Patient : The ring finger of my left hand always loses consciousness for no reason and can only be straight, not bent, just momentarily. I want to know what is the cause? Doctor : It may be the cause of tenosynovitis, or popping finger, which is a chronic aseptic inflammation caused by mechanical friction of the sheath tube that wraps around the flexor tendon. The tendon of the flexor finger is blocked from moving in the sheath tube it slides in, and popping or strangulation can occur. It is usually at the joint and may have pressure pain. Early closure therapy can be done, mostly with good results!