Extensor indicis muscle

Extensor indicis is a narrow and elongated skeletal muscle in the deep layer of the dorsal forearm. It extends the index finger, and by its continued action assists in extending (dorsiflexion) the wrist and the midcarpal joints.

Etymology

The term "extensor indicis" is derived from Latin, with "extensor" meaning "stretcher" and "indicis" referring to the index finger. Thus, the term can be translated as "stretcher of the index".

Structure

The extensor indicis muscle originates from the distal third of the dorsal part of the body of the ulna and the interosseous membrane. It runs through the fourth tendon compartment together with the extensor digitorum communis. It has a small muscle belly and a long, thin tendon, which joins the ulnar side of the tendon of the extensor digitorum communis of the index finger.

Function

The extensor indicis muscle primarily functions to extend the index finger. It also provides additional extension to the wrist and the midcarpal joints when the hand is clenched into a fist.

Clinical significance

Injury to the extensor indicis muscle can result in a loss of ability to extend the index finger, which can significantly impact hand function. This muscle is also often used in tendon transfer surgeries due to its independent function.

See also

• List of muscles of the human body
• Extensor digitorum muscle
• Extensor digiti minimi muscle
• Extensor carpi ulnaris muscle

References

Extensor indicis muscle Resources
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