The cause of sunken nose may be congenital nasal cartilage dysplasia and developmental deformity, or it may be formed by acquired factors. 1. Congenital cartilage dysplasia and developmental deformity: due to the lack of calcium and vitamins during the development of the fetus, it is easy to form cartilage nutritional disorders, causing congenital nasal cartilage dysplasia and developmental deformity, resulting in the middle of the nose sunken, flat and collapsed symptoms. 2. Trauma: Because most of the nose is supported by cartilage, which is relatively fragile, the collision caused by external factors will result in cartilage breakage and cartilage fracture, resulting in the middle of the nose being sunken, and the septum and other parts of the nose being damaged. There are other possibilities for the sunken nose, you should go to the hospital outpatient clinic in time, clarify the cause of the disease, and standardize the diagnosis and treatment under the guidance of professional physicians.