Extensor Digitorum Brevis

Original Editor - Ahmed Nasr Top Contributors - Ananya Bunglae Sudindar, Kim Jackson, Abbey Wright and Ahmed Nasr

Origin[edit | edit source]

Extensor digitorum brevis.png

Extensor Digitorum Brevis (EDB) is one of the intrinsic muscles on the dorsum of the foot. It arises from the upper and lateral surface of the calcaneus, the floor of tarsal sinus, the talocalcaneal ligament, and the stem of the inferior extensor retinaculum. [1][2]


Insertion[edit | edit source]

It inserts via tendons into the base of the proximal phalanx of the 1st toe, and the middle phalanx of the three medial digits joining with the extensor digitorum longus tendon (toes 2-4)[2][3]

Blood Supply[edit | edit source]

The extensor digitorum brevis muscle has a well-developed vascular network. It is supplied proximally by the branches of fibular artery and branches of anterior tibial artery. Distally it is supplied by the dorsalis pedis artery and its branches. [4]

Nerve Supply[edit | edit source]

Deep fibular nerve (S1, S2)[3]

Action[edit | edit source]

Assists Extensor digiorium longus in extending the metatarsophalangeal and interphalangeal joints of the 2nd, 3rd and 4th toes.[2] It also assists extensor hallucis longus and brevis in 1st toe metatarsophalangeal extension.

[5]

Clinical Relevance[edit | edit source]

  • EDB muscle flap can be used for small defects and infection prevention of bones and joints following traumatic injuries. The extensor digitorum brevis muscle flap proves to be a dependable option which can be attributed to the muscle tissue's inherent resistance to infections, its capacity for effective antibiotic distribution, and its acceptable donor-site morbidity. [6]
  • EDB is often incorporated into composite flaps. The EDB tendon along with a dorsal foot flap are used to repair soft tissue and tendon defects on the dorsal hand. The usage of EDB in the flap allows for simultaneous repair of defects and restoration of finger extension functions allowing for optimal outcomes. [7]
  • EDB muscle wasting is a decisive clinical indicator of significant lumbar canal stenosis as opposed to pure disc prolapsed. This clinical indicator can be used to plan for further investigative procedures. [8]

Assessment[edit | edit source]

Palpation[edit | edit source]

EDB can be palpated on the lateral dorsum of the foot. By encouraging extension of the digits of the foot you can palpate and observe what is described as a swelling where the muscle belly of EDB originates.

[9]

Muscle testing[edit | edit source]

EDB muscles can be tested by applying resistance over the toes towards flexions (excluding the hallux/ 1st toe) and asking the person to extend the toes against resistance. The video below demonstrates this examination:

[10]

Resources[edit | edit source]

KENHUB - Extensor Digitorum Brevis

References[edit | edit source]

  1. Anatomy next. Extensor digitorium brevis. Available fromhttps://www.anatomynext.com/extensor-digitorum-brevis/ accessed at (26july 2019)
  2. 2.0 2.1 2.2 Keith L. , Anne M. R . Clinically Oriented Anatomy . philidephia : Lippincott Williams & Wilkins.Feb 13, 2013
  3. 3.0 3.1 Drake RL, Vogl W, Mitchell AWM. Gray's Anatomy for Students. 39th ed. London; Elsevier; 2005. p574-575
  4. Moore KL, Dalley AF, Agur AM. Clinically oriented anatomy. Lippincott Williams & Wilkins; 2013 Feb 13.
  5. nabil ebraheim. Extensor Digitorum Brevis - Everything You Need To Know - Dr. Nabil Ebraheim. Available from: https://www.youtube.com/watch?v=GQvjwpXdQ38 [last accessed 30/1/2018]
  6. Woussen A, Feuvrier D, Woussen É, Fageot J, Sergent P, Leclerc G, Obert L, Pluvy I. Extensor digitorum brevis muscle flap for lower extremity coverage in a context of posttraumatic sepsis. Orthopaedics & Traumatology: Surgery & Research. 2021 Jun 1;107(4):102901.
  7. Tian H, Song D, Jin H, Liu Q, Zhao Y, Wang X, Qu W, Li R. Repair of soft tissue and extensor tendon defects on the dorsum of the hand by transfer of dorsal foot flap and extensor digitorum brevis tendon in a 3-year-old child: a case report. Medicine. 2020 Aug 8;99(34).
  8. Munakomi S, Kumar BM. Wasting of Extensor Digitorum Brevis as a Decisive Preoperative Clinical Indicator of Lumbar Canal Stenosis: A Single‑center Prospective Cohort Study. Annals of Medical and Health Sciences Research. 2016;6(5):296-300.
  9. C Blake. Extensor Digitorum Brevis. Available from: https://www.youtube.com/watch?v=LVpF_Mk1avM [last accessed 20/11/2012]
  10. 1. Extensor digitorum longus and brevis muscle test [Internet]. YouTube; 2012. Available from: https://www.youtube.com/watch?v=RM2iSBOBHIg