Bruising on the inner side of the wrist may be caused by excessive compression, acute injury, diabetes and hyperlipidemia. 1. Excessive pressure: the inner part of the wrist is subjected to excessive pressure, pressure for a longer period of time, will make the inner side of the wrist bruises, release the pressure, and appropriate activities, can return to normal. 2. Acute injury: such as contusion or sprain, may lead to bruising on the inner side of the wrist, may also be accompanied by mild pain and other symptoms, indicating that the degree of injury is relatively light, generally does not cause too much impact. 3. Diabetes and hyperlipidemia: Prolonged diabetes, hyperlipidemia and other diseases may lead to increased fragility of blood vessels, which will make the inner wrist bruises. Bruising on the inside of the wrist for a longer period of time, it is recommended to consult a doctor for examination, to clarify the specific cause, and timely treatment.