Tenosynovitis of extensor carpi radialis longus (ECRL), and extensor carpi radialis brevis (ECRB).
The tendons of first compartment (APL & EPB) pass superficially obliquely over ECRL and ECRB in the
2nd compartment at musculotendinous junction. This
intersection occurs dorsoradially at the junction of the middle and distal
thirds of the forearm, just proximal to the extensor retinaculum.
de Quervain tenosynovitis, 1st CMCJ osteoarthritis