Car accidents are also known as traffic accidents. Vehicle self or mutual collisions are prone to cause various injuries, such as various types of fractures, soft tissue contusions, traumatic brain injury, and various internal organ injuries. Most of them are compound injuries and should be examined comprehensively to prevent missed diagnosis. Here are some cases of concussion, skull fracture, chest and abdominal trauma. I. Concussion 1. Symptoms: Concussion is the lightest kind of closed cranial injury, without organic damage to the nervous system, with transient dysfunction. The function can be fully recovered after a few days of rest, and no other impairment remains. Clinical manifestations are the appearance of transient trance or coma after the injury, lasting a few seconds, minutes or even hours, waking up with no memory of the injury, or dizziness, headache, vomiting, etc., but the symptoms mostly disappear after a few days. 2, treatment: quiet rest for a few days, symptomatic treatment, or give a small amount of sedatives. If the symptoms do not improve within a short period of time by general treatment, or the opposite and aggravated, further examination and treatment is required. Second, skull fracture 1, symptoms and signs: open skull fracture with scalp fracture is easy to find. Closed skull fracture is sometimes seen as local depression or scalp with hematoma and elevation, mostly indicating skull base fracture with cerebrospinal fluid leakage. If the morning brain tissue is damaged to different degrees, or there is intracranial hematoma compression, the coma time is longer, or awake and then fall into coma, and accompanied by neurological localization symptoms, this is a bad omen, should be immediately outside the science, otherwise there is a risk to life. 2, first aid treatment: lay the casualty flat, head slightly cushioned. If there is a trauma or brain level strong overflow, deal with it according to the principles mentioned above. If there is overflow from the ear or nose, do not add pressure and fill. Should be sent to hospital for further treatment urgently. Thoracic trauma 1.Symptoms：After the injury, it often causes injury asphyxia, the patient has severe pain in the chest, pale face, cold sweat, cold limbs, and even shock, such as difficulty in breathing, coughing with bloody sputum, and subcutaneous emphysema in the thorax, which means there is injury in the lung and causes pneumothorax or hemothorax. 2, first aid measures: immediately take a semi-recumbent position, if there is a wound on the chest wall, resulting in open pneumothorax, the wound should be quickly bandaged closed, so that the open pneumothorax changes into a closed pneumothorax, quickly sent to the hospital. Fourth, abdominal organ injury 1, symptoms: patients feel persistent abdominal pain, paroxysmal intensification, do not dare to breathe deeply, abdominal wall tension such as plate, pressure pain is obvious, and even shock. To consider there is a rupture of the cavity organs (such as stomach, intestines). Cause peritonitis, or rupture and bleeding of substantial organs (such as liver, spleen, kidney). 2, first aid measures: avoid eating, drinking or using painkillers, and quickly send to hospital for medical treatment.