Many arthropathies are developmental, including aseptic necrosis of the femoral head Aseptic Necrosis of the Femoral Headin Dogs Aseptic necrosis of the right femoral head and neck in a dog, characterized by joint laxity and bone lysis. Aseptic necrosis, a deterioration of the femoral head seen in young miniature and... read more , patellar luxation Patellar Luxationin Dogs and Cats Right medial patellar luxation in a dog, characterized by displacement of the patella and inward rotation of the tibia, with increased medial soft tissue fibrosis. Patellar luxation, a hereditary... read more , osteochondrosis Osteochondrosisin Dogs Osteochondrosis of the shoulder in a 5-month-old Irish Wolfhound, characterized by subchondral bone lucency and flattening of the caudal humeral head. Osteochondrosis of the stifle in a dog... read more , elbow dysplasia Elbow Dysplasiain Dogs Ununited anconeal process, characterized by separation or cleavage of the bone tip from the proximal ulna. Elbow dysplasia is a generalized incongruency of the elbow joint in young, large, rapidly... read more , and hip dysplasia Hip Dysplasiain Dogs Hip dysplasia in a 2-year-old German Shepherd, characterized by subluxation, widening of both joint spaces, and thickening of the femoral necks. Hip dysplasia is a multifactorial abnormal development... read more . Other arthropathies are degenerative Degenerative Arthritisin Dogs and Cats Degenerative joint disease, ventrodorsal projection, characterized by irregular bone margins in the joint. Degenerative joint disease, lateral projection, characterized by irregular bone margins... read more , infectious or septic Septic Arthritisin Dogs and Cats Infectious arthritis is most frequently associated with bacterial agents such as staphylococci, streptococci, and coliforms. Causes include hematogenous spread or penetrating trauma, including... read more , immune-mediated Immune-mediated Arthritisin Dogs and Cats Inflammatory polyarthritis secondary to deposition of immune complexes can produce erosive (destruction of articular cartilage and subchondral bone) or nonerosive (periarticular inflammation)... read more , neoplastic Neoplastic Arthritisin Dogs and Cats Synovial cell sarcoma in a dog, showing complete destruction of the bones and soft tissues of the joint. Synovial cell sarcoma is the most common malignant tumor involving the joints. The tumor... read more , or traumatic Joint Traumain Dogs and Cats Rupture of the cranial cruciate ligament is most frequently due to excessive trauma and a possibly weakened ligament secondary to degeneration, immune-mediated diseases, or conformational defects... read more .