Osteogenesis imperfecta (osteogenisis imperfecta) is also known as fragililis ossium, idiopathic osteopsathyrosis and periosteal dysplasia. It is characterized by bone fragility, blue sclera, deafness, and joint laxity. It is a congenital hereditary pain due to underdevelopment of mesenchymal tissue and impaired collagen formation. I. Etiology/etiology is unknown and is a congenital developmental disorder. It is a congenital developmental disorder with equal incidence in males and females. It can be categorized as congenital or delayed. The congenital type refers to the onset of the disease in utero, and can be subdivided into fetal and infantile types. The disease is severe and most die, or die within a short period of time after delivery. It is autosomal recessive, while the delayed form is less severe and can be subdivided into childhood and adult forms. Most of the patients can survive for a long time, and it is autosomal dominant. more than 15% of the patients have family history. Pathological changes: Extensive mesenchymal defects inhibit the maturation of collagen fibers. In the process of chondrogenesis, the epiphyseal cartilage and cartilage calcification area are normal, but the osteoblasts and osteoid tissue are scarce in the metaphysis, and the small fibers formed are sparse and longitudinally aligned, with no intersecting bone trabeculae visible. The intramembranous ossification process was also affected, the periosteum was thickened but the bone cortex was thin and lacked the laminar structure of the ductal plate, the lumen of the Haver’s canal was enlarged, and there was a lot of fat and fibrous tissue in the bone marrow cavity, the bone was shorter than normal, and the circumference was thinned, and the ends of the bones were enlarged in the form of pestle and mortar. The skull is very thin, and there are scattered irregular foci of calcification, which in severe cases resemble a membrane bag with delayed closure of fontanel. Skin and sclera also have lesions. Third, the performance: 1, increased bone fragility: minor injuries can cause fracture, serious patients for spontaneous fracture. Congenital type has multiple fractures at birth. Most of the fractures are of the green branch type, with little displacement, mild pain, fast healing, relying on subperiosteal osteogenesis to complete, and thus often go unnoticed and cause malunion. The long bones and ribs are the most common sites. The deformity caused by multiple fractures further reduces the length of the bone. After puberty, the tendency of fracture decreases gradually. 2.Blue sclera: about 90% or more. This is due to the fact that the patient’s sclera becomes translucent and the color of the choroid beneath it can be seen. There is no abnormality in the thickness and structure of the sclera, and its translucency is due to the change in the nature of collagen fiber tissue. 3, deafness: often to 11 ~ 40 years of age, accounting for about 25%, may be due to sclerosis of the ear canal, attached to the oval window of the stapes foot plate due to osseous ankylosis and fixation, but some people believe that the auditory nerve out of the skull base when the pressure caused. 4, excessive joint laxity: especially wrist and ankle joints. This is due to impaired development of the collagenous tissue of tendons and ligaments. Osteogenesis imperfecta can also have knee valgus, flat foot. Sometimes there are habitual shoulder dislocation and radial head dislocation. Weak muscles. 6, head and face deformity: severe cranial dysplasia, at birth the skull has a sense of skin. Later, the skull is broad, parietal and occipital bone protrudes, the two temporal globular bulge, frontal bone protrudes forward, both ears are pushed downward, osteogenesis imperfecta face becomes inverted triangle. Some patients are accompanied by hydrocephalus. 7, dental dysplasia: the dentition can not be well developed, milk teeth and permanent teeth can be involved. Osteogenesis imperfecta teeth are yellow or blue-gray, easy to caries and early loss. 8, osteogenesis imperfecta dwarf. This is due to the development of a slightly shorter than normal, coupled with the spine and lower limbs multiple fracture deformity healing caused. x-ray manifestations Mainly for the lack of bone quality and extensive bone thinning.