A common form of tendonitis that affects both golfers and nongolfers involves the flexor tendons of the fingers. As the flexor tendons travel from the palm to their respective fingers, they pass through a tunnel of fibrous tissue called the "flexor tendon sheath". This sheath both nourishes and lubricates the tendon.

A "trigger finger" occurs when a flexor tendon becomes inflamed, resulting in a thickening in the tendon. The thickened tendon can then catch (trigger) as it passes into its sheath at the base of the finger (arrow). As the finger is then flexed and extended, a painful popping sensation is felt.