According to the American Society for Surgery of the Hand (ASSH), stenosing tenosynovitis is a condition commonly known as “trigger finger.” If it occurs in the thumb then it is called “trigger thumb”.
Normally, our fingers bend with the help of a pulley system. There are several pulleys along the length of our fingers and thumb.
When we make a fist, the tendons in our fingers glide easily with the help of pulleys. These pulleys hold the tendons close to the bone. This is similar to how a line is held on a fishing rod. If the pulley becomes too thick or inflammed, the tendon becomes ‘stuck’ as it tries to pass through the first pulley. Hence, causing a ‘pop’, ‘catch’, ‘snap’, ‘ or ‘lock’.