Broken Bones and Fractures
The bones in the human body are very strong; but they can be broken (fractured) as a result of trauma. Breaks can range in severity from hairline fractures that require minimal treatment to shattered bones that require surgery and may result in permanent damage.
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Ken knew the steps to the attic were steep, but when his little sister ran off with his toy airplane, he took the stairs two at a time. Halfway down he slipped. Ken landed in a heap at the bottom and immediately howled in pain. When he got up, his arm was twisted in a funny way, and his elbow would not bend.
Ken's mother rushed him to the emergency room where doctors took x-rays of his arm. He had broken the bone in the upper part of his arm as well as his elbow. The breaks were so bad that Ken had to have surgery that afternoon. The doctor put a metal pin in his elbow to hold the bones together while they healed. After surgery, Ken's arm had to be in traction for two weeks. This means that he had to lie on his back in bed while his elbow was held in place by a special device hanging from the ceiling. This device put tension on his arm and elbow in just the right places to allow them to heal properly. After getting out of the hospital, Ken had a plaster cast on his whole arm for another eight weeks. Ken's arm and elbow healed completely, but every so often his elbow aches when he plays baseball.
What Are Bone Fractures?
Bone is the hardest tissue in the human body, but when bones are subjected to forces that exceed their strength, they may break. The terms "break" and "fracture" mean the same thing.
- A simple fracture is the most common type of break. The bone breaks but does not break through the skin.
- A compound (open) fracture occurs when the broken bone breaks through the skin. This type of break is serious because, in addition to the damaged bone, bacteria can infect the body through the break in the skin. Sometimes the jagged edges of bone break blood vessels and cause bleeding.
A greenstick fracture is a type of incomplete fracture. Greenstick
fractures often affect children, whose bones are springy and resilient.
The best way to visualize a greenstick fracture is to think of trying to
break a small branch off a growing tree. It will not snap off; rather it
requires twisting. Twisting of the branch produces splinters. This is
similar to what happens in a greenstick bone fracture: the bone cracks
and splinters but does not break. If the bone does break into separate
pieces, it is called a complete fracture.
- Stress fractures are tiny hairline cracks that can occur when a bone is repeatedly stressed.
- An impacted fracture occurs when a bone breaks and the two pieces ram into each other.
- A comminuted fracture is one in which a bone shatters into pieces.
- Fractures also can occur through joints.
- Sometimes, people tear ligaments (tough bands of connective tissue that hold joints and bones together) even when a bone is not broken. Torn ligaments frequently affect the ankles and knees.
- Dislocations are injuries in which the bones in a joint are pulled apart or displaced in relation to each other. Ligament injuries and fractures often occur with dislocations.
What Causes Breaks and Fractures?
Bones break when they are subjected to extreme force or stress. The likelihood that a bone will break depends on the location of the bone in the body, the thickness of the bone, and the circumstances under which the force was applied. The most commonly broken bones are those in the wrist, hip, and ankle.
Bone is living tissue, and like other living tissue in the body, bone is affected by genetics, hormones, diet, physical activity, disease, and drugs. All of these things can make bones more or less prone to injury. In addition, the strength of bone and the forces acting on bone vary with age, so the types of fractures and the number of people affected by them vary with age as well.
Anatomy of Bone
The human skeleton consists of 206 bones that support the body and allow it to move. There are 29 bones in the skull, 27 in each hand, and 26 in each foot.
Bone is living tissue. It consists of cells, blood vessels, connective tissue, proteins, and fibers, as well as minerals such as calcium and phosphorus. Every bone contains both trabecular (tra-BEK-yoo-lar) and cortical (KOR-ti-kal) bone. Trabecular, or cancellous (KAN-sell-us) bone, looks like honeycomb. Despite being porous, it is very strong. Cortical bone is solid and dense. In cross-section, it has circular patterns like those seen in a tree trunk. It forms the outer layer of bones. Many bones also contain bone marrow, where blood cells are made.
The ratio of trabecular to cortical bone varies depending on the type of bone. Trabecular bone surrounded by a thin layer of cortical bone makes up the spine, skull, ribs, and sternum (breast bone), whereas the bones of the arms and legs consist mostly of cortical bone, with only a small amount of trabecular bone at both ends.
150 Years Ago:
The practice of military medicine during the U.S. Civil War contributed to the development of medical knowledge. Broken and shattered bones were frequent occurrences on battlefields. Treatment techniques were recorded in detailed reports by military physicians and were published in the Medical and Surgical History of the War of the Rebellion, written by Otis A. George and Joseph J. Woodward. The book's case studies of wounded soldiers, and its statistics about the nature of wounds and the effectiveness of various treatments, provided a basis for improved management of wounds and fractures in the decades that followed.
Many types of trauma (for example, skiing or car accidents) can cause a bone to break. However, some people are more prone to breaks because they have genetic conditions or bone diseases that weaken their bones. For example:
- Osteogenesis imperfecta, which means imperfect bone formation, is also called brittle bone disease. People with this condition have inherited genes that cause a defect in the production of bone. The result is weakened bones that break easily.
- Osteoporosis is a disease that causes a thinning and weakening of the bones, making them prone to fracture. It affects older adults, particularly women after they reach menopause.
- Osteopetrosis is a rare hereditary disease that causes the bones to thicken. Osteopetrosis comes in several forms, some of which cause joint problems. Osteopetrosis congenita is discovered in infancy or childhood and it affects the bone marrow; without a bone marrow transplant, this condition usually is fatal. Marble bone disease also is discovered in infancy. It causes short stature and mental retardation.
- Other diseases, such as bone cancer, osteomalacia (adult rickets), Paget's disease (in which the bones become enlarged, weak, and deformed), and exposure to radiation can weaken bones and make them susceptible to breaks.
How are Fractures Diagnosed and Treated?
A doctor may suspect a broken bone based on the appearance of the injured area. A fractured bone may cause swelling or bruising in the affected area. As in Ken's case, the affected limb might look deformed and it may hurt to move. Sometimes, a break is obvious because the bone has poked through the skin. By touching and pressing on the injured area, the doctor may be able to tell if a bone is broken. X-rays of the injured area usually confirm the diagnosis of a broken bone, although stress fractures or hairline fractures can be difficult to detect on x-rays.
Broken bones may be treated by realigning the bones back into their proper position, if necessary (a process called "reduction"), and then holding them in place while they heal.
Treating a broken bone depends on where in the body it is located and how severe the break is. In the case of a stress fracture, a device called a splint may be used to immobilize the injured area while it heals. An arm sling also may be used to keep a person from using an injured arm. When a person has a simple fracture, the doctor will guide the bones back into their proper place, if necessary, and then immobilize the injured area with a cast made of plaster or fiberglass.
Is It Broken?
People can break bones anytime and anywhere. To assess the situation, doctors often look for signs of fractures and ask about symptoms. Among the signs doctors look for:
- Is the area swollen and bruised?
- Is the limb hanging at a funny angle?
- Does the limb look out of place?
- Is the bone sticking out through the skin?
Among the symptoms doctors ask about:
- Did the injured person feel or hear anything breaking?
- Can they move the injured area?
- Does it hurt when touched?
Other more serious types of fractures can require surgery. For example, in Ken's case, realigning the bones was not a straightforward task. An orthopedic surgeon (bone specialist) needed to open the site of the fracture surgically and use metal pins and plates to hold the bones together temporarily, while they healed. Ken's injury required his arm to be in traction for several weeks before having a cast for another two months.
Splints, casts, and slings are used to keep bones in place while they heal. Healing occurs when the bone tissues produce a substance called callus, which binds the broken pieces together. Healing time varies with age. A fracture that may take three weeks to heal in a four-year-old may take three months to heal in an adult. Casts for simple breaks usually stay on for six to eight weeks, but more severe breaks may require a cast for much longer time periods.
Many people recover completely from breaks and fractures. One possible complication, however, is osteomyelitis, an infection of the bone. Usually, it affects the long bones in the arms and legs but it can be treated with antibiotics. Fractures through joints may increase the risk for arthritis in that joint later on in life, and older people, many of whom have osteoporosis, may not recover well from broken bones.
Perry, Clayton R., and John Elstrom. The Handbook of Fractures. New York: McGraw-Hill, 1998.
American Association of Orthopedic Surgeons, 6330 North River Road,
Rosemount, IL 60018.
Osteogenesis Imperfecta Foundation, 632 Center Street, Van Wert, OH 45891.