There are several common causes of pain at the root of the index finger: first, tenosynovitis of the flexor tendon, painful areas on the palmar side of the root of the index finger, which can be painful when pressed, aggravated when moving, and in severe cases, popping and even joint entrapment. Second, it is seen in acute trauma including sprains, contusions, and in serious cases, fractures, all of which can cause painful symptoms. Third, it is seen in chronic strain and bad factors stimulation, such as prolonged cold and manual work can lead to corresponding strain on the root of the index finger, which can lead to pain. Fourth, the compression of bone tumors, tendon sheath cysts and other masses can also lead to local pain symptoms.