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In Depth: Arm

The arm consists of several pieces that together make it one of the most useful tools of the human body. These parts are:

  • Upper arm: Extending from the shoulder to the elbow, the upper arm provides pulling and lifting strength.
  • Elbow: This hinged joint allows the arm to swing 180 degrees at full extension.
  • Forearm: The forearm is the area between the wrist and the elbow. The muscles in the forearm rotate the wrist.
  • Wrist: Located in the upper hand, 13 bones — along with multiple muscles and tendons — form this intricate area.
  • Hand: With five fingers, the hand allows humans to do much more complicated tasks than any other animal.

Bone fractures are among the most common injuries to the arm. These typically occur during high-impact collisions such as automobile accidents, falls, and sports injuries. The radius and ulna — the bones of the forearm — are commonly broken. They are often healed with casts to immobilize the bones, but compound fractures (multiple breaks) may require the surgical implantation of pins and other types of reinforcement.

The upper arm is also susceptible to painful inflammation of the outside muscle or tendon near the elbow. This is commonly known as tennis elbow. Repeated movements, such as a backhand stroke in tennis, cause this condition.

Carpal tunnel syndrome is another condition caused by repeated movements, such as regular use of a computer keyboard or mouse. Characterized by tingling and numbness in the hands or fingers, this condition causes pressure on the median nerve, which runs through the wrist on the thumb side of the hand. Special devices or technique change can improve the condition, but sometime carpal tunnel surgery is needed to relieve the pressure.

In cases of extreme injury, such as aggressive infection, circulatory disorders, or severe trauma, amputation may be needed. Amputation of the arm can be anything from a finger to the entire arm. Amputation is often a last resort when all other therapies or surgeries have been exhausted. However, thanks to prosthetics, many amputees continue to live normal, healthy lives after rehabilitation. 

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