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The extensor digitorum is a muscle found in the forearm. It is also sometimes known as the extensor digitorum communis. As the name suggests, it is an extensor muscle and is used in extending both the fingers and the wrist. An example of an everyday use of the muscle is pulling the hand back towards the forearm. The muscle is also used in extension of the elbow.
The origin of the extensor digitorum muscle is on the lateral side of the humerus. From this position, the muscle runs down the middle of the forearm before splitting into four different tendons. These tendons each attach to one of the four fingers. The innervation of the muscle is via the posterior inerosseous nerve.
The little, ring, and middle tendons are all attached by bands. These bands connect the tendons by running downwards and sideways. In some people, the tendon that attaches the muscle to the first finger is connected to the second by a thin piece of tissue, although this is not always present.
The primary use of the extensor digitorum is to help extend the fingers. When the muscle extends, the fingers they usually become more spread out during the process. The muscle is additionally an essential part of activities that require wrist extension. Although the muscle is involved in extension of the elbow, this isn't its primary action.
Due to the extensor digitorum muscle's location in the wrist and forearm, it is involved in many daily activities and tasks. Any action that requires extension will use the muscle, including things such as waving. For this reason, when an injury occurs to the muscle it can be frustrating and difficult to heal.
Tennis elbow is a common injury that can affect the extensor digitorum. This injury is often caused by overuse of the extensor muscles that attach to the elbow. Symptoms of the condition include pain on the outside of the elbow and a weakness in the wrist and fingers. Treatment involves rest, ice, and compression.
Stretching the extensor digitorum can be achieved through an extensor stretch. To perform this stretch, the person stands with the arm straight out in front of him and wrist relaxed. With the forearm facing towards the ceiling, the other hand should bend the wrist downwards until a stretch is felt. This position should be held for 30 seconds and repeated on both arms.