DeQuervain's tenosynovitis is a common cause of radial-sided wrist pain. 
Symptoms result from a narrow first dorsal compartment and associated tendinosis 
of the enclosed extensor pollicis brevis and/or abductor pollicis longus (APL). 
Surgical intervention, offered when conservative measures fail to adequately 
relieve symptoms, requires a detailed understanding of potentially aberrant 
anatomy in order to avoid persistence or recurrence of symptoms. We describe a 
case whereby the patient presented with complaints of thumb triggering in 
extension and associated disabling first dorsal compartment tendinosis. 
Intraoperatively, after supernumerary tendons were identified and addressed, the 
APL was at risk for subluxation over a prominent fibroosseous ridge. Routine 
first dorsal compartment release alone may have failed to address all of this 
patient's pathology.