Radiopaedia.org

There is hypoechoic retinacular thickening involving both tendons of the 1st extensor compartment of the wrist which correlates with the site of the pain. A thickened hypoechoic intertendinous septum is present separating both tendons which are abductor pollicis longus and extensor pollicis brevis. There is associated local hypervascularity in the retinaculum.

The asymptomatic side was examined for comparison. It does not show retinacular thickening. There is possibly a presence of the intertendinous septum.