This thicker pulley causes friction on the moving tendon. The undersurface of the pulley can also change and thicken. And the higher volume of fluid increases pressure. The bigger lining then produces more fluid. If the tendon becomes tight within the pulley, the lining gets squeezed and reacts with thickening. The change in size of any of the important finger structures can cause problems. The finger tendon and pulley system is designed to have the exact right sizes of each structure. the pulley becomes thicker (the opening for the tendon gets smaller). The lining increases in thickness (does not fit through pulley well) 3. The tendon enlarges (does not fit through pulley well) 2. The pulleys are similar to how a line is held on a fishing rod (Figure 1).Ī trigger finger, sometimes referred to as a trigger thumb or stenosing tenosynovitis, can occur if one of three things happen: 1. The tendon and its lining are designed to glide through the pulleys without friction. The tendon and lining are covered by a series of thick, soft tissue called pulleys. The flexor tendons that bend the fingers have a lining on the outside. It can occur in both fingers and the thumbs, which have tendons that help them to bend. A trigger finger is a very common and treatable problem.
