Most of the injuries that occur to people as a result of some sort of vehicular crash are musculo-skeletal in nature. Such injuries involve the bone and joints, muscles and tendons and the nervous system. To understand a little more detail with such injuries it is helpful to know some definitions and anatomy.
The Orthopedic System of the body involves its bone and joints and muscles and tendons for the most part. It is these systems couple with the nervous system which provide us the ability to stand and move about. The Nervous System is composed generally of the Central Nervous System, which is the brain and spinal cord and the Peripheral Nervous System which are the nerves which go from and into the spinal cord.
The Nervous System is also divided into a Motor System, nerves which cause movement, and a Sensory System, nerves which allow us to feel and sense position in space. A very detailed discussion of the anatomy and/or physiology is beyond the scope of this article but suffice it to say that the peripheral sensory nerves take impulses from the environment and converts them into an electric signal which is brought to the brain up the spinal cord. Contrary to this is the motor system which takes impulses originating in the brain and sends those signals down the spinal cord to all parts of the body.
The orthopedic system receives signals from the motor nervous system when a person wants to move. The signal instructs the muscles to contract on the side that will move and instructs the contra-balancing muscles on the other side to relax at the very same time. The movement of the muscle across a joint causes the movement.
If an accident occurs there are numerous ways the force and trauma can harm the above systems. An obvious effect is pain. When there is some sort of forceful contact with or violent motion in any part of the body this tends to cause injury. A nerve or muscle can be over-stretched or a bone and joint might be forced to bear too heavy a load. There can always be direct traumatic contact from a flying part that has come loose. At the simplest level any of the above injuries, no matter how slight, are capable of causing pain to the injured part. Greater degrees of trauma can go on to cause parts to stretch apart or even break (fracture).
At the scene of a crash it is important to try and make a basic assessment of the damages to yourself or others. Extreme pain is usually consistent with serious damage. For the most part, the pain will usually be where the injury is but that is not always true. Deformity of a part is another very quick way to determine the gravity of an injury as loss of normal anatomic shape is also associated with a more serious injury such as a fracture bone or dislocated joint. The presence of blue discoloration of the skin is also often associated with deep tissue injury. If there is crepitus, a grinding noise, from bone this is also a potential sign of a fracture being present. Holding or supporting the part to prevent motion is also a sign of possible serious injury.
It is not so common that life threatening hemorrhage (bleeding) occurs with the above sort of serious injuries. Usually, there will be bleeding with these types of injuries but it is self limited and will stop. It is usually venous bleeding and not the more dangerous arterial side hemorrhage. Bleeding from an artery can occur but in general arteries are anatomically situated very deep in the extremities and elsewhere for their protection. Veins, on the other hand, are more scattered about but they clot and stop bleeding on their own. An arterial bleed will be under pressure and will appear as a pulsatile, brisk bright red bleed. A venous bleed will usually be non-pulsatile and slower and of darker red color. Direct pressure on a venous bleed usually helps stop it and this can also help with an arterial bleed. Arterial bleeds may actually keep going even with pressure and so sometimes a tourniquet, a shirt, towel whatever, can be tied around the arm above the bleed to stop it. This must be released at short intervals to allow blood flow so that the parts below don’t die from loss of Oxygen. Usually, paramedics are on scene in time to deal with theses issues.
Extremities can be splinted with something rigid tied around to make them much more comfortable if response time is going to be long for 911. In general, the idea is not to use any part that is injured and to wait for the first responders to help you. Back injuries can be especially serious since all of the nerves and spine are in there so it is always safe to advise holding still if there is such an injury. Finally, the brain itself can be injured by both open and closed trauma to the head. The rigid skull does do a very good job of protecting the brain but sometimes the force of impact is so great that forces can be transmitted across the skull and into the brain without the appearance of any outside injury. If a person in any way seems to be dizzy or less aware of surroundings or language then a concussion or internal brain trauma should be suspected. This person should be protected in place until help arrives.