IⅡ.Pathogenesis(病因) multiple factors,regulated by hormones and genes I Anatomical Defects prepared for delivery from the 16th week of pregnancy-hip instability II Mechanical Factors Theory 1.Prenatal:Most often,the left hip is stressed,the left side is good. 2.In Production:Breech production,the incidence rate is 5 times higher. 3.Postpartum:Swaddling clothes,North>South
Ⅱ. Pathogenesis（病因） multiple factors, regulated by hormones and genes （ Ⅰ ）Anatomical Defects prepared for delivery from the 16th week of pregnancy→hip instability （ Ⅱ ）Mechanical Factors Theory 1.Prenatal: Most often, the left hip is stressed, the left side is good. 2.In Production: Breech production, the incidence rate is 5 times higher. 3.Postpartum: Swaddling clothes, North>South
(III)The Theory of Hormone-Induced Joint Relaxation Relaxin.Girls are susceptible. female male (IV)Genetic Theory: 1.family history 2.racial differences:White>Black 3.often accompanied by other malformations
(Ⅲ) The Theory of Hormone-Induced Joint Relaxation Relaxin. Girls are susceptible. female > male (Ⅳ) Genetic Theory： 1. family history 2. racial differences: White>Black 3. often accompanied by other malformations
Ⅲ.Pathology (病理) (I)Changes in the Skeleton 1.Femoral Head:small,irregular 2.Acetabulum:shallow and oblique,thick inner wall,forward leaning1,false acetabulum. 3.Femoral Neck:short and thick,the angle of forward leaning1 Normal DDH
Ⅲ . Pathology（病理） (Ⅰ) Changes in the Skeleton 1.Femoral Head: small, irregular 2.Acetabulum: shallow and oblique, thick inner wall, forward leaning↑, false acetabulum. 3.Femoral Neck: short and thick, the angle of forward leaning↑. Normal DDH
Pelvis and Spine Unilateral:pelvic tilt,compensatory scoliosis of the spine Bilateral:The lumbar lordosis is intensified,and the hips are protruding
Pelvis and Spine Unilateral: pelvic tilt, compensatory scoliosis of the spine Bilateral: The lumbar lordosis is intensified，and the hips are protruding
(II)Soft Tissue Changes 1.Glenoid Labrum（鱼唇)-thickening,valgus,involution 2.Joint Capsule(关节囊)-pulling,deforming 3.Round Ligament(圆韧带)-pulling 4.Muscle Fascia（筋膜)-spasming and shrinking 5.Ligamentum Transversum Acetabul(横韧带)i-thickening,introrsus Normal DDH
(Ⅱ) Soft Tissue Changes 1.Glenoid Labrum（鱼唇） - thickening, valgus, involution 2.Joint Capsule （关节囊）- pulling, deforming 3.Round Ligament（圆韧带） - pulling 4.Muscle Fascia （筋膜）- spasming and shrinking 5.Ligamentum Transversum Acetabul（横韧带）i - thickening, introrsus Normal DDH