Extensor Carpi Radialis Brevis

Original Editor Uchechukwu Chukwuemeka

Top Contributors - Uchechukwu Chukwuemeka, Kim Jackson and Aya Alhindi

Original Editor -

Top Contributors - Uchechukwu Chukwuemeka, Kim Jackson and Aya Alhindi

Description[edit | edit source]

ECR-brevis.png

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.It is the prime dorsiflexor of the wrist.[2]

Origin[edit | edit source]

It originates from the common extensor tendon with extensor carpi ulnarisextensor digiti minimi, and extensor digitorum at the Lateral epicondyle of humerus together[3].

Insertion[edit | edit source]

It attaches at the radial side dorsal surface of the base of the 3rd metacarpal[1]. The extensor carpi radialis brevis shares a common synovial sheath with the extensor carpi radialis longus.[2]

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[2][1] .

The posterior interosseous nerve provides motor innervation to the deep and superficial extensors of the posterior compartment and the extensor carpi radialis brevis.[4]

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[2].

Function[edit | edit source]

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

Clinical relevance[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.[2]

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.[2]

Assessment[edit | edit source]

With the hand in pronation, the ECRB muscle can be palpated during extension and abduction of the wrist against resistance.[2]

[5]

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 2.2 2.3 2.4 2.5 2.6 Walkowski AD, Goldman EM. Anatomy, shoulder and upper limb, forearm extensor carpi radialis brevis muscle. StatPearls Publishing; 2023.
  3. 3.0 3.1 Drake, RL, Vogl, W, Mitchell, AW, Gray, H. Gray's anatomy for Students 2nd ed.  Philadelphia : Churchill Livingstone/Elsevier, 2010
  4. Anderson TB, Bordoni B. Anatomy, Shoulder and Upper Limb, Forearm Nerves. 2024
  5. Classroom BOT. MMT Individual Muscle Extensor Carpi Radialis Brevis (ECRB) [Internet]. Youtube. Available from: https://www.youtube.com/watch?v=39HFvxSj8ZU