Chest injuries most often affect the ribs, upper part of the abdomen, lungs, blood vessels, heart, muscles, soft tissues, and breastbone. Sometimes the esophagus, collarbone, or shoulder blade is also injured.
The skin and the tissues under it are kept at a constant temperature (about 98.6° F, or 37° C) by the circulating blood and other mechanisms. The blood gets its heat mainly from the energy given off by cells when they burn (metabolize) food—a process that requires a steady supply of food and oxygen. A normal body temperature is necessary for proper functioning of all the cells and tissues in the body. In a person with low body temperature, most organs, especially the heart and brain, become sluggish and eventually stop working.
A dislocation is complete separation of the bones that form a joint. In subluxation, the bones in a joint are partly out of position. Often, a dislocated joint remains dislocated until it is put back in place (reduced) by a doctor, but sometimes it moves back in place on its own.
People who engage in deep-sea or scuba diving are at risk of a number of injuries, most of which are caused by changes in pressure. These disorders also can affect people who work in underwater tunnels or caissons (watertight enclosures used for construction work). Such structures contain air under high pressure to keep out water.
The goal of first aid is to save life, to prevent an injury or illness from worsening, or to help speed recovery. First aid for cardiac arrest, choking, internal bleeding, minor wounds, and minor soft tissue injuries is discussed in this chapter. Other chapters discuss first aid for the following:
The thick, hard bones of the skull help protect the brain from injury. Also, the brain is surrounded by layers of tissue (meninges) containing cerebrospinal fluid, which cushions the brain. Consequently, most bumps and knocks on the head do not injure the brain. Head injuries that do not affect the brain are considered minor.
Humans, who are warm-blooded animals, maintain their body temperature within 1 or 2 degrees of 98.6° F (37° C) as measured by mouth and 100.4° F (38° C) as measured rectally, despite large fluctuations in external temperatures. This internal temperature range must be maintained for the body to function normally. Body temperature that gets too high or too low can result in serious injury to organs or death.
The structure of the face and eyes is well suited for protecting the eyes from injury. The eyeball is set into the orbit, a socket surrounded by a strong, bony ridge. The eyelids close quickly to form a barrier to foreign objects, and the eye can at times tolerate minor impact without damage.
The kidneys and the rest of the urinary tract (the bladder, ureters [tubes that carry urine from the kidneys to the bladder], and urethra) may become injured in a number of ways. Examples include injuries due to a blunt force (most commonly motor vehicle crashes, falls, or sports injuries) or a penetrating force (most commonly gunshot or stab wounds), or surgery. Injuries to the urinary tract often occur together with injuries to other organs, especially abdominal organs. In men, the penis and testes may also be injured.
Mass-casualty weapons are weapons that can produce a mass-casualty incident. Mass-casualty incidents overwhelm available medical resources because they involve so many injured people (casualties). Mass-casualty weapons include a variety of
The spine consists of 24 back bones (vertebrae) plus the tailbone (sacrum). The vertebrae bear most of the body's weight and thus are under a lot of pressure. Disks of cartilage between each back bone help cushion and protect the bones. The spine forms a protective canal of bone in which the spinal cord is encased.
Sports injuries are common among athletes and other people who participate in sports. Certain injuries that are traditionally considered sports injuries can also occur in people who do not participate in sports. For example, homemakers and factory workers often develop tennis elbow, although they may never have played tennis.
Sprains are tears in ligaments (tissues that connect one bone to another). Other soft-tissue injuries include tears in muscles (strains) and tears (ruptures) in tendons (tissues that connect muscles to bones).