Difficulty opening the mouth is a clinical manifestation of temporomandibular joint disorder syndrome also known as TMJ syndrome, which is one of the common disorders of the oral and maxillofacial region. Among temporomandibular joint disorders, this disease is the most common. It is prevalent in young adults, with the highest prevalence in 20-30 years old. Touch examination: 1, such as the patient open mouth only two fingers, known as mild mouth opening restriction; 2, such as the degree of open mouth can only accommodate a finger, known as moderate mouth opening restriction; 3, such as after opening the mouth even a finger can not be accommodated is known as the teeth. Auxiliary examination: CT examination of bone joint and soft tissue 1, significance A method of examination of bone joint and soft tissue by CT. It is mainly for the injury and disease of bone, joint and soft tissue. 2, the need to check the crowd If there is pain in the limb and swelling (or lump) in the same place, low back pain, the emergence of unexplained limb pain, limbs, soft tissues of the swelling, localized lumps, pain and other symptoms, please carry out the CT examination of bone joints and soft tissues. 3.Check precautions Before the examination: drink water according to the doctor’s requirements, please take out the metal objects on the body surface before going to the examination bed (such as belts, keys, necklaces, hand jewelry coins, etc.). Before the examination: fasting 4, the results of the interpretation of the examination indicators Normal: according to the specific circumstances of the specific analysis. No specific normal range. Abnormal: Abnormal results: (1) Bone joint and soft tissue mass. (2) Bone and joint tumor. (3) Bone and joint injury.