Presentation
Wrist pain and swelling.
Patient Data
Abnormal intrasubstance increased signal and surrounding edema is seen along the course of extensor pollicis longus (EPL) when crossing the extensor carpi radialis longus (ECRL) and extensor carpi radialis brevis (ECRB) tendons associated with ECRL and ECRB tenosynovitis.
A skin marker has been placed by the technologist to indicate the location of the patient's wrist pain.
Case Discussion
The ECRB, ECRL and EPL tendons intersect distal to the Lister’s tubercle and radiocarpal joint. The tubercle acts as a pulley, changing the EPL tendon angle when it crosses superficially over the ECRL and ECRB tendons. This creates a mechanically disadvantageous arrangement, where motion of the thumb and hand may cause friction between this tendons.