Triple concavity sign is typically manifested as depression of the supraclavicular fossa, suprasternal fossa and soft tissues of the intercostal space during inspiration, and patients are advised to seek timely medical consultation if relevant symptoms occur. When a normal human body inhales, the thorax expands and the diaphragm descends, resulting in negative pressure inside the chest, thus drawing air into the lungs. However, when upper respiratory tract obstruction or serious lung diseases, such as laryngeal edema, tracheal tumor, foreign body, tracheal compression, emphysema, etc., the air can not enter the lungs in time or insufficiently, resulting in an increase in the negative pressure within the chest, which will cause the soft tissue portion of the thorax to appear concave phenomenon. When the triple concave sign appears, you should seek medical treatment in time to complete relevant examinations, such as X-ray, CT, lung function, etc., so as to identify the cause of the disease under the guidance of the doctor and carry out appropriate treatment.