Your forearm is made up of two bones, the radius and ulna. In most cases of adult forearm fractures, both bones are broken.
Fractures of the forearm can occur near the wrist at the farthest (distal) end of the bone, in the middle of the forearm, or near the elbow at the top (proximal) end of the bone. This article focuses on fractures that occur in the middle segments of the radius and ulna. Fractures that involve the wrist or the elbow are discussed in separate articles.
If you hold your arms at your side with your palms facing up, the ulna is the bone closest to your body and the radius is closest to your thumb. The ulna is larger at the elbow — it forms the “point” of your elbow — and the radius is larger at the wrist.
The primary motion of the forearm is rotation: the ability to turn our palms up or down. The ulna stays still while the radius rotates around it. This is the motion used to turn a screwdriver or twist in a light bulb. Forearm fractures can affect your ability to rotate your arm, as well as bend and straighten the wrist and elbow.
Forearm bones can break in several ways. The bone can crack just slightly, or can break into many pieces. The broken pieces of bone may line up straight or may be far out of place.
In some cases, the bone will break in such a way that bone fragments stick out through the skin or a wound penetrates down to the broken bone. This is called an open fracture and requires immediate medical attention because of the risk for infection.
Because of the strong force required to break the radius or ulna in the middle of the bone, it is more common for adults to break both bones during a forearm injury. When only one bone in the forearm is broken, it is typically the ulna — usually as a result of a direct blow to the outside of your arm when you have it raised in self defense.
The most common causes of forearm fractures include:
A broken forearm usually causes immediate pain. Because both bones are usually involved, forearm fractures often cause an obvious deformity — your forearm may appear bent and shorter than your other arm. You will most likely need to support your injured arm with your other hand.
Additional symptoms include:
Most people with forearm fractures will go to an urgent care center or emergency room for initial treatment.
It is important that your doctor knows the circumstances of your injury. For example, if you fell from a ladder, how far did you fall? It is just as important for your doctor to know if you sustained any other injuries and if you have any other medical problems, such as diabetes. Your doctor also needs to know if you take any medications.
After discussing your symptoms and medical history, your doctor will do a careful examination. Your doctor will:
X-rays are the most common and widely available diagnostic imaging technique. X-rays can show if the bone is broken and whether there is displacement (the gap between broken bones). They can also show how many pieces of broken bone there are.