Extensor medii proprius muscle
variant muscle of the forearm
The extensor medii proprius (so called the extensor digiti medii) is a rare anatomical variant in the extensor compartment of the forearm. The aberrant muscle is analogous to the extensor indicis with the insertion being the middle finger instead of the index finger.
Structure
The extensor medii proprius originates from the distal third of ulna near the extensor indicis and the adjacent interosseous membrane. It passes through the fourth extensor compartment along with the extensor indicis and the extensor digitorum. It inserts to the extensor expansion of the middle finger usually on the ulnar side of the tendon of the extensor digitorum of the middle finger, though, insertion deep to the extensor digirorum tendon was seen. Insertion to the fibrous tissue proximal to the metacarpophalangeal joint of the middle finger was also reported.
Prevalence
The reported incidence of the extensor medii proprius in cadaveric dissections ranges from 0% to 12%. Meta-analysis showed that the prevalence of this muscle was significantly higher in North American and Japanese populations than European and Indian populations.
Function
The extensor medii proprius extends the middle finger. The presence of this anomalous muscle results in a more independent movement of the middle finger.
Begin with the source’s own compact description: “Extensor medii proprius muscle” is variant muscle of the forearm. The dossier treats that line as a proposition to test through Extensor, medii and proprius, not as a finished interpretation.
Why this record matters
The phrase “variant muscle of the forearm” supplies a clear boundary for inquiry. It also exposes the unanswered questions: who defined that boundary, when it became stable and which sources sit outside it.
Named sources, stable identifiers and responsible institutions provide the strongest route from overview to verifiable evidence. The source revision retrieved here is dated Oct 28, 2025. The linked authority identifier is Q25348601. None of the 0 selected statements returned an explicit reference.
Overview language is designed for orientation and should not be treated as a substitute for the evidence cited beneath it. The lead is largely declarative, so disagreement and counter-evidence require a deliberate search beyond the opening account. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
How to read it
Use the entry as an orientation point, then follow its citations and revision history. Names, dates and institutional relationships should be checked against the original record.
- Subject orientation
- Search vocabulary
- Locating named sources
The closest primary source, responsible institution and strongest cited specialist reference.
Three-step research path
- Establish the record: confirm the title “Extensor medii proprius muscle”, its source revision and the description used here.
- Expand the search: follow Extensor medii proprius muscle primary sources, Extensor medii proprius muscle archive and Extensor research across catalogues and specialist indexes.
- Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.
Questions for further research
- Which source most directly establishes the central claim about “Extensor medii proprius muscle”?
- What terminology or title could unlock a more precise catalogue search?
- Which cited source is closest to the event, object or claim?
Search terms from this dossier
This entry incorporates text from “Extensor medii proprius muscle” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.