Flexor carpi radialis brevis: case report of a symptomatic tear

Anatomical variants of muscle are commonly encountered by surgeons and radiologists. The flexor carpi radialis brevis (FCRB) is an anomalous muscle in the distal forearm with an estimated prevalence of 2–8%. In the literature, there are a few case reports of symptomatic FCRB tenosynovitis without a concomitant tear, and treatment methods described include both conservative and surgical management. We present a case of one patient with radial sided wrist pain and a partial FCRB tear, which to our knowledge is the first case report of a symptomatic FCRB tear. We also review existing literature regarding FCRB anatomy, particularly related to intra-operative dissection and exposure. Identification of an anomalous FCRB on imaging may serve to guide clinicians in their differential diagnosis of radial-sided wrist pain, in which FCRB pathological conditions ought to be included.