Sprain mainly relies on the following aspects to diagnose: 1, the patient has a clear sprain process, generally in the process of walking or exercise, the limb or joint and other structures suddenly lose balance, the occurrence of more obvious deformation of the limb or joint range of motion, and lead to the occurrence of sprain. 2, the main symptoms of sprain is local pain and swelling symptoms, the soft tissues of the injury have obvious pressure pain, but the injury near the bone may not appear obvious pressure pain symptoms. But the bones near the injury may not appear obvious pressure pain symptoms, sprain patients will appear when the limb joint activity pain aggravated performance, but the limb bone weight, pain is not too obvious, may not feel pain, or only minor pain symptoms. 3, sprain 3 days later, there may be obvious subcutaneous bruising, but bruising symptoms generally occur in the limbs of location, 5 days later the swelling basically disappeared, pain symptoms will gradually begin to relieve.