Tiger mouth swelling is common for the following reasons: first, interosseous dorsal muscle strain, the 1st and 2nd metacarpal bone between the interosseous dorsal muscle, its role is to keep the index finger away from the middle finger, while assisting the earthworm muscle flexion metacarpophalangeal joint and extension interphalangeal joint, life often thumb, index finger and middle finger fixed cell phone, such as maintaining a fixed position for a long time, can lead to interosseous dorsal muscle strain, pathological changes are interosseous dorsal muscle congestion, edema, the occurrence of Inflammatory reaction, muscle stiffness and swelling, local pain on pressure, limited abduction and flexion of the index finger, treatment includes correction of poor posture, intermittent local hot compresses to improve the symptoms of swelling and pain of the interosseous dorsalis muscle. Second, local trauma, after the tiger’s mouth is stimulated by trauma, it can cause local soft tissue swelling and painful symptoms, accompanied by thumb and index finger activity restriction.