Extensor digitorum brevis manus muscle
Updates to Article Attributes
Body
was changed:
The extensor digitorum brevis manus (EDBM) muscle is an accessory muscle in the hand and is a normal anatomical variant.
Summary
- origin: distal radius and posterior radiocarpal ligament
- insertion: extensor hood of 2nd or 3rd digits (variable)
- innervation: posterior interosseous nerve
- action: extension of the digits
Epidemiology
It is thought to be present in ~3% of the population 1. It can be bilateral in up to half of cases.
Gross anatomy
The EDBM muscle lies along the ulnar side of the extensor tendon of the 2nd digit (usually fourth wrist compartment 5). It commonly arises at the distal end of the radius and posterior radiocarpal ligament to insert most commonly on the 2nd digit. However, insertion can also be seen on the 3rd, 4th, or 5th digits, as well as multiple insertions on more than one digit.
Arterial supply
-
pendinganterior interosseous artery 7
Innervation
Clinical presentation
The muscle is usually painless although rarely it can present as a painful mass over the dorsal aspect of the hand. Occasionally it may be associated with exercise-induced pain or tenosynovitis of the extensor tendons.
Radiographic features
Plain radiograph
Can be normal.
Ultrasound
Sonography may reveal a soft-tissue mass with muscle echotexture; in real time, it usually undergoes morphologic changes during active finger extension.
MRI
Signal characteristics include:
- T1/T2/PD: isointense to muscle on all sequences
- C+ (Gd): no enhancement in uncomplicated cases (e.g. unless there is inflammation)
-<p>The <strong>extensor digitorum brevis manus (EDBM)</strong> <strong>muscle</strong> is an <a href="/articles/accessory-muscle">accessory muscle</a> in the hand and is a <a title="Normal anatomical variants" href="/articles/anatomical-variants">normal anatomical variant</a>. </p><h4>Summary</h4><ul>- +<p>The <strong>extensor digitorum brevis manus (EDBM)</strong> <strong>muscle</strong> is an <a href="/articles/accessory-muscle">accessory muscle</a> in the hand and is a <a href="/articles/anatomical-variants">normal anatomical variant</a>. </p><h4>Summary</h4><ul>
-<strong>origin</strong>: <a title="Radius" href="/articles/radius">distal radius</a> and posterior radiocarpal ligament</li>- +<strong>origin</strong>: <a href="/articles/radius">distal radius</a> and posterior radiocarpal ligament</li>
-<strong>innervation</strong>: <a title="Posterior interosseous nerve" href="/articles/posterior-interosseous-nerve">posterior interosseous nerve</a>- +<strong>innervation</strong>: <a href="/articles/posterior-interosseous-nerve">posterior interosseous nerve</a>
-</ul><h4>Epidemiology</h4><p>It is thought to be present in ~3% of the population <sup>1</sup>. It can be bilateral in up to half of cases.</p><h4>Gross anatomy</h4><p>The EDBM muscle lies along the ulnar side of the extensor tendon of the 2<sup>nd</sup> digit (usually fourth wrist compartment <sup>5</sup>). It commonly arises at the distal end of the radius and posterior radiocarpal ligament to insert most commonly on the 2<sup>nd</sup> digit. However, insertion can also be seen on the 3<sup>rd</sup>, 4<sup>th</sup>, or 5<sup>th</sup> digits, as well as multiple insertions on more than one digit. </p><h4>Arterial supply</h4><ul><li>pending</li></ul><h4>Innervation</h4><ul><li><a href="/articles/posterior-interosseous-nerve">posterior interosseous nerve</a></li></ul><h4>Clinical presentation</h4><p>The muscle is usually painless although rarely it can present as a painful mass over the dorsal aspect of the hand. Occasionally it may be associated with exercise-induced pain or tenosynovitis of the extensor tendons.</p><h4>Radiographic features</h4><h5>Plain radiograph</h5><p>Can be normal.</p><h5>Ultrasound</h5><p>Sonography may reveal a soft-tissue mass with muscle echotexture; in real time, it usually undergoes morphologic changes during active finger extension.</p><h5>MRI</h5><p>Signal characteristics include:</p><ul>- +</ul><h4>Epidemiology</h4><p>It is thought to be present in ~3% of the population <sup>1</sup>. It can be bilateral in up to half of cases.</p><h4>Gross anatomy</h4><p>The EDBM muscle lies along the ulnar side of the extensor tendon of the 2<sup>nd</sup> digit (usually fourth wrist compartment <sup>5</sup>). It commonly arises at the distal end of the radius and posterior radiocarpal ligament to insert most commonly on the 2<sup>nd</sup> digit. However, insertion can also be seen on the 3<sup>rd</sup>, 4<sup>th</sup>, or 5<sup>th</sup> digits, as well as multiple insertions on more than one digit. </p><h4>Arterial supply</h4><ul><li>
- +<a title="Anterior interosseous artery" href="/articles/anterior-interosseous-artery">anterior interosseous artery</a><sup> 7</sup>
- +</li></ul><h4>Innervation</h4><ul><li>
- +<a href="/articles/posterior-interosseous-nerve">posterior interosseous nerve</a><sup> 7</sup>
- +</li></ul><h4>Clinical presentation</h4><p>The muscle is usually painless although rarely it can present as a painful mass over the dorsal aspect of the hand. Occasionally it may be associated with exercise-induced pain or tenosynovitis of the extensor tendons.</p><h4>Radiographic features</h4><h5>Plain radiograph</h5><p>Can be normal.</p><h5>Ultrasound</h5><p>Sonography may reveal a soft-tissue mass with muscle echotexture; in real time, it usually undergoes morphologic changes during active finger extension.</p><h5>MRI</h5><p>Signal characteristics include:</p><ul>
References changed:
- 7. Shereen R, Loukas M, Tubbs RS. Extensor Digitorum Brevis Manus: A Comprehensive Review of this Variant Muscle of the Dorsal Hand. (2017) Cureus. 9 (8): e1568. <a href="https://doi.org/10.7759/cureus.1568">doi:10.7759/cureus.1568</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/29057180">Pubmed</a> <span class="ref_v4"></span>
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