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Extensor indicis proprius

Extensor indicis proprius
Transverse section across distal ends of radius and ulna. (Label "Ext. indic. prop." visible at bottom center.)
The mucous sheaths of the tendons on the back of the wrist. (Extensor indicis proprius visible going into second digit.)
Latin musculus extensor indicis
Gray's subject #125 456
Origin: ulna
Insertion: index finger (extensor hood)
Nerve: posterior interosseous nerve
Action: extends index finger, wrist
Dorlands/Elsevier m_22/12548933

The extensor indicis proprius (Extensor indicis) is a narrow, elongated muscle, placed medial to, and parallel with, the extensor pollicis longus.

Origin and insertion

It arises, from the dorsal surface of the body of the ulna below the origin of the Extensor pollicis longus, and from the interosseous membrane.

Its tendon passes under the dorsal carpal ligament in the same compartment as that which transmits the tendons of the Extensor digitorum communis, and opposite the head of the second metacarpal bone, joins the ulnar side of the tendon of the Extensor digitorum communis which belongs to the index finger.


The Extensor indicis proprius extends the index finger, and by its continued action assists in extending the wrist.

Additional images

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant.

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Extensor_indicis_proprius". A list of authors is available in Wikipedia.
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