In United States of America there are near three million people injured in motor vehicle accidents (MVA) and near forty two thousand fatalities on this type of accidents each year according to the data provided by the national highway traffic safety administration. Of these injured people near 75% of them were using a seat belt when the accident occur. [NOR03].It is indisputable that seatbelts save lives and reduce the severity of the injuries in patients involved in MVA. But these devices could produce severe and even life-threatening injuries in a patient, especially if the seatbelt is worn improperly.To appropriately detect and treat the injuries a seat belt can produce, we need to know the pattern of the injuries that these devices can generate, the organs that could be affected, and the signs and symptoms a patient could develop as a consequence of these injuries, in that way we can be alert and suspect them when we are assessing the patient.Nowadays most of the new models of cars come with a three point seatbelt, that properly restraint the patient inside the car, and the injuries caused by these devices are less serious than the injuries caused by wearing only the lap part or the shoulder part of the seatbelt separately, but on the streets we still can find cars with this option of using only the shoulder or the lap part of the seatbelt, and either one cause different patrons of injuries that we are going to discuss later on this paper.When we have our first contact with a patient involved in a MVA, and as part of the scene size-up we need to look and asses whether the patient was using a seatbelt or not, and if he or she was using it properly. It is necessary to avoid the first instinct of just go inside and disconnect the seatbelt. Before we do that we need to check if the lap part of the seatbelt was properly positioned over the iliac crests and the shoulder part was properly positioned over the shoulder. After this is assessed we can safely disconnect the seatbelt.Seat Belt MarkPatients using seatbelts have a specific pattern of internal injuries that we need to be aware of. Some of them develop what is known as the "seat belt mark", that is defined as "linear contusions of the abdominal wall, chest, or neck at the place of the seat belt when the patient did not report any other causes for such bruises" [DEM99], this sign is associated with a high incidence of significant internal organ injuries, that can include musculoskeletal injuries and internal organ injuries associated to the use of these devices.The most common injuries associated with this syndrome are "lumbar spinal fractures, mesenteric tears, and intraabdominal hollow visceral blowouts"[DEM99].Blunt Carotid Artery InjuryIf the shoulder part of the seatbelt is used too close to the neck, or if the force involved in the crash is high enough to cause a rapid deceleration of the patient. He could develop a rare traumatic lesion known as "Blunt carotid artery injury", which is...