These are due to severe pressure of a heavy object over a part of the body. There may not be much of an external injury. But there can be extensive damage to the tissues underneath, e.g. muscles and bones. Internal hemorrhage is possible. Toxic materials released from the damaged tissue can enter the blood stream and cause failure of the kidneys.
First aid
1. Release the trapped part from under the heavy object.
2. Place the victim in a head-low position.
3. Treat hemorrhage and shock.
4. Splint fractures. Elevate the injured limb if possible.
5. Shift him to a hospital immediately.
BLAST INJURIES
Explosions can result from a bomb blast or from accidental ignition of explosive gases. Explosions generate waves of high pressure that can damage lungs and other organs of the body. That can rupture ear drums, cause fractures, and cause embedding of glass pieces in tissues.
First aid
1. Do not move the victim unless it is necessary to get him away from further danger at the site of the explosion.
2. Reassure the casualty.
3. Place him in a half-sitting position, supporting the head and shoulders.
4. Loosen any constricting clothing that may impair breathing movements.
5. Treat bleeding and shock.
6. Treat wounds and burns.
7. Treat fractures.
8. Shift him to a hospital immediately.