hyperextension/hyperflexion injury. Symptoms may include vertigo, blurring of vision, stiffness and pain in the cervical area, dull headaches in the occipital area, pain in the jaw, pain or tingling in one or both arms or legs, nausea, nervousness, restlessness, inability to concentrate, irritability and tension. Proof of such subjective complaints sometimes requires the injured person to rely, in large measure, on his/her credibility. Nevertheless, a clear understanding of the impact of the acceleration/deceleration forces on the intricate cervical structures will help your Tampa car accident lawyer make an effective presentation of his or her client’s injuries.


A hyperextension/hyperflexion injury can cause bleeding from the site of the soft-tissue injury into the area of the cervical spine. As blood escapes from its normal vascular location, it can act as an irritant and form an adhesion between adjacent tissue surfaces. Hemorrhaging into a muscle can lead to radiating pain. Likewise, contusions and overstretching or tearing of muscles or ligaments may produce edema, with resulting pain.

Tearing soft tissues in the cervical area may result in hemorrhage, causing pressure on adjacent nerve roots and a wide variety of neurological disturbances. Pain may radiate from the shoulders, down through the arms into the fingers. Sensory disturbances such as these suggest some degree of nerve root involvement and are an indicator that referral should be made to a neurologist for a determination of the degree of involvement.

Dizziness and headaches, even without a direct concussive blow to the head, can develop in hyperextension/hyperflexion injuries, notwithstanding the fact that neurological examinations may be negative. It is well documented that injury to the cervical spine is a common cause of headaches.


Our law firm has dealt with virtually every type of insurance company out there.  Some handle claims better than others.  Some are more reasonable than others.  We have an institutional knowledge of how to deal with all of them.

If you have been in an accident and you would like to discuss, call our Tampa Car Accident Lawyers and we can assist you during the insurance claims process,

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