The muscles of the forearm are attached to the end of the fingers by way of strong bands of connective tissue known as tendons. These tendons move the fingers by sliding through pulleys in the hand and fingers when the forearm muscles are contracted. Due to an injury or age-related changes in the tendon, a thickened nodule can develop, causing a restriction of the tendon’s ability to slide through the pulleys. This can lead to a ‘triggering’ as the tendon is forced through a pulley. Commonly, trigger fingers occur in individuals who suffers from systemic conditions including rheumatoid arthritis and diabetes.