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Extensor Carpi Radialis Brevis

   


- See: Forearm Extensors :

- Anatomy:
    - origin: lateral condyle of humerus;
    - insertion:
           - this tendon inserts into the base of 3rd metacarpal and is in direct relationship with the ECRL, which inserts into the base of the 3rd metacarpal;
    - action:
           - extension and abduction of the hand at the wrist;
           - ECRB is prime dorsiflexor of the hand;
    - synergists: ECRL, ECU;
    - nerve supply:
           - PIN (C6 > C7, C8) supplies ECRB & supinator muscles before entering arcade of Froshe;
           - PIN may be compressed by the tendinous origin of the ECRB;
           - w/ humerus frx need to r/o radial nerve palsy (1st nerve branches distal to frx site will be ECRB & supinator);

- Discussion:
    - pathology of origin of ECRB may cause tennis elbow syndrome, however, PIN syndrome may also cause "lateral epicondylitis;
    - osteophyte from 2nd & 3rd carpal metacarpal joint (capal boss) is just beneath ECRB & ECRL, and may cause a tendonitis;

- Rupture of ECRB:
    - important consideration for wrist prosthesis in R.A.;
    - balance of extensor tendons is of primary importance, esp ECRB;
    - w/o this tendon (due to rupture), there is no effective wrist extension;
    - do not confuse w/ rupture of ECRL  or  EDC;
         - if active wrist extension does not go beyond neutral, or if there is significant palmar carpal subluxation, integrity of ECRB should be questioned;
    - tendon transfers  have been successful, and therefore, when ECRB tendon is not intact, arthrodesis is indicated



Tennis elbow. The surgical treatment of lateral epicondylitis.

Lateral extensor release for tennis elbow. A prospective long-term follow-up study.

Microscopic histopathology of chronic refractory lateral epicondylitis.

Extensor carpi radialis brevis, an anatomical analysis of its origin

Anatomic Factors Related to the Cause of Tennis Elbow