Extensor Carpi Radialis Brevis

Original Editor Uchechukwu Chukwuemeka

Top Contributors - Uchechukwu Chukwuemeka and Kim Jackson

Original Editor -

Top Contributors - Uchechukwu Chukwuemeka and Kim Jackson

Description[edit | edit source]


Extensor carpi radialis brevis (ECRB) is a short muscle emerging underneath the extensor carpi radialis longus and both muscles share a common tendinous synovial sheath[1]. It is an extensor muscle located superficially at the posterior compartment of the forearm.

Origin[edit | edit source]

It originates from the common extensor tendon with extensor carpi ulnaris, extensor digiti minimi, and extensor digitorum at the Lateral epicondyle of humerus together[2].

Insertion[edit | edit source]

It attaches at dorsal surface of the base of the 3rd metacarpal[1]

Nerve[edit | edit source]

ECRB is innervated by the deep branch of radial nerve (7th and 8th cervical nerve root) before the nerve courses through the two heads of the supinator muscle[1][3]

Artery[edit | edit source]

The main blood supply to ECRB is from the radial artery. Other augmentation are from the radial collateral branch from profunda brachii and the radial recurrent artery[3].

Function[edit | edit source]

ECRB extends and abducts the wrist[2][3][1]

Clinical relevance[3][edit | edit source]

Lateral epicondylitis presents as pain on the lateral aspect of the elbow with or without loss of grip strength that is aggravated with activity and it will most likely have extensor carpi radialis brevis muscle affectation.

In cases of radial nerve compromise proximal to its division to deep and superficial branches at the cubital fossa, then some functional loss of wrist and digits extension will be present.

Assessment[edit | edit source]

With the hand in pronation, the ECRB muscle can be palpated during extension and abduction of the wrist against resistance.


References[edit | edit source]

  1. 1.0 1.1 1.2 1.3 Moore, KL, Dalley, AF, Agur, AM. Clinically oriented anatomy. 7th ed. Baltimore, MD: Lippincott Williams & Wilkins, 2014
  2. 2.0 2.1 Drake, RL, Vogl, W, Mitchell, AW, Gray, H. Gray's anatomy for Students 2nd ed.  Philadelphia : Churchill Livingstone/Elsevier, 2010
  3. 3.0 3.1 3.2 3.3 Walkowski AD, Goldman EM. Anatomy, Shoulder and Upper Limb, Forearm Extensor Carpi Radialis Brevis Muscle. Available from: https://www.ncbi.nlm.nih.gov/books/NBK539719/ (accessed 26 July 2019)
  4. OTstudentVids. MMT of Flexor Carpi Radialis/Ulnaris and Extensor Carpi Uln. Available from: https://www.youtube.com/watch?v=31Wbe7xv8Jk [last accessed 29/3/2019]