brachioradialis muscle | ![]() |
For the most part, the superficial and intermediate groups arise from the lateral epicondyle of the humerus.
Muscles of the Posterior Compartment of the Forearm |
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The Extensor Expansion |
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Once the muscles of the posterior compartment are identified and studied, take a look at the insertions of the tendons of the extensor digitorum. They are special and deserve closer attention.
The extensor tendons insert into the phalanges by way of a special connective attachment called the extensor expansion. |
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Dorsal View | ![]() |
Lateral View | ![]() |
When the extensor digitorum muscle contracts, it pulls on the extensor expansion and this, in turn extends the interphalangeal joints. You will also notice that the lumbrical muscle inserts into the hood part of the expansion and through this attachment can also extend the interphalangeal joints. This muscle can at the same time flex the metacarpophalangeal joint. Because of these two actions, the lumbricals are called the bye bye muscles. That is the action they perform. |
Nerves of the Hand![]() |
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![]() | This is copyrighted© 1999 by Wesley Norman, PhD, DSc |