Extensor Carpi Radialis, Longus and Brevis

Radial Nerve, Posterior Cord, Posterior Division, Upper and Middle Trunk, C6, C7. 

Longus The lower third of the supracondylar ridge of humerus. Brevis The lateral epicondyle of humerus. 

Longus Dorsal surface of base of second metacarpal. 

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The typical mechanism of injury is a large varus force on an extended supinated forearm, causing the extensor carpi radialis longus and brevis to avulse the lateral condylar physis. This may cause either a partial avulsion, leaving a cartilaginous epiph-... 

Lateral (wrist extensor) and supinator Supplied by the radial and the posterior interosseous nerve, this group consists of the supinator, extensor carpi radialis longus, extensor carpi radialis brevis, extensor digitorum communis, and the extensor carpi ulnaris. 

Owing to a differential diagnosis list which mainly includes wrist problems (i.e., de Quervain disease and Wartenberg neuropathy), the most important tendinopathy of the mobile wad compartment affecting the tendons of the extensor carpi radialis brevis and longus as they traverse the components of the first dorsal extensor tendon compartment, so-called intersection syndrome, will be discussed in Chapter 10. 

Fig.l0.17a-f. Extensor tendons second and third compartments, a-c Transverse 15-7 MHz US images obtained distal to the Lister tubercle with d-f diagram correlation. From cranial (a) to caudal (c), US shows the extensor pollicis longus tendon as a thin fibrillar band (arrowheads) crossing the extensor carpi radialis brevis (ECRB) and longus (ECRL)... 

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